1use proc_macro2::{Ident, Span, TokenStream};
2use quote::{quote, ToTokens};
3use syn::punctuated::Punctuated;
4use syn::{Token, TypeParamBound};
5
6pub type Supertraits = Punctuated<TypeParamBound, Token![+]>;
7
8pub enum InferredBound {
9 Send,
10 Sync,
11}
12
13pub fn has_bound(supertraits: &Supertraits, bound: &InferredBound) -> bool {
14 for supertrait: &TypeParamBound in supertraits {
15 if let TypeParamBound::Trait(supertrait: &TraitBound) = supertrait {
16 if supertrait.path.is_ident(bound)
17 || supertrait.path.segments.len() == 3
18 && (supertrait.path.segments[0].ident == "std"
19 || supertrait.path.segments[0].ident == "core")
20 && supertrait.path.segments[1].ident == "marker"
21 && supertrait.path.segments[2].ident == *bound
22 {
23 return true;
24 }
25 }
26 }
27 false
28}
29
30impl InferredBound {
31 fn as_str(&self) -> &str {
32 match self {
33 InferredBound::Send => "Send",
34 InferredBound::Sync => "Sync",
35 }
36 }
37}
38
39impl ToTokens for InferredBound {
40 fn to_tokens(&self, tokens: &mut TokenStream) {
41 let ident: Ident = Ident::new(self.as_str(), Span::call_site());
42 quote!(::core::marker::#ident).to_tokens(tokens);
43 }
44}
45
46impl PartialEq<InferredBound> for Ident {
47 fn eq(&self, bound: &InferredBound) -> bool {
48 self == bound.as_str()
49 }
50}
51