diff options
Diffstat (limited to 'src/test/ui/never_type/fallback-closure-ret.rs')
-rw-r--r-- | src/test/ui/never_type/fallback-closure-ret.rs | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/src/test/ui/never_type/fallback-closure-ret.rs b/src/test/ui/never_type/fallback-closure-ret.rs new file mode 100644 index 000000000..5c8ce48cb --- /dev/null +++ b/src/test/ui/never_type/fallback-closure-ret.rs @@ -0,0 +1,23 @@ +// This test verifies that never type fallback preserves the following code in a +// compiling state. This pattern is fairly common in the wild, notably seen in +// wasmtime v0.16. Typically this is some closure wrapper that expects a +// collection of 'known' signatures, and -> ! is not included in that set. +// +// This test is specifically targeted by the unit type fallback when +// encountering a set of obligations like `?T: Foo` and `Trait::Projection = +// ?T`. In the code below, these are `R: Bar` and `Fn::Output = R`. +// +// revisions: nofallback fallback +// check-pass + +#![cfg_attr(fallback, feature(never_type_fallback))] + +trait Bar { } +impl Bar for () { } +impl Bar for u32 { } + +fn foo<R: Bar>(_: impl Fn() -> R) {} + +fn main() { + foo(|| panic!()); +} |