diff --git a/src/test/ui/issues/issue-50687-ice-on-borrow.rs b/src/test/ui/issues/issue-50687-ice-on-borrow.rs new file mode 100644 index 00000000000..7a8a12c2a93 --- /dev/null +++ b/src/test/ui/issues/issue-50687-ice-on-borrow.rs @@ -0,0 +1,41 @@ +// This previously caused an ICE at: +// librustc/traits/structural_impls.rs:180: impossible case reached + +#![no_main] + +use std::borrow::Borrow; +use std::io; +use std::io::Write; + +trait Constraint {} + +struct Container { + t: T, +} + +struct Borrowed; +struct Owned; + +impl<'a, T> Write for &'a Container +where + T: Constraint, + &'a T: Write, +{ + fn write(&mut self, buf: &[u8]) -> io::Result { + Ok(buf.len()) + } + + fn flush(&mut self) -> io::Result<()> { + Ok(()) + } +} + +impl Borrow for Owned { + fn borrow(&self) -> &Borrowed { + &Borrowed + } +} + +fn func(owned: Owned) { + let _: () = Borrow::borrow(&owned); //~ ERROR mismatched types +} diff --git a/src/test/ui/issues/issue-50687-ice-on-borrow.stderr b/src/test/ui/issues/issue-50687-ice-on-borrow.stderr new file mode 100644 index 00000000000..f6adfc87dad --- /dev/null +++ b/src/test/ui/issues/issue-50687-ice-on-borrow.stderr @@ -0,0 +1,16 @@ +error[E0308]: mismatched types + --> $DIR/issue-50687-ice-on-borrow.rs:40:17 + | +LL | let _: () = Borrow::borrow(&owned); + | -- ^^^^^^^^^^^^^^^^^^^^^^ + | | | + | | expected `()`, found reference + | | help: consider dereferencing the borrow: `*Borrow::borrow(&owned)` + | expected due to this + | + = note: expected unit type `()` + found reference `&_` + +error: aborting due to previous error + +For more information about this error, try `rustc --explain E0308`.