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authorAleksey Kladov <[email protected]>2018-08-10 20:33:29 +0100
committerAleksey Kladov <[email protected]>2018-08-10 20:33:29 +0100
commit7c67612b8a894187fa3b64725531a5459f9211bf (patch)
tree9e2a536efa0c880d921fd8d4d74423afc9451fd4 /src/grammar/items/traits.rs
parent26262aaf05983c5b7f41cc438e287523268fe1eb (diff)
organizize
Diffstat (limited to 'src/grammar/items/traits.rs')
-rw-r--r--src/grammar/items/traits.rs87
1 files changed, 0 insertions, 87 deletions
diff --git a/src/grammar/items/traits.rs b/src/grammar/items/traits.rs
deleted file mode 100644
index 0b9fb2b0b..000000000
--- a/src/grammar/items/traits.rs
+++ /dev/null
@@ -1,87 +0,0 @@
1use super::*;
2
3// test trait_item
4// trait T<U>: Hash + Clone where U: Copy {}
5pub(super) fn trait_item(p: &mut Parser) {
6 assert!(p.at(TRAIT_KW));
7 p.bump();
8 name(p);
9 type_params::type_param_list(p);
10 if p.at(COLON) {
11 type_params::bounds(p);
12 }
13 type_params::where_clause(p);
14 p.expect(L_CURLY);
15 // test trait_item_items
16 // impl F {
17 // type A: Clone;
18 // const B: i32;
19 // fn foo() {}
20 // fn bar(&self);
21 // }
22 while !p.at(EOF) && !p.at(R_CURLY) {
23 item_or_macro(p, true);
24 }
25 p.expect(R_CURLY);
26}
27
28// test impl_item
29// impl Foo {}
30pub(super) fn impl_item(p: &mut Parser) {
31 assert!(p.at(IMPL_KW));
32 p.bump();
33 if choose_type_params_over_qpath(p) {
34 type_params::type_param_list(p);
35 }
36
37 // TODO: never type
38 // impl ! {}
39
40 // test impl_item_neg
41 // impl !Send for X {}
42 p.eat(EXCL);
43 types::type_(p);
44 if p.eat(FOR_KW) {
45 types::type_(p);
46 }
47 type_params::where_clause(p);
48 p.expect(L_CURLY);
49
50 // test impl_item_items
51 // impl F {
52 // type A = i32;
53 // const B: i32 = 92;
54 // fn foo() {}
55 // fn bar(&self) {}
56 // }
57 while !p.at(EOF) && !p.at(R_CURLY) {
58 item_or_macro(p, true);
59 }
60 p.expect(R_CURLY);
61}
62
63fn choose_type_params_over_qpath(p: &Parser) -> bool {
64 // There's an ambiguity between generic parameters and qualified paths in impls.
65 // If we see `<` it may start both, so we have to inspect some following tokens.
66 // The following combinations can only start generics,
67 // but not qualified paths (with one exception):
68 // `<` `>` - empty generic parameters
69 // `<` `#` - generic parameters with attributes
70 // `<` (LIFETIME|IDENT) `>` - single generic parameter
71 // `<` (LIFETIME|IDENT) `,` - first generic parameter in a list
72 // `<` (LIFETIME|IDENT) `:` - generic parameter with bounds
73 // `<` (LIFETIME|IDENT) `=` - generic parameter with a default
74 // The only truly ambiguous case is
75 // `<` IDENT `>` `::` IDENT ...
76 // we disambiguate it in favor of generics (`impl<T> ::absolute::Path<T> { ... }`)
77 // because this is what almost always expected in practice, qualified paths in impls
78 // (`impl <Type>::AssocTy { ... }`) aren't even allowed by type checker at the moment.
79 if !p.at(L_ANGLE) {
80 return false;
81 }
82 if p.nth(1) == POUND || p.nth(1) == R_ANGLE {
83 return true;
84 }
85 (p.nth(1) == LIFETIME || p.nth(1) == IDENT)
86 && (p.nth(2) == R_ANGLE || p.nth(2) == COMMA || p.nth(2) == COLON || p.nth(2) == EQ)
87}