diff --git a/src/test/ui/nll/issue-57642-higher-ranked-subtype.rs b/src/test/ui/nll/issue-57642-higher-ranked-subtype.rs new file mode 100644 index 0000000000000..36c54628317e9 --- /dev/null +++ b/src/test/ui/nll/issue-57642-higher-ranked-subtype.rs @@ -0,0 +1,41 @@ +// Regression test for issue #57642 +// Tests that we reject a bad higher-ranked subtype +// with `#![feature(nll)]` + +#![feature(nll)] + +trait X { + type G; + fn make_g() -> Self::G; +} + +impl<'a> X for fn(&'a ()) { + type G = &'a (); + + fn make_g() -> Self::G { + &() + } +} + +trait Y { + type F; + fn make_f() -> Self::F; +} + +impl Y for fn(T) { + type F = fn(T); + + fn make_f() -> Self::F { + |_| {} + } +} + +fn higher_ranked_region_has_lost_its_binder() { + let x = ::make_g(); //~ ERROR no function +} + +fn magical() { + let x = ::make_f(); //~ ERROR no function +} + +fn main() {} diff --git a/src/test/ui/nll/issue-57642-higher-ranked-subtype.stderr b/src/test/ui/nll/issue-57642-higher-ranked-subtype.stderr new file mode 100644 index 0000000000000..f69098193429c --- /dev/null +++ b/src/test/ui/nll/issue-57642-higher-ranked-subtype.stderr @@ -0,0 +1,31 @@ +error[E0599]: no function or associated item named `make_g` found for fn pointer `for<'r> fn(&'r ())` in the current scope + --> $DIR/issue-57642-higher-ranked-subtype.rs:34:25 + | +LL | let x = ::make_g(); + | ^^^^^^ function or associated item not found in `for<'r> fn(&'r ())` + | + = note: the method `make_g` exists but the following trait bounds were not satisfied: + `for<'r> fn(&'r ()): X` + = help: items from traits can only be used if the trait is implemented and in scope +note: `X` defines an item `make_g`, perhaps you need to implement it + --> $DIR/issue-57642-higher-ranked-subtype.rs:7:1 + | +LL | trait X { + | ^^^^^^^ + +error[E0599]: no function or associated item named `make_f` found for fn pointer `for<'r> fn(&'r ())` in the current scope + --> $DIR/issue-57642-higher-ranked-subtype.rs:38:25 + | +LL | let x = ::make_f(); + | ^^^^^^ function or associated item not found in `for<'r> fn(&'r ())` + | + = help: items from traits can only be used if the trait is implemented and in scope +note: `Y` defines an item `make_f`, perhaps you need to implement it + --> $DIR/issue-57642-higher-ranked-subtype.rs:20:1 + | +LL | trait Y { + | ^^^^^^^ + +error: aborting due to 2 previous errors + +For more information about this error, try `rustc --explain E0599`.