1	//===--- SemaDeclObjC.cpp - Semantic Analysis for ObjC Declarations -------===//
2	//
3	// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4	// See https://llvm.org/LICENSE.txt for license information.
5	// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6	//
7	//===----------------------------------------------------------------------===//
8	//
9	// This file implements semantic analysis for Objective C declarations.
10	//
11	//===----------------------------------------------------------------------===//
12
13	#include "TypeLocBuilder.h"
14	#include "clang/AST/ASTConsumer.h"
15	#include "clang/AST/ASTContext.h"
16	#include "clang/AST/ASTMutationListener.h"
17	#include "clang/AST/DeclObjC.h"
18	#include "clang/AST/Expr.h"
19	#include "clang/AST/ExprObjC.h"
20	#include "clang/AST/RecursiveASTVisitor.h"
21	#include "clang/Basic/SourceManager.h"
22	#include "clang/Basic/TargetInfo.h"
23	#include "clang/Sema/DeclSpec.h"
24	#include "clang/Sema/Lookup.h"
25	#include "clang/Sema/Scope.h"
26	#include "clang/Sema/ScopeInfo.h"
27	#include "clang/Sema/SemaInternal.h"
28	#include "llvm/ADT/DenseMap.h"
29	#include "llvm/ADT/DenseSet.h"
30
31	using namespace clang;
32
33	/// Check whether the given method, which must be in the 'init'
34	/// family, is a valid member of that family.
35	///
36	/// \param receiverTypeIfCall - if null, check this as if declaring it;
37	/// if non-null, check this as if making a call to it with the given
38	/// receiver type
39	///
40	/// \return true to indicate that there was an error and appropriate
41	/// actions were taken
42	bool Sema::checkInitMethod(ObjCMethodDecl *method,
43	QualType receiverTypeIfCall) {
44	if (method->isInvalidDecl()) return true;
45
46	// This castAs is safe: methods that don't return an object
47	// pointer won't be inferred as inits and will reject an explicit
48	// objc_method_family(init).
49
50	// We ignore protocols here. Should we? What about Class?
51
52	const ObjCObjectType *result =
53	method->getReturnType()->castAs<ObjCObjectPointerType>()->getObjectType();
54
55	if (result->isObjCId()) {
56	return false;
57	} else if (result->isObjCClass()) {
58	// fall through: always an error
59	} else {
60	ObjCInterfaceDecl *resultClass = result->getInterface();
61	assert(resultClass && "unexpected object type!");
62
63	// It's okay for the result type to still be a forward declaration
64	// if we're checking an interface declaration.
65	if (!resultClass->hasDefinition()) {
66	if (receiverTypeIfCall.isNull() &&
67	!isa<ObjCImplementationDecl>(method->getDeclContext()))
68	return false;
69
70	// Otherwise, we try to compare class types.
71	} else {
72	// If this method was declared in a protocol, we can't check
73	// anything unless we have a receiver type that's an interface.
74	const ObjCInterfaceDecl *receiverClass = nullptr;
75	if (isa<ObjCProtocolDecl>(method->getDeclContext())) {
76	if (receiverTypeIfCall.isNull())
77	return false;
78
79	receiverClass = receiverTypeIfCall->castAs<ObjCObjectPointerType>()
80	->getInterfaceDecl();
81
82	// This can be null for calls to e.g. id<Foo>.
83	if (!receiverClass) return false;
84	} else {
85	receiverClass = method->getClassInterface();
86	assert(receiverClass && "method not associated with a class!");
87	}
88
89	// If either class is a subclass of the other, it's fine.
90	if (receiverClass->isSuperClassOf(I: resultClass) ||
91	resultClass->isSuperClassOf(I: receiverClass))
92	return false;
93	}
94	}
95
96	SourceLocation loc = method->getLocation();
97
98	// If we're in a system header, and this is not a call, just make
99	// the method unusable.
100	if (receiverTypeIfCall.isNull() && getSourceManager().isInSystemHeader(Loc: loc)) {
101	method->addAttr(UnavailableAttr::CreateImplicit(Context, "",
102	UnavailableAttr::IR_ARCInitReturnsUnrelated, loc));
103	return true;
104	}
105
106	// Otherwise, it's an error.
107	Diag(loc, diag::err_arc_init_method_unrelated_result_type);
108	method->setInvalidDecl();
109	return true;
110	}
111
112	/// Issue a warning if the parameter of the overridden method is non-escaping
113	/// but the parameter of the overriding method is not.
114	static bool diagnoseNoescape(const ParmVarDecl *NewD, const ParmVarDecl *OldD,
115	Sema &S) {
116	if (OldD->hasAttr<NoEscapeAttr>() && !NewD->hasAttr<NoEscapeAttr>()) {
117	S.Diag(NewD->getLocation(), diag::warn_overriding_method_missing_noescape);
118	S.Diag(OldD->getLocation(), diag::note_overridden_marked_noescape);
119	return false;
120	}
121
122	return true;
123	}
124
125	/// Produce additional diagnostics if a category conforms to a protocol that
126	/// defines a method taking a non-escaping parameter.
127	static void diagnoseNoescape(const ParmVarDecl *NewD, const ParmVarDecl *OldD,
128	const ObjCCategoryDecl *CD,
129	const ObjCProtocolDecl *PD, Sema &S) {
130	if (!diagnoseNoescape(NewD, OldD, S))
131	S.Diag(CD->getLocation(), diag::note_cat_conform_to_noescape_prot)
132	<< CD->IsClassExtension() << PD
133	<< cast<ObjCMethodDecl>(NewD->getDeclContext());
134	}
135
136	void Sema::CheckObjCMethodOverride(ObjCMethodDecl *NewMethod,
137	const ObjCMethodDecl *Overridden) {
138	if (Overridden->hasRelatedResultType() &&
139	!NewMethod->hasRelatedResultType()) {
140	// This can only happen when the method follows a naming convention that
141	// implies a related result type, and the original (overridden) method has
142	// a suitable return type, but the new (overriding) method does not have
143	// a suitable return type.
144	QualType ResultType = NewMethod->getReturnType();
145	SourceRange ResultTypeRange = NewMethod->getReturnTypeSourceRange();
146
147	// Figure out which class this method is part of, if any.
148	ObjCInterfaceDecl *CurrentClass
149	= dyn_cast<ObjCInterfaceDecl>(NewMethod->getDeclContext());
150	if (!CurrentClass) {
151	DeclContext *DC = NewMethod->getDeclContext();
152	if (ObjCCategoryDecl *Cat = dyn_cast<ObjCCategoryDecl>(Val: DC))
153	CurrentClass = Cat->getClassInterface();
154	else if (ObjCImplDecl *Impl = dyn_cast<ObjCImplDecl>(Val: DC))
155	CurrentClass = Impl->getClassInterface();
156	else if (ObjCCategoryImplDecl *CatImpl
157	= dyn_cast<ObjCCategoryImplDecl>(Val: DC))
158	CurrentClass = CatImpl->getClassInterface();
159	}
160
161	if (CurrentClass) {
162	Diag(NewMethod->getLocation(),
163	diag::warn_related_result_type_compatibility_class)
164	<< Context.getObjCInterfaceType(CurrentClass)
165	<< ResultType
166	<< ResultTypeRange;
167	} else {
168	Diag(NewMethod->getLocation(),
169	diag::warn_related_result_type_compatibility_protocol)
170	<< ResultType
171	<< ResultTypeRange;
172	}
173
174	if (ObjCMethodFamily Family = Overridden->getMethodFamily())
175	Diag(Overridden->getLocation(),
176	diag::note_related_result_type_family)
177	<< /*overridden method*/ 0
178	<< Family;
179	else
180	Diag(Overridden->getLocation(),
181	diag::note_related_result_type_overridden);
182	}
183
184	if ((NewMethod->hasAttr<NSReturnsRetainedAttr>() !=
185	Overridden->hasAttr<NSReturnsRetainedAttr>())) {
186	Diag(NewMethod->getLocation(),
187	getLangOpts().ObjCAutoRefCount
188	? diag::err_nsreturns_retained_attribute_mismatch
189	: diag::warn_nsreturns_retained_attribute_mismatch)
190	<< 1;
191	Diag(Overridden->getLocation(), diag::note_previous_decl) << "method";
192	}
193	if ((NewMethod->hasAttr<NSReturnsNotRetainedAttr>() !=
194	Overridden->hasAttr<NSReturnsNotRetainedAttr>())) {
195	Diag(NewMethod->getLocation(),
196	getLangOpts().ObjCAutoRefCount
197	? diag::err_nsreturns_retained_attribute_mismatch
198	: diag::warn_nsreturns_retained_attribute_mismatch)
199	<< 0;
200	Diag(Overridden->getLocation(), diag::note_previous_decl) << "method";
201	}
202
203	ObjCMethodDecl::param_const_iterator oi = Overridden->param_begin(),
204	oe = Overridden->param_end();
205	for (ObjCMethodDecl::param_iterator ni = NewMethod->param_begin(),
206	ne = NewMethod->param_end();
207	ni != ne && oi != oe; ++ni, ++oi) {
208	const ParmVarDecl *oldDecl = (*oi);
209	ParmVarDecl *newDecl = (*ni);
210	if (newDecl->hasAttr<NSConsumedAttr>() !=
211	oldDecl->hasAttr<NSConsumedAttr>()) {
212	Diag(newDecl->getLocation(),
213	getLangOpts().ObjCAutoRefCount
214	? diag::err_nsconsumed_attribute_mismatch
215	: diag::warn_nsconsumed_attribute_mismatch);
216	Diag(oldDecl->getLocation(), diag::note_previous_decl) << "parameter";
217	}
218
219	diagnoseNoescape(NewD: newDecl, OldD: oldDecl, S&: *this);
220	}
221	}
222
223	/// Check a method declaration for compatibility with the Objective-C
224	/// ARC conventions.
225	bool Sema::CheckARCMethodDecl(ObjCMethodDecl *method) {
226	ObjCMethodFamily family = method->getMethodFamily();
227	switch (family) {
228	case OMF_None:
229	case OMF_finalize:
230	case OMF_retain:
231	case OMF_release:
232	case OMF_autorelease:
233	case OMF_retainCount:
234	case OMF_self:
235	case OMF_initialize:
236	case OMF_performSelector:
237	return false;
238
239	case OMF_dealloc:
240	if (!Context.hasSameType(method->getReturnType(), Context.VoidTy)) {
241	SourceRange ResultTypeRange = method->getReturnTypeSourceRange();
242	if (ResultTypeRange.isInvalid())
243	Diag(method->getLocation(), diag::err_dealloc_bad_result_type)
244	<< method->getReturnType()
245	<< FixItHint::CreateInsertion(method->getSelectorLoc(0), "(void)");
246	else
247	Diag(method->getLocation(), diag::err_dealloc_bad_result_type)
248	<< method->getReturnType()
249	<< FixItHint::CreateReplacement(ResultTypeRange, "void");
250	return true;
251	}
252	return false;
253
254	case OMF_init:
255	// If the method doesn't obey the init rules, don't bother annotating it.
256	if (checkInitMethod(method, receiverTypeIfCall: QualType()))
257	return true;
258
259	method->addAttr(NSConsumesSelfAttr::CreateImplicit(Context));
260
261	// Don't add a second copy of this attribute, but otherwise don't
262	// let it be suppressed.
263	if (method->hasAttr<NSReturnsRetainedAttr>())
264	return false;
265	break;
266
267	case OMF_alloc:
268	case OMF_copy:
269	case OMF_mutableCopy:
270	case OMF_new:
271	if (method->hasAttr<NSReturnsRetainedAttr>() ||
272	method->hasAttr<NSReturnsNotRetainedAttr>() ||
273	method->hasAttr<NSReturnsAutoreleasedAttr>())
274	return false;
275	break;
276	}
277
278	method->addAttr(NSReturnsRetainedAttr::CreateImplicit(Context));
279	return false;
280	}
281
282	static void DiagnoseObjCImplementedDeprecations(Sema &S, const NamedDecl *ND,
283	SourceLocation ImplLoc) {
284	if (!ND)
285	return;
286	bool IsCategory = false;
287	StringRef RealizedPlatform;
288	AvailabilityResult Availability = ND->getAvailability(
289	/*Message=*/nullptr, /*EnclosingVersion=*/VersionTuple(),
290	&RealizedPlatform);
291	if (Availability != AR_Deprecated) {
292	if (isa<ObjCMethodDecl>(Val: ND)) {
293	if (Availability != AR_Unavailable)
294	return;
295	if (RealizedPlatform.empty())
296	RealizedPlatform = S.Context.getTargetInfo().getPlatformName();
297	// Warn about implementing unavailable methods, unless the unavailable
298	// is for an app extension.
299	if (RealizedPlatform.ends_with(Suffix: "_app_extension"))
300	return;
301	S.Diag(ImplLoc, diag::warn_unavailable_def);
302	S.Diag(ND->getLocation(), diag::note_method_declared_at)
303	<< ND->getDeclName();
304	return;
305	}
306	if (const auto *CD = dyn_cast<ObjCCategoryDecl>(Val: ND)) {
307	if (!CD->getClassInterface()->isDeprecated())
308	return;
309	ND = CD->getClassInterface();
310	IsCategory = true;
311	} else
312	return;
313	}
314	S.Diag(ImplLoc, diag::warn_deprecated_def)
315	<< (isa<ObjCMethodDecl>(ND)
316	? /*Method*/ 0
317	: isa<ObjCCategoryDecl>(ND) || IsCategory ? /*Category*/ 2
318	: /*Class*/ 1);
319	if (isa<ObjCMethodDecl>(ND))
320	S.Diag(ND->getLocation(), diag::note_method_declared_at)
321	<< ND->getDeclName();
322	else
323	S.Diag(ND->getLocation(), diag::note_previous_decl)
324	<< (isa<ObjCCategoryDecl>(ND) ? "category" : "class");
325	}
326
327	/// AddAnyMethodToGlobalPool - Add any method, instance or factory to global
328	/// pool.
329	void Sema::AddAnyMethodToGlobalPool(Decl *D) {
330	ObjCMethodDecl *MDecl = dyn_cast_or_null<ObjCMethodDecl>(Val: D);
331
332	// If we don't have a valid method decl, simply return.
333	if (!MDecl)
334	return;
335	if (MDecl->isInstanceMethod())
336	AddInstanceMethodToGlobalPool(Method: MDecl, impl: true);
337	else
338	AddFactoryMethodToGlobalPool(Method: MDecl, impl: true);
339	}
340
341	/// HasExplicitOwnershipAttr - returns true when pointer to ObjC pointer
342	/// has explicit ownership attribute; false otherwise.
343	static bool
344	HasExplicitOwnershipAttr(Sema &S, ParmVarDecl *Param) {
345	QualType T = Param->getType();
346
347	if (const PointerType *PT = T->getAs<PointerType>()) {
348	T = PT->getPointeeType();
349	} else if (const ReferenceType *RT = T->getAs<ReferenceType>()) {
350	T = RT->getPointeeType();
351	} else {
352	return true;
353	}
354
355	// If we have a lifetime qualifier, but it's local, we must have
356	// inferred it. So, it is implicit.
357	return !T.getLocalQualifiers().hasObjCLifetime();
358	}
359
360	/// ActOnStartOfObjCMethodDef - This routine sets up parameters; invisible
361	/// and user declared, in the method definition's AST.
362	void Sema::ActOnStartOfObjCMethodDef(Scope *FnBodyScope, Decl *D) {
363	ImplicitlyRetainedSelfLocs.clear();
364	assert((getCurMethodDecl() == nullptr) && "Methodparsing confused");
365	ObjCMethodDecl *MDecl = dyn_cast_or_null<ObjCMethodDecl>(Val: D);
366
367	PushExpressionEvaluationContext(NewContext: ExprEvalContexts.back().Context);
368
369	// If we don't have a valid method decl, simply return.
370	if (!MDecl)
371	return;
372
373	QualType ResultType = MDecl->getReturnType();
374	if (!ResultType->isDependentType() && !ResultType->isVoidType() &&
375	!MDecl->isInvalidDecl() &&
376	RequireCompleteType(MDecl->getLocation(), ResultType,
377	diag::err_func_def_incomplete_result))
378	MDecl->setInvalidDecl();
379
380	// Allow all of Sema to see that we are entering a method definition.
381	PushDeclContext(FnBodyScope, MDecl);
382	PushFunctionScope();
383
384	// Create Decl objects for each parameter, entrring them in the scope for
385	// binding to their use.
386
387	// Insert the invisible arguments, self and _cmd!
388	MDecl->createImplicitParams(Context, ID: MDecl->getClassInterface());
389
390	PushOnScopeChains(MDecl->getSelfDecl(), FnBodyScope);
391	PushOnScopeChains(MDecl->getCmdDecl(), FnBodyScope);
392
393	// The ObjC parser requires parameter names so there's no need to check.
394	CheckParmsForFunctionDef(Parameters: MDecl->parameters(),
395	/*CheckParameterNames=*/false);
396
397	// Introduce all of the other parameters into this scope.
398	for (auto *Param : MDecl->parameters()) {
399	if (!Param->isInvalidDecl() &&
400	getLangOpts().ObjCAutoRefCount &&
401	!HasExplicitOwnershipAttr(*this, Param))
402	Diag(Param->getLocation(), diag::warn_arc_strong_pointer_objc_pointer) <<
403	Param->getType();
404
405	if (Param->getIdentifier())
406	PushOnScopeChains(Param, FnBodyScope);
407	}
408
409	// In ARC, disallow definition of retain/release/autorelease/retainCount
410	if (getLangOpts().ObjCAutoRefCount) {
411	switch (MDecl->getMethodFamily()) {
412	case OMF_retain:
413	case OMF_retainCount:
414	case OMF_release:
415	case OMF_autorelease:
416	Diag(MDecl->getLocation(), diag::err_arc_illegal_method_def)
417	<< 0 << MDecl->getSelector();
418	break;
419
420	case OMF_None:
421	case OMF_dealloc:
422	case OMF_finalize:
423	case OMF_alloc:
424	case OMF_init:
425	case OMF_mutableCopy:
426	case OMF_copy:
427	case OMF_new:
428	case OMF_self:
429	case OMF_initialize:
430	case OMF_performSelector:
431	break;
432	}
433	}
434
435	// Warn on deprecated methods under -Wdeprecated-implementations,
436	// and prepare for warning on missing super calls.
437	if (ObjCInterfaceDecl *IC = MDecl->getClassInterface()) {
438	ObjCMethodDecl *IMD =
439	IC->lookupMethod(Sel: MDecl->getSelector(), isInstance: MDecl->isInstanceMethod());
440
441	if (IMD) {
442	ObjCImplDecl *ImplDeclOfMethodDef =
443	dyn_cast<ObjCImplDecl>(MDecl->getDeclContext());
444	ObjCContainerDecl *ContDeclOfMethodDecl =
445	dyn_cast<ObjCContainerDecl>(IMD->getDeclContext());
446	ObjCImplDecl *ImplDeclOfMethodDecl = nullptr;
447	if (ObjCInterfaceDecl *OID = dyn_cast<ObjCInterfaceDecl>(Val: ContDeclOfMethodDecl))
448	ImplDeclOfMethodDecl = OID->getImplementation();
449	else if (ObjCCategoryDecl *CD = dyn_cast<ObjCCategoryDecl>(Val: ContDeclOfMethodDecl)) {
450	if (CD->IsClassExtension()) {
451	if (ObjCInterfaceDecl *OID = CD->getClassInterface())
452	ImplDeclOfMethodDecl = OID->getImplementation();
453	} else
454	ImplDeclOfMethodDecl = CD->getImplementation();
455	}
456	// No need to issue deprecated warning if deprecated mehod in class/category
457	// is being implemented in its own implementation (no overriding is involved).
458	if (!ImplDeclOfMethodDecl || ImplDeclOfMethodDecl != ImplDeclOfMethodDef)
459	DiagnoseObjCImplementedDeprecations(*this, IMD, MDecl->getLocation());
460	}
461
462	if (MDecl->getMethodFamily() == OMF_init) {
463	if (MDecl->isDesignatedInitializerForTheInterface()) {
464	getCurFunction()->ObjCIsDesignatedInit = true;
465	getCurFunction()->ObjCWarnForNoDesignatedInitChain =
466	IC->getSuperClass() != nullptr;
467	} else if (IC->hasDesignatedInitializers()) {
468	getCurFunction()->ObjCIsSecondaryInit = true;
469	getCurFunction()->ObjCWarnForNoInitDelegation = true;
470	}
471	}
472
473	// If this is "dealloc" or "finalize", set some bit here.
474	// Then in ActOnSuperMessage() (SemaExprObjC), set it back to false.
475	// Finally, in ActOnFinishFunctionBody() (SemaDecl), warn if flag is set.
476	// Only do this if the current class actually has a superclass.
477	if (const ObjCInterfaceDecl *SuperClass = IC->getSuperClass()) {
478	ObjCMethodFamily Family = MDecl->getMethodFamily();
479	if (Family == OMF_dealloc) {
480	if (!(getLangOpts().ObjCAutoRefCount ||
481	getLangOpts().getGC() == LangOptions::GCOnly))
482	getCurFunction()->ObjCShouldCallSuper = true;
483
484	} else if (Family == OMF_finalize) {
485	if (Context.getLangOpts().getGC() != LangOptions::NonGC)
486	getCurFunction()->ObjCShouldCallSuper = true;
487
488	} else {
489	const ObjCMethodDecl *SuperMethod =
490	SuperClass->lookupMethod(Sel: MDecl->getSelector(),
491	isInstance: MDecl->isInstanceMethod());
492	getCurFunction()->ObjCShouldCallSuper =
493	(SuperMethod && SuperMethod->hasAttr<ObjCRequiresSuperAttr>());
494	}
495	}
496	}
497	}
498
499	namespace {
500
501	// Callback to only accept typo corrections that are Objective-C classes.
502	// If an ObjCInterfaceDecl* is given to the constructor, then the validation
503	// function will reject corrections to that class.
504	class ObjCInterfaceValidatorCCC final : public CorrectionCandidateCallback {
505	public:
506	ObjCInterfaceValidatorCCC() : CurrentIDecl(nullptr) {}
507	explicit ObjCInterfaceValidatorCCC(ObjCInterfaceDecl *IDecl)
508	: CurrentIDecl(IDecl) {}
509
510	bool ValidateCandidate(const TypoCorrection &candidate) override {
511	ObjCInterfaceDecl *ID = candidate.getCorrectionDeclAs<ObjCInterfaceDecl>();
512	return ID && !declaresSameEntity(ID, CurrentIDecl);
513	}
514
515	std::unique_ptr<CorrectionCandidateCallback> clone() override {
516	return std::make_unique<ObjCInterfaceValidatorCCC>(args&: *this);
517	}
518
519	private:
520	ObjCInterfaceDecl *CurrentIDecl;
521	};
522
523	} // end anonymous namespace
524
525	static void diagnoseUseOfProtocols(Sema &TheSema,
526	ObjCContainerDecl *CD,
527	ObjCProtocolDecl *const *ProtoRefs,
528	unsigned NumProtoRefs,
529	const SourceLocation *ProtoLocs) {
530	assert(ProtoRefs);
531	// Diagnose availability in the context of the ObjC container.
532	Sema::ContextRAII SavedContext(TheSema, CD);
533	for (unsigned i = 0; i < NumProtoRefs; ++i) {
534	(void)TheSema.DiagnoseUseOfDecl(ProtoRefs[i], ProtoLocs[i],
535	/*UnknownObjCClass=*/nullptr,
536	/*ObjCPropertyAccess=*/false,
537	/*AvoidPartialAvailabilityChecks=*/true);
538	}
539	}
540
541	void Sema::
542	ActOnSuperClassOfClassInterface(Scope *S,
543	SourceLocation AtInterfaceLoc,
544	ObjCInterfaceDecl *IDecl,
545	IdentifierInfo *ClassName,
546	SourceLocation ClassLoc,
547	IdentifierInfo *SuperName,
548	SourceLocation SuperLoc,
549	ArrayRef<ParsedType> SuperTypeArgs,
550	SourceRange SuperTypeArgsRange) {
551	// Check if a different kind of symbol declared in this scope.
552	NamedDecl *PrevDecl = LookupSingleName(S: TUScope, Name: SuperName, Loc: SuperLoc,
553	NameKind: LookupOrdinaryName);
554
555	if (!PrevDecl) {
556	// Try to correct for a typo in the superclass name without correcting
557	// to the class we're defining.
558	ObjCInterfaceValidatorCCC CCC(IDecl);
559	if (TypoCorrection Corrected = CorrectTypo(
560	Typo: DeclarationNameInfo(SuperName, SuperLoc), LookupKind: LookupOrdinaryName,
561	S: TUScope, SS: nullptr, CCC, Mode: CTK_ErrorRecovery)) {
562	diagnoseTypo(Corrected, PDiag(diag::err_undef_superclass_suggest)
563	<< SuperName << ClassName);
564	PrevDecl = Corrected.getCorrectionDeclAs<ObjCInterfaceDecl>();
565	}
566	}
567
568	if (declaresSameEntity(PrevDecl, IDecl)) {
569	Diag(SuperLoc, diag::err_recursive_superclass)
570	<< SuperName << ClassName << SourceRange(AtInterfaceLoc, ClassLoc);
571	IDecl->setEndOfDefinitionLoc(ClassLoc);
572	} else {
573	ObjCInterfaceDecl *SuperClassDecl =
574	dyn_cast_or_null<ObjCInterfaceDecl>(Val: PrevDecl);
575	QualType SuperClassType;
576
577	// Diagnose classes that inherit from deprecated classes.
578	if (SuperClassDecl) {
579	(void)DiagnoseUseOfDecl(SuperClassDecl, SuperLoc);
580	SuperClassType = Context.getObjCInterfaceType(Decl: SuperClassDecl);
581	}
582
583	if (PrevDecl && !SuperClassDecl) {
584	// The previous declaration was not a class decl. Check if we have a
585	// typedef. If we do, get the underlying class type.
586	if (const TypedefNameDecl *TDecl =
587	dyn_cast_or_null<TypedefNameDecl>(Val: PrevDecl)) {
588	QualType T = TDecl->getUnderlyingType();
589	if (T->isObjCObjectType()) {
590	if (NamedDecl *IDecl = T->castAs<ObjCObjectType>()->getInterface()) {
591	SuperClassDecl = dyn_cast<ObjCInterfaceDecl>(Val: IDecl);
592	SuperClassType = Context.getTypeDeclType(TDecl);
593
594	// This handles the following case:
595	// @interface NewI @end
596	// typedef NewI DeprI __attribute__((deprecated("blah")))
597	// @interface SI : DeprI /* warn here */ @end
598	(void)DiagnoseUseOfDecl(const_cast<TypedefNameDecl*>(TDecl), SuperLoc);
599	}
600	}
601	}
602
603	// This handles the following case:
604	//
605	// typedef int SuperClass;
606	// @interface MyClass : SuperClass {} @end
607	//
608	if (!SuperClassDecl) {
609	Diag(SuperLoc, diag::err_redefinition_different_kind) << SuperName;
610	Diag(PrevDecl->getLocation(), diag::note_previous_definition);
611	}
612	}
613
614	if (!isa_and_nonnull<TypedefNameDecl>(Val: PrevDecl)) {
615	if (!SuperClassDecl)
616	Diag(SuperLoc, diag::err_undef_superclass)
617	<< SuperName << ClassName << SourceRange(AtInterfaceLoc, ClassLoc);
618	else if (RequireCompleteType(SuperLoc,
619	SuperClassType,
620	diag::err_forward_superclass,
621	SuperClassDecl->getDeclName(),
622	ClassName,
623	SourceRange(AtInterfaceLoc, ClassLoc))) {
624	SuperClassDecl = nullptr;
625	SuperClassType = QualType();
626	}
627	}
628
629	if (SuperClassType.isNull()) {
630	assert(!SuperClassDecl && "Failed to set SuperClassType?");
631	return;
632	}
633
634	// Handle type arguments on the superclass.
635	TypeSourceInfo *SuperClassTInfo = nullptr;
636	if (!SuperTypeArgs.empty()) {
637	TypeResult fullSuperClassType = actOnObjCTypeArgsAndProtocolQualifiers(
638	S,
639	Loc: SuperLoc,
640	BaseType: CreateParsedType(T: SuperClassType,
641	TInfo: nullptr),
642	TypeArgsLAngleLoc: SuperTypeArgsRange.getBegin(),
643	TypeArgs: SuperTypeArgs,
644	TypeArgsRAngleLoc: SuperTypeArgsRange.getEnd(),
645	ProtocolLAngleLoc: SourceLocation(),
646	Protocols: { },
647	ProtocolLocs: { },
648	ProtocolRAngleLoc: SourceLocation());
649	if (!fullSuperClassType.isUsable())
650	return;
651
652	SuperClassType = GetTypeFromParser(Ty: fullSuperClassType.get(),
653	TInfo: &SuperClassTInfo);
654	}
655
656	if (!SuperClassTInfo) {
657	SuperClassTInfo = Context.getTrivialTypeSourceInfo(T: SuperClassType,
658	Loc: SuperLoc);
659	}
660
661	IDecl->setSuperClass(SuperClassTInfo);
662	IDecl->setEndOfDefinitionLoc(SuperClassTInfo->getTypeLoc().getEndLoc());
663	}
664	}
665
666	DeclResult Sema::actOnObjCTypeParam(Scope *S,
667	ObjCTypeParamVariance variance,
668	SourceLocation varianceLoc,
669	unsigned index,
670	IdentifierInfo *paramName,
671	SourceLocation paramLoc,
672	SourceLocation colonLoc,
673	ParsedType parsedTypeBound) {
674	// If there was an explicitly-provided type bound, check it.
675	TypeSourceInfo *typeBoundInfo = nullptr;
676	if (parsedTypeBound) {
677	// The type bound can be any Objective-C pointer type.
678	QualType typeBound = GetTypeFromParser(Ty: parsedTypeBound, TInfo: &typeBoundInfo);
679	if (typeBound->isObjCObjectPointerType()) {
680	// okay
681	} else if (typeBound->isObjCObjectType()) {
682	// The user forgot the * on an Objective-C pointer type, e.g.,
683	// "T : NSView".
684	SourceLocation starLoc = getLocForEndOfToken(
685	Loc: typeBoundInfo->getTypeLoc().getEndLoc());
686	Diag(typeBoundInfo->getTypeLoc().getBeginLoc(),
687	diag::err_objc_type_param_bound_missing_pointer)
688	<< typeBound << paramName
689	<< FixItHint::CreateInsertion(starLoc, " *");
690
691	// Create a new type location builder so we can update the type
692	// location information we have.
693	TypeLocBuilder builder;
694	builder.pushFullCopy(L: typeBoundInfo->getTypeLoc());
695
696	// Create the Objective-C pointer type.
697	typeBound = Context.getObjCObjectPointerType(OIT: typeBound);
698	ObjCObjectPointerTypeLoc newT
699	= builder.push<ObjCObjectPointerTypeLoc>(T: typeBound);
700	newT.setStarLoc(starLoc);
701
702	// Form the new type source information.
703	typeBoundInfo = builder.getTypeSourceInfo(Context, T: typeBound);
704	} else {
705	// Not a valid type bound.
706	Diag(typeBoundInfo->getTypeLoc().getBeginLoc(),
707	diag::err_objc_type_param_bound_nonobject)
708	<< typeBound << paramName;
709
710	// Forget the bound; we'll default to id later.
711	typeBoundInfo = nullptr;
712	}
713
714	// Type bounds cannot have qualifiers (even indirectly) or explicit
715	// nullability.
716	if (typeBoundInfo) {
717	QualType typeBound = typeBoundInfo->getType();
718	TypeLoc qual = typeBoundInfo->getTypeLoc().findExplicitQualifierLoc();
719	if (qual || typeBound.hasQualifiers()) {
720	bool diagnosed = false;
721	SourceRange rangeToRemove;
722	if (qual) {
723	if (auto attr = qual.getAs<AttributedTypeLoc>()) {
724	rangeToRemove = attr.getLocalSourceRange();
725	if (attr.getTypePtr()->getImmediateNullability()) {
726	Diag(attr.getBeginLoc(),
727	diag::err_objc_type_param_bound_explicit_nullability)
728	<< paramName << typeBound
729	<< FixItHint::CreateRemoval(rangeToRemove);
730	diagnosed = true;
731	}
732	}
733	}
734
735	if (!diagnosed) {
736	Diag(qual ? qual.getBeginLoc()
737	: typeBoundInfo->getTypeLoc().getBeginLoc(),
738	diag::err_objc_type_param_bound_qualified)
739	<< paramName << typeBound
740	<< typeBound.getQualifiers().getAsString()
741	<< FixItHint::CreateRemoval(rangeToRemove);
742	}
743
744	// If the type bound has qualifiers other than CVR, we need to strip
745	// them or we'll probably assert later when trying to apply new
746	// qualifiers.
747	Qualifiers quals = typeBound.getQualifiers();
748	quals.removeCVRQualifiers();
749	if (!quals.empty()) {
750	typeBoundInfo =
751	Context.getTrivialTypeSourceInfo(T: typeBound.getUnqualifiedType());
752	}
753	}
754	}
755	}
756
757	// If there was no explicit type bound (or we removed it due to an error),
758	// use 'id' instead.
759	if (!typeBoundInfo) {
760	colonLoc = SourceLocation();
761	typeBoundInfo = Context.getTrivialTypeSourceInfo(T: Context.getObjCIdType());
762	}
763
764	// Create the type parameter.
765	return ObjCTypeParamDecl::Create(ctx&: Context, dc: CurContext, variance, varianceLoc,
766	index, nameLoc: paramLoc, name: paramName, colonLoc,
767	boundInfo: typeBoundInfo);
768	}
769
770	ObjCTypeParamList *Sema::actOnObjCTypeParamList(Scope *S,
771	SourceLocation lAngleLoc,
772	ArrayRef<Decl *> typeParamsIn,
773	SourceLocation rAngleLoc) {
774	// We know that the array only contains Objective-C type parameters.
775	ArrayRef<ObjCTypeParamDecl *>
776	typeParams(
777	reinterpret_cast<ObjCTypeParamDecl * const *>(typeParamsIn.data()),
778	typeParamsIn.size());
779
780	// Diagnose redeclarations of type parameters.
781	// We do this now because Objective-C type parameters aren't pushed into
782	// scope until later (after the instance variable block), but we want the
783	// diagnostics to occur right after we parse the type parameter list.
784	llvm::SmallDenseMap<IdentifierInfo *, ObjCTypeParamDecl *> knownParams;
785	for (auto *typeParam : typeParams) {
786	auto known = knownParams.find(typeParam->getIdentifier());
787	if (known != knownParams.end()) {
788	Diag(typeParam->getLocation(), diag::err_objc_type_param_redecl)
789	<< typeParam->getIdentifier()
790	<< SourceRange(known->second->getLocation());
791
792	typeParam->setInvalidDecl();
793	} else {
794	knownParams.insert(std::make_pair(typeParam->getIdentifier(), typeParam));
795
796	// Push the type parameter into scope.
797	PushOnScopeChains(typeParam, S, /*AddToContext=*/false);
798	}
799	}
800
801	// Create the parameter list.
802	return ObjCTypeParamList::create(ctx&: Context, lAngleLoc, typeParams, rAngleLoc);
803	}
804
805	void Sema::popObjCTypeParamList(Scope *S, ObjCTypeParamList *typeParamList) {
806	for (auto *typeParam : *typeParamList) {
807	if (!typeParam->isInvalidDecl()) {
808	S->RemoveDecl(typeParam);
809	IdResolver.RemoveDecl(typeParam);
810	}
811	}
812	}
813
814	namespace {
815	/// The context in which an Objective-C type parameter list occurs, for use
816	/// in diagnostics.
817	enum class TypeParamListContext {
818	ForwardDeclaration,
819	Definition,
820	Category,
821	Extension
822	};
823	} // end anonymous namespace
824
825	/// Check consistency between two Objective-C type parameter lists, e.g.,
826	/// between a category/extension and an \@interface or between an \@class and an
827	/// \@interface.
828	static bool checkTypeParamListConsistency(Sema &S,
829	ObjCTypeParamList *prevTypeParams,
830	ObjCTypeParamList *newTypeParams,
831	TypeParamListContext newContext) {
832	// If the sizes don't match, complain about that.
833	if (prevTypeParams->size() != newTypeParams->size()) {
834	SourceLocation diagLoc;
835	if (newTypeParams->size() > prevTypeParams->size()) {
836	diagLoc = newTypeParams->begin()[prevTypeParams->size()]->getLocation();
837	} else {
838	diagLoc = S.getLocForEndOfToken(Loc: newTypeParams->back()->getEndLoc());
839	}
840
841	S.Diag(diagLoc, diag::err_objc_type_param_arity_mismatch)
842	<< static_cast<unsigned>(newContext)
843	<< (newTypeParams->size() > prevTypeParams->size())
844	<< prevTypeParams->size()
845	<< newTypeParams->size();
846
847	return true;
848	}
849
850	// Match up the type parameters.
851	for (unsigned i = 0, n = prevTypeParams->size(); i != n; ++i) {
852	ObjCTypeParamDecl *prevTypeParam = prevTypeParams->begin()[i];
853	ObjCTypeParamDecl *newTypeParam = newTypeParams->begin()[i];
854
855	// Check for consistency of the variance.
856	if (newTypeParam->getVariance() != prevTypeParam->getVariance()) {
857	if (newTypeParam->getVariance() == ObjCTypeParamVariance::Invariant &&
858	newContext != TypeParamListContext::Definition) {
859	// When the new type parameter is invariant and is not part
860	// of the definition, just propagate the variance.
861	newTypeParam->setVariance(prevTypeParam->getVariance());
862	} else if (prevTypeParam->getVariance()
863	== ObjCTypeParamVariance::Invariant &&
864	!(isa<ObjCInterfaceDecl>(prevTypeParam->getDeclContext()) &&
865	cast<ObjCInterfaceDecl>(prevTypeParam->getDeclContext())
866	->getDefinition() == prevTypeParam->getDeclContext())) {
867	// When the old parameter is invariant and was not part of the
868	// definition, just ignore the difference because it doesn't
869	// matter.
870	} else {
871	{
872	// Diagnose the conflict and update the second declaration.
873	SourceLocation diagLoc = newTypeParam->getVarianceLoc();
874	if (diagLoc.isInvalid())
875	diagLoc = newTypeParam->getBeginLoc();
876
877	auto diag = S.Diag(diagLoc,
878	diag::err_objc_type_param_variance_conflict)
879	<< static_cast<unsigned>(newTypeParam->getVariance())
880	<< newTypeParam->getDeclName()
881	<< static_cast<unsigned>(prevTypeParam->getVariance())
882	<< prevTypeParam->getDeclName();
883	switch (prevTypeParam->getVariance()) {
884	case ObjCTypeParamVariance::Invariant:
885	diag << FixItHint::CreateRemoval(RemoveRange: newTypeParam->getVarianceLoc());
886	break;
887
888	case ObjCTypeParamVariance::Covariant:
889	case ObjCTypeParamVariance::Contravariant: {
890	StringRef newVarianceStr
891	= prevTypeParam->getVariance() == ObjCTypeParamVariance::Covariant
892	? "__covariant"
893	: "__contravariant";
894	if (newTypeParam->getVariance()
895	== ObjCTypeParamVariance::Invariant) {
896	diag << FixItHint::CreateInsertion(InsertionLoc: newTypeParam->getBeginLoc(),
897	Code: (newVarianceStr + " ").str());
898	} else {
899	diag << FixItHint::CreateReplacement(RemoveRange: newTypeParam->getVarianceLoc(),
900	Code: newVarianceStr);
901	}
902	}
903	}
904	}
905
906	S.Diag(prevTypeParam->getLocation(), diag::note_objc_type_param_here)
907	<< prevTypeParam->getDeclName();
908
909	// Override the variance.
910	newTypeParam->setVariance(prevTypeParam->getVariance());
911	}
912	}
913
914	// If the bound types match, there's nothing to do.
915	if (S.Context.hasSameType(prevTypeParam->getUnderlyingType(),
916	newTypeParam->getUnderlyingType()))
917	continue;
918
919	// If the new type parameter's bound was explicit, complain about it being
920	// different from the original.
921	if (newTypeParam->hasExplicitBound()) {
922	SourceRange newBoundRange = newTypeParam->getTypeSourceInfo()
923	->getTypeLoc().getSourceRange();
924	S.Diag(newBoundRange.getBegin(), diag::err_objc_type_param_bound_conflict)
925	<< newTypeParam->getUnderlyingType()
926	<< newTypeParam->getDeclName()
927	<< prevTypeParam->hasExplicitBound()
928	<< prevTypeParam->getUnderlyingType()
929	<< (newTypeParam->getDeclName() == prevTypeParam->getDeclName())
930	<< prevTypeParam->getDeclName()
931	<< FixItHint::CreateReplacement(
932	newBoundRange,
933	prevTypeParam->getUnderlyingType().getAsString(
934	S.Context.getPrintingPolicy()));
935
936	S.Diag(prevTypeParam->getLocation(), diag::note_objc_type_param_here)
937	<< prevTypeParam->getDeclName();
938
939	// Override the new type parameter's bound type with the previous type,
940	// so that it's consistent.
941	S.Context.adjustObjCTypeParamBoundType(Orig: prevTypeParam, New: newTypeParam);
942	continue;
943	}
944
945	// The new type parameter got the implicit bound of 'id'. That's okay for
946	// categories and extensions (overwrite it later), but not for forward
947	// declarations and @interfaces, because those must be standalone.
948	if (newContext == TypeParamListContext::ForwardDeclaration ||
949	newContext == TypeParamListContext::Definition) {
950	// Diagnose this problem for forward declarations and definitions.
951	SourceLocation insertionLoc
952	= S.getLocForEndOfToken(Loc: newTypeParam->getLocation());
953	std::string newCode
954	= " : " + prevTypeParam->getUnderlyingType().getAsString(
955	S.Context.getPrintingPolicy());
956	S.Diag(newTypeParam->getLocation(),
957	diag::err_objc_type_param_bound_missing)
958	<< prevTypeParam->getUnderlyingType()
959	<< newTypeParam->getDeclName()
960	<< (newContext == TypeParamListContext::ForwardDeclaration)
961	<< FixItHint::CreateInsertion(insertionLoc, newCode);
962
963	S.Diag(prevTypeParam->getLocation(), diag::note_objc_type_param_here)
964	<< prevTypeParam->getDeclName();
965	}
966
967	// Update the new type parameter's bound to match the previous one.
968	S.Context.adjustObjCTypeParamBoundType(Orig: prevTypeParam, New: newTypeParam);
969	}
970
971	return false;
972	}
973
974	ObjCInterfaceDecl *Sema::ActOnStartClassInterface(
975	Scope *S, SourceLocation AtInterfaceLoc, IdentifierInfo *ClassName,
976	SourceLocation ClassLoc, ObjCTypeParamList *typeParamList,
977	IdentifierInfo *SuperName, SourceLocation SuperLoc,
978	ArrayRef<ParsedType> SuperTypeArgs, SourceRange SuperTypeArgsRange,
979	Decl *const *ProtoRefs, unsigned NumProtoRefs,
980	const SourceLocation *ProtoLocs, SourceLocation EndProtoLoc,
981	const ParsedAttributesView &AttrList, SkipBodyInfo *SkipBody) {
982	assert(ClassName && "Missing class identifier");
983
984	// Check for another declaration kind with the same name.
985	NamedDecl *PrevDecl =
986	LookupSingleName(S: TUScope, Name: ClassName, Loc: ClassLoc, NameKind: LookupOrdinaryName,
987	Redecl: forRedeclarationInCurContext());
988
989	if (PrevDecl && !isa<ObjCInterfaceDecl>(Val: PrevDecl)) {
990	Diag(ClassLoc, diag::err_redefinition_different_kind) << ClassName;
991	Diag(PrevDecl->getLocation(), diag::note_previous_definition);
992	}
993
994	// Create a declaration to describe this @interface.
995	ObjCInterfaceDecl* PrevIDecl = dyn_cast_or_null<ObjCInterfaceDecl>(Val: PrevDecl);
996
997	if (PrevIDecl && PrevIDecl->getIdentifier() != ClassName) {
998	// A previous decl with a different name is because of
999	// @compatibility_alias, for example:
1000	// \code
1001	// @class NewImage;
1002	// @compatibility_alias OldImage NewImage;
1003	// \endcode
1004	// A lookup for 'OldImage' will return the 'NewImage' decl.
1005	//
1006	// In such a case use the real declaration name, instead of the alias one,
1007	// otherwise we will break IdentifierResolver and redecls-chain invariants.
1008	// FIXME: If necessary, add a bit to indicate that this ObjCInterfaceDecl
1009	// has been aliased.
1010	ClassName = PrevIDecl->getIdentifier();
1011	}
1012
1013	// If there was a forward declaration with type parameters, check
1014	// for consistency.
1015	if (PrevIDecl) {
1016	if (ObjCTypeParamList *prevTypeParamList = PrevIDecl->getTypeParamList()) {
1017	if (typeParamList) {
1018	// Both have type parameter lists; check for consistency.
1019	if (checkTypeParamListConsistency(S&: *this, prevTypeParams: prevTypeParamList,
1020	newTypeParams: typeParamList,
1021	newContext: TypeParamListContext::Definition)) {
1022	typeParamList = nullptr;
1023	}
1024	} else {
1025	Diag(ClassLoc, diag::err_objc_parameterized_forward_class_first)
1026	<< ClassName;
1027	Diag(prevTypeParamList->getLAngleLoc(), diag::note_previous_decl)
1028	<< ClassName;
1029
1030	// Clone the type parameter list.
1031	SmallVector<ObjCTypeParamDecl *, 4> clonedTypeParams;
1032	for (auto *typeParam : *prevTypeParamList) {
1033	clonedTypeParams.push_back(
1034	Elt: ObjCTypeParamDecl::Create(
1035	ctx&: Context,
1036	dc: CurContext,
1037	variance: typeParam->getVariance(),
1038	varianceLoc: SourceLocation(),
1039	index: typeParam->getIndex(),
1040	nameLoc: SourceLocation(),
1041	name: typeParam->getIdentifier(),
1042	colonLoc: SourceLocation(),
1043	boundInfo: Context.getTrivialTypeSourceInfo(T: typeParam->getUnderlyingType())));
1044	}
1045
1046	typeParamList = ObjCTypeParamList::create(ctx&: Context,
1047	lAngleLoc: SourceLocation(),
1048	typeParams: clonedTypeParams,
1049	rAngleLoc: SourceLocation());
1050	}
1051	}
1052	}
1053
1054	ObjCInterfaceDecl *IDecl
1055	= ObjCInterfaceDecl::Create(C: Context, DC: CurContext, atLoc: AtInterfaceLoc, Id: ClassName,
1056	typeParamList, PrevDecl: PrevIDecl, ClassLoc);
1057	if (PrevIDecl) {
1058	// Class already seen. Was it a definition?
1059	if (ObjCInterfaceDecl *Def = PrevIDecl->getDefinition()) {
1060	if (SkipBody && !hasVisibleDefinition(Def)) {
1061	SkipBody->CheckSameAsPrevious = true;
1062	SkipBody->New = IDecl;
1063	SkipBody->Previous = Def;
1064	} else {
1065	Diag(AtInterfaceLoc, diag::err_duplicate_class_def)
1066	<< PrevIDecl->getDeclName();
1067	Diag(Def->getLocation(), diag::note_previous_definition);
1068	IDecl->setInvalidDecl();
1069	}
1070	}
1071	}
1072
1073	ProcessDeclAttributeList(TUScope, IDecl, AttrList);
1074	AddPragmaAttributes(TUScope, IDecl);
1075
1076	// Merge attributes from previous declarations.
1077	if (PrevIDecl)
1078	mergeDeclAttributes(IDecl, PrevIDecl);
1079
1080	PushOnScopeChains(IDecl, TUScope);
1081
1082	// Start the definition of this class. If we're in a redefinition case, there
1083	// may already be a definition, so we'll end up adding to it.
1084	if (SkipBody && SkipBody->CheckSameAsPrevious)
1085	IDecl->startDuplicateDefinitionForComparison();
1086	else if (!IDecl->hasDefinition())
1087	IDecl->startDefinition();
1088
1089	if (SuperName) {
1090	// Diagnose availability in the context of the @interface.
1091	ContextRAII SavedContext(*this, IDecl);
1092
1093	ActOnSuperClassOfClassInterface(S, AtInterfaceLoc, IDecl,
1094	ClassName, ClassLoc,
1095	SuperName, SuperLoc, SuperTypeArgs,
1096	SuperTypeArgsRange);
1097	} else { // we have a root class.
1098	IDecl->setEndOfDefinitionLoc(ClassLoc);
1099	}
1100
1101	// Check then save referenced protocols.
1102	if (NumProtoRefs) {
1103	diagnoseUseOfProtocols(*this, IDecl, (ObjCProtocolDecl*const*)ProtoRefs,
1104	NumProtoRefs, ProtoLocs);
1105	IDecl->setProtocolList(List: (ObjCProtocolDecl*const*)ProtoRefs, Num: NumProtoRefs,
1106	Locs: ProtoLocs, C&: Context);
1107	IDecl->setEndOfDefinitionLoc(EndProtoLoc);
1108	}
1109
1110	CheckObjCDeclScope(IDecl);
1111	ActOnObjCContainerStartDefinition(IDecl);
1112	return IDecl;
1113	}
1114
1115	/// ActOnTypedefedProtocols - this action finds protocol list as part of the
1116	/// typedef'ed use for a qualified super class and adds them to the list
1117	/// of the protocols.
1118	void Sema::ActOnTypedefedProtocols(SmallVectorImpl<Decl *> &ProtocolRefs,
1119	SmallVectorImpl<SourceLocation> &ProtocolLocs,
1120	IdentifierInfo *SuperName,
1121	SourceLocation SuperLoc) {
1122	if (!SuperName)
1123	return;
1124	NamedDecl* IDecl = LookupSingleName(S: TUScope, Name: SuperName, Loc: SuperLoc,
1125	NameKind: LookupOrdinaryName);
1126	if (!IDecl)
1127	return;
1128
1129	if (const TypedefNameDecl *TDecl = dyn_cast_or_null<TypedefNameDecl>(Val: IDecl)) {
1130	QualType T = TDecl->getUnderlyingType();
1131	if (T->isObjCObjectType())
1132	if (const ObjCObjectType *OPT = T->getAs<ObjCObjectType>()) {
1133	ProtocolRefs.append(OPT->qual_begin(), OPT->qual_end());
1134	// FIXME: Consider whether this should be an invalid loc since the loc
1135	// is not actually pointing to a protocol name reference but to the
1136	// typedef reference. Note that the base class name loc is also pointing
1137	// at the typedef.
1138	ProtocolLocs.append(OPT->getNumProtocols(), SuperLoc);
1139	}
1140	}
1141	}
1142
1143	/// ActOnCompatibilityAlias - this action is called after complete parsing of
1144	/// a \@compatibility_alias declaration. It sets up the alias relationships.
1145	Decl *Sema::ActOnCompatibilityAlias(SourceLocation AtLoc,
1146	IdentifierInfo *AliasName,
1147	SourceLocation AliasLocation,
1148	IdentifierInfo *ClassName,
1149	SourceLocation ClassLocation) {
1150	// Look for previous declaration of alias name
1151	NamedDecl *ADecl =
1152	LookupSingleName(S: TUScope, Name: AliasName, Loc: AliasLocation, NameKind: LookupOrdinaryName,
1153	Redecl: forRedeclarationInCurContext());
1154	if (ADecl) {
1155	Diag(AliasLocation, diag::err_conflicting_aliasing_type) << AliasName;
1156	Diag(ADecl->getLocation(), diag::note_previous_declaration);
1157	return nullptr;
1158	}
1159	// Check for class declaration
1160	NamedDecl *CDeclU =
1161	LookupSingleName(S: TUScope, Name: ClassName, Loc: ClassLocation, NameKind: LookupOrdinaryName,
1162	Redecl: forRedeclarationInCurContext());
1163	if (const TypedefNameDecl *TDecl =
1164	dyn_cast_or_null<TypedefNameDecl>(Val: CDeclU)) {
1165	QualType T = TDecl->getUnderlyingType();
1166	if (T->isObjCObjectType()) {
1167	if (NamedDecl *IDecl = T->castAs<ObjCObjectType>()->getInterface()) {
1168	ClassName = IDecl->getIdentifier();
1169	CDeclU = LookupSingleName(S: TUScope, Name: ClassName, Loc: ClassLocation,
1170	NameKind: LookupOrdinaryName,
1171	Redecl: forRedeclarationInCurContext());
1172	}
1173	}
1174	}
1175	ObjCInterfaceDecl *CDecl = dyn_cast_or_null<ObjCInterfaceDecl>(Val: CDeclU);
1176	if (!CDecl) {
1177	Diag(ClassLocation, diag::warn_undef_interface) << ClassName;
1178	if (CDeclU)
1179	Diag(CDeclU->getLocation(), diag::note_previous_declaration);
1180	return nullptr;
1181	}
1182
1183	// Everything checked out, instantiate a new alias declaration AST.
1184	ObjCCompatibleAliasDecl *AliasDecl =
1185	ObjCCompatibleAliasDecl::Create(C&: Context, DC: CurContext, L: AtLoc, Id: AliasName, aliasedClass: CDecl);
1186
1187	if (!CheckObjCDeclScope(AliasDecl))
1188	PushOnScopeChains(AliasDecl, TUScope);
1189
1190	return AliasDecl;
1191	}
1192
1193	bool Sema::CheckForwardProtocolDeclarationForCircularDependency(
1194	IdentifierInfo *PName,
1195	SourceLocation &Ploc, SourceLocation PrevLoc,
1196	const ObjCList<ObjCProtocolDecl> &PList) {
1197
1198	bool res = false;
1199	for (ObjCList<ObjCProtocolDecl>::iterator I = PList.begin(),
1200	E = PList.end(); I != E; ++I) {
1201	if (ObjCProtocolDecl *PDecl = LookupProtocol(II: (*I)->getIdentifier(),
1202	IdLoc: Ploc)) {
1203	if (PDecl->getIdentifier() == PName) {
1204	Diag(Ploc, diag::err_protocol_has_circular_dependency);
1205	Diag(PrevLoc, diag::note_previous_definition);
1206	res = true;
1207	}
1208
1209	if (!PDecl->hasDefinition())
1210	continue;
1211
1212	if (CheckForwardProtocolDeclarationForCircularDependency(PName, Ploc,
1213	PrevLoc: PDecl->getLocation(), PList: PDecl->getReferencedProtocols()))
1214	res = true;
1215	}
1216	}
1217	return res;
1218	}
1219
1220	ObjCProtocolDecl *Sema::ActOnStartProtocolInterface(
1221	SourceLocation AtProtoInterfaceLoc, IdentifierInfo *ProtocolName,
1222	SourceLocation ProtocolLoc, Decl *const *ProtoRefs, unsigned NumProtoRefs,
1223	const SourceLocation *ProtoLocs, SourceLocation EndProtoLoc,
1224	const ParsedAttributesView &AttrList, SkipBodyInfo *SkipBody) {
1225	bool err = false;
1226	// FIXME: Deal with AttrList.
1227	assert(ProtocolName && "Missing protocol identifier");
1228	ObjCProtocolDecl *PrevDecl = LookupProtocol(II: ProtocolName, IdLoc: ProtocolLoc,
1229	Redecl: forRedeclarationInCurContext());
1230	ObjCProtocolDecl *PDecl = nullptr;
1231	if (ObjCProtocolDecl *Def = PrevDecl? PrevDecl->getDefinition() : nullptr) {
1232	// Create a new protocol that is completely distinct from previous
1233	// declarations, and do not make this protocol available for name lookup.
1234	// That way, we'll end up completely ignoring the duplicate.
1235	// FIXME: Can we turn this into an error?
1236	PDecl = ObjCProtocolDecl::Create(C&: Context, DC: CurContext, Id: ProtocolName,
1237	nameLoc: ProtocolLoc, atStartLoc: AtProtoInterfaceLoc,
1238	/*PrevDecl=*/Def);
1239
1240	if (SkipBody && !hasVisibleDefinition(Def)) {
1241	SkipBody->CheckSameAsPrevious = true;
1242	SkipBody->New = PDecl;
1243	SkipBody->Previous = Def;
1244	} else {
1245	// If we already have a definition, complain.
1246	Diag(ProtocolLoc, diag::warn_duplicate_protocol_def) << ProtocolName;
1247	Diag(Def->getLocation(), diag::note_previous_definition);
1248	}
1249
1250	// If we are using modules, add the decl to the context in order to
1251	// serialize something meaningful.
1252	if (getLangOpts().Modules)
1253	PushOnScopeChains(PDecl, TUScope);
1254	PDecl->startDuplicateDefinitionForComparison();
1255	} else {
1256	if (PrevDecl) {
1257	// Check for circular dependencies among protocol declarations. This can
1258	// only happen if this protocol was forward-declared.
1259	ObjCList<ObjCProtocolDecl> PList;
1260	PList.set(InList: (ObjCProtocolDecl *const*)ProtoRefs, Elts: NumProtoRefs, Ctx&: Context);
1261	err = CheckForwardProtocolDeclarationForCircularDependency(
1262	PName: ProtocolName, Ploc&: ProtocolLoc, PrevLoc: PrevDecl->getLocation(), PList);
1263	}
1264
1265	// Create the new declaration.
1266	PDecl = ObjCProtocolDecl::Create(C&: Context, DC: CurContext, Id: ProtocolName,
1267	nameLoc: ProtocolLoc, atStartLoc: AtProtoInterfaceLoc,
1268	/*PrevDecl=*/PrevDecl);
1269
1270	PushOnScopeChains(PDecl, TUScope);
1271	PDecl->startDefinition();
1272	}
1273
1274	ProcessDeclAttributeList(TUScope, PDecl, AttrList);
1275	AddPragmaAttributes(TUScope, PDecl);
1276
1277	// Merge attributes from previous declarations.
1278	if (PrevDecl)
1279	mergeDeclAttributes(PDecl, PrevDecl);
1280
1281	if (!err && NumProtoRefs ) {
1282	/// Check then save referenced protocols.
1283	diagnoseUseOfProtocols(*this, PDecl, (ObjCProtocolDecl*const*)ProtoRefs,
1284	NumProtoRefs, ProtoLocs);
1285	PDecl->setProtocolList(List: (ObjCProtocolDecl*const*)ProtoRefs, Num: NumProtoRefs,
1286	Locs: ProtoLocs, C&: Context);
1287	}
1288
1289	CheckObjCDeclScope(PDecl);
1290	ActOnObjCContainerStartDefinition(PDecl);
1291	return PDecl;
1292	}
1293
1294	static bool NestedProtocolHasNoDefinition(ObjCProtocolDecl *PDecl,
1295	ObjCProtocolDecl *&UndefinedProtocol) {
1296	if (!PDecl->hasDefinition() ||
1297	!PDecl->getDefinition()->isUnconditionallyVisible()) {
1298	UndefinedProtocol = PDecl;
1299	return true;
1300	}
1301
1302	for (auto *PI : PDecl->protocols())
1303	if (NestedProtocolHasNoDefinition(PDecl: PI, UndefinedProtocol)) {
1304	UndefinedProtocol = PI;
1305	return true;
1306	}
1307	return false;
1308	}
1309
1310	/// FindProtocolDeclaration - This routine looks up protocols and
1311	/// issues an error if they are not declared. It returns list of
1312	/// protocol declarations in its 'Protocols' argument.
1313	void
1314	Sema::FindProtocolDeclaration(bool WarnOnDeclarations, bool ForObjCContainer,
1315	ArrayRef<IdentifierLocPair> ProtocolId,
1316	SmallVectorImpl<Decl *> &Protocols) {
1317	for (const IdentifierLocPair &Pair : ProtocolId) {
1318	ObjCProtocolDecl *PDecl = LookupProtocol(II: Pair.first, IdLoc: Pair.second);
1319	if (!PDecl) {
1320	DeclFilterCCC<ObjCProtocolDecl> CCC{};
1321	TypoCorrection Corrected = CorrectTypo(
1322	Typo: DeclarationNameInfo(Pair.first, Pair.second), LookupKind: LookupObjCProtocolName,
1323	S: TUScope, SS: nullptr, CCC, Mode: CTK_ErrorRecovery);
1324	if ((PDecl = Corrected.getCorrectionDeclAs<ObjCProtocolDecl>()))
1325	diagnoseTypo(Corrected, PDiag(diag::err_undeclared_protocol_suggest)
1326	<< Pair.first);
1327	}
1328
1329	if (!PDecl) {
1330	Diag(Pair.second, diag::err_undeclared_protocol) << Pair.first;
1331	continue;
1332	}
1333	// If this is a forward protocol declaration, get its definition.
1334	if (!PDecl->isThisDeclarationADefinition() && PDecl->getDefinition())
1335	PDecl = PDecl->getDefinition();
1336
1337	// For an objc container, delay protocol reference checking until after we
1338	// can set the objc decl as the availability context, otherwise check now.
1339	if (!ForObjCContainer) {
1340	(void)DiagnoseUseOfDecl(PDecl, Pair.second);
1341	}
1342
1343	// If this is a forward declaration and we are supposed to warn in this
1344	// case, do it.
1345	// FIXME: Recover nicely in the hidden case.
1346	ObjCProtocolDecl *UndefinedProtocol;
1347
1348	if (WarnOnDeclarations &&
1349	NestedProtocolHasNoDefinition(PDecl, UndefinedProtocol)) {
1350	Diag(Pair.second, diag::warn_undef_protocolref) << Pair.first;
1351	Diag(UndefinedProtocol->getLocation(), diag::note_protocol_decl_undefined)
1352	<< UndefinedProtocol;
1353	}
1354	Protocols.push_back(PDecl);
1355	}
1356	}
1357
1358	namespace {
1359	// Callback to only accept typo corrections that are either
1360	// Objective-C protocols or valid Objective-C type arguments.
1361	class ObjCTypeArgOrProtocolValidatorCCC final
1362	: public CorrectionCandidateCallback {
1363	ASTContext &Context;
1364	Sema::LookupNameKind LookupKind;
1365	public:
1366	ObjCTypeArgOrProtocolValidatorCCC(ASTContext &context,
1367	Sema::LookupNameKind lookupKind)
1368	: Context(context), LookupKind(lookupKind) { }
1369
1370	bool ValidateCandidate(const TypoCorrection &candidate) override {
1371	// If we're allowed to find protocols and we have a protocol, accept it.
1372	if (LookupKind != Sema::LookupOrdinaryName) {
1373	if (candidate.getCorrectionDeclAs<ObjCProtocolDecl>())
1374	return true;
1375	}
1376
1377	// If we're allowed to find type names and we have one, accept it.
1378	if (LookupKind != Sema::LookupObjCProtocolName) {
1379	// If we have a type declaration, we might accept this result.
1380	if (auto typeDecl = candidate.getCorrectionDeclAs<TypeDecl>()) {
1381	// If we found a tag declaration outside of C++, skip it. This
1382	// can happy because we look for any name when there is no
1383	// bias to protocol or type names.
1384	if (isa<RecordDecl>(Val: typeDecl) && !Context.getLangOpts().CPlusPlus)
1385	return false;
1386
1387	// Make sure the type is something we would accept as a type
1388	// argument.
1389	auto type = Context.getTypeDeclType(Decl: typeDecl);
1390	if (type->isObjCObjectPointerType() ||
1391	type->isBlockPointerType() ||
1392	type->isDependentType() ||
1393	type->isObjCObjectType())
1394	return true;
1395
1396	return false;
1397	}
1398
1399	// If we have an Objective-C class type, accept it; there will
1400	// be another fix to add the '*'.
1401	if (candidate.getCorrectionDeclAs<ObjCInterfaceDecl>())
1402	return true;
1403
1404	return false;
1405	}
1406
1407	return false;
1408	}
1409
1410	std::unique_ptr<CorrectionCandidateCallback> clone() override {
1411	return std::make_unique<ObjCTypeArgOrProtocolValidatorCCC>(args&: *this);
1412	}
1413	};
1414	} // end anonymous namespace
1415
1416	void Sema::DiagnoseTypeArgsAndProtocols(IdentifierInfo *ProtocolId,
1417	SourceLocation ProtocolLoc,
1418	IdentifierInfo *TypeArgId,
1419	SourceLocation TypeArgLoc,
1420	bool SelectProtocolFirst) {
1421	Diag(TypeArgLoc, diag::err_objc_type_args_and_protocols)
1422	<< SelectProtocolFirst << TypeArgId << ProtocolId
1423	<< SourceRange(ProtocolLoc);
1424	}
1425
1426	void Sema::actOnObjCTypeArgsOrProtocolQualifiers(
1427	Scope *S,
1428	ParsedType baseType,
1429	SourceLocation lAngleLoc,
1430	ArrayRef<IdentifierInfo *> identifiers,
1431	ArrayRef<SourceLocation> identifierLocs,
1432	SourceLocation rAngleLoc,
1433	SourceLocation &typeArgsLAngleLoc,
1434	SmallVectorImpl<ParsedType> &typeArgs,
1435	SourceLocation &typeArgsRAngleLoc,
1436	SourceLocation &protocolLAngleLoc,
1437	SmallVectorImpl<Decl *> &protocols,
1438	SourceLocation &protocolRAngleLoc,
1439	bool warnOnIncompleteProtocols) {
1440	// Local function that updates the declaration specifiers with
1441	// protocol information.
1442	unsigned numProtocolsResolved = 0;
1443	auto resolvedAsProtocols = [&] {
1444	assert(numProtocolsResolved == identifiers.size() && "Unresolved protocols");
1445
1446	// Determine whether the base type is a parameterized class, in
1447	// which case we want to warn about typos such as
1448	// "NSArray<NSObject>" (that should be NSArray<NSObject *>).
1449	ObjCInterfaceDecl *baseClass = nullptr;
1450	QualType base = GetTypeFromParser(Ty: baseType, TInfo: nullptr);
1451	bool allAreTypeNames = false;
1452	SourceLocation firstClassNameLoc;
1453	if (!base.isNull()) {
1454	if (const auto *objcObjectType = base->getAs<ObjCObjectType>()) {
1455	baseClass = objcObjectType->getInterface();
1456	if (baseClass) {
1457	if (auto typeParams = baseClass->getTypeParamList()) {
1458	if (typeParams->size() == numProtocolsResolved) {
1459	// Note that we should be looking for type names, too.
1460	allAreTypeNames = true;
1461	}
1462	}
1463	}
1464	}
1465	}
1466
1467	for (unsigned i = 0, n = protocols.size(); i != n; ++i) {
1468	ObjCProtocolDecl *&proto
1469	= reinterpret_cast<ObjCProtocolDecl *&>(protocols[i]);
1470	// For an objc container, delay protocol reference checking until after we
1471	// can set the objc decl as the availability context, otherwise check now.
1472	if (!warnOnIncompleteProtocols) {
1473	(void)DiagnoseUseOfDecl(proto, identifierLocs[i]);
1474	}
1475
1476	// If this is a forward protocol declaration, get its definition.
1477	if (!proto->isThisDeclarationADefinition() && proto->getDefinition())
1478	proto = proto->getDefinition();
1479
1480	// If this is a forward declaration and we are supposed to warn in this
1481	// case, do it.
1482	// FIXME: Recover nicely in the hidden case.
1483	ObjCProtocolDecl *forwardDecl = nullptr;
1484	if (warnOnIncompleteProtocols &&
1485	NestedProtocolHasNoDefinition(PDecl: proto, UndefinedProtocol&: forwardDecl)) {
1486	Diag(identifierLocs[i], diag::warn_undef_protocolref)
1487	<< proto->getDeclName();
1488	Diag(forwardDecl->getLocation(), diag::note_protocol_decl_undefined)
1489	<< forwardDecl;
1490	}
1491
1492	// If everything this far has been a type name (and we care
1493	// about such things), check whether this name refers to a type
1494	// as well.
1495	if (allAreTypeNames) {
1496	if (auto *decl = LookupSingleName(S, Name: identifiers[i], Loc: identifierLocs[i],
1497	NameKind: LookupOrdinaryName)) {
1498	if (isa<ObjCInterfaceDecl>(Val: decl)) {
1499	if (firstClassNameLoc.isInvalid())
1500	firstClassNameLoc = identifierLocs[i];
1501	} else if (!isa<TypeDecl>(Val: decl)) {
1502	// Not a type.
1503	allAreTypeNames = false;
1504	}
1505	} else {
1506	allAreTypeNames = false;
1507	}
1508	}
1509	}
1510
1511	// All of the protocols listed also have type names, and at least
1512	// one is an Objective-C class name. Check whether all of the
1513	// protocol conformances are declared by the base class itself, in
1514	// which case we warn.
1515	if (allAreTypeNames && firstClassNameLoc.isValid()) {
1516	llvm::SmallPtrSet<ObjCProtocolDecl*, 8> knownProtocols;
1517	Context.CollectInheritedProtocols(baseClass, knownProtocols);
1518	bool allProtocolsDeclared = true;
1519	for (auto *proto : protocols) {
1520	if (knownProtocols.count(Ptr: static_cast<ObjCProtocolDecl *>(proto)) == 0) {
1521	allProtocolsDeclared = false;
1522	break;
1523	}
1524	}
1525
1526	if (allProtocolsDeclared) {
1527	Diag(firstClassNameLoc, diag::warn_objc_redundant_qualified_class_type)
1528	<< baseClass->getDeclName() << SourceRange(lAngleLoc, rAngleLoc)
1529	<< FixItHint::CreateInsertion(getLocForEndOfToken(firstClassNameLoc),
1530	" *");
1531	}
1532	}
1533
1534	protocolLAngleLoc = lAngleLoc;
1535	protocolRAngleLoc = rAngleLoc;
1536	assert(protocols.size() == identifierLocs.size());
1537	};
1538
1539	// Attempt to resolve all of the identifiers as protocols.
1540	for (unsigned i = 0, n = identifiers.size(); i != n; ++i) {
1541	ObjCProtocolDecl *proto = LookupProtocol(II: identifiers[i], IdLoc: identifierLocs[i]);
1542	protocols.push_back(proto);
1543	if (proto)
1544	++numProtocolsResolved;
1545	}
1546
1547	// If all of the names were protocols, these were protocol qualifiers.
1548	if (numProtocolsResolved == identifiers.size())
1549	return resolvedAsProtocols();
1550
1551	// Attempt to resolve all of the identifiers as type names or
1552	// Objective-C class names. The latter is technically ill-formed,
1553	// but is probably something like \c NSArray<NSView *> missing the
1554	// \c*.
1555	typedef llvm::PointerUnion<TypeDecl *, ObjCInterfaceDecl *> TypeOrClassDecl;
1556	SmallVector<TypeOrClassDecl, 4> typeDecls;
1557	unsigned numTypeDeclsResolved = 0;
1558	for (unsigned i = 0, n = identifiers.size(); i != n; ++i) {
1559	NamedDecl *decl = LookupSingleName(S, Name: identifiers[i], Loc: identifierLocs[i],
1560	NameKind: LookupOrdinaryName);
1561	if (!decl) {
1562	typeDecls.push_back(Elt: TypeOrClassDecl());
1563	continue;
1564	}
1565
1566	if (auto typeDecl = dyn_cast<TypeDecl>(Val: decl)) {
1567	typeDecls.push_back(Elt: typeDecl);
1568	++numTypeDeclsResolved;
1569	continue;
1570	}
1571
1572	if (auto objcClass = dyn_cast<ObjCInterfaceDecl>(Val: decl)) {
1573	typeDecls.push_back(Elt: objcClass);
1574	++numTypeDeclsResolved;
1575	continue;
1576	}
1577
1578	typeDecls.push_back(Elt: TypeOrClassDecl());
1579	}
1580
1581	AttributeFactory attrFactory;
1582
1583	// Local function that forms a reference to the given type or
1584	// Objective-C class declaration.
1585	auto resolveTypeReference = [&](TypeOrClassDecl typeDecl, SourceLocation loc)
1586	-> TypeResult {
1587	// Form declaration specifiers. They simply refer to the type.
1588	DeclSpec DS(attrFactory);
1589	const char* prevSpec; // unused
1590	unsigned diagID; // unused
1591	QualType type;
1592	if (auto *actualTypeDecl = typeDecl.dyn_cast<TypeDecl *>())
1593	type = Context.getTypeDeclType(Decl: actualTypeDecl);
1594	else
1595	type = Context.getObjCInterfaceType(Decl: typeDecl.get<ObjCInterfaceDecl *>());
1596	TypeSourceInfo *parsedTSInfo = Context.getTrivialTypeSourceInfo(T: type, Loc: loc);
1597	ParsedType parsedType = CreateParsedType(T: type, TInfo: parsedTSInfo);
1598	DS.SetTypeSpecType(T: DeclSpec::TST_typename, Loc: loc, PrevSpec&: prevSpec, DiagID&: diagID,
1599	Rep: parsedType, Policy: Context.getPrintingPolicy());
1600	// Use the identifier location for the type source range.
1601	DS.SetRangeStart(loc);
1602	DS.SetRangeEnd(loc);
1603
1604	// Form the declarator.
1605	Declarator D(DS, ParsedAttributesView::none(), DeclaratorContext::TypeName);
1606
1607	// If we have a typedef of an Objective-C class type that is missing a '*',
1608	// add the '*'.
1609	if (type->getAs<ObjCInterfaceType>()) {
1610	SourceLocation starLoc = getLocForEndOfToken(Loc: loc);
1611	D.AddTypeInfo(TI: DeclaratorChunk::getPointer(/*TypeQuals=*/0, Loc: starLoc,
1612	ConstQualLoc: SourceLocation(),
1613	VolatileQualLoc: SourceLocation(),
1614	RestrictQualLoc: SourceLocation(),
1615	AtomicQualLoc: SourceLocation(),
1616	UnalignedQualLoc: SourceLocation()),
1617	EndLoc: starLoc);
1618
1619	// Diagnose the missing '*'.
1620	Diag(loc, diag::err_objc_type_arg_missing_star)
1621	<< type
1622	<< FixItHint::CreateInsertion(starLoc, " *");
1623	}
1624
1625	// Convert this to a type.
1626	return ActOnTypeName(D);
1627	};
1628
1629	// Local function that updates the declaration specifiers with
1630	// type argument information.
1631	auto resolvedAsTypeDecls = [&] {
1632	// We did not resolve these as protocols.
1633	protocols.clear();
1634
1635	assert(numTypeDeclsResolved == identifiers.size() && "Unresolved type decl");
1636	// Map type declarations to type arguments.
1637	for (unsigned i = 0, n = identifiers.size(); i != n; ++i) {
1638	// Map type reference to a type.
1639	TypeResult type = resolveTypeReference(typeDecls[i], identifierLocs[i]);
1640	if (!type.isUsable()) {
1641	typeArgs.clear();
1642	return;
1643	}
1644
1645	typeArgs.push_back(Elt: type.get());
1646	}
1647
1648	typeArgsLAngleLoc = lAngleLoc;
1649	typeArgsRAngleLoc = rAngleLoc;
1650	};
1651
1652	// If all of the identifiers can be resolved as type names or
1653	// Objective-C class names, we have type arguments.
1654	if (numTypeDeclsResolved == identifiers.size())
1655	return resolvedAsTypeDecls();
1656
1657	// Error recovery: some names weren't found, or we have a mix of
1658	// type and protocol names. Go resolve all of the unresolved names
1659	// and complain if we can't find a consistent answer.
1660	LookupNameKind lookupKind = LookupAnyName;
1661	for (unsigned i = 0, n = identifiers.size(); i != n; ++i) {
1662	// If we already have a protocol or type. Check whether it is the
1663	// right thing.
1664	if (protocols[i] || typeDecls[i]) {
1665	// If we haven't figured out whether we want types or protocols
1666	// yet, try to figure it out from this name.
1667	if (lookupKind == LookupAnyName) {
1668	// If this name refers to both a protocol and a type (e.g., \c
1669	// NSObject), don't conclude anything yet.
1670	if (protocols[i] && typeDecls[i])
1671	continue;
1672
1673	// Otherwise, let this name decide whether we'll be correcting
1674	// toward types or protocols.
1675	lookupKind = protocols[i] ? LookupObjCProtocolName
1676	: LookupOrdinaryName;
1677	continue;
1678	}
1679
1680	// If we want protocols and we have a protocol, there's nothing
1681	// more to do.
1682	if (lookupKind == LookupObjCProtocolName && protocols[i])
1683	continue;
1684
1685	// If we want types and we have a type declaration, there's
1686	// nothing more to do.
1687	if (lookupKind == LookupOrdinaryName && typeDecls[i])
1688	continue;
1689
1690	// We have a conflict: some names refer to protocols and others
1691	// refer to types.
1692	DiagnoseTypeArgsAndProtocols(ProtocolId: identifiers[0], ProtocolLoc: identifierLocs[0],
1693	TypeArgId: identifiers[i], TypeArgLoc: identifierLocs[i],
1694	SelectProtocolFirst: protocols[i] != nullptr);
1695
1696	protocols.clear();
1697	typeArgs.clear();
1698	return;
1699	}
1700
1701	// Perform typo correction on the name.
1702	ObjCTypeArgOrProtocolValidatorCCC CCC(Context, lookupKind);
1703	TypoCorrection corrected =
1704	CorrectTypo(Typo: DeclarationNameInfo(identifiers[i], identifierLocs[i]),
1705	LookupKind: lookupKind, S, SS: nullptr, CCC, Mode: CTK_ErrorRecovery);
1706	if (corrected) {
1707	// Did we find a protocol?
1708	if (auto proto = corrected.getCorrectionDeclAs<ObjCProtocolDecl>()) {
1709	diagnoseTypo(corrected,
1710	PDiag(diag::err_undeclared_protocol_suggest)
1711	<< identifiers[i]);
1712	lookupKind = LookupObjCProtocolName;
1713	protocols[i] = proto;
1714	++numProtocolsResolved;
1715	continue;
1716	}
1717
1718	// Did we find a type?
1719	if (auto typeDecl = corrected.getCorrectionDeclAs<TypeDecl>()) {
1720	diagnoseTypo(corrected,
1721	PDiag(diag::err_unknown_typename_suggest)
1722	<< identifiers[i]);
1723	lookupKind = LookupOrdinaryName;
1724	typeDecls[i] = typeDecl;
1725	++numTypeDeclsResolved;
1726	continue;
1727	}
1728
1729	// Did we find an Objective-C class?
1730	if (auto objcClass = corrected.getCorrectionDeclAs<ObjCInterfaceDecl>()) {
1731	diagnoseTypo(corrected,
1732	PDiag(diag::err_unknown_type_or_class_name_suggest)
1733	<< identifiers[i] << true);
1734	lookupKind = LookupOrdinaryName;
1735	typeDecls[i] = objcClass;
1736	++numTypeDeclsResolved;
1737	continue;
1738	}
1739	}
1740
1741	// We couldn't find anything.
1742	Diag(identifierLocs[i],
1743	(lookupKind == LookupAnyName ? diag::err_objc_type_arg_missing
1744	: lookupKind == LookupObjCProtocolName ? diag::err_undeclared_protocol
1745	: diag::err_unknown_typename))
1746	<< identifiers[i];
1747	protocols.clear();
1748	typeArgs.clear();
1749	return;
1750	}
1751
1752	// If all of the names were (corrected to) protocols, these were
1753	// protocol qualifiers.
1754	if (numProtocolsResolved == identifiers.size())
1755	return resolvedAsProtocols();
1756
1757	// Otherwise, all of the names were (corrected to) types.
1758	assert(numTypeDeclsResolved == identifiers.size() && "Not all types?");
1759	return resolvedAsTypeDecls();
1760	}
1761
1762	/// DiagnoseClassExtensionDupMethods - Check for duplicate declaration of
1763	/// a class method in its extension.
1764	///
1765	void Sema::DiagnoseClassExtensionDupMethods(ObjCCategoryDecl *CAT,
1766	ObjCInterfaceDecl *ID) {
1767	if (!ID)
1768	return; // Possibly due to previous error
1769
1770	llvm::DenseMap<Selector, const ObjCMethodDecl*> MethodMap;
1771	for (auto *MD : ID->methods())
1772	MethodMap[MD->getSelector()] = MD;
1773
1774	if (MethodMap.empty())
1775	return;
1776	for (const auto *Method : CAT->methods()) {
1777	const ObjCMethodDecl *&PrevMethod = MethodMap[Method->getSelector()];
1778	if (PrevMethod &&
1779	(PrevMethod->isInstanceMethod() == Method->isInstanceMethod()) &&
1780	!MatchTwoMethodDeclarations(Method, PrevMethod)) {
1781	Diag(Method->getLocation(), diag::err_duplicate_method_decl)
1782	<< Method->getDeclName();
1783	Diag(PrevMethod->getLocation(), diag::note_previous_declaration);
1784	}
1785	}
1786	}
1787
1788	/// ActOnForwardProtocolDeclaration - Handle \@protocol foo;
1789	Sema::DeclGroupPtrTy
1790	Sema::ActOnForwardProtocolDeclaration(SourceLocation AtProtocolLoc,
1791	ArrayRef<IdentifierLocPair> IdentList,
1792	const ParsedAttributesView &attrList) {
1793	SmallVector<Decl *, 8> DeclsInGroup;
1794	for (const IdentifierLocPair &IdentPair : IdentList) {
1795	IdentifierInfo *Ident = IdentPair.first;
1796	ObjCProtocolDecl *PrevDecl = LookupProtocol(II: Ident, IdLoc: IdentPair.second,
1797	Redecl: forRedeclarationInCurContext());
1798	ObjCProtocolDecl *PDecl
1799	= ObjCProtocolDecl::Create(C&: Context, DC: CurContext, Id: Ident,
1800	nameLoc: IdentPair.second, atStartLoc: AtProtocolLoc,
1801	PrevDecl);
1802
1803	PushOnScopeChains(PDecl, TUScope);
1804	CheckObjCDeclScope(PDecl);
1805
1806	ProcessDeclAttributeList(TUScope, PDecl, attrList);
1807	AddPragmaAttributes(TUScope, PDecl);
1808
1809	if (PrevDecl)
1810	mergeDeclAttributes(PDecl, PrevDecl);
1811
1812	DeclsInGroup.push_back(PDecl);
1813	}
1814
1815	return BuildDeclaratorGroup(Group: DeclsInGroup);
1816	}
1817
1818	ObjCCategoryDecl *Sema::ActOnStartCategoryInterface(
1819	SourceLocation AtInterfaceLoc, IdentifierInfo *ClassName,
1820	SourceLocation ClassLoc, ObjCTypeParamList *typeParamList,
1821	IdentifierInfo *CategoryName, SourceLocation CategoryLoc,
1822	Decl *const *ProtoRefs, unsigned NumProtoRefs,
1823	const SourceLocation *ProtoLocs, SourceLocation EndProtoLoc,
1824	const ParsedAttributesView &AttrList) {
1825	ObjCCategoryDecl *CDecl;
1826	ObjCInterfaceDecl *IDecl = getObjCInterfaceDecl(Id&: ClassName, IdLoc: ClassLoc, TypoCorrection: true);
1827
1828	/// Check that class of this category is already completely declared.
1829
1830	if (!IDecl
1831	|| RequireCompleteType(ClassLoc, Context.getObjCInterfaceType(IDecl),
1832	diag::err_category_forward_interface,
1833	CategoryName == nullptr)) {
1834	// Create an invalid ObjCCategoryDecl to serve as context for
1835	// the enclosing method declarations. We mark the decl invalid
1836	// to make it clear that this isn't a valid AST.
1837	CDecl = ObjCCategoryDecl::Create(C&: Context, DC: CurContext, AtLoc: AtInterfaceLoc,
1838	ClassNameLoc: ClassLoc, CategoryNameLoc: CategoryLoc, Id: CategoryName,
1839	IDecl, typeParamList);
1840	CDecl->setInvalidDecl();
1841	CurContext->addDecl(CDecl);
1842
1843	if (!IDecl)
1844	Diag(ClassLoc, diag::err_undef_interface) << ClassName;
1845	ActOnObjCContainerStartDefinition(CDecl);
1846	return CDecl;
1847	}
1848
1849	if (!CategoryName && IDecl->getImplementation()) {
1850	Diag(ClassLoc, diag::err_class_extension_after_impl) << ClassName;
1851	Diag(IDecl->getImplementation()->getLocation(),
1852	diag::note_implementation_declared);
1853	}
1854
1855	if (CategoryName) {
1856	/// Check for duplicate interface declaration for this category
1857	if (ObjCCategoryDecl *Previous
1858	= IDecl->FindCategoryDeclaration(CategoryId: CategoryName)) {
1859	// Class extensions can be declared multiple times, categories cannot.
1860	Diag(CategoryLoc, diag::warn_dup_category_def)
1861	<< ClassName << CategoryName;
1862	Diag(Previous->getLocation(), diag::note_previous_definition);
1863	}
1864	}
1865
1866	// If we have a type parameter list, check it.
1867	if (typeParamList) {
1868	if (auto prevTypeParamList = IDecl->getTypeParamList()) {
1869	if (checkTypeParamListConsistency(S&: *this, prevTypeParams: prevTypeParamList, newTypeParams: typeParamList,
1870	newContext: CategoryName
1871	? TypeParamListContext::Category
1872	: TypeParamListContext::Extension))
1873	typeParamList = nullptr;
1874	} else {
1875	Diag(typeParamList->getLAngleLoc(),
1876	diag::err_objc_parameterized_category_nonclass)
1877	<< (CategoryName != nullptr)
1878	<< ClassName
1879	<< typeParamList->getSourceRange();
1880
1881	typeParamList = nullptr;
1882	}
1883	}
1884
1885	CDecl = ObjCCategoryDecl::Create(C&: Context, DC: CurContext, AtLoc: AtInterfaceLoc,
1886	ClassNameLoc: ClassLoc, CategoryNameLoc: CategoryLoc, Id: CategoryName, IDecl,
1887	typeParamList);
1888	// FIXME: PushOnScopeChains?
1889	CurContext->addDecl(CDecl);
1890
1891	// Process the attributes before looking at protocols to ensure that the
1892	// availability attribute is attached to the category to provide availability
1893	// checking for protocol uses.
1894	ProcessDeclAttributeList(TUScope, CDecl, AttrList);
1895	AddPragmaAttributes(TUScope, CDecl);
1896
1897	if (NumProtoRefs) {
1898	diagnoseUseOfProtocols(*this, CDecl, (ObjCProtocolDecl*const*)ProtoRefs,
1899	NumProtoRefs, ProtoLocs);
1900	CDecl->setProtocolList(List: (ObjCProtocolDecl*const*)ProtoRefs, Num: NumProtoRefs,
1901	Locs: ProtoLocs, C&: Context);
1902	// Protocols in the class extension belong to the class.
1903	if (CDecl->IsClassExtension())
1904	IDecl->mergeClassExtensionProtocolList(List: (ObjCProtocolDecl*const*)ProtoRefs,
1905	Num: NumProtoRefs, C&: Context);
1906	}
1907
1908	CheckObjCDeclScope(CDecl);
1909	ActOnObjCContainerStartDefinition(CDecl);
1910	return CDecl;
1911	}
1912
1913	/// ActOnStartCategoryImplementation - Perform semantic checks on the
1914	/// category implementation declaration and build an ObjCCategoryImplDecl
1915	/// object.
1916	ObjCCategoryImplDecl *Sema::ActOnStartCategoryImplementation(
1917	SourceLocation AtCatImplLoc, IdentifierInfo *ClassName,
1918	SourceLocation ClassLoc, IdentifierInfo *CatName, SourceLocation CatLoc,
1919	const ParsedAttributesView &Attrs) {
1920	ObjCInterfaceDecl *IDecl = getObjCInterfaceDecl(Id&: ClassName, IdLoc: ClassLoc, TypoCorrection: true);
1921	ObjCCategoryDecl *CatIDecl = nullptr;
1922	if (IDecl && IDecl->hasDefinition()) {
1923	CatIDecl = IDecl->FindCategoryDeclaration(CategoryId: CatName);
1924	if (!CatIDecl) {
1925	// Category @implementation with no corresponding @interface.
1926	// Create and install one.
1927	CatIDecl = ObjCCategoryDecl::Create(C&: Context, DC: CurContext, AtLoc: AtCatImplLoc,
1928	ClassNameLoc: ClassLoc, CategoryNameLoc: CatLoc,
1929	Id: CatName, IDecl,
1930	/*typeParamList=*/nullptr);
1931	CatIDecl->setImplicit();
1932	}
1933	}
1934
1935	ObjCCategoryImplDecl *CDecl =
1936	ObjCCategoryImplDecl::Create(C&: Context, DC: CurContext, Id: CatName, classInterface: IDecl,
1937	nameLoc: ClassLoc, atStartLoc: AtCatImplLoc, CategoryNameLoc: CatLoc);
1938	/// Check that class of this category is already completely declared.
1939	if (!IDecl) {
1940	Diag(ClassLoc, diag::err_undef_interface) << ClassName;
1941	CDecl->setInvalidDecl();
1942	} else if (RequireCompleteType(ClassLoc, Context.getObjCInterfaceType(IDecl),
1943	diag::err_undef_interface)) {
1944	CDecl->setInvalidDecl();
1945	}
1946
1947	ProcessDeclAttributeList(TUScope, CDecl, Attrs);
1948	AddPragmaAttributes(TUScope, CDecl);
1949
1950	// FIXME: PushOnScopeChains?
1951	CurContext->addDecl(CDecl);
1952
1953	// If the interface has the objc_runtime_visible attribute, we
1954	// cannot implement a category for it.
1955	if (IDecl && IDecl->hasAttr<ObjCRuntimeVisibleAttr>()) {
1956	Diag(ClassLoc, diag::err_objc_runtime_visible_category)
1957	<< IDecl->getDeclName();
1958	}
1959
1960	/// Check that CatName, category name, is not used in another implementation.
1961	if (CatIDecl) {
1962	if (CatIDecl->getImplementation()) {
1963	Diag(ClassLoc, diag::err_dup_implementation_category) << ClassName
1964	<< CatName;
1965	Diag(CatIDecl->getImplementation()->getLocation(),
1966	diag::note_previous_definition);
1967	CDecl->setInvalidDecl();
1968	} else {
1969	CatIDecl->setImplementation(CDecl);
1970	// Warn on implementating category of deprecated class under
1971	// -Wdeprecated-implementations flag.
1972	DiagnoseObjCImplementedDeprecations(*this, CatIDecl,
1973	CDecl->getLocation());
1974	}
1975	}
1976
1977	CheckObjCDeclScope(CDecl);
1978	ActOnObjCContainerStartDefinition(CDecl);
1979	return CDecl;
1980	}
1981
1982	ObjCImplementationDecl *Sema::ActOnStartClassImplementation(
1983	SourceLocation AtClassImplLoc, IdentifierInfo *ClassName,
1984	SourceLocation ClassLoc, IdentifierInfo *SuperClassname,
1985	SourceLocation SuperClassLoc, const ParsedAttributesView &Attrs) {
1986	ObjCInterfaceDecl *IDecl = nullptr;
1987	// Check for another declaration kind with the same name.
1988	NamedDecl *PrevDecl
1989	= LookupSingleName(S: TUScope, Name: ClassName, Loc: ClassLoc, NameKind: LookupOrdinaryName,
1990	Redecl: forRedeclarationInCurContext());
1991	if (PrevDecl && !isa<ObjCInterfaceDecl>(Val: PrevDecl)) {
1992	Diag(ClassLoc, diag::err_redefinition_different_kind) << ClassName;
1993	Diag(PrevDecl->getLocation(), diag::note_previous_definition);
1994	} else if ((IDecl = dyn_cast_or_null<ObjCInterfaceDecl>(Val: PrevDecl))) {
1995	// FIXME: This will produce an error if the definition of the interface has
1996	// been imported from a module but is not visible.
1997	RequireCompleteType(ClassLoc, Context.getObjCInterfaceType(IDecl),
1998	diag::warn_undef_interface);
1999	} else {
2000	// We did not find anything with the name ClassName; try to correct for
2001	// typos in the class name.
2002	ObjCInterfaceValidatorCCC CCC{};
2003	TypoCorrection Corrected =
2004	CorrectTypo(Typo: DeclarationNameInfo(ClassName, ClassLoc),
2005	LookupKind: LookupOrdinaryName, S: TUScope, SS: nullptr, CCC, Mode: CTK_NonError);
2006	if (Corrected.getCorrectionDeclAs<ObjCInterfaceDecl>()) {
2007	// Suggest the (potentially) correct interface name. Don't provide a
2008	// code-modification hint or use the typo name for recovery, because
2009	// this is just a warning. The program may actually be correct.
2010	diagnoseTypo(Corrected,
2011	PDiag(diag::warn_undef_interface_suggest) << ClassName,
2012	/*ErrorRecovery*/false);
2013	} else {
2014	Diag(ClassLoc, diag::warn_undef_interface) << ClassName;
2015	}
2016	}
2017
2018	// Check that super class name is valid class name
2019	ObjCInterfaceDecl *SDecl = nullptr;
2020	if (SuperClassname) {
2021	// Check if a different kind of symbol declared in this scope.
2022	PrevDecl = LookupSingleName(S: TUScope, Name: SuperClassname, Loc: SuperClassLoc,
2023	NameKind: LookupOrdinaryName);
2024	if (PrevDecl && !isa<ObjCInterfaceDecl>(Val: PrevDecl)) {
2025	Diag(SuperClassLoc, diag::err_redefinition_different_kind)
2026	<< SuperClassname;
2027	Diag(PrevDecl->getLocation(), diag::note_previous_definition);
2028	} else {
2029	SDecl = dyn_cast_or_null<ObjCInterfaceDecl>(Val: PrevDecl);
2030	if (SDecl && !SDecl->hasDefinition())
2031	SDecl = nullptr;
2032	if (!SDecl)
2033	Diag(SuperClassLoc, diag::err_undef_superclass)
2034	<< SuperClassname << ClassName;
2035	else if (IDecl && !declaresSameEntity(IDecl->getSuperClass(), SDecl)) {
2036	// This implementation and its interface do not have the same
2037	// super class.
2038	Diag(SuperClassLoc, diag::err_conflicting_super_class)
2039	<< SDecl->getDeclName();
2040	Diag(SDecl->getLocation(), diag::note_previous_definition);
2041	}
2042	}
2043	}
2044
2045	if (!IDecl) {
2046	// Legacy case of @implementation with no corresponding @interface.
2047	// Build, chain & install the interface decl into the identifier.
2048
2049	// FIXME: Do we support attributes on the @implementation? If so we should
2050	// copy them over.
2051	IDecl = ObjCInterfaceDecl::Create(C: Context, DC: CurContext, atLoc: AtClassImplLoc,
2052	Id: ClassName, /*typeParamList=*/nullptr,
2053	/*PrevDecl=*/nullptr, ClassLoc,
2054	isInternal: true);
2055	AddPragmaAttributes(TUScope, IDecl);
2056	IDecl->startDefinition();
2057	if (SDecl) {
2058	IDecl->setSuperClass(Context.getTrivialTypeSourceInfo(
2059	T: Context.getObjCInterfaceType(Decl: SDecl),
2060	Loc: SuperClassLoc));
2061	IDecl->setEndOfDefinitionLoc(SuperClassLoc);
2062	} else {
2063	IDecl->setEndOfDefinitionLoc(ClassLoc);
2064	}
2065
2066	PushOnScopeChains(IDecl, TUScope);
2067	} else {
2068	// Mark the interface as being completed, even if it was just as
2069	// @class ....;
2070	// declaration; the user cannot reopen it.
2071	if (!IDecl->hasDefinition())
2072	IDecl->startDefinition();
2073	}
2074
2075	ObjCImplementationDecl* IMPDecl =
2076	ObjCImplementationDecl::Create(C&: Context, DC: CurContext, classInterface: IDecl, superDecl: SDecl,
2077	nameLoc: ClassLoc, atStartLoc: AtClassImplLoc, superLoc: SuperClassLoc);
2078
2079	ProcessDeclAttributeList(TUScope, IMPDecl, Attrs);
2080	AddPragmaAttributes(TUScope, IMPDecl);
2081
2082	if (CheckObjCDeclScope(IMPDecl)) {
2083	ActOnObjCContainerStartDefinition(IMPDecl);
2084	return IMPDecl;
2085	}
2086
2087	// Check that there is no duplicate implementation of this class.
2088	if (IDecl->getImplementation()) {
2089	// FIXME: Don't leak everything!
2090	Diag(ClassLoc, diag::err_dup_implementation_class) << ClassName;
2091	Diag(IDecl->getImplementation()->getLocation(),
2092	diag::note_previous_definition);
2093	IMPDecl->setInvalidDecl();
2094	} else { // add it to the list.
2095	IDecl->setImplementation(IMPDecl);
2096	PushOnScopeChains(IMPDecl, TUScope);
2097	// Warn on implementating deprecated class under
2098	// -Wdeprecated-implementations flag.
2099	DiagnoseObjCImplementedDeprecations(*this, IDecl, IMPDecl->getLocation());
2100	}
2101
2102	// If the superclass has the objc_runtime_visible attribute, we
2103	// cannot implement a subclass of it.
2104	if (IDecl->getSuperClass() &&
2105	IDecl->getSuperClass()->hasAttr<ObjCRuntimeVisibleAttr>()) {
2106	Diag(ClassLoc, diag::err_objc_runtime_visible_subclass)
2107	<< IDecl->getDeclName()
2108	<< IDecl->getSuperClass()->getDeclName();
2109	}
2110
2111	ActOnObjCContainerStartDefinition(IMPDecl);
2112	return IMPDecl;
2113	}
2114
2115	Sema::DeclGroupPtrTy
2116	Sema::ActOnFinishObjCImplementation(Decl *ObjCImpDecl, ArrayRef<Decl *> Decls) {
2117	SmallVector<Decl *, 64> DeclsInGroup;
2118	DeclsInGroup.reserve(N: Decls.size() + 1);
2119
2120	for (unsigned i = 0, e = Decls.size(); i != e; ++i) {
2121	Decl *Dcl = Decls[i];
2122	if (!Dcl)
2123	continue;
2124	if (Dcl->getDeclContext()->isFileContext())
2125	Dcl->setTopLevelDeclInObjCContainer();
2126	DeclsInGroup.push_back(Elt: Dcl);
2127	}
2128
2129	DeclsInGroup.push_back(Elt: ObjCImpDecl);
2130
2131	return BuildDeclaratorGroup(Group: DeclsInGroup);
2132	}
2133
2134	void Sema::CheckImplementationIvars(ObjCImplementationDecl *ImpDecl,
2135	ObjCIvarDecl **ivars, unsigned numIvars,
2136	SourceLocation RBrace) {
2137	assert(ImpDecl && "missing implementation decl");
2138	ObjCInterfaceDecl* IDecl = ImpDecl->getClassInterface();
2139	if (!IDecl)
2140	return;
2141	/// Check case of non-existing \@interface decl.
2142	/// (legacy objective-c \@implementation decl without an \@interface decl).
2143	/// Add implementations's ivar to the synthesize class's ivar list.
2144	if (IDecl->isImplicitInterfaceDecl()) {
2145	IDecl->setEndOfDefinitionLoc(RBrace);
2146	// Add ivar's to class's DeclContext.
2147	for (unsigned i = 0, e = numIvars; i != e; ++i) {
2148	ivars[i]->setLexicalDeclContext(ImpDecl);
2149	// In a 'fragile' runtime the ivar was added to the implicit
2150	// ObjCInterfaceDecl while in a 'non-fragile' runtime the ivar is
2151	// only in the ObjCImplementationDecl. In the non-fragile case the ivar
2152	// therefore also needs to be propagated to the ObjCInterfaceDecl.
2153	if (!LangOpts.ObjCRuntime.isFragile())
2154	IDecl->makeDeclVisibleInContext(ivars[i]);
2155	ImpDecl->addDecl(ivars[i]);
2156	}
2157
2158	return;
2159	}
2160	// If implementation has empty ivar list, just return.
2161	if (numIvars == 0)
2162	return;
2163
2164	assert(ivars && "missing @implementation ivars");
2165	if (LangOpts.ObjCRuntime.isNonFragile()) {
2166	if (ImpDecl->getSuperClass())
2167	Diag(ImpDecl->getLocation(), diag::warn_on_superclass_use);
2168	for (unsigned i = 0; i < numIvars; i++) {
2169	ObjCIvarDecl* ImplIvar = ivars[i];
2170	if (const ObjCIvarDecl *ClsIvar =
2171	IDecl->getIvarDecl(Id: ImplIvar->getIdentifier())) {
2172	Diag(ImplIvar->getLocation(), diag::err_duplicate_ivar_declaration);
2173	Diag(ClsIvar->getLocation(), diag::note_previous_definition);
2174	continue;
2175	}
2176	// Check class extensions (unnamed categories) for duplicate ivars.
2177	for (const auto *CDecl : IDecl->visible_extensions()) {
2178	if (const ObjCIvarDecl *ClsExtIvar =
2179	CDecl->getIvarDecl(ImplIvar->getIdentifier())) {
2180	Diag(ImplIvar->getLocation(), diag::err_duplicate_ivar_declaration);
2181	Diag(ClsExtIvar->getLocation(), diag::note_previous_definition);
2182	continue;
2183	}
2184	}
2185	// Instance ivar to Implementation's DeclContext.
2186	ImplIvar->setLexicalDeclContext(ImpDecl);
2187	IDecl->makeDeclVisibleInContext(ImplIvar);
2188	ImpDecl->addDecl(ImplIvar);
2189	}
2190	return;
2191	}
2192	// Check interface's Ivar list against those in the implementation.
2193	// names and types must match.
2194	//
2195	unsigned j = 0;
2196	ObjCInterfaceDecl::ivar_iterator
2197	IVI = IDecl->ivar_begin(), IVE = IDecl->ivar_end();
2198	for (; numIvars > 0 && IVI != IVE; ++IVI) {
2199	ObjCIvarDecl* ImplIvar = ivars[j++];
2200	ObjCIvarDecl* ClsIvar = *IVI;
2201	assert (ImplIvar && "missing implementation ivar");
2202	assert (ClsIvar && "missing class ivar");
2203
2204	// First, make sure the types match.
2205	if (!Context.hasSameType(ImplIvar->getType(), ClsIvar->getType())) {
2206	Diag(ImplIvar->getLocation(), diag::err_conflicting_ivar_type)
2207	<< ImplIvar->getIdentifier()
2208	<< ImplIvar->getType() << ClsIvar->getType();
2209	Diag(ClsIvar->getLocation(), diag::note_previous_definition);
2210	} else if (ImplIvar->isBitField() && ClsIvar->isBitField() &&
2211	ImplIvar->getBitWidthValue(Context) !=
2212	ClsIvar->getBitWidthValue(Context)) {
2213	Diag(ImplIvar->getBitWidth()->getBeginLoc(),
2214	diag::err_conflicting_ivar_bitwidth)
2215	<< ImplIvar->getIdentifier();
2216	Diag(ClsIvar->getBitWidth()->getBeginLoc(),
2217	diag::note_previous_definition);
2218	}
2219	// Make sure the names are identical.
2220	if (ImplIvar->getIdentifier() != ClsIvar->getIdentifier()) {
2221	Diag(ImplIvar->getLocation(), diag::err_conflicting_ivar_name)
2222	<< ImplIvar->getIdentifier() << ClsIvar->getIdentifier();
2223	Diag(ClsIvar->getLocation(), diag::note_previous_definition);
2224	}
2225	--numIvars;
2226	}
2227
2228	if (numIvars > 0)
2229	Diag(ivars[j]->getLocation(), diag::err_inconsistent_ivar_count);
2230	else if (IVI != IVE)
2231	Diag(IVI->getLocation(), diag::err_inconsistent_ivar_count);
2232	}
2233
2234	static void WarnUndefinedMethod(Sema &S, ObjCImplDecl *Impl,
2235	ObjCMethodDecl *method, bool &IncompleteImpl,
2236	unsigned DiagID,
2237	NamedDecl *NeededFor = nullptr) {
2238	// No point warning no definition of method which is 'unavailable'.
2239	if (method->getAvailability() == AR_Unavailable)
2240	return;
2241
2242	// FIXME: For now ignore 'IncompleteImpl'.
2243	// Previously we grouped all unimplemented methods under a single
2244	// warning, but some users strongly voiced that they would prefer
2245	// separate warnings. We will give that approach a try, as that
2246	// matches what we do with protocols.
2247	{
2248	const Sema::SemaDiagnosticBuilder &B = S.Diag(Impl->getLocation(), DiagID);
2249	B << method;
2250	if (NeededFor)
2251	B << NeededFor;
2252
2253	// Add an empty definition at the end of the @implementation.
2254	std::string FixItStr;
2255	llvm::raw_string_ostream Out(FixItStr);
2256	method->print(Out, Impl->getASTContext().getPrintingPolicy());
2257	Out << " {\n}\n\n";
2258
2259	SourceLocation Loc = Impl->getAtEndRange().getBegin();
2260	B << FixItHint::CreateInsertion(InsertionLoc: Loc, Code: FixItStr);
2261	}
2262
2263	// Issue a note to the original declaration.
2264	SourceLocation MethodLoc = method->getBeginLoc();
2265	if (MethodLoc.isValid())
2266	S.Diag(MethodLoc, diag::note_method_declared_at) << method;
2267	}
2268
2269	/// Determines if type B can be substituted for type A. Returns true if we can
2270	/// guarantee that anything that the user will do to an object of type A can
2271	/// also be done to an object of type B. This is trivially true if the two
2272	/// types are the same, or if B is a subclass of A. It becomes more complex
2273	/// in cases where protocols are involved.
2274	///
2275	/// Object types in Objective-C describe the minimum requirements for an
2276	/// object, rather than providing a complete description of a type. For
2277	/// example, if A is a subclass of B, then B* may refer to an instance of A.
2278	/// The principle of substitutability means that we may use an instance of A
2279	/// anywhere that we may use an instance of B - it will implement all of the
2280	/// ivars of B and all of the methods of B.
2281	///
2282	/// This substitutability is important when type checking methods, because
2283	/// the implementation may have stricter type definitions than the interface.
2284	/// The interface specifies minimum requirements, but the implementation may
2285	/// have more accurate ones. For example, a method may privately accept
2286	/// instances of B, but only publish that it accepts instances of A. Any
2287	/// object passed to it will be type checked against B, and so will implicitly
2288	/// by a valid A*. Similarly, a method may return a subclass of the class that
2289	/// it is declared as returning.
2290	///
2291	/// This is most important when considering subclassing. A method in a
2292	/// subclass must accept any object as an argument that its superclass's
2293	/// implementation accepts. It may, however, accept a more general type
2294	/// without breaking substitutability (i.e. you can still use the subclass
2295	/// anywhere that you can use the superclass, but not vice versa). The
2296	/// converse requirement applies to return types: the return type for a
2297	/// subclass method must be a valid object of the kind that the superclass
2298	/// advertises, but it may be specified more accurately. This avoids the need
2299	/// for explicit down-casting by callers.
2300	///
2301	/// Note: This is a stricter requirement than for assignment.
2302	static bool isObjCTypeSubstitutable(ASTContext &Context,
2303	const ObjCObjectPointerType *A,
2304	const ObjCObjectPointerType *B,
2305	bool rejectId) {
2306	// Reject a protocol-unqualified id.
2307	if (rejectId && B->isObjCIdType()) return false;
2308
2309	// If B is a qualified id, then A must also be a qualified id and it must
2310	// implement all of the protocols in B. It may not be a qualified class.
2311	// For example, MyClass<A> can be assigned to id<A>, but MyClass<A> is a
2312	// stricter definition so it is not substitutable for id<A>.
2313	if (B->isObjCQualifiedIdType()) {
2314	return A->isObjCQualifiedIdType() &&
2315	Context.ObjCQualifiedIdTypesAreCompatible(LHS: A, RHS: B, ForCompare: false);
2316	}
2317
2318	/*
2319	// id is a special type that bypasses type checking completely. We want a
2320	// warning when it is used in one place but not another.
2321	if (C.isObjCIdType(A) || C.isObjCIdType(B)) return false;
2322
2323
2324	// If B is a qualified id, then A must also be a qualified id (which it isn't
2325	// if we've got this far)
2326	if (B->isObjCQualifiedIdType()) return false;
2327	*/
2328
2329	// Now we know that A and B are (potentially-qualified) class types. The
2330	// normal rules for assignment apply.
2331	return Context.canAssignObjCInterfaces(LHSOPT: A, RHSOPT: B);
2332	}
2333
2334	static SourceRange getTypeRange(TypeSourceInfo *TSI) {
2335	return (TSI ? TSI->getTypeLoc().getSourceRange() : SourceRange());
2336	}
2337
2338	/// Determine whether two set of Objective-C declaration qualifiers conflict.
2339	static bool objcModifiersConflict(Decl::ObjCDeclQualifier x,
2340	Decl::ObjCDeclQualifier y) {
2341	return (x & ~Decl::OBJC_TQ_CSNullability) !=
2342	(y & ~Decl::OBJC_TQ_CSNullability);
2343	}
2344
2345	static bool CheckMethodOverrideReturn(Sema &S,
2346	ObjCMethodDecl *MethodImpl,
2347	ObjCMethodDecl *MethodDecl,
2348	bool IsProtocolMethodDecl,
2349	bool IsOverridingMode,
2350	bool Warn) {
2351	if (IsProtocolMethodDecl &&
2352	objcModifiersConflict(x: MethodDecl->getObjCDeclQualifier(),
2353	y: MethodImpl->getObjCDeclQualifier())) {
2354	if (Warn) {
2355	S.Diag(MethodImpl->getLocation(),
2356	(IsOverridingMode
2357	? diag::warn_conflicting_overriding_ret_type_modifiers
2358	: diag::warn_conflicting_ret_type_modifiers))
2359	<< MethodImpl->getDeclName()
2360	<< MethodImpl->getReturnTypeSourceRange();
2361	S.Diag(MethodDecl->getLocation(), diag::note_previous_declaration)
2362	<< MethodDecl->getReturnTypeSourceRange();
2363	}
2364	else
2365	return false;
2366	}
2367	if (Warn && IsOverridingMode &&
2368	!isa<ObjCImplementationDecl>(MethodImpl->getDeclContext()) &&
2369	!S.Context.hasSameNullabilityTypeQualifier(SubT: MethodImpl->getReturnType(),
2370	SuperT: MethodDecl->getReturnType(),
2371	IsParam: false)) {
2372	auto nullabilityMethodImpl = *MethodImpl->getReturnType()->getNullability();
2373	auto nullabilityMethodDecl = *MethodDecl->getReturnType()->getNullability();
2374	S.Diag(MethodImpl->getLocation(),
2375	diag::warn_conflicting_nullability_attr_overriding_ret_types)
2376	<< DiagNullabilityKind(nullabilityMethodImpl,
2377	((MethodImpl->getObjCDeclQualifier() &
2378	Decl::OBJC_TQ_CSNullability) != 0))
2379	<< DiagNullabilityKind(nullabilityMethodDecl,
2380	((MethodDecl->getObjCDeclQualifier() &
2381	Decl::OBJC_TQ_CSNullability) != 0));
2382	S.Diag(MethodDecl->getLocation(), diag::note_previous_declaration);
2383	}
2384
2385	if (S.Context.hasSameUnqualifiedType(T1: MethodImpl->getReturnType(),
2386	T2: MethodDecl->getReturnType()))
2387	return true;
2388	if (!Warn)
2389	return false;
2390
2391	unsigned DiagID =
2392	IsOverridingMode ? diag::warn_conflicting_overriding_ret_types
2393	: diag::warn_conflicting_ret_types;
2394
2395	// Mismatches between ObjC pointers go into a different warning
2396	// category, and sometimes they're even completely explicitly allowed.
2397	if (const ObjCObjectPointerType *ImplPtrTy =
2398	MethodImpl->getReturnType()->getAs<ObjCObjectPointerType>()) {
2399	if (const ObjCObjectPointerType *IfacePtrTy =
2400	MethodDecl->getReturnType()->getAs<ObjCObjectPointerType>()) {
2401	// Allow non-matching return types as long as they don't violate
2402	// the principle of substitutability. Specifically, we permit
2403	// return types that are subclasses of the declared return type,
2404	// or that are more-qualified versions of the declared type.
2405	if (isObjCTypeSubstitutable(Context&: S.Context, A: IfacePtrTy, B: ImplPtrTy, rejectId: false))
2406	return false;
2407
2408	DiagID =
2409	IsOverridingMode ? diag::warn_non_covariant_overriding_ret_types
2410	: diag::warn_non_covariant_ret_types;
2411	}
2412	}
2413
2414	S.Diag(MethodImpl->getLocation(), DiagID)
2415	<< MethodImpl->getDeclName() << MethodDecl->getReturnType()
2416	<< MethodImpl->getReturnType()
2417	<< MethodImpl->getReturnTypeSourceRange();
2418	S.Diag(MethodDecl->getLocation(), IsOverridingMode
2419	? diag::note_previous_declaration
2420	: diag::note_previous_definition)
2421	<< MethodDecl->getReturnTypeSourceRange();
2422	return false;
2423	}
2424
2425	static bool CheckMethodOverrideParam(Sema &S,
2426	ObjCMethodDecl *MethodImpl,
2427	ObjCMethodDecl *MethodDecl,
2428	ParmVarDecl *ImplVar,
2429	ParmVarDecl *IfaceVar,
2430	bool IsProtocolMethodDecl,
2431	bool IsOverridingMode,
2432	bool Warn) {
2433	if (IsProtocolMethodDecl &&
2434	objcModifiersConflict(x: ImplVar->getObjCDeclQualifier(),
2435	y: IfaceVar->getObjCDeclQualifier())) {
2436	if (Warn) {
2437	if (IsOverridingMode)
2438	S.Diag(ImplVar->getLocation(),
2439	diag::warn_conflicting_overriding_param_modifiers)
2440	<< getTypeRange(ImplVar->getTypeSourceInfo())
2441	<< MethodImpl->getDeclName();
2442	else S.Diag(ImplVar->getLocation(),
2443	diag::warn_conflicting_param_modifiers)
2444	<< getTypeRange(ImplVar->getTypeSourceInfo())
2445	<< MethodImpl->getDeclName();
2446	S.Diag(IfaceVar->getLocation(), diag::note_previous_declaration)
2447	<< getTypeRange(IfaceVar->getTypeSourceInfo());
2448	}
2449	else
2450	return false;
2451	}
2452
2453	QualType ImplTy = ImplVar->getType();
2454	QualType IfaceTy = IfaceVar->getType();
2455	if (Warn && IsOverridingMode &&
2456	!isa<ObjCImplementationDecl>(MethodImpl->getDeclContext()) &&
2457	!S.Context.hasSameNullabilityTypeQualifier(SubT: ImplTy, SuperT: IfaceTy, IsParam: true)) {
2458	S.Diag(ImplVar->getLocation(),
2459	diag::warn_conflicting_nullability_attr_overriding_param_types)
2460	<< DiagNullabilityKind(*ImplTy->getNullability(),
2461	((ImplVar->getObjCDeclQualifier() &
2462	Decl::OBJC_TQ_CSNullability) != 0))
2463	<< DiagNullabilityKind(*IfaceTy->getNullability(),
2464	((IfaceVar->getObjCDeclQualifier() &
2465	Decl::OBJC_TQ_CSNullability) != 0));
2466	S.Diag(IfaceVar->getLocation(), diag::note_previous_declaration);
2467	}
2468	if (S.Context.hasSameUnqualifiedType(T1: ImplTy, T2: IfaceTy))
2469	return true;
2470
2471	if (!Warn)
2472	return false;
2473	unsigned DiagID =
2474	IsOverridingMode ? diag::warn_conflicting_overriding_param_types
2475	: diag::warn_conflicting_param_types;
2476
2477	// Mismatches between ObjC pointers go into a different warning
2478	// category, and sometimes they're even completely explicitly allowed..
2479	if (const ObjCObjectPointerType *ImplPtrTy =
2480	ImplTy->getAs<ObjCObjectPointerType>()) {
2481	if (const ObjCObjectPointerType *IfacePtrTy =
2482	IfaceTy->getAs<ObjCObjectPointerType>()) {
2483	// Allow non-matching argument types as long as they don't
2484	// violate the principle of substitutability. Specifically, the
2485	// implementation must accept any objects that the superclass
2486	// accepts, however it may also accept others.
2487	if (isObjCTypeSubstitutable(Context&: S.Context, A: ImplPtrTy, B: IfacePtrTy, rejectId: true))
2488	return false;
2489
2490	DiagID =
2491	IsOverridingMode ? diag::warn_non_contravariant_overriding_param_types
2492	: diag::warn_non_contravariant_param_types;
2493	}
2494	}
2495
2496	S.Diag(ImplVar->getLocation(), DiagID)
2497	<< getTypeRange(ImplVar->getTypeSourceInfo())
2498	<< MethodImpl->getDeclName() << IfaceTy << ImplTy;
2499	S.Diag(IfaceVar->getLocation(),
2500	(IsOverridingMode ? diag::note_previous_declaration
2501	: diag::note_previous_definition))
2502	<< getTypeRange(IfaceVar->getTypeSourceInfo());
2503	return false;
2504	}
2505
2506	/// In ARC, check whether the conventional meanings of the two methods
2507	/// match. If they don't, it's a hard error.
2508	static bool checkMethodFamilyMismatch(Sema &S, ObjCMethodDecl *impl,
2509	ObjCMethodDecl *decl) {
2510	ObjCMethodFamily implFamily = impl->getMethodFamily();
2511	ObjCMethodFamily declFamily = decl->getMethodFamily();
2512	if (implFamily == declFamily) return false;
2513
2514	// Since conventions are sorted by selector, the only possibility is
2515	// that the types differ enough to cause one selector or the other
2516	// to fall out of the family.
2517	assert(implFamily == OMF_None || declFamily == OMF_None);
2518
2519	// No further diagnostics required on invalid declarations.
2520	if (impl->isInvalidDecl() || decl->isInvalidDecl()) return true;
2521
2522	const ObjCMethodDecl *unmatched = impl;
2523	ObjCMethodFamily family = declFamily;
2524	unsigned errorID = diag::err_arc_lost_method_convention;
2525	unsigned noteID = diag::note_arc_lost_method_convention;
2526	if (declFamily == OMF_None) {
2527	unmatched = decl;
2528	family = implFamily;
2529	errorID = diag::err_arc_gained_method_convention;
2530	noteID = diag::note_arc_gained_method_convention;
2531	}
2532
2533	// Indexes into a %select clause in the diagnostic.
2534	enum FamilySelector {
2535	F_alloc, F_copy, F_mutableCopy = F_copy, F_init, F_new
2536	};
2537	FamilySelector familySelector = FamilySelector();
2538
2539	switch (family) {
2540	case OMF_None: llvm_unreachable("logic error, no method convention");
2541	case OMF_retain:
2542	case OMF_release:
2543	case OMF_autorelease:
2544	case OMF_dealloc:
2545	case OMF_finalize:
2546	case OMF_retainCount:
2547	case OMF_self:
2548	case OMF_initialize:
2549	case OMF_performSelector:
2550	// Mismatches for these methods don't change ownership
2551	// conventions, so we don't care.
2552	return false;
2553
2554	case OMF_init: familySelector = F_init; break;
2555	case OMF_alloc: familySelector = F_alloc; break;
2556	case OMF_copy: familySelector = F_copy; break;
2557	case OMF_mutableCopy: familySelector = F_mutableCopy; break;
2558	case OMF_new: familySelector = F_new; break;
2559	}
2560
2561	enum ReasonSelector { R_NonObjectReturn, R_UnrelatedReturn };
2562	ReasonSelector reasonSelector;
2563
2564	// The only reason these methods don't fall within their families is
2565	// due to unusual result types.
2566	if (unmatched->getReturnType()->isObjCObjectPointerType()) {
2567	reasonSelector = R_UnrelatedReturn;
2568	} else {
2569	reasonSelector = R_NonObjectReturn;
2570	}
2571
2572	S.Diag(impl->getLocation(), errorID) << int(familySelector) << int(reasonSelector);
2573	S.Diag(decl->getLocation(), noteID) << int(familySelector) << int(reasonSelector);
2574
2575	return true;
2576	}
2577
2578	void Sema::WarnConflictingTypedMethods(ObjCMethodDecl *ImpMethodDecl,
2579	ObjCMethodDecl *MethodDecl,
2580	bool IsProtocolMethodDecl) {
2581	if (getLangOpts().ObjCAutoRefCount &&
2582	checkMethodFamilyMismatch(S&: *this, impl: ImpMethodDecl, decl: MethodDecl))
2583	return;
2584
2585	CheckMethodOverrideReturn(S&: *this, MethodImpl: ImpMethodDecl, MethodDecl,
2586	IsProtocolMethodDecl, IsOverridingMode: false,
2587	Warn: true);
2588
2589	for (ObjCMethodDecl::param_iterator IM = ImpMethodDecl->param_begin(),
2590	IF = MethodDecl->param_begin(), EM = ImpMethodDecl->param_end(),
2591	EF = MethodDecl->param_end();
2592	IM != EM && IF != EF; ++IM, ++IF) {
2593	CheckMethodOverrideParam(S&: *this, MethodImpl: ImpMethodDecl, MethodDecl, ImplVar: *IM, IfaceVar: *IF,
2594	IsProtocolMethodDecl, IsOverridingMode: false, Warn: true);
2595	}
2596
2597	if (ImpMethodDecl->isVariadic() != MethodDecl->isVariadic()) {
2598	Diag(ImpMethodDecl->getLocation(),
2599	diag::warn_conflicting_variadic);
2600	Diag(MethodDecl->getLocation(), diag::note_previous_declaration);
2601	}
2602	}
2603
2604	void Sema::CheckConflictingOverridingMethod(ObjCMethodDecl *Method,
2605	ObjCMethodDecl *Overridden,
2606	bool IsProtocolMethodDecl) {
2607
2608	CheckMethodOverrideReturn(S&: *this, MethodImpl: Method, MethodDecl: Overridden,
2609	IsProtocolMethodDecl, IsOverridingMode: true,
2610	Warn: true);
2611
2612	for (ObjCMethodDecl::param_iterator IM = Method->param_begin(),
2613	IF = Overridden->param_begin(), EM = Method->param_end(),
2614	EF = Overridden->param_end();
2615	IM != EM && IF != EF; ++IM, ++IF) {
2616	CheckMethodOverrideParam(S&: *this, MethodImpl: Method, MethodDecl: Overridden, ImplVar: *IM, IfaceVar: *IF,
2617	IsProtocolMethodDecl, IsOverridingMode: true, Warn: true);
2618	}
2619
2620	if (Method->isVariadic() != Overridden->isVariadic()) {
2621	Diag(Method->getLocation(),
2622	diag::warn_conflicting_overriding_variadic);
2623	Diag(Overridden->getLocation(), diag::note_previous_declaration);
2624	}
2625	}
2626
2627	/// WarnExactTypedMethods - This routine issues a warning if method
2628	/// implementation declaration matches exactly that of its declaration.
2629	void Sema::WarnExactTypedMethods(ObjCMethodDecl *ImpMethodDecl,
2630	ObjCMethodDecl *MethodDecl,
2631	bool IsProtocolMethodDecl) {
2632	// don't issue warning when protocol method is optional because primary
2633	// class is not required to implement it and it is safe for protocol
2634	// to implement it.
2635	if (MethodDecl->getImplementationControl() ==
2636	ObjCImplementationControl::Optional)
2637	return;
2638	// don't issue warning when primary class's method is
2639	// deprecated/unavailable.
2640	if (MethodDecl->hasAttr<UnavailableAttr>() ||
2641	MethodDecl->hasAttr<DeprecatedAttr>())
2642	return;
2643
2644	bool match = CheckMethodOverrideReturn(S&: *this, MethodImpl: ImpMethodDecl, MethodDecl,
2645	IsProtocolMethodDecl, IsOverridingMode: false, Warn: false);
2646	if (match)
2647	for (ObjCMethodDecl::param_iterator IM = ImpMethodDecl->param_begin(),
2648	IF = MethodDecl->param_begin(), EM = ImpMethodDecl->param_end(),
2649	EF = MethodDecl->param_end();
2650	IM != EM && IF != EF; ++IM, ++IF) {
2651	match = CheckMethodOverrideParam(S&: *this, MethodImpl: ImpMethodDecl, MethodDecl,
2652	ImplVar: *IM, IfaceVar: *IF,
2653	IsProtocolMethodDecl, IsOverridingMode: false, Warn: false);
2654	if (!match)
2655	break;
2656	}
2657	if (match)
2658	match = (ImpMethodDecl->isVariadic() == MethodDecl->isVariadic());
2659	if (match)
2660	match = !(MethodDecl->isClassMethod() &&
2661	MethodDecl->getSelector() == GetNullarySelector(name: "load", Ctx&: Context));
2662
2663	if (match) {
2664	Diag(ImpMethodDecl->getLocation(),
2665	diag::warn_category_method_impl_match);
2666	Diag(MethodDecl->getLocation(), diag::note_method_declared_at)
2667	<< MethodDecl->getDeclName();
2668	}
2669	}
2670
2671	/// FIXME: Type hierarchies in Objective-C can be deep. We could most likely
2672	/// improve the efficiency of selector lookups and type checking by associating
2673	/// with each protocol / interface / category the flattened instance tables. If
2674	/// we used an immutable set to keep the table then it wouldn't add significant
2675	/// memory cost and it would be handy for lookups.
2676
2677	typedef llvm::DenseSet<IdentifierInfo*> ProtocolNameSet;
2678	typedef std::unique_ptr<ProtocolNameSet> LazyProtocolNameSet;
2679
2680	static void findProtocolsWithExplicitImpls(const ObjCProtocolDecl *PDecl,
2681	ProtocolNameSet &PNS) {
2682	if (PDecl->hasAttr<ObjCExplicitProtocolImplAttr>())
2683	PNS.insert(PDecl->getIdentifier());
2684	for (const auto *PI : PDecl->protocols())
2685	findProtocolsWithExplicitImpls(PDecl: PI, PNS);
2686	}
2687
2688	/// Recursively populates a set with all conformed protocols in a class
2689	/// hierarchy that have the 'objc_protocol_requires_explicit_implementation'
2690	/// attribute.
2691	static void findProtocolsWithExplicitImpls(const ObjCInterfaceDecl *Super,
2692	ProtocolNameSet &PNS) {
2693	if (!Super)
2694	return;
2695
2696	for (const auto *I : Super->all_referenced_protocols())
2697	findProtocolsWithExplicitImpls(PDecl: I, PNS);
2698
2699	findProtocolsWithExplicitImpls(Super: Super->getSuperClass(), PNS);
2700	}
2701
2702	/// CheckProtocolMethodDefs - This routine checks unimplemented methods
2703	/// Declared in protocol, and those referenced by it.
2704	static void CheckProtocolMethodDefs(
2705	Sema &S, ObjCImplDecl *Impl, ObjCProtocolDecl *PDecl, bool &IncompleteImpl,
2706	const Sema::SelectorSet &InsMap, const Sema::SelectorSet &ClsMap,
2707	ObjCContainerDecl *CDecl, LazyProtocolNameSet &ProtocolsExplictImpl) {
2708	ObjCCategoryDecl *C = dyn_cast<ObjCCategoryDecl>(Val: CDecl);
2709	ObjCInterfaceDecl *IDecl = C ? C->getClassInterface()
2710	: dyn_cast<ObjCInterfaceDecl>(Val: CDecl);
2711	assert (IDecl && "CheckProtocolMethodDefs - IDecl is null");
2712
2713	ObjCInterfaceDecl *Super = IDecl->getSuperClass();
2714	ObjCInterfaceDecl *NSIDecl = nullptr;
2715
2716	// If this protocol is marked 'objc_protocol_requires_explicit_implementation'
2717	// then we should check if any class in the super class hierarchy also
2718	// conforms to this protocol, either directly or via protocol inheritance.
2719	// If so, we can skip checking this protocol completely because we
2720	// know that a parent class already satisfies this protocol.
2721	//
2722	// Note: we could generalize this logic for all protocols, and merely
2723	// add the limit on looking at the super class chain for just
2724	// specially marked protocols. This may be a good optimization. This
2725	// change is restricted to 'objc_protocol_requires_explicit_implementation'
2726	// protocols for now for controlled evaluation.
2727	if (PDecl->hasAttr<ObjCExplicitProtocolImplAttr>()) {
2728	if (!ProtocolsExplictImpl) {
2729	ProtocolsExplictImpl.reset(p: new ProtocolNameSet);
2730	findProtocolsWithExplicitImpls(Super, PNS&: *ProtocolsExplictImpl);
2731	}
2732	if (ProtocolsExplictImpl->contains(V: PDecl->getIdentifier()))
2733	return;
2734
2735	// If no super class conforms to the protocol, we should not search
2736	// for methods in the super class to implicitly satisfy the protocol.
2737	Super = nullptr;
2738	}
2739
2740	if (S.getLangOpts().ObjCRuntime.isNeXTFamily()) {
2741	// check to see if class implements forwardInvocation method and objects
2742	// of this class are derived from 'NSProxy' so that to forward requests
2743	// from one object to another.
2744	// Under such conditions, which means that every method possible is
2745	// implemented in the class, we should not issue "Method definition not
2746	// found" warnings.
2747	// FIXME: Use a general GetUnarySelector method for this.
2748	IdentifierInfo* II = &S.Context.Idents.get(Name: "forwardInvocation");
2749	Selector fISelector = S.Context.Selectors.getSelector(NumArgs: 1, IIV: &II);
2750	if (InsMap.count(Ptr: fISelector))
2751	// Is IDecl derived from 'NSProxy'? If so, no instance methods
2752	// need be implemented in the implementation.
2753	NSIDecl = IDecl->lookupInheritedClass(ICName: &S.Context.Idents.get(Name: "NSProxy"));
2754	}
2755
2756	// If this is a forward protocol declaration, get its definition.
2757	if (!PDecl->isThisDeclarationADefinition() &&
2758	PDecl->getDefinition())
2759	PDecl = PDecl->getDefinition();
2760
2761	// If a method lookup fails locally we still need to look and see if
2762	// the method was implemented by a base class or an inherited
2763	// protocol. This lookup is slow, but occurs rarely in correct code
2764	// and otherwise would terminate in a warning.
2765
2766	// check unimplemented instance methods.
2767	if (!NSIDecl)
2768	for (auto *method : PDecl->instance_methods()) {
2769	if (method->getImplementationControl() !=
2770	ObjCImplementationControl::Optional &&
2771	!method->isPropertyAccessor() &&
2772	!InsMap.count(method->getSelector()) &&
2773	(!Super || !Super->lookupMethod(
2774	method->getSelector(), true /* instance */,
2775	false /* shallowCategory */, true /* followsSuper */,
2776	nullptr /* category */))) {
2777	// If a method is not implemented in the category implementation but
2778	// has been declared in its primary class, superclass,
2779	// or in one of their protocols, no need to issue the warning.
2780	// This is because method will be implemented in the primary class
2781	// or one of its super class implementation.
2782
2783	// Ugly, but necessary. Method declared in protocol might have
2784	// have been synthesized due to a property declared in the class which
2785	// uses the protocol.
2786	if (ObjCMethodDecl *MethodInClass = IDecl->lookupMethod(
2787	method->getSelector(), true /* instance */,
2788	true /* shallowCategoryLookup */, false /* followSuper */))
2789	if (C || MethodInClass->isPropertyAccessor())
2790	continue;
2791	unsigned DIAG = diag::warn_unimplemented_protocol_method;
2792	if (!S.Diags.isIgnored(DIAG, Impl->getLocation())) {
2793	WarnUndefinedMethod(S, Impl, method, IncompleteImpl, DIAG, PDecl);
2794	}
2795	}
2796	}
2797	// check unimplemented class methods
2798	for (auto *method : PDecl->class_methods()) {
2799	if (method->getImplementationControl() !=
2800	ObjCImplementationControl::Optional &&
2801	!ClsMap.count(method->getSelector()) &&
2802	(!Super || !Super->lookupMethod(
2803	method->getSelector(), false /* class method */,
2804	false /* shallowCategoryLookup */,
2805	true /* followSuper */, nullptr /* category */))) {
2806	// See above comment for instance method lookups.
2807	if (C && IDecl->lookupMethod(method->getSelector(),
2808	false /* class */,
2809	true /* shallowCategoryLookup */,
2810	false /* followSuper */))
2811	continue;
2812
2813	unsigned DIAG = diag::warn_unimplemented_protocol_method;
2814	if (!S.Diags.isIgnored(DIAG, Impl->getLocation())) {
2815	WarnUndefinedMethod(S, Impl, method, IncompleteImpl, DIAG, PDecl);
2816	}
2817	}
2818	}
2819	// Check on this protocols's referenced protocols, recursively.
2820	for (auto *PI : PDecl->protocols())
2821	CheckProtocolMethodDefs(S, Impl, PDecl: PI, IncompleteImpl, InsMap, ClsMap, CDecl,
2822	ProtocolsExplictImpl);
2823	}
2824
2825	/// MatchAllMethodDeclarations - Check methods declared in interface
2826	/// or protocol against those declared in their implementations.
2827	///
2828	void Sema::MatchAllMethodDeclarations(const SelectorSet &InsMap,
2829	const SelectorSet &ClsMap,
2830	SelectorSet &InsMapSeen,
2831	SelectorSet &ClsMapSeen,
2832	ObjCImplDecl* IMPDecl,
2833	ObjCContainerDecl* CDecl,
2834	bool &IncompleteImpl,
2835	bool ImmediateClass,
2836	bool WarnCategoryMethodImpl) {
2837	// Check and see if instance methods in class interface have been
2838	// implemented in the implementation class. If so, their types match.
2839	for (auto *I : CDecl->instance_methods()) {
2840	if (!InsMapSeen.insert(Ptr: I->getSelector()).second)
2841	continue;
2842	if (!I->isPropertyAccessor() &&
2843	!InsMap.count(Ptr: I->getSelector())) {
2844	if (ImmediateClass)
2845	WarnUndefinedMethod(*this, IMPDecl, I, IncompleteImpl,
2846	diag::warn_undef_method_impl);
2847	continue;
2848	} else {
2849	ObjCMethodDecl *ImpMethodDecl =
2850	IMPDecl->getInstanceMethod(I->getSelector());
2851	assert(CDecl->getInstanceMethod(I->getSelector(), true/*AllowHidden*/) &&
2852	"Expected to find the method through lookup as well");
2853	// ImpMethodDecl may be null as in a @dynamic property.
2854	if (ImpMethodDecl) {
2855	// Skip property accessor function stubs.
2856	if (ImpMethodDecl->isSynthesizedAccessorStub())
2857	continue;
2858	if (!WarnCategoryMethodImpl)
2859	WarnConflictingTypedMethods(ImpMethodDecl, MethodDecl: I,
2860	IsProtocolMethodDecl: isa<ObjCProtocolDecl>(Val: CDecl));
2861	else if (!I->isPropertyAccessor())
2862	WarnExactTypedMethods(ImpMethodDecl, MethodDecl: I, IsProtocolMethodDecl: isa<ObjCProtocolDecl>(Val: CDecl));
2863	}
2864	}
2865	}
2866
2867	// Check and see if class methods in class interface have been
2868	// implemented in the implementation class. If so, their types match.
2869	for (auto *I : CDecl->class_methods()) {
2870	if (!ClsMapSeen.insert(Ptr: I->getSelector()).second)
2871	continue;
2872	if (!I->isPropertyAccessor() &&
2873	!ClsMap.count(Ptr: I->getSelector())) {
2874	if (ImmediateClass)
2875	WarnUndefinedMethod(*this, IMPDecl, I, IncompleteImpl,
2876	diag::warn_undef_method_impl);
2877	} else {
2878	ObjCMethodDecl *ImpMethodDecl =
2879	IMPDecl->getClassMethod(I->getSelector());
2880	assert(CDecl->getClassMethod(I->getSelector(), true/*AllowHidden*/) &&
2881	"Expected to find the method through lookup as well");
2882	// ImpMethodDecl may be null as in a @dynamic property.
2883	if (ImpMethodDecl) {
2884	// Skip property accessor function stubs.
2885	if (ImpMethodDecl->isSynthesizedAccessorStub())
2886	continue;
2887	if (!WarnCategoryMethodImpl)
2888	WarnConflictingTypedMethods(ImpMethodDecl, MethodDecl: I,
2889	IsProtocolMethodDecl: isa<ObjCProtocolDecl>(Val: CDecl));
2890	else if (!I->isPropertyAccessor())
2891	WarnExactTypedMethods(ImpMethodDecl, MethodDecl: I, IsProtocolMethodDecl: isa<ObjCProtocolDecl>(Val: CDecl));
2892	}
2893	}
2894	}
2895
2896	if (ObjCProtocolDecl *PD = dyn_cast<ObjCProtocolDecl> (Val: CDecl)) {
2897	// Also, check for methods declared in protocols inherited by
2898	// this protocol.
2899	for (auto *PI : PD->protocols())
2900	MatchAllMethodDeclarations(InsMap, ClsMap, InsMapSeen, ClsMapSeen,
2901	IMPDecl, PI, IncompleteImpl, false,
2902	WarnCategoryMethodImpl);
2903	}
2904
2905	if (ObjCInterfaceDecl *I = dyn_cast<ObjCInterfaceDecl> (Val: CDecl)) {
2906	// when checking that methods in implementation match their declaration,
2907	// i.e. when WarnCategoryMethodImpl is false, check declarations in class
2908	// extension; as well as those in categories.
2909	if (!WarnCategoryMethodImpl) {
2910	for (auto *Cat : I->visible_categories())
2911	MatchAllMethodDeclarations(InsMap, ClsMap, InsMapSeen, ClsMapSeen,
2912	IMPDecl, Cat, IncompleteImpl,
2913	ImmediateClass && Cat->IsClassExtension(),
2914	WarnCategoryMethodImpl);
2915	} else {
2916	// Also methods in class extensions need be looked at next.
2917	for (auto *Ext : I->visible_extensions())
2918	MatchAllMethodDeclarations(InsMap, ClsMap, InsMapSeen, ClsMapSeen,
2919	IMPDecl, Ext, IncompleteImpl, false,
2920	WarnCategoryMethodImpl);
2921	}
2922
2923	// Check for any implementation of a methods declared in protocol.
2924	for (auto *PI : I->all_referenced_protocols())
2925	MatchAllMethodDeclarations(InsMap, ClsMap, InsMapSeen, ClsMapSeen,
2926	IMPDecl, PI, IncompleteImpl, false,
2927	WarnCategoryMethodImpl);
2928
2929	// FIXME. For now, we are not checking for exact match of methods
2930	// in category implementation and its primary class's super class.
2931	if (!WarnCategoryMethodImpl && I->getSuperClass())
2932	MatchAllMethodDeclarations(InsMap, ClsMap, InsMapSeen, ClsMapSeen,
2933	IMPDecl,
2934	I->getSuperClass(), IncompleteImpl, false);
2935	}
2936	}
2937
2938	/// CheckCategoryVsClassMethodMatches - Checks that methods implemented in
2939	/// category matches with those implemented in its primary class and
2940	/// warns each time an exact match is found.
2941	void Sema::CheckCategoryVsClassMethodMatches(
2942	ObjCCategoryImplDecl *CatIMPDecl) {
2943	// Get category's primary class.
2944	ObjCCategoryDecl *CatDecl = CatIMPDecl->getCategoryDecl();
2945	if (!CatDecl)
2946	return;
2947	ObjCInterfaceDecl *IDecl = CatDecl->getClassInterface();
2948	if (!IDecl)
2949	return;
2950	ObjCInterfaceDecl *SuperIDecl = IDecl->getSuperClass();
2951	SelectorSet InsMap, ClsMap;
2952
2953	for (const auto *I : CatIMPDecl->instance_methods()) {
2954	Selector Sel = I->getSelector();
2955	// When checking for methods implemented in the category, skip over
2956	// those declared in category class's super class. This is because
2957	// the super class must implement the method.
2958	if (SuperIDecl && SuperIDecl->lookupMethod(Sel, true))
2959	continue;
2960	InsMap.insert(Sel);
2961	}
2962
2963	for (const auto *I : CatIMPDecl->class_methods()) {
2964	Selector Sel = I->getSelector();
2965	if (SuperIDecl && SuperIDecl->lookupMethod(Sel, false))
2966	continue;
2967	ClsMap.insert(Sel);
2968	}
2969	if (InsMap.empty() && ClsMap.empty())
2970	return;
2971
2972	SelectorSet InsMapSeen, ClsMapSeen;
2973	bool IncompleteImpl = false;
2974	MatchAllMethodDeclarations(InsMap, ClsMap, InsMapSeen, ClsMapSeen,
2975	CatIMPDecl, IDecl,
2976	IncompleteImpl, false,
2977	true /*WarnCategoryMethodImpl*/);
2978	}
2979
2980	void Sema::ImplMethodsVsClassMethods(Scope *S, ObjCImplDecl* IMPDecl,
2981	ObjCContainerDecl* CDecl,
2982	bool IncompleteImpl) {
2983	SelectorSet InsMap;
2984	// Check and see if instance methods in class interface have been
2985	// implemented in the implementation class.
2986	for (const auto *I : IMPDecl->instance_methods())
2987	InsMap.insert(I->getSelector());
2988
2989	// Add the selectors for getters/setters of @dynamic properties.
2990	for (const auto *PImpl : IMPDecl->property_impls()) {
2991	// We only care about @dynamic implementations.
2992	if (PImpl->getPropertyImplementation() != ObjCPropertyImplDecl::Dynamic)
2993	continue;
2994
2995	const auto *P = PImpl->getPropertyDecl();
2996	if (!P) continue;
2997
2998	InsMap.insert(Ptr: P->getGetterName());
2999	if (!P->getSetterName().isNull())
3000	InsMap.insert(Ptr: P->getSetterName());
3001	}
3002
3003	// Check and see if properties declared in the interface have either 1)
3004	// an implementation or 2) there is a @synthesize/@dynamic implementation
3005	// of the property in the @implementation.
3006	if (const ObjCInterfaceDecl *IDecl = dyn_cast<ObjCInterfaceDecl>(Val: CDecl)) {
3007	bool SynthesizeProperties = LangOpts.ObjCDefaultSynthProperties &&
3008	LangOpts.ObjCRuntime.isNonFragile() &&
3009	!IDecl->isObjCRequiresPropertyDefs();
3010	DiagnoseUnimplementedProperties(S, IMPDecl, CDecl, SynthesizeProperties);
3011	}
3012
3013	// Diagnose null-resettable synthesized setters.
3014	diagnoseNullResettableSynthesizedSetters(impDecl: IMPDecl);
3015
3016	SelectorSet ClsMap;
3017	for (const auto *I : IMPDecl->class_methods())
3018	ClsMap.insert(I->getSelector());
3019
3020	// Check for type conflict of methods declared in a class/protocol and
3021	// its implementation; if any.
3022	SelectorSet InsMapSeen, ClsMapSeen;
3023	MatchAllMethodDeclarations(InsMap, ClsMap, InsMapSeen, ClsMapSeen,
3024	IMPDecl, CDecl,
3025	IncompleteImpl, ImmediateClass: true);
3026
3027	// check all methods implemented in category against those declared
3028	// in its primary class.
3029	if (ObjCCategoryImplDecl *CatDecl =
3030	dyn_cast<ObjCCategoryImplDecl>(Val: IMPDecl))
3031	CheckCategoryVsClassMethodMatches(CatIMPDecl: CatDecl);
3032
3033	// Check the protocol list for unimplemented methods in the @implementation
3034	// class.
3035	// Check and see if class methods in class interface have been
3036	// implemented in the implementation class.
3037
3038	LazyProtocolNameSet ExplicitImplProtocols;
3039
3040	if (ObjCInterfaceDecl *I = dyn_cast<ObjCInterfaceDecl> (Val: CDecl)) {
3041	for (auto *PI : I->all_referenced_protocols())
3042	CheckProtocolMethodDefs(*this, IMPDecl, PI, IncompleteImpl, InsMap,
3043	ClsMap, I, ExplicitImplProtocols);
3044	} else if (ObjCCategoryDecl *C = dyn_cast<ObjCCategoryDecl>(Val: CDecl)) {
3045	// For extended class, unimplemented methods in its protocols will
3046	// be reported in the primary class.
3047	if (!C->IsClassExtension()) {
3048	for (auto *P : C->protocols())
3049	CheckProtocolMethodDefs(S&: *this, Impl: IMPDecl, PDecl: P, IncompleteImpl, InsMap,
3050	ClsMap, CDecl, ProtocolsExplictImpl&: ExplicitImplProtocols);
3051	DiagnoseUnimplementedProperties(S, IMPDecl, CDecl,
3052	/*SynthesizeProperties=*/false);
3053	}
3054	} else
3055	llvm_unreachable("invalid ObjCContainerDecl type.");
3056	}
3057
3058	Sema::DeclGroupPtrTy
3059	Sema::ActOnForwardClassDeclaration(SourceLocation AtClassLoc,
3060	IdentifierInfo **IdentList,
3061	SourceLocation *IdentLocs,
3062	ArrayRef<ObjCTypeParamList *> TypeParamLists,
3063	unsigned NumElts) {
3064	SmallVector<Decl *, 8> DeclsInGroup;
3065	for (unsigned i = 0; i != NumElts; ++i) {
3066	// Check for another declaration kind with the same name.
3067	NamedDecl *PrevDecl
3068	= LookupSingleName(S: TUScope, Name: IdentList[i], Loc: IdentLocs[i],
3069	NameKind: LookupOrdinaryName, Redecl: forRedeclarationInCurContext());
3070	if (PrevDecl && !isa<ObjCInterfaceDecl>(Val: PrevDecl)) {
3071	// GCC apparently allows the following idiom:
3072	//
3073	// typedef NSObject < XCElementTogglerP > XCElementToggler;
3074	// @class XCElementToggler;
3075	//
3076	// Here we have chosen to ignore the forward class declaration
3077	// with a warning. Since this is the implied behavior.
3078	TypedefNameDecl *TDD = dyn_cast<TypedefNameDecl>(Val: PrevDecl);
3079	if (!TDD || !TDD->getUnderlyingType()->isObjCObjectType()) {
3080	Diag(AtClassLoc, diag::err_redefinition_different_kind) << IdentList[i];
3081	Diag(PrevDecl->getLocation(), diag::note_previous_definition);
3082	} else {
3083	// a forward class declaration matching a typedef name of a class refers
3084	// to the underlying class. Just ignore the forward class with a warning
3085	// as this will force the intended behavior which is to lookup the
3086	// typedef name.
3087	if (isa<ObjCObjectType>(Val: TDD->getUnderlyingType())) {
3088	Diag(AtClassLoc, diag::warn_forward_class_redefinition)
3089	<< IdentList[i];
3090	Diag(PrevDecl->getLocation(), diag::note_previous_definition);
3091	continue;
3092	}
3093	}
3094	}
3095
3096	// Create a declaration to describe this forward declaration.
3097	ObjCInterfaceDecl *PrevIDecl
3098	= dyn_cast_or_null<ObjCInterfaceDecl>(Val: PrevDecl);
3099
3100	IdentifierInfo *ClassName = IdentList[i];
3101	if (PrevIDecl && PrevIDecl->getIdentifier() != ClassName) {
3102	// A previous decl with a different name is because of
3103	// @compatibility_alias, for example:
3104	// \code
3105	// @class NewImage;
3106	// @compatibility_alias OldImage NewImage;
3107	// \endcode
3108	// A lookup for 'OldImage' will return the 'NewImage' decl.
3109	//
3110	// In such a case use the real declaration name, instead of the alias one,
3111	// otherwise we will break IdentifierResolver and redecls-chain invariants.
3112	// FIXME: If necessary, add a bit to indicate that this ObjCInterfaceDecl
3113	// has been aliased.
3114	ClassName = PrevIDecl->getIdentifier();
3115	}
3116
3117	// If this forward declaration has type parameters, compare them with the
3118	// type parameters of the previous declaration.
3119	ObjCTypeParamList *TypeParams = TypeParamLists[i];
3120	if (PrevIDecl && TypeParams) {
3121	if (ObjCTypeParamList *PrevTypeParams = PrevIDecl->getTypeParamList()) {
3122	// Check for consistency with the previous declaration.
3123	if (checkTypeParamListConsistency(
3124	S&: *this, prevTypeParams: PrevTypeParams, newTypeParams: TypeParams,
3125	newContext: TypeParamListContext::ForwardDeclaration)) {
3126	TypeParams = nullptr;
3127	}
3128	} else if (ObjCInterfaceDecl *Def = PrevIDecl->getDefinition()) {
3129	// The @interface does not have type parameters. Complain.
3130	Diag(IdentLocs[i], diag::err_objc_parameterized_forward_class)
3131	<< ClassName
3132	<< TypeParams->getSourceRange();
3133	Diag(Def->getLocation(), diag::note_defined_here)
3134	<< ClassName;
3135
3136	TypeParams = nullptr;
3137	}
3138	}
3139
3140	ObjCInterfaceDecl *IDecl
3141	= ObjCInterfaceDecl::Create(C: Context, DC: CurContext, atLoc: AtClassLoc,
3142	Id: ClassName, typeParamList: TypeParams, PrevDecl: PrevIDecl,
3143	ClassLoc: IdentLocs[i]);
3144	IDecl->setAtEndRange(IdentLocs[i]);
3145
3146	if (PrevIDecl)
3147	mergeDeclAttributes(IDecl, PrevIDecl);
3148
3149	PushOnScopeChains(IDecl, TUScope);
3150	CheckObjCDeclScope(IDecl);
3151	DeclsInGroup.push_back(IDecl);
3152	}
3153
3154	return BuildDeclaratorGroup(Group: DeclsInGroup);
3155	}
3156
3157	static bool tryMatchRecordTypes(ASTContext &Context,
3158	Sema::MethodMatchStrategy strategy,
3159	const Type *left, const Type *right);
3160
3161	static bool matchTypes(ASTContext &Context, Sema::MethodMatchStrategy strategy,
3162	QualType leftQT, QualType rightQT) {
3163	const Type *left =
3164	Context.getCanonicalType(T: leftQT).getUnqualifiedType().getTypePtr();
3165	const Type *right =
3166	Context.getCanonicalType(T: rightQT).getUnqualifiedType().getTypePtr();
3167
3168	if (left == right) return true;
3169
3170	// If we're doing a strict match, the types have to match exactly.
3171	if (strategy == Sema::MMS_strict) return false;
3172
3173	if (left->isIncompleteType() || right->isIncompleteType()) return false;
3174
3175	// Otherwise, use this absurdly complicated algorithm to try to
3176	// validate the basic, low-level compatibility of the two types.
3177
3178	// As a minimum, require the sizes and alignments to match.
3179	TypeInfo LeftTI = Context.getTypeInfo(T: left);
3180	TypeInfo RightTI = Context.getTypeInfo(T: right);
3181	if (LeftTI.Width != RightTI.Width)
3182	return false;
3183
3184	if (LeftTI.Align != RightTI.Align)
3185	return false;
3186
3187	// Consider all the kinds of non-dependent canonical types:
3188	// - functions and arrays aren't possible as return and parameter types
3189
3190	// - vector types of equal size can be arbitrarily mixed
3191	if (isa<VectorType>(Val: left)) return isa<VectorType>(Val: right);
3192	if (isa<VectorType>(Val: right)) return false;
3193
3194	// - references should only match references of identical type
3195	// - structs, unions, and Objective-C objects must match more-or-less
3196	// exactly
3197	// - everything else should be a scalar
3198	if (!left->isScalarType() || !right->isScalarType())
3199	return tryMatchRecordTypes(Context, strategy, left, right);
3200
3201	// Make scalars agree in kind, except count bools as chars, and group
3202	// all non-member pointers together.
3203	Type::ScalarTypeKind leftSK = left->getScalarTypeKind();
3204	Type::ScalarTypeKind rightSK = right->getScalarTypeKind();
3205	if (leftSK == Type::STK_Bool) leftSK = Type::STK_Integral;
3206	if (rightSK == Type::STK_Bool) rightSK = Type::STK_Integral;
3207	if (leftSK == Type::STK_CPointer || leftSK == Type::STK_BlockPointer)
3208	leftSK = Type::STK_ObjCObjectPointer;
3209	if (rightSK == Type::STK_CPointer || rightSK == Type::STK_BlockPointer)
3210	rightSK = Type::STK_ObjCObjectPointer;
3211
3212	// Note that data member pointers and function member pointers don't
3213	// intermix because of the size differences.
3214
3215	return (leftSK == rightSK);
3216	}
3217
3218	static bool tryMatchRecordTypes(ASTContext &Context,
3219	Sema::MethodMatchStrategy strategy,
3220	const Type *lt, const Type *rt) {
3221	assert(lt && rt && lt != rt);
3222
3223	if (!isa<RecordType>(Val: lt) || !isa<RecordType>(Val: rt)) return false;
3224	RecordDecl *left = cast<RecordType>(Val: lt)->getDecl();
3225	RecordDecl *right = cast<RecordType>(Val: rt)->getDecl();
3226
3227	// Require union-hood to match.
3228	if (left->isUnion() != right->isUnion()) return false;
3229
3230	// Require an exact match if either is non-POD.
3231	if ((isa<CXXRecordDecl>(Val: left) && !cast<CXXRecordDecl>(Val: left)->isPOD()) ||
3232	(isa<CXXRecordDecl>(Val: right) && !cast<CXXRecordDecl>(Val: right)->isPOD()))
3233	return false;
3234
3235	// Require size and alignment to match.
3236	TypeInfo LeftTI = Context.getTypeInfo(T: lt);
3237	TypeInfo RightTI = Context.getTypeInfo(T: rt);
3238	if (LeftTI.Width != RightTI.Width)
3239	return false;
3240
3241	if (LeftTI.Align != RightTI.Align)
3242	return false;
3243
3244	// Require fields to match.
3245	RecordDecl::field_iterator li = left->field_begin(), le = left->field_end();
3246	RecordDecl::field_iterator ri = right->field_begin(), re = right->field_end();
3247	for (; li != le && ri != re; ++li, ++ri) {
3248	if (!matchTypes(Context, strategy, li->getType(), ri->getType()))
3249	return false;
3250	}
3251	return (li == le && ri == re);
3252	}
3253
3254	/// MatchTwoMethodDeclarations - Checks that two methods have matching type and
3255	/// returns true, or false, accordingly.
3256	/// TODO: Handle protocol list; such as id<p1,p2> in type comparisons
3257	bool Sema::MatchTwoMethodDeclarations(const ObjCMethodDecl *left,
3258	const ObjCMethodDecl *right,
3259	MethodMatchStrategy strategy) {
3260	if (!matchTypes(Context, strategy, leftQT: left->getReturnType(),
3261	rightQT: right->getReturnType()))
3262	return false;
3263
3264	// If either is hidden, it is not considered to match.
3265	if (!left->isUnconditionallyVisible() || !right->isUnconditionallyVisible())
3266	return false;
3267
3268	if (left->isDirectMethod() != right->isDirectMethod())
3269	return false;
3270
3271	if (getLangOpts().ObjCAutoRefCount &&
3272	(left->hasAttr<NSReturnsRetainedAttr>()
3273	!= right->hasAttr<NSReturnsRetainedAttr>() ||
3274	left->hasAttr<NSConsumesSelfAttr>()
3275	!= right->hasAttr<NSConsumesSelfAttr>()))
3276	return false;
3277
3278	ObjCMethodDecl::param_const_iterator
3279	li = left->param_begin(), le = left->param_end(), ri = right->param_begin(),
3280	re = right->param_end();
3281
3282	for (; li != le && ri != re; ++li, ++ri) {
3283	assert(ri != right->param_end() && "Param mismatch");
3284	const ParmVarDecl *lparm = *li, *rparm = *ri;
3285
3286	if (!matchTypes(Context, strategy, lparm->getType(), rparm->getType()))
3287	return false;
3288
3289	if (getLangOpts().ObjCAutoRefCount &&
3290	lparm->hasAttr<NSConsumedAttr>() != rparm->hasAttr<NSConsumedAttr>())
3291	return false;
3292	}
3293	return true;
3294	}
3295
3296	static bool isMethodContextSameForKindofLookup(ObjCMethodDecl *Method,
3297	ObjCMethodDecl *MethodInList) {
3298	auto *MethodProtocol = dyn_cast<ObjCProtocolDecl>(Method->getDeclContext());
3299	auto *MethodInListProtocol =
3300	dyn_cast<ObjCProtocolDecl>(MethodInList->getDeclContext());
3301	// If this method belongs to a protocol but the method in list does not, or
3302	// vice versa, we say the context is not the same.
3303	if ((MethodProtocol && !MethodInListProtocol) ||
3304	(!MethodProtocol && MethodInListProtocol))
3305	return false;
3306
3307	if (MethodProtocol && MethodInListProtocol)
3308	return true;
3309
3310	ObjCInterfaceDecl *MethodInterface = Method->getClassInterface();
3311	ObjCInterfaceDecl *MethodInListInterface =
3312	MethodInList->getClassInterface();
3313	return MethodInterface == MethodInListInterface;
3314	}
3315
3316	void Sema::addMethodToGlobalList(ObjCMethodList *List,
3317	ObjCMethodDecl *Method) {
3318	// Record at the head of the list whether there were 0, 1, or >= 2 methods
3319	// inside categories.
3320	if (ObjCCategoryDecl *CD =
3321	dyn_cast<ObjCCategoryDecl>(Method->getDeclContext()))
3322	if (!CD->IsClassExtension() && List->getBits() < 2)
3323	List->setBits(List->getBits() + 1);
3324
3325	// If the list is empty, make it a singleton list.
3326	if (List->getMethod() == nullptr) {
3327	List->setMethod(Method);
3328	List->setNext(nullptr);
3329	return;
3330	}
3331
3332	// We've seen a method with this name, see if we have already seen this type
3333	// signature.
3334	ObjCMethodList *Previous = List;
3335	ObjCMethodList *ListWithSameDeclaration = nullptr;
3336	for (; List; Previous = List, List = List->getNext()) {
3337	// If we are building a module, keep all of the methods.
3338	if (getLangOpts().isCompilingModule())
3339	continue;
3340
3341	bool SameDeclaration = MatchTwoMethodDeclarations(left: Method,
3342	right: List->getMethod());
3343	// Looking for method with a type bound requires the correct context exists.
3344	// We need to insert a method into the list if the context is different.
3345	// If the method's declaration matches the list
3346	// a> the method belongs to a different context: we need to insert it, in
3347	// order to emit the availability message, we need to prioritize over
3348	// availability among the methods with the same declaration.
3349	// b> the method belongs to the same context: there is no need to insert a
3350	// new entry.
3351	// If the method's declaration does not match the list, we insert it to the
3352	// end.
3353	if (!SameDeclaration ||
3354	!isMethodContextSameForKindofLookup(Method, MethodInList: List->getMethod())) {
3355	// Even if two method types do not match, we would like to say
3356	// there is more than one declaration so unavailability/deprecated
3357	// warning is not too noisy.
3358	if (!Method->isDefined())
3359	List->setHasMoreThanOneDecl(true);
3360
3361	// For methods with the same declaration, the one that is deprecated
3362	// should be put in the front for better diagnostics.
3363	if (Method->isDeprecated() && SameDeclaration &&
3364	!ListWithSameDeclaration && !List->getMethod()->isDeprecated())
3365	ListWithSameDeclaration = List;
3366
3367	if (Method->isUnavailable() && SameDeclaration &&
3368	!ListWithSameDeclaration &&
3369	List->getMethod()->getAvailability() < AR_Deprecated)
3370	ListWithSameDeclaration = List;
3371	continue;
3372	}
3373
3374	ObjCMethodDecl *PrevObjCMethod = List->getMethod();
3375
3376	// Propagate the 'defined' bit.
3377	if (Method->isDefined())
3378	PrevObjCMethod->setDefined(true);
3379	else {
3380	// Objective-C doesn't allow an @interface for a class after its
3381	// @implementation. So if Method is not defined and there already is
3382	// an entry for this type signature, Method has to be for a different
3383	// class than PrevObjCMethod.
3384	List->setHasMoreThanOneDecl(true);
3385	}
3386
3387	// If a method is deprecated, push it in the global pool.
3388	// This is used for better diagnostics.
3389	if (Method->isDeprecated()) {
3390	if (!PrevObjCMethod->isDeprecated())
3391	List->setMethod(Method);
3392	}
3393	// If the new method is unavailable, push it into global pool
3394	// unless previous one is deprecated.
3395	if (Method->isUnavailable()) {
3396	if (PrevObjCMethod->getAvailability() < AR_Deprecated)
3397	List->setMethod(Method);
3398	}
3399
3400	return;
3401	}
3402
3403	// We have a new signature for an existing method - add it.
3404	// This is extremely rare. Only 1% of Cocoa selectors are "overloaded".
3405	ObjCMethodList *Mem = BumpAlloc.Allocate<ObjCMethodList>();
3406
3407	// We insert it right before ListWithSameDeclaration.
3408	if (ListWithSameDeclaration) {
3409	auto *List = new (Mem) ObjCMethodList(*ListWithSameDeclaration);
3410	// FIXME: should we clear the other bits in ListWithSameDeclaration?
3411	ListWithSameDeclaration->setMethod(Method);
3412	ListWithSameDeclaration->setNext(List);
3413	return;
3414	}
3415
3416	Previous->setNext(new (Mem) ObjCMethodList(Method));
3417	}
3418
3419	/// Read the contents of the method pool for a given selector from
3420	/// external storage.
3421	void Sema::ReadMethodPool(Selector Sel) {
3422	assert(ExternalSource && "We need an external AST source");
3423	ExternalSource->ReadMethodPool(Sel);
3424	}
3425
3426	void Sema::updateOutOfDateSelector(Selector Sel) {
3427	if (!ExternalSource)
3428	return;
3429	ExternalSource->updateOutOfDateSelector(Sel);
3430	}
3431
3432	void Sema::AddMethodToGlobalPool(ObjCMethodDecl *Method, bool impl,
3433	bool instance) {
3434	// Ignore methods of invalid containers.
3435	if (cast<Decl>(Method->getDeclContext())->isInvalidDecl())
3436	return;
3437
3438	if (ExternalSource)
3439	ReadMethodPool(Sel: Method->getSelector());
3440
3441	GlobalMethodPool::iterator Pos = MethodPool.find(Sel: Method->getSelector());
3442	if (Pos == MethodPool.end())
3443	Pos = MethodPool
3444	.insert(Val: std::make_pair(x: Method->getSelector(),
3445	y: GlobalMethodPool::Lists()))
3446	.first;
3447
3448	Method->setDefined(impl);
3449
3450	ObjCMethodList &Entry = instance ? Pos->second.first : Pos->second.second;
3451	addMethodToGlobalList(List: &Entry, Method);
3452	}
3453
3454	/// Determines if this is an "acceptable" loose mismatch in the global
3455	/// method pool. This exists mostly as a hack to get around certain
3456	/// global mismatches which we can't afford to make warnings / errors.
3457	/// Really, what we want is a way to take a method out of the global
3458	/// method pool.
3459	static bool isAcceptableMethodMismatch(ObjCMethodDecl *chosen,
3460	ObjCMethodDecl *other) {
3461	if (!chosen->isInstanceMethod())
3462	return false;
3463
3464	if (chosen->isDirectMethod() != other->isDirectMethod())
3465	return false;
3466
3467	Selector sel = chosen->getSelector();
3468	if (!sel.isUnarySelector() || sel.getNameForSlot(argIndex: 0) != "length")
3469	return false;
3470
3471	// Don't complain about mismatches for -length if the method we
3472	// chose has an integral result type.
3473	return (chosen->getReturnType()->isIntegerType());
3474	}
3475
3476	/// Return true if the given method is wthin the type bound.
3477	static bool FilterMethodsByTypeBound(ObjCMethodDecl *Method,
3478	const ObjCObjectType *TypeBound) {
3479	if (!TypeBound)
3480	return true;
3481
3482	if (TypeBound->isObjCId())
3483	// FIXME: should we handle the case of bounding to id<A, B> differently?
3484	return true;
3485
3486	auto *BoundInterface = TypeBound->getInterface();
3487	assert(BoundInterface && "unexpected object type!");
3488
3489	// Check if the Method belongs to a protocol. We should allow any method
3490	// defined in any protocol, because any subclass could adopt the protocol.
3491	auto *MethodProtocol = dyn_cast<ObjCProtocolDecl>(Method->getDeclContext());
3492	if (MethodProtocol) {
3493	return true;
3494	}
3495
3496	// If the Method belongs to a class, check if it belongs to the class
3497	// hierarchy of the class bound.
3498	if (ObjCInterfaceDecl *MethodInterface = Method->getClassInterface()) {
3499	// We allow methods declared within classes that are part of the hierarchy
3500	// of the class bound (superclass of, subclass of, or the same as the class
3501	// bound).
3502	return MethodInterface == BoundInterface ||
3503	MethodInterface->isSuperClassOf(I: BoundInterface) ||
3504	BoundInterface->isSuperClassOf(I: MethodInterface);
3505	}
3506	llvm_unreachable("unknown method context");
3507	}
3508
3509	/// We first select the type of the method: Instance or Factory, then collect
3510	/// all methods with that type.
3511	bool Sema::CollectMultipleMethodsInGlobalPool(
3512	Selector Sel, SmallVectorImpl<ObjCMethodDecl *> &Methods,
3513	bool InstanceFirst, bool CheckTheOther,
3514	const ObjCObjectType *TypeBound) {
3515	if (ExternalSource)
3516	ReadMethodPool(Sel);
3517
3518	GlobalMethodPool::iterator Pos = MethodPool.find(Sel);
3519	if (Pos == MethodPool.end())
3520	return false;
3521
3522	// Gather the non-hidden methods.
3523	ObjCMethodList &MethList = InstanceFirst ? Pos->second.first :
3524	Pos->second.second;
3525	for (ObjCMethodList *M = &MethList; M; M = M->getNext())
3526	if (M->getMethod() && M->getMethod()->isUnconditionallyVisible()) {
3527	if (FilterMethodsByTypeBound(Method: M->getMethod(), TypeBound))
3528	Methods.push_back(Elt: M->getMethod());
3529	}
3530
3531	// Return if we find any method with the desired kind.
3532	if (!Methods.empty())
3533	return Methods.size() > 1;
3534
3535	if (!CheckTheOther)
3536	return false;
3537
3538	// Gather the other kind.
3539	ObjCMethodList &MethList2 = InstanceFirst ? Pos->second.second :
3540	Pos->second.first;
3541	for (ObjCMethodList *M = &MethList2; M; M = M->getNext())
3542	if (M->getMethod() && M->getMethod()->isUnconditionallyVisible()) {
3543	if (FilterMethodsByTypeBound(Method: M->getMethod(), TypeBound))
3544	Methods.push_back(Elt: M->getMethod());
3545	}
3546
3547	return Methods.size() > 1;
3548	}
3549
3550	bool Sema::AreMultipleMethodsInGlobalPool(
3551	Selector Sel, ObjCMethodDecl *BestMethod, SourceRange R,
3552	bool receiverIdOrClass, SmallVectorImpl<ObjCMethodDecl *> &Methods) {
3553	// Diagnose finding more than one method in global pool.
3554	SmallVector<ObjCMethodDecl *, 4> FilteredMethods;
3555	FilteredMethods.push_back(Elt: BestMethod);
3556
3557	for (auto *M : Methods)
3558	if (M != BestMethod && !M->hasAttr<UnavailableAttr>())
3559	FilteredMethods.push_back(Elt: M);
3560
3561	if (FilteredMethods.size() > 1)
3562	DiagnoseMultipleMethodInGlobalPool(Methods&: FilteredMethods, Sel, R,
3563	receiverIdOrClass);
3564
3565	GlobalMethodPool::iterator Pos = MethodPool.find(Sel);
3566	// Test for no method in the pool which should not trigger any warning by
3567	// caller.
3568	if (Pos == MethodPool.end())
3569	return true;
3570	ObjCMethodList &MethList =
3571	BestMethod->isInstanceMethod() ? Pos->second.first : Pos->second.second;
3572	return MethList.hasMoreThanOneDecl();
3573	}
3574
3575	ObjCMethodDecl *Sema::LookupMethodInGlobalPool(Selector Sel, SourceRange R,
3576	bool receiverIdOrClass,
3577	bool instance) {
3578	if (ExternalSource)
3579	ReadMethodPool(Sel);
3580
3581	GlobalMethodPool::iterator Pos = MethodPool.find(Sel);
3582	if (Pos == MethodPool.end())
3583	return nullptr;
3584
3585	// Gather the non-hidden methods.
3586	ObjCMethodList &MethList = instance ? Pos->second.first : Pos->second.second;
3587	SmallVector<ObjCMethodDecl *, 4> Methods;
3588	for (ObjCMethodList *M = &MethList; M; M = M->getNext()) {
3589	if (M->getMethod() && M->getMethod()->isUnconditionallyVisible())
3590	return M->getMethod();
3591	}
3592	return nullptr;
3593	}
3594
3595	void Sema::DiagnoseMultipleMethodInGlobalPool(SmallVectorImpl<ObjCMethodDecl*> &Methods,
3596	Selector Sel, SourceRange R,
3597	bool receiverIdOrClass) {
3598	// We found multiple methods, so we may have to complain.
3599	bool issueDiagnostic = false, issueError = false;
3600
3601	// We support a warning which complains about *any* difference in
3602	// method signature.
3603	bool strictSelectorMatch =
3604	receiverIdOrClass &&
3605	!Diags.isIgnored(diag::warn_strict_multiple_method_decl, R.getBegin());
3606	if (strictSelectorMatch) {
3607	for (unsigned I = 1, N = Methods.size(); I != N; ++I) {
3608	if (!MatchTwoMethodDeclarations(left: Methods[0], right: Methods[I], strategy: MMS_strict)) {
3609	issueDiagnostic = true;
3610	break;
3611	}
3612	}
3613	}
3614
3615	// If we didn't see any strict differences, we won't see any loose
3616	// differences. In ARC, however, we also need to check for loose
3617	// mismatches, because most of them are errors.
3618	if (!strictSelectorMatch ||
3619	(issueDiagnostic && getLangOpts().ObjCAutoRefCount))
3620	for (unsigned I = 1, N = Methods.size(); I != N; ++I) {
3621	// This checks if the methods differ in type mismatch.
3622	if (!MatchTwoMethodDeclarations(left: Methods[0], right: Methods[I], strategy: MMS_loose) &&
3623	!isAcceptableMethodMismatch(chosen: Methods[0], other: Methods[I])) {
3624	issueDiagnostic = true;
3625	if (getLangOpts().ObjCAutoRefCount)
3626	issueError = true;
3627	break;
3628	}
3629	}
3630
3631	if (issueDiagnostic) {
3632	if (issueError)
3633	Diag(R.getBegin(), diag::err_arc_multiple_method_decl) << Sel << R;
3634	else if (strictSelectorMatch)
3635	Diag(R.getBegin(), diag::warn_strict_multiple_method_decl) << Sel << R;
3636	else
3637	Diag(R.getBegin(), diag::warn_multiple_method_decl) << Sel << R;
3638
3639	Diag(Methods[0]->getBeginLoc(),
3640	issueError ? diag::note_possibility : diag::note_using)
3641	<< Methods[0]->getSourceRange();
3642	for (unsigned I = 1, N = Methods.size(); I != N; ++I) {
3643	Diag(Methods[I]->getBeginLoc(), diag::note_also_found)
3644	<< Methods[I]->getSourceRange();
3645	}
3646	}
3647	}
3648
3649	ObjCMethodDecl *Sema::LookupImplementedMethodInGlobalPool(Selector Sel) {
3650	GlobalMethodPool::iterator Pos = MethodPool.find(Sel);
3651	if (Pos == MethodPool.end())
3652	return nullptr;
3653
3654	GlobalMethodPool::Lists &Methods = Pos->second;
3655	for (const ObjCMethodList *Method = &Methods.first; Method;
3656	Method = Method->getNext())
3657	if (Method->getMethod() &&
3658	(Method->getMethod()->isDefined() ||
3659	Method->getMethod()->isPropertyAccessor()))
3660	return Method->getMethod();
3661
3662	for (const ObjCMethodList *Method = &Methods.second; Method;
3663	Method = Method->getNext())
3664	if (Method->getMethod() &&
3665	(Method->getMethod()->isDefined() ||
3666	Method->getMethod()->isPropertyAccessor()))
3667	return Method->getMethod();
3668	return nullptr;
3669	}
3670
3671	static void
3672	HelperSelectorsForTypoCorrection(
3673	SmallVectorImpl<const ObjCMethodDecl *> &BestMethod,
3674	StringRef Typo, const ObjCMethodDecl * Method) {
3675	const unsigned MaxEditDistance = 1;
3676	unsigned BestEditDistance = MaxEditDistance + 1;
3677	std::string MethodName = Method->getSelector().getAsString();
3678
3679	unsigned MinPossibleEditDistance = abs(x: (int)MethodName.size() - (int)Typo.size());
3680	if (MinPossibleEditDistance > 0 &&
3681	Typo.size() / MinPossibleEditDistance < 1)
3682	return;
3683	unsigned EditDistance = Typo.edit_distance(Other: MethodName, AllowReplacements: true, MaxEditDistance);
3684	if (EditDistance > MaxEditDistance)
3685	return;
3686	if (EditDistance == BestEditDistance)
3687	BestMethod.push_back(Elt: Method);
3688	else if (EditDistance < BestEditDistance) {
3689	BestMethod.clear();
3690	BestMethod.push_back(Elt: Method);
3691	}
3692	}
3693
3694	static bool HelperIsMethodInObjCType(Sema &S, Selector Sel,
3695	QualType ObjectType) {
3696	if (ObjectType.isNull())
3697	return true;
3698	if (S.LookupMethodInObjectType(Sel, Ty: ObjectType, IsInstance: true/*Instance method*/))
3699	return true;
3700	return S.LookupMethodInObjectType(Sel, Ty: ObjectType, IsInstance: false/*Class method*/) !=
3701	nullptr;
3702	}
3703
3704	const ObjCMethodDecl *
3705	Sema::SelectorsForTypoCorrection(Selector Sel,
3706	QualType ObjectType) {
3707	unsigned NumArgs = Sel.getNumArgs();
3708	SmallVector<const ObjCMethodDecl *, 8> Methods;
3709	bool ObjectIsId = true, ObjectIsClass = true;
3710	if (ObjectType.isNull())
3711	ObjectIsId = ObjectIsClass = false;
3712	else if (!ObjectType->isObjCObjectPointerType())
3713	return nullptr;
3714	else if (const ObjCObjectPointerType *ObjCPtr =
3715	ObjectType->getAsObjCInterfacePointerType()) {
3716	ObjectType = QualType(ObjCPtr->getInterfaceType(), 0);
3717	ObjectIsId = ObjectIsClass = false;
3718	}
3719	else if (ObjectType->isObjCIdType() || ObjectType->isObjCQualifiedIdType())
3720	ObjectIsClass = false;
3721	else if (ObjectType->isObjCClassType() || ObjectType->isObjCQualifiedClassType())
3722	ObjectIsId = false;
3723	else
3724	return nullptr;
3725
3726	for (GlobalMethodPool::iterator b = MethodPool.begin(),
3727	e = MethodPool.end(); b != e; b++) {
3728	// instance methods
3729	for (ObjCMethodList *M = &b->second.first; M; M=M->getNext())
3730	if (M->getMethod() &&
3731	(M->getMethod()->getSelector().getNumArgs() == NumArgs) &&
3732	(M->getMethod()->getSelector() != Sel)) {
3733	if (ObjectIsId)
3734	Methods.push_back(Elt: M->getMethod());
3735	else if (!ObjectIsClass &&
3736	HelperIsMethodInObjCType(S&: *this, Sel: M->getMethod()->getSelector(),
3737	ObjectType))
3738	Methods.push_back(Elt: M->getMethod());
3739	}
3740	// class methods
3741	for (ObjCMethodList *M = &b->second.second; M; M=M->getNext())
3742	if (M->getMethod() &&
3743	(M->getMethod()->getSelector().getNumArgs() == NumArgs) &&
3744	(M->getMethod()->getSelector() != Sel)) {
3745	if (ObjectIsClass)
3746	Methods.push_back(Elt: M->getMethod());
3747	else if (!ObjectIsId &&
3748	HelperIsMethodInObjCType(S&: *this, Sel: M->getMethod()->getSelector(),
3749	ObjectType))
3750	Methods.push_back(Elt: M->getMethod());
3751	}
3752	}
3753
3754	SmallVector<const ObjCMethodDecl *, 8> SelectedMethods;
3755	for (unsigned i = 0, e = Methods.size(); i < e; i++) {
3756	HelperSelectorsForTypoCorrection(BestMethod&: SelectedMethods,
3757	Typo: Sel.getAsString(), Method: Methods[i]);
3758	}
3759	return (SelectedMethods.size() == 1) ? SelectedMethods[0] : nullptr;
3760	}
3761
3762	/// DiagnoseDuplicateIvars -
3763	/// Check for duplicate ivars in the entire class at the start of
3764	/// \@implementation. This becomes necessary because class extension can
3765	/// add ivars to a class in random order which will not be known until
3766	/// class's \@implementation is seen.
3767	void Sema::DiagnoseDuplicateIvars(ObjCInterfaceDecl *ID,
3768	ObjCInterfaceDecl *SID) {
3769	for (auto *Ivar : ID->ivars()) {
3770	if (Ivar->isInvalidDecl())
3771	continue;
3772	if (IdentifierInfo *II = Ivar->getIdentifier()) {
3773	ObjCIvarDecl* prevIvar = SID->lookupInstanceVariable(IVarName: II);
3774	if (prevIvar) {
3775	Diag(Ivar->getLocation(), diag::err_duplicate_member) << II;
3776	Diag(prevIvar->getLocation(), diag::note_previous_declaration);
3777	Ivar->setInvalidDecl();
3778	}
3779	}
3780	}
3781	}
3782
3783	/// Diagnose attempts to define ARC-__weak ivars when __weak is disabled.
3784	static void DiagnoseWeakIvars(Sema &S, ObjCImplementationDecl *ID) {
3785	if (S.getLangOpts().ObjCWeak) return;
3786
3787	for (auto ivar = ID->getClassInterface()->all_declared_ivar_begin();
3788	ivar; ivar = ivar->getNextIvar()) {
3789	if (ivar->isInvalidDecl()) continue;
3790	if (ivar->getType().getObjCLifetime() == Qualifiers::OCL_Weak) {
3791	if (S.getLangOpts().ObjCWeakRuntime) {
3792	S.Diag(ivar->getLocation(), diag::err_arc_weak_disabled);
3793	} else {
3794	S.Diag(ivar->getLocation(), diag::err_arc_weak_no_runtime);
3795	}
3796	}
3797	}
3798	}
3799
3800	/// Diagnose attempts to use flexible array member with retainable object type.
3801	static void DiagnoseRetainableFlexibleArrayMember(Sema &S,
3802	ObjCInterfaceDecl *ID) {
3803	if (!S.getLangOpts().ObjCAutoRefCount)
3804	return;
3805
3806	for (auto ivar = ID->all_declared_ivar_begin(); ivar;
3807	ivar = ivar->getNextIvar()) {
3808	if (ivar->isInvalidDecl())
3809	continue;
3810	QualType IvarTy = ivar->getType();
3811	if (IvarTy->isIncompleteArrayType() &&
3812	(IvarTy.getObjCLifetime() != Qualifiers::OCL_ExplicitNone) &&
3813	IvarTy->isObjCLifetimeType()) {
3814	S.Diag(ivar->getLocation(), diag::err_flexible_array_arc_retainable);
3815	ivar->setInvalidDecl();
3816	}
3817	}
3818	}
3819
3820	Sema::ObjCContainerKind Sema::getObjCContainerKind() const {
3821	switch (CurContext->getDeclKind()) {
3822	case Decl::ObjCInterface:
3823	return Sema::OCK_Interface;
3824	case Decl::ObjCProtocol:
3825	return Sema::OCK_Protocol;
3826	case Decl::ObjCCategory:
3827	if (cast<ObjCCategoryDecl>(Val: CurContext)->IsClassExtension())
3828	return Sema::OCK_ClassExtension;
3829	return Sema::OCK_Category;
3830	case Decl::ObjCImplementation:
3831	return Sema::OCK_Implementation;
3832	case Decl::ObjCCategoryImpl:
3833	return Sema::OCK_CategoryImplementation;
3834
3835	default:
3836	return Sema::OCK_None;
3837	}
3838	}
3839
3840	static bool IsVariableSizedType(QualType T) {
3841	if (T->isIncompleteArrayType())
3842	return true;
3843	const auto *RecordTy = T->getAs<RecordType>();
3844	return (RecordTy && RecordTy->getDecl()->hasFlexibleArrayMember());
3845	}
3846
3847	static void DiagnoseVariableSizedIvars(Sema &S, ObjCContainerDecl *OCD) {
3848	ObjCInterfaceDecl *IntfDecl = nullptr;
3849	ObjCInterfaceDecl::ivar_range Ivars = llvm::make_range(
3850	x: ObjCInterfaceDecl::ivar_iterator(), y: ObjCInterfaceDecl::ivar_iterator());
3851	if ((IntfDecl = dyn_cast<ObjCInterfaceDecl>(Val: OCD))) {
3852	Ivars = IntfDecl->ivars();
3853	} else if (auto *ImplDecl = dyn_cast<ObjCImplementationDecl>(Val: OCD)) {
3854	IntfDecl = ImplDecl->getClassInterface();
3855	Ivars = ImplDecl->ivars();
3856	} else if (auto *CategoryDecl = dyn_cast<ObjCCategoryDecl>(Val: OCD)) {
3857	if (CategoryDecl->IsClassExtension()) {
3858	IntfDecl = CategoryDecl->getClassInterface();
3859	Ivars = CategoryDecl->ivars();
3860	}
3861	}
3862
3863	// Check if variable sized ivar is in interface and visible to subclasses.
3864	if (!isa<ObjCInterfaceDecl>(Val: OCD)) {
3865	for (auto *ivar : Ivars) {
3866	if (!ivar->isInvalidDecl() && IsVariableSizedType(ivar->getType())) {
3867	S.Diag(ivar->getLocation(), diag::warn_variable_sized_ivar_visibility)
3868	<< ivar->getDeclName() << ivar->getType();
3869	}
3870	}
3871	}
3872
3873	// Subsequent checks require interface decl.
3874	if (!IntfDecl)
3875	return;
3876
3877	// Check if variable sized ivar is followed by another ivar.
3878	for (ObjCIvarDecl *ivar = IntfDecl->all_declared_ivar_begin(); ivar;
3879	ivar = ivar->getNextIvar()) {
3880	if (ivar->isInvalidDecl() || !ivar->getNextIvar())
3881	continue;
3882	QualType IvarTy = ivar->getType();
3883	bool IsInvalidIvar = false;
3884	if (IvarTy->isIncompleteArrayType()) {
3885	S.Diag(ivar->getLocation(), diag::err_flexible_array_not_at_end)
3886	<< ivar->getDeclName() << IvarTy
3887	<< llvm::to_underlying(TagTypeKind::Class); // Use "class" for Obj-C.
3888	IsInvalidIvar = true;
3889	} else if (const RecordType *RecordTy = IvarTy->getAs<RecordType>()) {
3890	if (RecordTy->getDecl()->hasFlexibleArrayMember()) {
3891	S.Diag(ivar->getLocation(),
3892	diag::err_objc_variable_sized_type_not_at_end)
3893	<< ivar->getDeclName() << IvarTy;
3894	IsInvalidIvar = true;
3895	}
3896	}
3897	if (IsInvalidIvar) {
3898	S.Diag(ivar->getNextIvar()->getLocation(),
3899	diag::note_next_ivar_declaration)
3900	<< ivar->getNextIvar()->getSynthesize();
3901	ivar->setInvalidDecl();
3902	}
3903	}
3904
3905	// Check if ObjC container adds ivars after variable sized ivar in superclass.
3906	// Perform the check only if OCD is the first container to declare ivars to
3907	// avoid multiple warnings for the same ivar.
3908	ObjCIvarDecl *FirstIvar =
3909	(Ivars.begin() == Ivars.end()) ? nullptr : *Ivars.begin();
3910	if (FirstIvar && (FirstIvar == IntfDecl->all_declared_ivar_begin())) {
3911	const ObjCInterfaceDecl *SuperClass = IntfDecl->getSuperClass();
3912	while (SuperClass && SuperClass->ivar_empty())
3913	SuperClass = SuperClass->getSuperClass();
3914	if (SuperClass) {
3915	auto IvarIter = SuperClass->ivar_begin();
3916	std::advance(i&: IvarIter, n: SuperClass->ivar_size() - 1);
3917	const ObjCIvarDecl *LastIvar = *IvarIter;
3918	if (IsVariableSizedType(LastIvar->getType())) {
3919	S.Diag(FirstIvar->getLocation(),
3920	diag::warn_superclass_variable_sized_type_not_at_end)
3921	<< FirstIvar->getDeclName() << LastIvar->getDeclName()
3922	<< LastIvar->getType() << SuperClass->getDeclName();
3923	S.Diag(LastIvar->getLocation(), diag::note_entity_declared_at)
3924	<< LastIvar->getDeclName();
3925	}
3926	}
3927	}
3928	}
3929
3930	static void DiagnoseCategoryDirectMembersProtocolConformance(
3931	Sema &S, ObjCProtocolDecl *PDecl, ObjCCategoryDecl *CDecl);
3932
3933	static void DiagnoseCategoryDirectMembersProtocolConformance(
3934	Sema &S, ObjCCategoryDecl *CDecl,
3935	const llvm::iterator_range<ObjCProtocolList::iterator> &Protocols) {
3936	for (auto *PI : Protocols)
3937	DiagnoseCategoryDirectMembersProtocolConformance(S, PDecl: PI, CDecl);
3938	}
3939
3940	static void DiagnoseCategoryDirectMembersProtocolConformance(
3941	Sema &S, ObjCProtocolDecl *PDecl, ObjCCategoryDecl *CDecl) {
3942	if (!PDecl->isThisDeclarationADefinition() && PDecl->getDefinition())
3943	PDecl = PDecl->getDefinition();
3944
3945	llvm::SmallVector<const Decl *, 4> DirectMembers;
3946	const auto *IDecl = CDecl->getClassInterface();
3947	for (auto *MD : PDecl->methods()) {
3948	if (!MD->isPropertyAccessor()) {
3949	if (const auto *CMD =
3950	IDecl->getMethod(MD->getSelector(), MD->isInstanceMethod())) {
3951	if (CMD->isDirectMethod())
3952	DirectMembers.push_back(CMD);
3953	}
3954	}
3955	}
3956	for (auto *PD : PDecl->properties()) {
3957	if (const auto *CPD = IDecl->FindPropertyVisibleInPrimaryClass(
3958	PD->getIdentifier(),
3959	PD->isClassProperty()
3960	? ObjCPropertyQueryKind::OBJC_PR_query_class
3961	: ObjCPropertyQueryKind::OBJC_PR_query_instance)) {
3962	if (CPD->isDirectProperty())
3963	DirectMembers.push_back(CPD);
3964	}
3965	}
3966	if (!DirectMembers.empty()) {
3967	S.Diag(CDecl->getLocation(), diag::err_objc_direct_protocol_conformance)
3968	<< CDecl->IsClassExtension() << CDecl << PDecl << IDecl;
3969	for (const auto *MD : DirectMembers)
3970	S.Diag(MD->getLocation(), diag::note_direct_member_here);
3971	return;
3972	}
3973
3974	// Check on this protocols's referenced protocols, recursively.
3975	DiagnoseCategoryDirectMembersProtocolConformance(S, CDecl,
3976	Protocols: PDecl->protocols());
3977	}
3978
3979	// Note: For class/category implementations, allMethods is always null.
3980	Decl *Sema::ActOnAtEnd(Scope *S, SourceRange AtEnd, ArrayRef<Decl *> allMethods,
3981	ArrayRef<DeclGroupPtrTy> allTUVars) {
3982	if (getObjCContainerKind() == Sema::OCK_None)
3983	return nullptr;
3984
3985	assert(AtEnd.isValid() && "Invalid location for '@end'");
3986
3987	auto *OCD = cast<ObjCContainerDecl>(Val: CurContext);
3988	Decl *ClassDecl = OCD;
3989
3990	bool isInterfaceDeclKind =
3991	isa<ObjCInterfaceDecl>(Val: ClassDecl) || isa<ObjCCategoryDecl>(Val: ClassDecl)
3992	|| isa<ObjCProtocolDecl>(Val: ClassDecl);
3993	bool checkIdenticalMethods = isa<ObjCImplementationDecl>(Val: ClassDecl);
3994
3995	// Make synthesized accessor stub functions visible.
3996	// ActOnPropertyImplDecl() creates them as not visible in case
3997	// they are overridden by an explicit method that is encountered
3998	// later.
3999	if (auto *OID = dyn_cast<ObjCImplementationDecl>(Val: CurContext)) {
4000	for (auto *PropImpl : OID->property_impls()) {
4001	if (auto *Getter = PropImpl->getGetterMethodDecl())
4002	if (Getter->isSynthesizedAccessorStub())
4003	OID->addDecl(Getter);
4004	if (auto *Setter = PropImpl->getSetterMethodDecl())
4005	if (Setter->isSynthesizedAccessorStub())
4006	OID->addDecl(Setter);
4007	}
4008	}
4009
4010	// FIXME: Remove these and use the ObjCContainerDecl/DeclContext.
4011	llvm::DenseMap<Selector, const ObjCMethodDecl*> InsMap;
4012	llvm::DenseMap<Selector, const ObjCMethodDecl*> ClsMap;
4013
4014	for (unsigned i = 0, e = allMethods.size(); i != e; i++ ) {
4015	ObjCMethodDecl *Method =
4016	cast_or_null<ObjCMethodDecl>(Val: allMethods[i]);
4017
4018	if (!Method) continue; // Already issued a diagnostic.
4019	if (Method->isInstanceMethod()) {
4020	/// Check for instance method of the same name with incompatible types
4021	const ObjCMethodDecl *&PrevMethod = InsMap[Method->getSelector()];
4022	bool match = PrevMethod ? MatchTwoMethodDeclarations(left: Method, right: PrevMethod)
4023	: false;
4024	if ((isInterfaceDeclKind && PrevMethod && !match)
4025	|| (checkIdenticalMethods && match)) {
4026	Diag(Method->getLocation(), diag::err_duplicate_method_decl)
4027	<< Method->getDeclName();
4028	Diag(PrevMethod->getLocation(), diag::note_previous_declaration);
4029	Method->setInvalidDecl();
4030	} else {
4031	if (PrevMethod) {
4032	Method->setAsRedeclaration(PrevMethod);
4033	if (!Context.getSourceManager().isInSystemHeader(
4034	Method->getLocation()))
4035	Diag(Method->getLocation(), diag::warn_duplicate_method_decl)
4036	<< Method->getDeclName();
4037	Diag(PrevMethod->getLocation(), diag::note_previous_declaration);
4038	}
4039	InsMap[Method->getSelector()] = Method;
4040	/// The following allows us to typecheck messages to "id".
4041	AddInstanceMethodToGlobalPool(Method);
4042	}
4043	} else {
4044	/// Check for class method of the same name with incompatible types
4045	const ObjCMethodDecl *&PrevMethod = ClsMap[Method->getSelector()];
4046	bool match = PrevMethod ? MatchTwoMethodDeclarations(left: Method, right: PrevMethod)
4047	: false;
4048	if ((isInterfaceDeclKind && PrevMethod && !match)
4049	|| (checkIdenticalMethods && match)) {
4050	Diag(Method->getLocation(), diag::err_duplicate_method_decl)
4051	<< Method->getDeclName();
4052	Diag(PrevMethod->getLocation(), diag::note_previous_declaration);
4053	Method->setInvalidDecl();
4054	} else {
4055	if (PrevMethod) {
4056	Method->setAsRedeclaration(PrevMethod);
4057	if (!Context.getSourceManager().isInSystemHeader(
4058	Method->getLocation()))
4059	Diag(Method->getLocation(), diag::warn_duplicate_method_decl)
4060	<< Method->getDeclName();
4061	Diag(PrevMethod->getLocation(), diag::note_previous_declaration);
4062	}
4063	ClsMap[Method->getSelector()] = Method;
4064	AddFactoryMethodToGlobalPool(Method);
4065	}
4066	}
4067	}
4068	if (isa<ObjCInterfaceDecl>(Val: ClassDecl)) {
4069	// Nothing to do here.
4070	} else if (ObjCCategoryDecl *C = dyn_cast<ObjCCategoryDecl>(Val: ClassDecl)) {
4071	// Categories are used to extend the class by declaring new methods.
4072	// By the same token, they are also used to add new properties. No
4073	// need to compare the added property to those in the class.
4074
4075	if (C->IsClassExtension()) {
4076	ObjCInterfaceDecl *CCPrimary = C->getClassInterface();
4077	DiagnoseClassExtensionDupMethods(CAT: C, ID: CCPrimary);
4078	}
4079
4080	DiagnoseCategoryDirectMembersProtocolConformance(S&: *this, CDecl: C, Protocols: C->protocols());
4081	}
4082	if (ObjCContainerDecl *CDecl = dyn_cast<ObjCContainerDecl>(Val: ClassDecl)) {
4083	if (CDecl->getIdentifier())
4084	// ProcessPropertyDecl is responsible for diagnosing conflicts with any
4085	// user-defined setter/getter. It also synthesizes setter/getter methods
4086	// and adds them to the DeclContext and global method pools.
4087	for (auto *I : CDecl->properties())
4088	ProcessPropertyDecl(I);
4089	CDecl->setAtEndRange(AtEnd);
4090	}
4091	if (ObjCImplementationDecl *IC=dyn_cast<ObjCImplementationDecl>(Val: ClassDecl)) {
4092	IC->setAtEndRange(AtEnd);
4093	if (ObjCInterfaceDecl* IDecl = IC->getClassInterface()) {
4094	// Any property declared in a class extension might have user
4095	// declared setter or getter in current class extension or one
4096	// of the other class extensions. Mark them as synthesized as
4097	// property will be synthesized when property with same name is
4098	// seen in the @implementation.
4099	for (const auto *Ext : IDecl->visible_extensions()) {
4100	for (const auto *Property : Ext->instance_properties()) {
4101	// Skip over properties declared @dynamic
4102	if (const ObjCPropertyImplDecl *PIDecl
4103	= IC->FindPropertyImplDecl(Property->getIdentifier(),
4104	Property->getQueryKind()))
4105	if (PIDecl->getPropertyImplementation()
4106	== ObjCPropertyImplDecl::Dynamic)
4107	continue;
4108
4109	for (const auto *Ext : IDecl->visible_extensions()) {
4110	if (ObjCMethodDecl *GetterMethod =
4111	Ext->getInstanceMethod(Property->getGetterName()))
4112	GetterMethod->setPropertyAccessor(true);
4113	if (!Property->isReadOnly())
4114	if (ObjCMethodDecl *SetterMethod
4115	= Ext->getInstanceMethod(Property->getSetterName()))
4116	SetterMethod->setPropertyAccessor(true);
4117	}
4118	}
4119	}
4120	ImplMethodsVsClassMethods(S, IC, IDecl);
4121	AtomicPropertySetterGetterRules(IC, IDecl);
4122	DiagnoseOwningPropertyGetterSynthesis(D: IC);
4123	DiagnoseUnusedBackingIvarInAccessor(S, ImplD: IC);
4124	if (IDecl->hasDesignatedInitializers())
4125	DiagnoseMissingDesignatedInitOverrides(ImplD: IC, IFD: IDecl);
4126	DiagnoseWeakIvars(S&: *this, ID: IC);
4127	DiagnoseRetainableFlexibleArrayMember(S&: *this, ID: IDecl);
4128
4129	bool HasRootClassAttr = IDecl->hasAttr<ObjCRootClassAttr>();
4130	if (IDecl->getSuperClass() == nullptr) {
4131	// This class has no superclass, so check that it has been marked with
4132	// __attribute((objc_root_class)).
4133	if (!HasRootClassAttr) {
4134	SourceLocation DeclLoc(IDecl->getLocation());
4135	SourceLocation SuperClassLoc(getLocForEndOfToken(Loc: DeclLoc));
4136	Diag(DeclLoc, diag::warn_objc_root_class_missing)
4137	<< IDecl->getIdentifier();
4138	// See if NSObject is in the current scope, and if it is, suggest
4139	// adding " : NSObject " to the class declaration.
4140	NamedDecl *IF = LookupSingleName(S: TUScope,
4141	Name: NSAPIObj->getNSClassId(K: NSAPI::ClassId_NSObject),
4142	Loc: DeclLoc, NameKind: LookupOrdinaryName);
4143	ObjCInterfaceDecl *NSObjectDecl = dyn_cast_or_null<ObjCInterfaceDecl>(Val: IF);
4144	if (NSObjectDecl && NSObjectDecl->getDefinition()) {
4145	Diag(SuperClassLoc, diag::note_objc_needs_superclass)
4146	<< FixItHint::CreateInsertion(SuperClassLoc, " : NSObject ");
4147	} else {
4148	Diag(SuperClassLoc, diag::note_objc_needs_superclass);
4149	}
4150	}
4151	} else if (HasRootClassAttr) {
4152	// Complain that only root classes may have this attribute.
4153	Diag(IDecl->getLocation(), diag::err_objc_root_class_subclass);
4154	}
4155
4156	if (const ObjCInterfaceDecl *Super = IDecl->getSuperClass()) {
4157	// An interface can subclass another interface with a
4158	// objc_subclassing_restricted attribute when it has that attribute as
4159	// well (because of interfaces imported from Swift). Therefore we have
4160	// to check if we can subclass in the implementation as well.
4161	if (IDecl->hasAttr<ObjCSubclassingRestrictedAttr>() &&
4162	Super->hasAttr<ObjCSubclassingRestrictedAttr>()) {
4163	Diag(IC->getLocation(), diag::err_restricted_superclass_mismatch);
4164	Diag(Super->getLocation(), diag::note_class_declared);
4165	}
4166	}
4167
4168	if (IDecl->hasAttr<ObjCClassStubAttr>())
4169	Diag(IC->getLocation(), diag::err_implementation_of_class_stub);
4170
4171	if (LangOpts.ObjCRuntime.isNonFragile()) {
4172	while (IDecl->getSuperClass()) {
4173	DiagnoseDuplicateIvars(ID: IDecl, SID: IDecl->getSuperClass());
4174	IDecl = IDecl->getSuperClass();
4175	}
4176	}
4177	}
4178	SetIvarInitializers(IC);
4179	} else if (ObjCCategoryImplDecl* CatImplClass =
4180	dyn_cast<ObjCCategoryImplDecl>(Val: ClassDecl)) {
4181	CatImplClass->setAtEndRange(AtEnd);
4182
4183	// Find category interface decl and then check that all methods declared
4184	// in this interface are implemented in the category @implementation.
4185	if (ObjCInterfaceDecl* IDecl = CatImplClass->getClassInterface()) {
4186	if (ObjCCategoryDecl *Cat
4187	= IDecl->FindCategoryDeclaration(CategoryId: CatImplClass->getIdentifier())) {
4188	ImplMethodsVsClassMethods(S, CatImplClass, Cat);
4189	}
4190	}
4191	} else if (const auto *IntfDecl = dyn_cast<ObjCInterfaceDecl>(ClassDecl)) {
4192	if (const ObjCInterfaceDecl *Super = IntfDecl->getSuperClass()) {
4193	if (!IntfDecl->hasAttr<ObjCSubclassingRestrictedAttr>() &&
4194	Super->hasAttr<ObjCSubclassingRestrictedAttr>()) {
4195	Diag(IntfDecl->getLocation(), diag::err_restricted_superclass_mismatch);
4196	Diag(Super->getLocation(), diag::note_class_declared);
4197	}
4198	}
4199
4200	if (IntfDecl->hasAttr<ObjCClassStubAttr>() &&
4201	!IntfDecl->hasAttr<ObjCSubclassingRestrictedAttr>())
4202	Diag(IntfDecl->getLocation(), diag::err_class_stub_subclassing_mismatch);
4203	}
4204	DiagnoseVariableSizedIvars(S&: *this, OCD);
4205	if (isInterfaceDeclKind) {
4206	// Reject invalid vardecls.
4207	for (unsigned i = 0, e = allTUVars.size(); i != e; i++) {
4208	DeclGroupRef DG = allTUVars[i].get();
4209	for (DeclGroupRef::iterator I = DG.begin(), E = DG.end(); I != E; ++I)
4210	if (VarDecl *VDecl = dyn_cast<VarDecl>(Val: *I)) {
4211	if (!VDecl->hasExternalStorage())
4212	Diag(VDecl->getLocation(), diag::err_objc_var_decl_inclass);
4213	}
4214	}
4215	}
4216	ActOnObjCContainerFinishDefinition();
4217
4218	for (unsigned i = 0, e = allTUVars.size(); i != e; i++) {
4219	DeclGroupRef DG = allTUVars[i].get();
4220	for (DeclGroupRef::iterator I = DG.begin(), E = DG.end(); I != E; ++I)
4221	(*I)->setTopLevelDeclInObjCContainer();
4222	Consumer.HandleTopLevelDeclInObjCContainer(D: DG);
4223	}
4224
4225	ActOnDocumentableDecl(D: ClassDecl);
4226	return ClassDecl;
4227	}
4228
4229	/// CvtQTToAstBitMask - utility routine to produce an AST bitmask for
4230	/// objective-c's type qualifier from the parser version of the same info.
4231	static Decl::ObjCDeclQualifier
4232	CvtQTToAstBitMask(ObjCDeclSpec::ObjCDeclQualifier PQTVal) {
4233	return (Decl::ObjCDeclQualifier) (unsigned) PQTVal;
4234	}
4235
4236	/// Check whether the declared result type of the given Objective-C
4237	/// method declaration is compatible with the method's class.
4238	///
4239	static Sema::ResultTypeCompatibilityKind
4240	CheckRelatedResultTypeCompatibility(Sema &S, ObjCMethodDecl *Method,
4241	ObjCInterfaceDecl *CurrentClass) {
4242	QualType ResultType = Method->getReturnType();
4243
4244	// If an Objective-C method inherits its related result type, then its
4245	// declared result type must be compatible with its own class type. The
4246	// declared result type is compatible if:
4247	if (const ObjCObjectPointerType *ResultObjectType
4248	= ResultType->getAs<ObjCObjectPointerType>()) {
4249	// - it is id or qualified id, or
4250	if (ResultObjectType->isObjCIdType() ||
4251	ResultObjectType->isObjCQualifiedIdType())
4252	return Sema::RTC_Compatible;
4253
4254	if (CurrentClass) {
4255	if (ObjCInterfaceDecl *ResultClass
4256	= ResultObjectType->getInterfaceDecl()) {
4257	// - it is the same as the method's class type, or
4258	if (declaresSameEntity(CurrentClass, ResultClass))
4259	return Sema::RTC_Compatible;
4260
4261	// - it is a superclass of the method's class type
4262	if (ResultClass->isSuperClassOf(I: CurrentClass))
4263	return Sema::RTC_Compatible;
4264	}
4265	} else {
4266	// Any Objective-C pointer type might be acceptable for a protocol
4267	// method; we just don't know.
4268	return Sema::RTC_Unknown;
4269	}
4270	}
4271
4272	return Sema::RTC_Incompatible;
4273	}
4274
4275	namespace {
4276	/// A helper class for searching for methods which a particular method
4277	/// overrides.
4278	class OverrideSearch {
4279	public:
4280	const ObjCMethodDecl *Method;
4281	llvm::SmallSetVector<ObjCMethodDecl*, 4> Overridden;
4282	bool Recursive;
4283
4284	public:
4285	OverrideSearch(Sema &S, const ObjCMethodDecl *method) : Method(method) {
4286	Selector selector = method->getSelector();
4287
4288	// Bypass this search if we've never seen an instance/class method
4289	// with this selector before.
4290	Sema::GlobalMethodPool::iterator it = S.MethodPool.find(Sel: selector);
4291	if (it == S.MethodPool.end()) {
4292	if (!S.getExternalSource()) return;
4293	S.ReadMethodPool(Sel: selector);
4294
4295	it = S.MethodPool.find(Sel: selector);
4296	if (it == S.MethodPool.end())
4297	return;
4298	}
4299	const ObjCMethodList &list =
4300	method->isInstanceMethod() ? it->second.first : it->second.second;
4301	if (!list.getMethod()) return;
4302
4303	const ObjCContainerDecl *container
4304	= cast<ObjCContainerDecl>(method->getDeclContext());
4305
4306	// Prevent the search from reaching this container again. This is
4307	// important with categories, which override methods from the
4308	// interface and each other.
4309	if (const ObjCCategoryDecl *Category =
4310	dyn_cast<ObjCCategoryDecl>(container)) {
4311	searchFromContainer(container);
4312	if (const ObjCInterfaceDecl *Interface = Category->getClassInterface())
4313	searchFromContainer(Interface);
4314	} else {
4315	searchFromContainer(container);
4316	}
4317	}
4318
4319	typedef decltype(Overridden)::iterator iterator;
4320	iterator begin() const { return Overridden.begin(); }
4321	iterator end() const { return Overridden.end(); }
4322
4323	private:
4324	void searchFromContainer(const ObjCContainerDecl *container) {
4325	if (container->isInvalidDecl()) return;
4326
4327	switch (container->getDeclKind()) {
4328	#define OBJCCONTAINER(type, base) \
4329	case Decl::type: \
4330	searchFrom(cast<type##Decl>(container)); \
4331	break;
4332	#define ABSTRACT_DECL(expansion)
4333	#define DECL(type, base) \
4334	case Decl::type:
4335	#include "clang/AST/DeclNodes.inc"
4336	llvm_unreachable("not an ObjC container!");
4337	}
4338	}
4339
4340	void searchFrom(const ObjCProtocolDecl *protocol) {
4341	if (!protocol->hasDefinition())
4342	return;
4343
4344	// A method in a protocol declaration overrides declarations from
4345	// referenced ("parent") protocols.
4346	search(protocols: protocol->getReferencedProtocols());
4347	}
4348
4349	void searchFrom(const ObjCCategoryDecl *category) {
4350	// A method in a category declaration overrides declarations from
4351	// the main class and from protocols the category references.
4352	// The main class is handled in the constructor.
4353	search(protocols: category->getReferencedProtocols());
4354	}
4355
4356	void searchFrom(const ObjCCategoryImplDecl *impl) {
4357	// A method in a category definition that has a category
4358	// declaration overrides declarations from the category
4359	// declaration.
4360	if (ObjCCategoryDecl *category = impl->getCategoryDecl()) {
4361	search(category);
4362	if (ObjCInterfaceDecl *Interface = category->getClassInterface())
4363	search(Interface);
4364
4365	// Otherwise it overrides declarations from the class.
4366	} else if (const auto *Interface = impl->getClassInterface()) {
4367	search(Interface);
4368	}
4369	}
4370
4371	void searchFrom(const ObjCInterfaceDecl *iface) {
4372	// A method in a class declaration overrides declarations from
4373	if (!iface->hasDefinition())
4374	return;
4375
4376	// - categories,
4377	for (auto *Cat : iface->known_categories())
4378	search(Cat);
4379
4380	// - the super class, and
4381	if (ObjCInterfaceDecl *super = iface->getSuperClass())
4382	search(super);
4383
4384	// - any referenced protocols.
4385	search(protocols: iface->getReferencedProtocols());
4386	}
4387
4388	void searchFrom(const ObjCImplementationDecl *impl) {
4389	// A method in a class implementation overrides declarations from
4390	// the class interface.
4391	if (const auto *Interface = impl->getClassInterface())
4392	search(Interface);
4393	}
4394
4395	void search(const ObjCProtocolList &protocols) {
4396	for (const auto *Proto : protocols)
4397	search(Proto);
4398	}
4399
4400	void search(const ObjCContainerDecl *container) {
4401	// Check for a method in this container which matches this selector.
4402	ObjCMethodDecl *meth = container->getMethod(Sel: Method->getSelector(),
4403	isInstance: Method->isInstanceMethod(),
4404	/*AllowHidden=*/true);
4405
4406	// If we find one, record it and bail out.
4407	if (meth) {
4408	Overridden.insert(X: meth);
4409	return;
4410	}
4411
4412	// Otherwise, search for methods that a hypothetical method here
4413	// would have overridden.
4414
4415	// Note that we're now in a recursive case.
4416	Recursive = true;
4417
4418	searchFromContainer(container);
4419	}
4420	};
4421	} // end anonymous namespace
4422
4423	void Sema::CheckObjCMethodDirectOverrides(ObjCMethodDecl *method,
4424	ObjCMethodDecl *overridden) {
4425	if (overridden->isDirectMethod()) {
4426	const auto *attr = overridden->getAttr<ObjCDirectAttr>();
4427	Diag(method->getLocation(), diag::err_objc_override_direct_method);
4428	Diag(attr->getLocation(), diag::note_previous_declaration);
4429	} else if (method->isDirectMethod()) {
4430	const auto *attr = method->getAttr<ObjCDirectAttr>();
4431	Diag(attr->getLocation(), diag::err_objc_direct_on_override)
4432	<< isa<ObjCProtocolDecl>(overridden->getDeclContext());
4433	Diag(overridden->getLocation(), diag::note_previous_declaration);
4434	}
4435	}
4436
4437	void Sema::CheckObjCMethodOverrides(ObjCMethodDecl *ObjCMethod,
4438	ObjCInterfaceDecl *CurrentClass,
4439	ResultTypeCompatibilityKind RTC) {
4440	if (!ObjCMethod)
4441	return;
4442	auto IsMethodInCurrentClass = [CurrentClass](const ObjCMethodDecl *M) {
4443	// Checking canonical decl works across modules.
4444	return M->getClassInterface()->getCanonicalDecl() ==
4445	CurrentClass->getCanonicalDecl();
4446	};
4447	// Search for overridden methods and merge information down from them.
4448	OverrideSearch overrides(*this, ObjCMethod);
4449	// Keep track if the method overrides any method in the class's base classes,
4450	// its protocols, or its categories' protocols; we will keep that info
4451	// in the ObjCMethodDecl.
4452	// For this info, a method in an implementation is not considered as
4453	// overriding the same method in the interface or its categories.
4454	bool hasOverriddenMethodsInBaseOrProtocol = false;
4455	for (ObjCMethodDecl *overridden : overrides) {
4456	if (!hasOverriddenMethodsInBaseOrProtocol) {
4457	if (isa<ObjCProtocolDecl>(overridden->getDeclContext()) ||
4458	!IsMethodInCurrentClass(overridden) || overridden->isOverriding()) {
4459	CheckObjCMethodDirectOverrides(method: ObjCMethod, overridden);
4460	hasOverriddenMethodsInBaseOrProtocol = true;
4461	} else if (isa<ObjCImplDecl>(ObjCMethod->getDeclContext())) {
4462	// OverrideSearch will return as "overridden" the same method in the
4463	// interface. For hasOverriddenMethodsInBaseOrProtocol, we need to
4464	// check whether a category of a base class introduced a method with the
4465	// same selector, after the interface method declaration.
4466	// To avoid unnecessary lookups in the majority of cases, we use the
4467	// extra info bits in GlobalMethodPool to check whether there were any
4468	// category methods with this selector.
4469	GlobalMethodPool::iterator It =
4470	MethodPool.find(Sel: ObjCMethod->getSelector());
4471	if (It != MethodPool.end()) {
4472	ObjCMethodList &List =
4473	ObjCMethod->isInstanceMethod()? It->second.first: It->second.second;
4474	unsigned CategCount = List.getBits();
4475	if (CategCount > 0) {
4476	// If the method is in a category we'll do lookup if there were at
4477	// least 2 category methods recorded, otherwise only one will do.
4478	if (CategCount > 1 ||
4479	!isa<ObjCCategoryImplDecl>(overridden->getDeclContext())) {
4480	OverrideSearch overrides(*this, overridden);
4481	for (ObjCMethodDecl *SuperOverridden : overrides) {
4482	if (isa<ObjCProtocolDecl>(SuperOverridden->getDeclContext()) ||
4483	!IsMethodInCurrentClass(SuperOverridden)) {
4484	CheckObjCMethodDirectOverrides(method: ObjCMethod, overridden: SuperOverridden);
4485	hasOverriddenMethodsInBaseOrProtocol = true;
4486	overridden->setOverriding(true);
4487	break;
4488	}
4489	}
4490	}
4491	}
4492	}
4493	}
4494	}
4495
4496	// Propagate down the 'related result type' bit from overridden methods.
4497	if (RTC != Sema::RTC_Incompatible && overridden->hasRelatedResultType())
4498	ObjCMethod->setRelatedResultType();
4499
4500	// Then merge the declarations.
4501	mergeObjCMethodDecls(New: ObjCMethod, Old: overridden);
4502
4503	if (ObjCMethod->isImplicit() && overridden->isImplicit())
4504	continue; // Conflicting properties are detected elsewhere.
4505
4506	// Check for overriding methods
4507	if (isa<ObjCInterfaceDecl>(ObjCMethod->getDeclContext()) ||
4508	isa<ObjCImplementationDecl>(ObjCMethod->getDeclContext()))
4509	CheckConflictingOverridingMethod(Method: ObjCMethod, Overridden: overridden,
4510	IsProtocolMethodDecl: isa<ObjCProtocolDecl>(overridden->getDeclContext()));
4511
4512	if (CurrentClass && overridden->getDeclContext() != CurrentClass &&
4513	isa<ObjCInterfaceDecl>(overridden->getDeclContext()) &&
4514	!overridden->isImplicit() /* not meant for properties */) {
4515	ObjCMethodDecl::param_iterator ParamI = ObjCMethod->param_begin(),
4516	E = ObjCMethod->param_end();
4517	ObjCMethodDecl::param_iterator PrevI = overridden->param_begin(),
4518	PrevE = overridden->param_end();
4519	for (; ParamI != E && PrevI != PrevE; ++ParamI, ++PrevI) {
4520	assert(PrevI != overridden->param_end() && "Param mismatch");
4521	QualType T1 = Context.getCanonicalType((*ParamI)->getType());
4522	QualType T2 = Context.getCanonicalType((*PrevI)->getType());
4523	// If type of argument of method in this class does not match its
4524	// respective argument type in the super class method, issue warning;
4525	if (!Context.typesAreCompatible(T1, T2)) {
4526	Diag((*ParamI)->getLocation(), diag::ext_typecheck_base_super)
4527	<< T1 << T2;
4528	Diag(overridden->getLocation(), diag::note_previous_declaration);
4529	break;
4530	}
4531	}
4532	}
4533	}
4534
4535	ObjCMethod->setOverriding(hasOverriddenMethodsInBaseOrProtocol);
4536	}
4537
4538	/// Merge type nullability from for a redeclaration of the same entity,
4539	/// producing the updated type of the redeclared entity.
4540	static QualType mergeTypeNullabilityForRedecl(Sema &S, SourceLocation loc,
4541	QualType type,
4542	bool usesCSKeyword,
4543	SourceLocation prevLoc,
4544	QualType prevType,
4545	bool prevUsesCSKeyword) {
4546	// Determine the nullability of both types.
4547	auto nullability = type->getNullability();
4548	auto prevNullability = prevType->getNullability();
4549
4550	// Easy case: both have nullability.
4551	if (nullability.has_value() == prevNullability.has_value()) {
4552	// Neither has nullability; continue.
4553	if (!nullability)
4554	return type;
4555
4556	// The nullabilities are equivalent; do nothing.
4557	if (*nullability == *prevNullability)
4558	return type;
4559
4560	// Complain about mismatched nullability.
4561	S.Diag(loc, diag::err_nullability_conflicting)
4562	<< DiagNullabilityKind(*nullability, usesCSKeyword)
4563	<< DiagNullabilityKind(*prevNullability, prevUsesCSKeyword);
4564	return type;
4565	}
4566
4567	// If it's the redeclaration that has nullability, don't change anything.
4568	if (nullability)
4569	return type;
4570
4571	// Otherwise, provide the result with the same nullability.
4572	return S.Context.getAttributedType(
4573	attrKind: AttributedType::getNullabilityAttrKind(kind: *prevNullability),
4574	modifiedType: type, equivalentType: type);
4575	}
4576
4577	/// Merge information from the declaration of a method in the \@interface
4578	/// (or a category/extension) into the corresponding method in the
4579	/// @implementation (for a class or category).
4580	static void mergeInterfaceMethodToImpl(Sema &S,
4581	ObjCMethodDecl *method,
4582	ObjCMethodDecl *prevMethod) {
4583	// Merge the objc_requires_super attribute.
4584	if (prevMethod->hasAttr<ObjCRequiresSuperAttr>() &&
4585	!method->hasAttr<ObjCRequiresSuperAttr>()) {
4586	// merge the attribute into implementation.
4587	method->addAttr(
4588	ObjCRequiresSuperAttr::CreateImplicit(S.Context,
4589	method->getLocation()));
4590	}
4591
4592	// Merge nullability of the result type.
4593	QualType newReturnType
4594	= mergeTypeNullabilityForRedecl(
4595	S, loc: method->getReturnTypeSourceRange().getBegin(),
4596	type: method->getReturnType(),
4597	usesCSKeyword: method->getObjCDeclQualifier() & Decl::OBJC_TQ_CSNullability,
4598	prevLoc: prevMethod->getReturnTypeSourceRange().getBegin(),
4599	prevType: prevMethod->getReturnType(),
4600	prevUsesCSKeyword: prevMethod->getObjCDeclQualifier() & Decl::OBJC_TQ_CSNullability);
4601	method->setReturnType(newReturnType);
4602
4603	// Handle each of the parameters.
4604	unsigned numParams = method->param_size();
4605	unsigned numPrevParams = prevMethod->param_size();
4606	for (unsigned i = 0, n = std::min(a: numParams, b: numPrevParams); i != n; ++i) {
4607	ParmVarDecl *param = method->param_begin()[i];
4608	ParmVarDecl *prevParam = prevMethod->param_begin()[i];
4609
4610	// Merge nullability.
4611	QualType newParamType
4612	= mergeTypeNullabilityForRedecl(
4613	S, param->getLocation(), param->getType(),
4614	param->getObjCDeclQualifier() & Decl::OBJC_TQ_CSNullability,
4615	prevParam->getLocation(), prevParam->getType(),
4616	prevParam->getObjCDeclQualifier() & Decl::OBJC_TQ_CSNullability);
4617	param->setType(newParamType);
4618	}
4619	}
4620
4621	/// Verify that the method parameters/return value have types that are supported
4622	/// by the x86 target.
4623	static void checkObjCMethodX86VectorTypes(Sema &SemaRef,
4624	const ObjCMethodDecl *Method) {
4625	assert(SemaRef.getASTContext().getTargetInfo().getTriple().getArch() ==
4626	llvm::Triple::x86 &&
4627	"x86-specific check invoked for a different target");
4628	SourceLocation Loc;
4629	QualType T;
4630	for (const ParmVarDecl *P : Method->parameters()) {
4631	if (P->getType()->isVectorType()) {
4632	Loc = P->getBeginLoc();
4633	T = P->getType();
4634	break;
4635	}
4636	}
4637	if (Loc.isInvalid()) {
4638	if (Method->getReturnType()->isVectorType()) {
4639	Loc = Method->getReturnTypeSourceRange().getBegin();
4640	T = Method->getReturnType();
4641	} else
4642	return;
4643	}
4644
4645	// Vector parameters/return values are not supported by objc_msgSend on x86 in
4646	// iOS < 9 and macOS < 10.11.
4647	const auto &Triple = SemaRef.getASTContext().getTargetInfo().getTriple();
4648	VersionTuple AcceptedInVersion;
4649	if (Triple.getOS() == llvm::Triple::IOS)
4650	AcceptedInVersion = VersionTuple(/*Major=*/9);
4651	else if (Triple.isMacOSX())
4652	AcceptedInVersion = VersionTuple(/*Major=*/10, /*Minor=*/11);
4653	else
4654	return;
4655	if (SemaRef.getASTContext().getTargetInfo().getPlatformMinVersion() >=
4656	AcceptedInVersion)
4657	return;
4658	SemaRef.Diag(Loc, diag::err_objc_method_unsupported_param_ret_type)
4659	<< T << (Method->getReturnType()->isVectorType() ? /*return value*/ 1
4660	: /*parameter*/ 0)
4661	<< (Triple.isMacOSX() ? "macOS 10.11" : "iOS 9");
4662	}
4663
4664	static void mergeObjCDirectMembers(Sema &S, Decl *CD, ObjCMethodDecl *Method) {
4665	if (!Method->isDirectMethod() && !Method->hasAttr<UnavailableAttr>() &&
4666	CD->hasAttr<ObjCDirectMembersAttr>()) {
4667	Method->addAttr(
4668	ObjCDirectAttr::CreateImplicit(S.Context, Method->getLocation()));
4669	}
4670	}
4671
4672	static void checkObjCDirectMethodClashes(Sema &S, ObjCInterfaceDecl *IDecl,
4673	ObjCMethodDecl *Method,
4674	ObjCImplDecl *ImpDecl = nullptr) {
4675	auto Sel = Method->getSelector();
4676	bool isInstance = Method->isInstanceMethod();
4677	bool diagnosed = false;
4678
4679	auto diagClash = [&](const ObjCMethodDecl *IMD) {
4680	if (diagnosed || IMD->isImplicit())
4681	return;
4682	if (Method->isDirectMethod() || IMD->isDirectMethod()) {
4683	S.Diag(Method->getLocation(), diag::err_objc_direct_duplicate_decl)
4684	<< Method->isDirectMethod() << /* method */ 0 << IMD->isDirectMethod()
4685	<< Method->getDeclName();
4686	S.Diag(IMD->getLocation(), diag::note_previous_declaration);
4687	diagnosed = true;
4688	}
4689	};
4690
4691	// Look for any other declaration of this method anywhere we can see in this
4692	// compilation unit.
4693	//
4694	// We do not use IDecl->lookupMethod() because we have specific needs:
4695	//
4696	// - we absolutely do not need to walk protocols, because
4697	// diag::err_objc_direct_on_protocol has already been emitted
4698	// during parsing if there's a conflict,
4699	//
4700	// - when we do not find a match in a given @interface container,
4701	// we need to attempt looking it up in the @implementation block if the
4702	// translation unit sees it to find more clashes.
4703
4704	if (auto *IMD = IDecl->getMethod(Sel, isInstance))
4705	diagClash(IMD);
4706	else if (auto *Impl = IDecl->getImplementation())
4707	if (Impl != ImpDecl)
4708	if (auto *IMD = IDecl->getImplementation()->getMethod(Sel, isInstance))
4709	diagClash(IMD);
4710
4711	for (const auto *Cat : IDecl->visible_categories())
4712	if (auto *IMD = Cat->getMethod(Sel, isInstance))
4713	diagClash(IMD);
4714	else if (auto CatImpl = Cat->getImplementation())
4715	if (CatImpl != ImpDecl)
4716	if (auto *IMD = Cat->getMethod(Sel, isInstance))
4717	diagClash(IMD);
4718	}
4719
4720	Decl *Sema::ActOnMethodDeclaration(
4721	Scope *S, SourceLocation MethodLoc, SourceLocation EndLoc,
4722	tok::TokenKind MethodType, ObjCDeclSpec &ReturnQT, ParsedType ReturnType,
4723	ArrayRef<SourceLocation> SelectorLocs, Selector Sel,
4724	// optional arguments. The number of types/arguments is obtained
4725	// from the Sel.getNumArgs().
4726	ObjCArgInfo *ArgInfo, DeclaratorChunk::ParamInfo *CParamInfo,
4727	unsigned CNumArgs, // c-style args
4728	const ParsedAttributesView &AttrList, tok::ObjCKeywordKind MethodDeclKind,
4729	bool isVariadic, bool MethodDefinition) {
4730	// Make sure we can establish a context for the method.
4731	if (!CurContext->isObjCContainer()) {
4732	Diag(MethodLoc, diag::err_missing_method_context);
4733	return nullptr;
4734	}
4735
4736	Decl *ClassDecl = cast<ObjCContainerDecl>(Val: CurContext);
4737	QualType resultDeclType;
4738
4739	bool HasRelatedResultType = false;
4740	TypeSourceInfo *ReturnTInfo = nullptr;
4741	if (ReturnType) {
4742	resultDeclType = GetTypeFromParser(Ty: ReturnType, TInfo: &ReturnTInfo);
4743
4744	if (CheckFunctionReturnType(T: resultDeclType, Loc: MethodLoc))
4745	return nullptr;
4746
4747	QualType bareResultType = resultDeclType;
4748	(void)AttributedType::stripOuterNullability(T&: bareResultType);
4749	HasRelatedResultType = (bareResultType == Context.getObjCInstanceType());
4750	} else { // get the type for "id".
4751	resultDeclType = Context.getObjCIdType();
4752	Diag(MethodLoc, diag::warn_missing_method_return_type)
4753	<< FixItHint::CreateInsertion(SelectorLocs.front(), "(id)");
4754	}
4755
4756	ObjCMethodDecl *ObjCMethod = ObjCMethodDecl::Create(
4757	C&: Context, beginLoc: MethodLoc, endLoc: EndLoc, SelInfo: Sel, T: resultDeclType, ReturnTInfo, contextDecl: CurContext,
4758	isInstance: MethodType == tok::minus, isVariadic,
4759	/*isPropertyAccessor=*/false, /*isSynthesizedAccessorStub=*/false,
4760	/*isImplicitlyDeclared=*/false, /*isDefined=*/false,
4761	impControl: MethodDeclKind == tok::objc_optional
4762	? ObjCImplementationControl::Optional
4763	: ObjCImplementationControl::Required,
4764	HasRelatedResultType);
4765
4766	SmallVector<ParmVarDecl*, 16> Params;
4767
4768	for (unsigned i = 0, e = Sel.getNumArgs(); i != e; ++i) {
4769	QualType ArgType;
4770	TypeSourceInfo *DI;
4771
4772	if (!ArgInfo[i].Type) {
4773	ArgType = Context.getObjCIdType();
4774	DI = nullptr;
4775	} else {
4776	ArgType = GetTypeFromParser(Ty: ArgInfo[i].Type, TInfo: &DI);
4777	}
4778
4779	LookupResult R(*this, ArgInfo[i].Name, ArgInfo[i].NameLoc,
4780	LookupOrdinaryName, forRedeclarationInCurContext());
4781	LookupName(R, S);
4782	if (R.isSingleResult()) {
4783	NamedDecl *PrevDecl = R.getFoundDecl();
4784	if (S->isDeclScope(PrevDecl)) {
4785	Diag(ArgInfo[i].NameLoc,
4786	(MethodDefinition ? diag::warn_method_param_redefinition
4787	: diag::warn_method_param_declaration))
4788	<< ArgInfo[i].Name;
4789	Diag(PrevDecl->getLocation(),
4790	diag::note_previous_declaration);
4791	}
4792	}
4793
4794	SourceLocation StartLoc = DI
4795	? DI->getTypeLoc().getBeginLoc()
4796	: ArgInfo[i].NameLoc;
4797
4798	ParmVarDecl* Param = CheckParameter(ObjCMethod, StartLoc,
4799	ArgInfo[i].NameLoc, ArgInfo[i].Name,
4800	ArgType, DI, SC_None);
4801
4802	Param->setObjCMethodScopeInfo(i);
4803
4804	Param->setObjCDeclQualifier(
4805	CvtQTToAstBitMask(PQTVal: ArgInfo[i].DeclSpec.getObjCDeclQualifier()));
4806
4807	// Apply the attributes to the parameter.
4808	ProcessDeclAttributeList(TUScope, Param, ArgInfo[i].ArgAttrs);
4809	AddPragmaAttributes(TUScope, Param);
4810
4811	if (Param->hasAttr<BlocksAttr>()) {
4812	Diag(Param->getLocation(), diag::err_block_on_nonlocal);
4813	Param->setInvalidDecl();
4814	}
4815	S->AddDecl(Param);
4816	IdResolver.AddDecl(Param);
4817
4818	Params.push_back(Elt: Param);
4819	}
4820
4821	for (unsigned i = 0, e = CNumArgs; i != e; ++i) {
4822	ParmVarDecl *Param = cast<ParmVarDecl>(Val: CParamInfo[i].Param);
4823	QualType ArgType = Param->getType();
4824	if (ArgType.isNull())
4825	ArgType = Context.getObjCIdType();
4826	else
4827	// Perform the default array/function conversions (C99 6.7.5.3p[7,8]).
4828	ArgType = Context.getAdjustedParameterType(T: ArgType);
4829
4830	Param->setDeclContext(ObjCMethod);
4831	Params.push_back(Elt: Param);
4832	}
4833
4834	ObjCMethod->setMethodParams(C&: Context, Params, SelLocs: SelectorLocs);
4835	ObjCMethod->setObjCDeclQualifier(
4836	CvtQTToAstBitMask(PQTVal: ReturnQT.getObjCDeclQualifier()));
4837
4838	ProcessDeclAttributeList(TUScope, ObjCMethod, AttrList);
4839	AddPragmaAttributes(TUScope, ObjCMethod);
4840
4841	// Add the method now.
4842	const ObjCMethodDecl *PrevMethod = nullptr;
4843	if (ObjCImplDecl *ImpDecl = dyn_cast<ObjCImplDecl>(Val: ClassDecl)) {
4844	if (MethodType == tok::minus) {
4845	PrevMethod = ImpDecl->getInstanceMethod(Sel);
4846	ImpDecl->addInstanceMethod(method: ObjCMethod);
4847	} else {
4848	PrevMethod = ImpDecl->getClassMethod(Sel);
4849	ImpDecl->addClassMethod(method: ObjCMethod);
4850	}
4851
4852	// If this method overrides a previous @synthesize declaration,
4853	// register it with the property. Linear search through all
4854	// properties here, because the autosynthesized stub hasn't been
4855	// made visible yet, so it can be overridden by a later
4856	// user-specified implementation.
4857	for (ObjCPropertyImplDecl *PropertyImpl : ImpDecl->property_impls()) {
4858	if (auto *Setter = PropertyImpl->getSetterMethodDecl())
4859	if (Setter->getSelector() == Sel &&
4860	Setter->isInstanceMethod() == ObjCMethod->isInstanceMethod()) {
4861	assert(Setter->isSynthesizedAccessorStub() && "autosynth stub expected");
4862	PropertyImpl->setSetterMethodDecl(ObjCMethod);
4863	}
4864	if (auto *Getter = PropertyImpl->getGetterMethodDecl())
4865	if (Getter->getSelector() == Sel &&
4866	Getter->isInstanceMethod() == ObjCMethod->isInstanceMethod()) {
4867	assert(Getter->isSynthesizedAccessorStub() && "autosynth stub expected");
4868	PropertyImpl->setGetterMethodDecl(ObjCMethod);
4869	break;
4870	}
4871	}
4872
4873	// A method is either tagged direct explicitly, or inherits it from its
4874	// canonical declaration.
4875	//
4876	// We have to do the merge upfront and not in mergeInterfaceMethodToImpl()
4877	// because IDecl->lookupMethod() returns more possible matches than just
4878	// the canonical declaration.
4879	if (!ObjCMethod->isDirectMethod()) {
4880	const ObjCMethodDecl *CanonicalMD = ObjCMethod->getCanonicalDecl();
4881	if (CanonicalMD->isDirectMethod()) {
4882	const auto *attr = CanonicalMD->getAttr<ObjCDirectAttr>();
4883	ObjCMethod->addAttr(
4884	ObjCDirectAttr::CreateImplicit(Context, attr->getLocation()));
4885	}
4886	}
4887
4888	// Merge information from the @interface declaration into the
4889	// @implementation.
4890	if (ObjCInterfaceDecl *IDecl = ImpDecl->getClassInterface()) {
4891	if (auto *IMD = IDecl->lookupMethod(ObjCMethod->getSelector(),
4892	ObjCMethod->isInstanceMethod())) {
4893	mergeInterfaceMethodToImpl(*this, ObjCMethod, IMD);
4894
4895	// The Idecl->lookupMethod() above will find declarations for ObjCMethod
4896	// in one of these places:
4897	//
4898	// (1) the canonical declaration in an @interface container paired
4899	// with the ImplDecl,
4900	// (2) non canonical declarations in @interface not paired with the
4901	// ImplDecl for the same Class,
4902	// (3) any superclass container.
4903	//
4904	// Direct methods only allow for canonical declarations in the matching
4905	// container (case 1).
4906	//
4907	// Direct methods overriding a superclass declaration (case 3) is
4908	// handled during overrides checks in CheckObjCMethodOverrides().
4909	//
4910	// We deal with same-class container mismatches (Case 2) here.
4911	if (IDecl == IMD->getClassInterface()) {
4912	auto diagContainerMismatch = [&] {
4913	int decl = 0, impl = 0;
4914
4915	if (auto *Cat = dyn_cast<ObjCCategoryDecl>(IMD->getDeclContext()))
4916	decl = Cat->IsClassExtension() ? 1 : 2;
4917
4918	if (isa<ObjCCategoryImplDecl>(Val: ImpDecl))
4919	impl = 1 + (decl != 0);
4920
4921	Diag(ObjCMethod->getLocation(),
4922	diag::err_objc_direct_impl_decl_mismatch)
4923	<< decl << impl;
4924	Diag(IMD->getLocation(), diag::note_previous_declaration);
4925	};
4926
4927	if (ObjCMethod->isDirectMethod()) {
4928	const auto *attr = ObjCMethod->getAttr<ObjCDirectAttr>();
4929	if (ObjCMethod->getCanonicalDecl() != IMD) {
4930	diagContainerMismatch();
4931	} else if (!IMD->isDirectMethod()) {
4932	Diag(attr->getLocation(), diag::err_objc_direct_missing_on_decl);
4933	Diag(IMD->getLocation(), diag::note_previous_declaration);
4934	}
4935	} else if (IMD->isDirectMethod()) {
4936	const auto *attr = IMD->getAttr<ObjCDirectAttr>();
4937	if (ObjCMethod->getCanonicalDecl() != IMD) {
4938	diagContainerMismatch();
4939	} else {
4940	ObjCMethod->addAttr(
4941	ObjCDirectAttr::CreateImplicit(Context, attr->getLocation()));
4942	}
4943	}
4944	}
4945
4946	// Warn about defining -dealloc in a category.
4947	if (isa<ObjCCategoryImplDecl>(Val: ImpDecl) && IMD->isOverriding() &&
4948	ObjCMethod->getSelector().getMethodFamily() == OMF_dealloc) {
4949	Diag(ObjCMethod->getLocation(), diag::warn_dealloc_in_category)
4950	<< ObjCMethod->getDeclName();
4951	}
4952	} else {
4953	mergeObjCDirectMembers(S&: *this, CD: ClassDecl, Method: ObjCMethod);
4954	checkObjCDirectMethodClashes(S&: *this, IDecl, Method: ObjCMethod, ImpDecl);
4955	}
4956
4957	// Warn if a method declared in a protocol to which a category or
4958	// extension conforms is non-escaping and the implementation's method is
4959	// escaping.
4960	for (auto *C : IDecl->visible_categories())
4961	for (auto &P : C->protocols())
4962	if (auto *IMD = P->lookupMethod(ObjCMethod->getSelector(),
4963	ObjCMethod->isInstanceMethod())) {
4964	assert(ObjCMethod->parameters().size() ==
4965	IMD->parameters().size() &&
4966	"Methods have different number of parameters");
4967	auto OI = IMD->param_begin(), OE = IMD->param_end();
4968	auto NI = ObjCMethod->param_begin();
4969	for (; OI != OE; ++OI, ++NI)
4970	diagnoseNoescape(*NI, *OI, C, P, *this);
4971	}
4972	}
4973	} else {
4974	if (!isa<ObjCProtocolDecl>(Val: ClassDecl)) {
4975	mergeObjCDirectMembers(S&: *this, CD: ClassDecl, Method: ObjCMethod);
4976
4977	ObjCInterfaceDecl *IDecl = dyn_cast<ObjCInterfaceDecl>(Val: ClassDecl);
4978	if (!IDecl)
4979	IDecl = cast<ObjCCategoryDecl>(Val: ClassDecl)->getClassInterface();
4980	// For valid code, we should always know the primary interface
4981	// declaration by now, however for invalid code we'll keep parsing
4982	// but we won't find the primary interface and IDecl will be nil.
4983	if (IDecl)
4984	checkObjCDirectMethodClashes(S&: *this, IDecl, Method: ObjCMethod);
4985	}
4986
4987	cast<DeclContext>(Val: ClassDecl)->addDecl(ObjCMethod);
4988	}
4989
4990	if (PrevMethod) {
4991	// You can never have two method definitions with the same name.
4992	Diag(ObjCMethod->getLocation(), diag::err_duplicate_method_decl)
4993	<< ObjCMethod->getDeclName();
4994	Diag(PrevMethod->getLocation(), diag::note_previous_declaration);
4995	ObjCMethod->setInvalidDecl();
4996	return ObjCMethod;
4997	}
4998
4999	// If this Objective-C method does not have a related result type, but we
5000	// are allowed to infer related result types, try to do so based on the
5001	// method family.
5002	ObjCInterfaceDecl *CurrentClass = dyn_cast<ObjCInterfaceDecl>(Val: ClassDecl);
5003	if (!CurrentClass) {
5004	if (ObjCCategoryDecl *Cat = dyn_cast<ObjCCategoryDecl>(Val: ClassDecl))
5005	CurrentClass = Cat->getClassInterface();
5006	else if (ObjCImplDecl *Impl = dyn_cast<ObjCImplDecl>(Val: ClassDecl))
5007	CurrentClass = Impl->getClassInterface();
5008	else if (ObjCCategoryImplDecl *CatImpl
5009	= dyn_cast<ObjCCategoryImplDecl>(Val: ClassDecl))
5010	CurrentClass = CatImpl->getClassInterface();
5011	}
5012
5013	ResultTypeCompatibilityKind RTC
5014	= CheckRelatedResultTypeCompatibility(S&: *this, Method: ObjCMethod, CurrentClass);
5015
5016	CheckObjCMethodOverrides(ObjCMethod, CurrentClass, RTC);
5017
5018	bool ARCError = false;
5019	if (getLangOpts().ObjCAutoRefCount)
5020	ARCError = CheckARCMethodDecl(method: ObjCMethod);
5021
5022	// Infer the related result type when possible.
5023	if (!ARCError && RTC == Sema::RTC_Compatible &&
5024	!ObjCMethod->hasRelatedResultType() &&
5025	LangOpts.ObjCInferRelatedResultType) {
5026	bool InferRelatedResultType = false;
5027	switch (ObjCMethod->getMethodFamily()) {
5028	case OMF_None:
5029	case OMF_copy:
5030	case OMF_dealloc:
5031	case OMF_finalize:
5032	case OMF_mutableCopy:
5033	case OMF_release:
5034	case OMF_retainCount:
5035	case OMF_initialize:
5036	case OMF_performSelector:
5037	break;
5038
5039	case OMF_alloc:
5040	case OMF_new:
5041	InferRelatedResultType = ObjCMethod->isClassMethod();
5042	break;
5043
5044	case OMF_init:
5045	case OMF_autorelease:
5046	case OMF_retain:
5047	case OMF_self:
5048	InferRelatedResultType = ObjCMethod->isInstanceMethod();
5049	break;
5050	}
5051
5052	if (InferRelatedResultType &&
5053	!ObjCMethod->getReturnType()->isObjCIndependentClassType())
5054	ObjCMethod->setRelatedResultType();
5055	}
5056
5057	if (MethodDefinition &&
5058	Context.getTargetInfo().getTriple().getArch() == llvm::Triple::x86)
5059	checkObjCMethodX86VectorTypes(SemaRef&: *this, Method: ObjCMethod);
5060
5061	// + load method cannot have availability attributes. It get called on
5062	// startup, so it has to have the availability of the deployment target.
5063	if (const auto *attr = ObjCMethod->getAttr<AvailabilityAttr>()) {
5064	if (ObjCMethod->isClassMethod() &&
5065	ObjCMethod->getSelector().getAsString() == "load") {
5066	Diag(attr->getLocation(), diag::warn_availability_on_static_initializer)
5067	<< 0;
5068	ObjCMethod->dropAttr<AvailabilityAttr>();
5069	}
5070	}
5071
5072	// Insert the invisible arguments, self and _cmd!
5073	ObjCMethod->createImplicitParams(Context, ID: ObjCMethod->getClassInterface());
5074
5075	ActOnDocumentableDecl(ObjCMethod);
5076
5077	return ObjCMethod;
5078	}
5079
5080	bool Sema::CheckObjCDeclScope(Decl *D) {
5081	// Following is also an error. But it is caused by a missing @end
5082	// and diagnostic is issued elsewhere.
5083	if (isa<ObjCContainerDecl>(Val: CurContext->getRedeclContext()))
5084	return false;
5085
5086	// If we switched context to translation unit while we are still lexically in
5087	// an objc container, it means the parser missed emitting an error.
5088	if (isa<TranslationUnitDecl>(Val: getCurLexicalContext()->getRedeclContext()))
5089	return false;
5090
5091	Diag(D->getLocation(), diag::err_objc_decls_may_only_appear_in_global_scope);
5092	D->setInvalidDecl();
5093
5094	return true;
5095	}
5096
5097	/// Called whenever \@defs(ClassName) is encountered in the source. Inserts the
5098	/// instance variables of ClassName into Decls.
5099	void Sema::ActOnDefs(Scope *S, Decl *TagD, SourceLocation DeclStart,
5100	IdentifierInfo *ClassName,
5101	SmallVectorImpl<Decl*> &Decls) {
5102	// Check that ClassName is a valid class
5103	ObjCInterfaceDecl *Class = getObjCInterfaceDecl(Id&: ClassName, IdLoc: DeclStart);
5104	if (!Class) {
5105	Diag(DeclStart, diag::err_undef_interface) << ClassName;
5106	return;
5107	}
5108	if (LangOpts.ObjCRuntime.isNonFragile()) {
5109	Diag(DeclStart, diag::err_atdef_nonfragile_interface);
5110	return;
5111	}
5112
5113	// Collect the instance variables
5114	SmallVector<const ObjCIvarDecl*, 32> Ivars;
5115	Context.DeepCollectObjCIvars(OI: Class, leafClass: true, Ivars);
5116	// For each ivar, create a fresh ObjCAtDefsFieldDecl.
5117	for (unsigned i = 0; i < Ivars.size(); i++) {
5118	const FieldDecl* ID = Ivars[i];
5119	RecordDecl *Record = dyn_cast<RecordDecl>(Val: TagD);
5120	Decl *FD = ObjCAtDefsFieldDecl::Create(C&: Context, DC: Record,
5121	/*FIXME: StartL=*/StartLoc: ID->getLocation(),
5122	IdLoc: ID->getLocation(),
5123	Id: ID->getIdentifier(), T: ID->getType(),
5124	BW: ID->getBitWidth());
5125	Decls.push_back(Elt: FD);
5126	}
5127
5128	// Introduce all of these fields into the appropriate scope.
5129	for (SmallVectorImpl<Decl*>::iterator D = Decls.begin();
5130	D != Decls.end(); ++D) {
5131	FieldDecl *FD = cast<FieldDecl>(Val: *D);
5132	if (getLangOpts().CPlusPlus)
5133	PushOnScopeChains(FD, S);
5134	else if (RecordDecl *Record = dyn_cast<RecordDecl>(Val: TagD))
5135	Record->addDecl(FD);
5136	}
5137	}
5138
5139	/// Build a type-check a new Objective-C exception variable declaration.
5140	VarDecl *Sema::BuildObjCExceptionDecl(TypeSourceInfo *TInfo, QualType T,
5141	SourceLocation StartLoc,
5142	SourceLocation IdLoc,
5143	IdentifierInfo *Id,
5144	bool Invalid) {
5145	// ISO/IEC TR 18037 S6.7.3: "The type of an object with automatic storage
5146	// duration shall not be qualified by an address-space qualifier."
5147	// Since all parameters have automatic store duration, they can not have
5148	// an address space.
5149	if (T.getAddressSpace() != LangAS::Default) {
5150	Diag(IdLoc, diag::err_arg_with_address_space);
5151	Invalid = true;
5152	}
5153
5154	// An @catch parameter must be an unqualified object pointer type;
5155	// FIXME: Recover from "NSObject foo" by inserting the * in "NSObject *foo"?
5156	if (Invalid) {
5157	// Don't do any further checking.
5158	} else if (T->isDependentType()) {
5159	// Okay: we don't know what this type will instantiate to.
5160	} else if (T->isObjCQualifiedIdType()) {
5161	Invalid = true;
5162	Diag(IdLoc, diag::err_illegal_qualifiers_on_catch_parm);
5163	} else if (T->isObjCIdType()) {
5164	// Okay: we don't know what this type will instantiate to.
5165	} else if (!T->isObjCObjectPointerType()) {
5166	Invalid = true;
5167	Diag(IdLoc, diag::err_catch_param_not_objc_type);
5168	} else if (!T->castAs<ObjCObjectPointerType>()->getInterfaceType()) {
5169	Invalid = true;
5170	Diag(IdLoc, diag::err_catch_param_not_objc_type);
5171	}
5172
5173	VarDecl *New = VarDecl::Create(C&: Context, DC: CurContext, StartLoc, IdLoc, Id,
5174	T, TInfo, S: SC_None);
5175	New->setExceptionVariable(true);
5176
5177	// In ARC, infer 'retaining' for variables of retainable type.
5178	if (getLangOpts().ObjCAutoRefCount && inferObjCARCLifetime(New))
5179	Invalid = true;
5180
5181	if (Invalid)
5182	New->setInvalidDecl();
5183	return New;
5184	}
5185
5186	Decl *Sema::ActOnObjCExceptionDecl(Scope *S, Declarator &D) {
5187	const DeclSpec &DS = D.getDeclSpec();
5188
5189	// We allow the "register" storage class on exception variables because
5190	// GCC did, but we drop it completely. Any other storage class is an error.
5191	if (DS.getStorageClassSpec() == DeclSpec::SCS_register) {
5192	Diag(DS.getStorageClassSpecLoc(), diag::warn_register_objc_catch_parm)
5193	<< FixItHint::CreateRemoval(SourceRange(DS.getStorageClassSpecLoc()));
5194	} else if (DeclSpec::SCS SCS = DS.getStorageClassSpec()) {
5195	Diag(DS.getStorageClassSpecLoc(), diag::err_storage_spec_on_catch_parm)
5196	<< DeclSpec::getSpecifierName(SCS);
5197	}
5198	if (DS.isInlineSpecified())
5199	Diag(DS.getInlineSpecLoc(), diag::err_inline_non_function)
5200	<< getLangOpts().CPlusPlus17;
5201	if (DeclSpec::TSCS TSCS = D.getDeclSpec().getThreadStorageClassSpec())
5202	Diag(D.getDeclSpec().getThreadStorageClassSpecLoc(),
5203	diag::err_invalid_thread)
5204	<< DeclSpec::getSpecifierName(TSCS);
5205	D.getMutableDeclSpec().ClearStorageClassSpecs();
5206
5207	DiagnoseFunctionSpecifiers(DS: D.getDeclSpec());
5208
5209	// Check that there are no default arguments inside the type of this
5210	// exception object (C++ only).
5211	if (getLangOpts().CPlusPlus)
5212	CheckExtraCXXDefaultArguments(D);
5213
5214	TypeSourceInfo *TInfo = GetTypeForDeclarator(D);
5215	QualType ExceptionType = TInfo->getType();
5216
5217	VarDecl *New = BuildObjCExceptionDecl(TInfo, T: ExceptionType,
5218	StartLoc: D.getSourceRange().getBegin(),
5219	IdLoc: D.getIdentifierLoc(),
5220	Id: D.getIdentifier(),
5221	Invalid: D.isInvalidType());
5222
5223	// Parameter declarators cannot be qualified (C++ [dcl.meaning]p1).
5224	if (D.getCXXScopeSpec().isSet()) {
5225	Diag(D.getIdentifierLoc(), diag::err_qualified_objc_catch_parm)
5226	<< D.getCXXScopeSpec().getRange();
5227	New->setInvalidDecl();
5228	}
5229
5230	// Add the parameter declaration into this scope.
5231	S->AddDecl(New);
5232	if (D.getIdentifier())
5233	IdResolver.AddDecl(New);
5234
5235	ProcessDeclAttributes(S, New, D);
5236
5237	if (New->hasAttr<BlocksAttr>())
5238	Diag(New->getLocation(), diag::err_block_on_nonlocal);
5239	return New;
5240	}
5241
5242	/// CollectIvarsToConstructOrDestruct - Collect those ivars which require
5243	/// initialization.
5244	void Sema::CollectIvarsToConstructOrDestruct(ObjCInterfaceDecl *OI,
5245	SmallVectorImpl<ObjCIvarDecl*> &Ivars) {
5246	for (ObjCIvarDecl *Iv = OI->all_declared_ivar_begin(); Iv;
5247	Iv= Iv->getNextIvar()) {
5248	QualType QT = Context.getBaseElementType(Iv->getType());
5249	if (QT->isRecordType())
5250	Ivars.push_back(Elt: Iv);
5251	}
5252	}
5253
5254	void Sema::DiagnoseUseOfUnimplementedSelectors() {
5255	// Load referenced selectors from the external source.
5256	if (ExternalSource) {
5257	SmallVector<std::pair<Selector, SourceLocation>, 4> Sels;
5258	ExternalSource->ReadReferencedSelectors(Sels);
5259	for (unsigned I = 0, N = Sels.size(); I != N; ++I)
5260	ReferencedSelectors[Sels[I].first] = Sels[I].second;
5261	}
5262
5263	// Warning will be issued only when selector table is
5264	// generated (which means there is at lease one implementation
5265	// in the TU). This is to match gcc's behavior.
5266	if (ReferencedSelectors.empty() ||
5267	!Context.AnyObjCImplementation())
5268	return;
5269	for (auto &SelectorAndLocation : ReferencedSelectors) {
5270	Selector Sel = SelectorAndLocation.first;
5271	SourceLocation Loc = SelectorAndLocation.second;
5272	if (!LookupImplementedMethodInGlobalPool(Sel))
5273	Diag(Loc, diag::warn_unimplemented_selector) << Sel;
5274	}
5275	}
5276
5277	ObjCIvarDecl *
5278	Sema::GetIvarBackingPropertyAccessor(const ObjCMethodDecl *Method,
5279	const ObjCPropertyDecl *&PDecl) const {
5280	if (Method->isClassMethod())
5281	return nullptr;
5282	const ObjCInterfaceDecl *IDecl = Method->getClassInterface();
5283	if (!IDecl)
5284	return nullptr;
5285	Method = IDecl->lookupMethod(Sel: Method->getSelector(), /*isInstance=*/true,
5286	/*shallowCategoryLookup=*/false,
5287	/*followSuper=*/false);
5288	if (!Method || !Method->isPropertyAccessor())
5289	return nullptr;
5290	if ((PDecl = Method->findPropertyDecl()))
5291	if (ObjCIvarDecl *IV = PDecl->getPropertyIvarDecl()) {
5292	// property backing ivar must belong to property's class
5293	// or be a private ivar in class's implementation.
5294	// FIXME. fix the const-ness issue.
5295	IV = const_cast<ObjCInterfaceDecl *>(IDecl)->lookupInstanceVariable(
5296	IV->getIdentifier());
5297	return IV;
5298	}
5299	return nullptr;
5300	}
5301
5302	namespace {
5303	/// Used by Sema::DiagnoseUnusedBackingIvarInAccessor to check if a property
5304	/// accessor references the backing ivar.
5305	class UnusedBackingIvarChecker :
5306	public RecursiveASTVisitor<UnusedBackingIvarChecker> {
5307	public:
5308	Sema &S;
5309	const ObjCMethodDecl *Method;
5310	const ObjCIvarDecl *IvarD;
5311	bool AccessedIvar;
5312	bool InvokedSelfMethod;
5313
5314	UnusedBackingIvarChecker(Sema &S, const ObjCMethodDecl *Method,
5315	const ObjCIvarDecl *IvarD)
5316	: S(S), Method(Method), IvarD(IvarD),
5317	AccessedIvar(false), InvokedSelfMethod(false) {
5318	assert(IvarD);
5319	}
5320
5321	bool VisitObjCIvarRefExpr(ObjCIvarRefExpr *E) {
5322	if (E->getDecl() == IvarD) {
5323	AccessedIvar = true;
5324	return false;
5325	}
5326	return true;
5327	}
5328
5329	bool VisitObjCMessageExpr(ObjCMessageExpr *E) {
5330	if (E->getReceiverKind() == ObjCMessageExpr::Instance &&
5331	S.isSelfExpr(RExpr: E->getInstanceReceiver(), Method)) {
5332	InvokedSelfMethod = true;
5333	}
5334	return true;
5335	}
5336	};
5337	} // end anonymous namespace
5338
5339	void Sema::DiagnoseUnusedBackingIvarInAccessor(Scope *S,
5340	const ObjCImplementationDecl *ImplD) {
5341	if (S->hasUnrecoverableErrorOccurred())
5342	return;
5343
5344	for (const auto *CurMethod : ImplD->instance_methods()) {
5345	unsigned DIAG = diag::warn_unused_property_backing_ivar;
5346	SourceLocation Loc = CurMethod->getLocation();
5347	if (Diags.isIgnored(DIAG, Loc))
5348	continue;
5349
5350	const ObjCPropertyDecl *PDecl;
5351	const ObjCIvarDecl *IV = GetIvarBackingPropertyAccessor(CurMethod, PDecl);
5352	if (!IV)
5353	continue;
5354
5355	if (CurMethod->isSynthesizedAccessorStub())
5356	continue;
5357
5358	UnusedBackingIvarChecker Checker(*this, CurMethod, IV);
5359	Checker.TraverseStmt(CurMethod->getBody());
5360	if (Checker.AccessedIvar)
5361	continue;
5362
5363	// Do not issue this warning if backing ivar is used somewhere and accessor
5364	// implementation makes a self call. This is to prevent false positive in
5365	// cases where the ivar is accessed by another method that the accessor
5366	// delegates to.
5367	if (!IV->isReferenced() || !Checker.InvokedSelfMethod) {
5368	Diag(Loc, DIAG) << IV;
5369	Diag(PDecl->getLocation(), diag::note_property_declare);
5370	}
5371	}
5372	}
5373