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0731742a XL |
1 | // run-pass |
2 | ||
dc9dc135 XL |
3 | // Check that resolving, in the value namespace, to an `enum` variant |
4 | // through a type alias is well behaved in the presence of generics. | |
5 | // We check for situations with: | |
6 | // 1. a generic type `Alias<T>`, we can type-apply `Alias` when referring to a variant. | |
7 | // 2. a monotype `AliasFixed` of generic `Enum<T>`, we can refer to variants | |
8 | // and the type-application of `T` in `AliasFixed` is kept. | |
0731742a XL |
9 | |
10 | #![allow(irrefutable_let_patterns)] | |
11 | ||
064997fb | 12 | enum Enum<T> { TSVariant(#[allow(unused_tuple_struct_fields)] T), SVariant { _v: T }, UVariant } |
0731742a XL |
13 | type Alias<T> = Enum<T>; |
14 | type AliasFixed = Enum<()>; | |
15 | ||
16 | macro_rules! is_variant { | |
17 | (TSVariant, $expr:expr) => (is_variant!(@check TSVariant, (_), $expr)); | |
e1599b0c | 18 | (SVariant, $expr:expr) => (is_variant!(@check SVariant, { _v: _ }, $expr)); |
dc9dc135 | 19 | (UVariant, $expr:expr) => (is_variant!(@check UVariant, {}, $expr)); |
0731742a XL |
20 | (@check $variant:ident, $matcher:tt, $expr:expr) => ( |
21 | assert!(if let Enum::$variant::<()> $matcher = $expr { true } else { false }, | |
22 | "expr does not have correct type"); | |
23 | ); | |
24 | } | |
25 | ||
26 | fn main() { | |
27 | // Tuple struct variant | |
28 | ||
29 | is_variant!(TSVariant, Enum::TSVariant(())); | |
30 | is_variant!(TSVariant, Enum::TSVariant::<()>(())); | |
31 | is_variant!(TSVariant, Enum::<()>::TSVariant(())); | |
32 | ||
33 | is_variant!(TSVariant, Alias::TSVariant(())); | |
34 | is_variant!(TSVariant, Alias::<()>::TSVariant(())); | |
35 | ||
36 | is_variant!(TSVariant, AliasFixed::TSVariant(())); | |
37 | ||
38 | // Struct variant | |
39 | ||
e1599b0c XL |
40 | is_variant!(SVariant, Enum::SVariant { _v: () }); |
41 | is_variant!(SVariant, Enum::SVariant::<()> { _v: () }); | |
42 | is_variant!(SVariant, Enum::<()>::SVariant { _v: () }); | |
0731742a | 43 | |
e1599b0c XL |
44 | is_variant!(SVariant, Alias::SVariant { _v: () }); |
45 | is_variant!(SVariant, Alias::<()>::SVariant { _v: () }); | |
0731742a | 46 | |
e1599b0c | 47 | is_variant!(SVariant, AliasFixed::SVariant { _v: () }); |
dc9dc135 XL |
48 | |
49 | // Unit variant | |
50 | ||
51 | is_variant!(UVariant, Enum::UVariant); | |
52 | is_variant!(UVariant, Enum::UVariant::<()>); | |
53 | is_variant!(UVariant, Enum::<()>::UVariant); | |
54 | ||
55 | is_variant!(UVariant, Alias::UVariant); | |
56 | is_variant!(UVariant, Alias::<()>::UVariant); | |
57 | ||
58 | is_variant!(UVariant, AliasFixed::UVariant); | |
0731742a | 59 | } |