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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
commit | 698f8c2f01ea549d77d7dc3338a12e04c11057b9 (patch) | |
tree | 173a775858bd501c378080a10dca74132f05bc50 /src/test/ui/specialization/specialization-default-projection.rs | |
parent | Initial commit. (diff) | |
download | rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.tar.xz rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.zip |
Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/test/ui/specialization/specialization-default-projection.rs')
-rw-r--r-- | src/test/ui/specialization/specialization-default-projection.rs | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/src/test/ui/specialization/specialization-default-projection.rs b/src/test/ui/specialization/specialization-default-projection.rs new file mode 100644 index 000000000..7f3ae9512 --- /dev/null +++ b/src/test/ui/specialization/specialization-default-projection.rs @@ -0,0 +1,36 @@ +#![feature(specialization)] //~ WARN the feature `specialization` is incomplete + +// Make sure we can't project defaulted associated types + +trait Foo { + type Assoc; +} + +impl<T> Foo for T { + default type Assoc = (); +} + +impl Foo for u8 { + type Assoc = String; +} + +fn generic<T>() -> <T as Foo>::Assoc { + // `T` could be some downstream crate type that specializes (or, + // for that matter, `u8`). + + () //~ ERROR mismatched types +} + +fn monomorphic() -> () { + // Even though we know that `()` is not specialized in a + // downstream crate, typeck refuses to project here. + + generic::<()>() //~ ERROR mismatched types +} + +fn main() { + // No error here, we CAN project from `u8`, as there is no `default` + // in that impl. + let s: String = generic::<u8>(); + println!("{}", s); // bad news if this all compiles +} |