Auto merge of #26275 - arielb1:unconstrained-projection, r=nikomatsakis

Fixes #26262

Because this rejects code that previously compiled, this is a [breaking-change]

r? @nikomatsakis

1 files changed, 32 insertions, 0 deletions

diff --git a/src/test/compile-fail/issue-26262.rs b/src/test/compile-fail/issue-26262.rs
new file mode 100644
index 00000000000..8d79fd4570d
--- /dev/null
+++ b/src/test/compile-fail/issue-26262.rs
@@ -0,0 +1,32 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// Check that projections don't count as constraining type parameters.
+
+struct S<T>(T);
+
+trait Tr { type Assoc; fn test(); }
+
+impl<T: Tr> S<T::Assoc> {
+//~^ ERROR the type parameter `T` is not constrained
+    fn foo(self, _: T) {
+        T::test();
+    }
+}
+
+trait Trait1<T> { type Bar; }
+trait Trait2<'x> { type Foo; }
+
+impl<'a,T: Trait2<'a>> Trait1<<T as Trait2<'a>>::Foo> for T {
+//~^ ERROR the lifetime parameter `'a` is not constrained
+    type Bar = &'a ();
+}
+
+fn main() {}