bjoernager/rust
bjoernager/rust
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Remove incorrect delay_span_bug

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The following code is supposed to compile

```rust
use std::ops::BitOr;

pub trait IntWrapper {
    type InternalStorage;
}

impl<T> BitOr for dyn IntWrapper<InternalStorage = T>
where
    Self: Sized,
    T: BitOr + BitOr<Output = T>,
{
    type Output = Self;
    fn bitor(self, _other: Self) -> Self {
        todo!()
    }
}
```

Before this change it would ICE. In #70998 the removed logic was added
to provide better suggestions, and the `delay_span_bug` guard was added
to  protect against a potential logic error when returning traits. As it
happens, there are cases, like the one above, where traits can indeed be
returned, so valid code was being rejected.

Fix #80207.
This commit is contained in:
Esteban Küber 2021-01-29 11:47:47 -08:00
parent b81f5811f9
commit ede0a71b9e
2 changed files with 20 additions and 1 deletions
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1
compiler/rustc_typeck/src/check/check.rs
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@ -192,7 +192,6 @@ pub(super) fn check_fn<'a, 'tcx>(
// possible cases.
fcx.check_expr(&body.value);
fcx.require_type_is_sized(declared_ret_ty, decl.output.span(), traits::SizedReturnType);
tcx.sess.delay_span_bug(decl.output.span(), "`!Sized` return type");
} else {
fcx.require_type_is_sized(declared_ret_ty, decl.output.span(), traits::SizedReturnType);
fcx.check_return_expr(&body.value);