1use crate::internals::respan::respan;
2use proc_macro2::Span;
3use quote::ToTokens;
4use std::mem;
5use syn::punctuated::Punctuated;
6use syn::{
7 parse_quote, Data, DeriveInput, Expr, ExprPath, GenericArgument, GenericParam, Generics, Macro,
8 Path, PathArguments, QSelf, ReturnType, Token, Type, TypeParamBound, TypePath, WherePredicate,
9};
10
11pub fn replace_receiver(input: &mut DeriveInput) {
12 let self_ty: TypePath = {
13 let ident: &Ident = &input.ident;
14 let ty_generics: TypeGenerics<'_> = input.generics.split_for_impl().1;
15 parse_quote!(#ident #ty_generics)
16 };
17 let mut visitor: ReplaceReceiver<'_> = ReplaceReceiver(&self_ty);
18 visitor.visit_generics_mut(&mut input.generics);
19 visitor.visit_data_mut(&mut input.data);
20}
21
22struct ReplaceReceiver<'a>(&'a TypePath);
23
24impl ReplaceReceiver<'_> {
25 fn self_ty(&self, span: Span) -> TypePath {
26 let tokens = self.0.to_token_stream();
27 let respanned = respan(tokens, span);
28 syn::parse2(respanned).unwrap()
29 }
30
31 fn self_to_qself(&self, qself: &mut Option<QSelf>, path: &mut Path) {
32 if path.leading_colon.is_some() || path.segments[0].ident != "Self" {
33 return;
34 }
35
36 if path.segments.len() == 1 {
37 self.self_to_expr_path(path);
38 return;
39 }
40
41 let span = path.segments[0].ident.span();
42 *qself = Some(QSelf {
43 lt_token: Token![<](span),
44 ty: Box::new(Type::Path(self.self_ty(span))),
45 position: 0,
46 as_token: None,
47 gt_token: Token![>](span),
48 });
49
50 path.leading_colon = Some(**path.segments.pairs().next().unwrap().punct().unwrap());
51
52 let segments = mem::replace(&mut path.segments, Punctuated::new());
53 path.segments = segments.into_pairs().skip(1).collect();
54 }
55
56 fn self_to_expr_path(&self, path: &mut Path) {
57 let self_ty = self.self_ty(path.segments[0].ident.span());
58 let variant = mem::replace(path, self_ty.path);
59 for segment in &mut path.segments {
60 if let PathArguments::AngleBracketed(bracketed) = &mut segment.arguments {
61 if bracketed.colon2_token.is_none() && !bracketed.args.is_empty() {
62 bracketed.colon2_token = Some(<Token![::]>::default());
63 }
64 }
65 }
66 if variant.segments.len() > 1 {
67 path.segments.push_punct(<Token![::]>::default());
68 path.segments.extend(variant.segments.into_pairs().skip(1));
69 }
70 }
71}
72
73impl ReplaceReceiver<'_> {
74 // `Self` -> `Receiver`
75 fn visit_type_mut(&mut self, ty: &mut Type) {
76 let span = if let Type::Path(node) = ty {
77 if node.qself.is_none() && node.path.is_ident("Self") {
78 node.path.segments[0].ident.span()
79 } else {
80 self.visit_type_path_mut(node);
81 return;
82 }
83 } else {
84 self.visit_type_mut_impl(ty);
85 return;
86 };
87 *ty = self.self_ty(span).into();
88 }
89
90 // `Self::Assoc` -> `<Receiver>::Assoc`
91 fn visit_type_path_mut(&mut self, ty: &mut TypePath) {
92 if ty.qself.is_none() {
93 self.self_to_qself(&mut ty.qself, &mut ty.path);
94 }
95 self.visit_type_path_mut_impl(ty);
96 }
97
98 // `Self::method` -> `<Receiver>::method`
99 fn visit_expr_path_mut(&mut self, expr: &mut ExprPath) {
100 if expr.qself.is_none() {
101 self.self_to_qself(&mut expr.qself, &mut expr.path);
102 }
103 self.visit_expr_path_mut_impl(expr);
104 }
105
106 // Everything below is simply traversing the syntax tree.
107
108 fn visit_type_mut_impl(&mut self, ty: &mut Type) {
109 match ty {
110 #![cfg_attr(all(test, exhaustive), deny(non_exhaustive_omitted_patterns))]
111 Type::Array(ty) => {
112 self.visit_type_mut(&mut ty.elem);
113 self.visit_expr_mut(&mut ty.len);
114 }
115 Type::BareFn(ty) => {
116 for arg in &mut ty.inputs {
117 self.visit_type_mut(&mut arg.ty);
118 }
119 self.visit_return_type_mut(&mut ty.output);
120 }
121 Type::Group(ty) => self.visit_type_mut(&mut ty.elem),
122 Type::ImplTrait(ty) => {
123 for bound in &mut ty.bounds {
124 self.visit_type_param_bound_mut(bound);
125 }
126 }
127 Type::Macro(ty) => self.visit_macro_mut(&mut ty.mac),
128 Type::Paren(ty) => self.visit_type_mut(&mut ty.elem),
129 Type::Path(ty) => {
130 if let Some(qself) = &mut ty.qself {
131 self.visit_type_mut(&mut qself.ty);
132 }
133 self.visit_path_mut(&mut ty.path);
134 }
135 Type::Ptr(ty) => self.visit_type_mut(&mut ty.elem),
136 Type::Reference(ty) => self.visit_type_mut(&mut ty.elem),
137 Type::Slice(ty) => self.visit_type_mut(&mut ty.elem),
138 Type::TraitObject(ty) => {
139 for bound in &mut ty.bounds {
140 self.visit_type_param_bound_mut(bound);
141 }
142 }
143 Type::Tuple(ty) => {
144 for elem in &mut ty.elems {
145 self.visit_type_mut(elem);
146 }
147 }
148
149 Type::Infer(_) | Type::Never(_) | Type::Verbatim(_) => {}
150
151 _ => {}
152 }
153 }
154
155 fn visit_type_path_mut_impl(&mut self, ty: &mut TypePath) {
156 if let Some(qself) = &mut ty.qself {
157 self.visit_type_mut(&mut qself.ty);
158 }
159 self.visit_path_mut(&mut ty.path);
160 }
161
162 fn visit_expr_path_mut_impl(&mut self, expr: &mut ExprPath) {
163 if let Some(qself) = &mut expr.qself {
164 self.visit_type_mut(&mut qself.ty);
165 }
166 self.visit_path_mut(&mut expr.path);
167 }
168
169 fn visit_path_mut(&mut self, path: &mut Path) {
170 for segment in &mut path.segments {
171 self.visit_path_arguments_mut(&mut segment.arguments);
172 }
173 }
174
175 fn visit_path_arguments_mut(&mut self, arguments: &mut PathArguments) {
176 match arguments {
177 PathArguments::None => {}
178 PathArguments::AngleBracketed(arguments) => {
179 for arg in &mut arguments.args {
180 match arg {
181 #![cfg_attr(all(test, exhaustive), deny(non_exhaustive_omitted_patterns))]
182 GenericArgument::Type(arg) => self.visit_type_mut(arg),
183 GenericArgument::AssocType(arg) => self.visit_type_mut(&mut arg.ty),
184 GenericArgument::Lifetime(_)
185 | GenericArgument::Const(_)
186 | GenericArgument::AssocConst(_)
187 | GenericArgument::Constraint(_) => {}
188 _ => {}
189 }
190 }
191 }
192 PathArguments::Parenthesized(arguments) => {
193 for argument in &mut arguments.inputs {
194 self.visit_type_mut(argument);
195 }
196 self.visit_return_type_mut(&mut arguments.output);
197 }
198 }
199 }
200
201 fn visit_return_type_mut(&mut self, return_type: &mut ReturnType) {
202 match return_type {
203 ReturnType::Default => {}
204 ReturnType::Type(_, output) => self.visit_type_mut(output),
205 }
206 }
207
208 fn visit_type_param_bound_mut(&mut self, bound: &mut TypeParamBound) {
209 match bound {
210 #![cfg_attr(all(test, exhaustive), deny(non_exhaustive_omitted_patterns))]
211 TypeParamBound::Trait(bound) => self.visit_path_mut(&mut bound.path),
212 TypeParamBound::Lifetime(_) | TypeParamBound::Verbatim(_) => {}
213 _ => {}
214 }
215 }
216
217 fn visit_generics_mut(&mut self, generics: &mut Generics) {
218 for param in &mut generics.params {
219 match param {
220 GenericParam::Type(param) => {
221 for bound in &mut param.bounds {
222 self.visit_type_param_bound_mut(bound);
223 }
224 }
225 GenericParam::Lifetime(_) | GenericParam::Const(_) => {}
226 }
227 }
228 if let Some(where_clause) = &mut generics.where_clause {
229 for predicate in &mut where_clause.predicates {
230 match predicate {
231 #![cfg_attr(all(test, exhaustive), deny(non_exhaustive_omitted_patterns))]
232 WherePredicate::Type(predicate) => {
233 self.visit_type_mut(&mut predicate.bounded_ty);
234 for bound in &mut predicate.bounds {
235 self.visit_type_param_bound_mut(bound);
236 }
237 }
238 WherePredicate::Lifetime(_) => {}
239 _ => {}
240 }
241 }
242 }
243 }
244
245 fn visit_data_mut(&mut self, data: &mut Data) {
246 match data {
247 Data::Struct(data) => {
248 for field in &mut data.fields {
249 self.visit_type_mut(&mut field.ty);
250 }
251 }
252 Data::Enum(data) => {
253 for variant in &mut data.variants {
254 for field in &mut variant.fields {
255 self.visit_type_mut(&mut field.ty);
256 }
257 }
258 }
259 Data::Union(_) => {}
260 }
261 }
262
263 fn visit_expr_mut(&mut self, expr: &mut Expr) {
264 match expr {
265 Expr::Binary(expr) => {
266 self.visit_expr_mut(&mut expr.left);
267 self.visit_expr_mut(&mut expr.right);
268 }
269 Expr::Call(expr) => {
270 self.visit_expr_mut(&mut expr.func);
271 for arg in &mut expr.args {
272 self.visit_expr_mut(arg);
273 }
274 }
275 Expr::Cast(expr) => {
276 self.visit_expr_mut(&mut expr.expr);
277 self.visit_type_mut(&mut expr.ty);
278 }
279 Expr::Field(expr) => self.visit_expr_mut(&mut expr.base),
280 Expr::Index(expr) => {
281 self.visit_expr_mut(&mut expr.expr);
282 self.visit_expr_mut(&mut expr.index);
283 }
284 Expr::Paren(expr) => self.visit_expr_mut(&mut expr.expr),
285 Expr::Path(expr) => self.visit_expr_path_mut(expr),
286 Expr::Unary(expr) => self.visit_expr_mut(&mut expr.expr),
287 _ => {}
288 }
289 }
290
291 fn visit_macro_mut(&mut self, _mac: &mut Macro) {}
292}
293