Don't leak the compiler's internal representation of scopes in error messages.

src/test/compile-fail/issue-27942.rs

@@ -0,0 +1,31 @@
+// Copyright 2016 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.
+
+pub trait Resources<'a> {}
+
+pub trait Buffer<'a, R: Resources<'a>> {
+    fn select(&self) -> BufferViewHandle<R>;
+    //~^ ERROR mismatched types
+    //~| lifetime mismatch
+    //~| NOTE expected type `Resources<'_>`
+    //~| NOTE    found type `Resources<'a>`
+    //~| NOTE the lifetime 'a as defined on the method body at 14:4...
+    //~| NOTE ...does not necessarily outlive the anonymous lifetime #1 defined on the method body
+    //~| ERROR mismatched types
+    //~| lifetime mismatch
+    //~| NOTE expected type `Resources<'_>`
+    //~| NOTE    found type `Resources<'a>`
+    //~| NOTE the anonymous lifetime #1 defined on the method body at 14:4...
+    //~| NOTE ...does not necessarily outlive the lifetime 'a as defined on the method body
+}
+
+pub struct BufferViewHandle<'a, R: 'a+Resources<'a>>(&'a R);
+
+fn main() {}

src/test/compile-fail/issue-37884.rs

@@ -0,0 +1,27 @@
+// Copyright 2016 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.
+
+struct RepeatMut<'a, T>(T, &'a ());
+
+impl<'a, T: 'a> Iterator for RepeatMut<'a, T> {
+    type Item = &'a mut T;
+    fn next(&'a mut self) -> Option<Self::Item>
+    //~^ ERROR method not compatible with trait
+    //~| lifetime mismatch
+    //~| NOTE expected type `fn(&mut RepeatMut<'a, T>) -> std::option::Option<&mut T>`
+    //~| NOTE    found type `fn(&'a mut RepeatMut<'a, T>) -> std::option::Option<&mut T>`
+    {
+    //~^ NOTE the anonymous lifetime #1 defined on the body
+    //~| NOTE ...does not necessarily outlive the lifetime 'a as defined on the body
+        Some(&mut self.0)
+    }
+}
+
+fn main() {}