Merging upstream version 1.68.2+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 26 insertions, 0 deletions

diff --git a/tests/ui/coherence/coherence-fn-covariant-bound-vs-static.rs b/tests/ui/coherence/coherence-fn-covariant-bound-vs-static.rs
new file mode 100644
index 000000000..99f805f7f
--- /dev/null
+++ b/tests/ui/coherence/coherence-fn-covariant-bound-vs-static.rs
@@ -0,0 +1,26 @@
+// Test that impls for these two types are considered ovelapping:
+//
+// * `for<'r> fn(fn(&'r u32))`
+// * `fn(fn(&'a u32)` where `'a` is free
+//
+// This is because, for `'a = 'static`, the two types overlap.
+// Effectively for them to be equal to you get:
+//
+// * `for<'r> fn(fn(&'r u32)) <: fn(fn(&'static u32))`
+//   * true if `exists<'r> { 'r: 'static }` (obviously true)
+// * `fn(fn(&'static u32)) <: for<'r> fn(fn(&'r u32))`
+//   * true if `forall<'r> { 'static: 'r }` (also true)
+
+trait Trait {}
+
+impl Trait for for<'r> fn(fn(&'r ())) {}
+impl<'a> Trait for fn(fn(&'a ())) {}
+//~^ ERROR conflicting implementations
+//
+// Note in particular that we do NOT get a future-compatibility warning
+// here. This is because the new leak-check proposed in [MCP 295] does not
+// "error" when these two types are equated.
+//
+// [MCP 295]: https://github.com/rust-lang/compiler-team/issues/295
+
+fn main() {}