Regression test.

Author: pnkfelix

src/test/run-pass/regions-no-variance-from-fn-generics.rs

@@ -0,0 +1,45 @@
+// Copyright 2014 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.
+
+// Issue #12856: a lifetime formal binding introduced by a generic fn
+// should not upset the variance inference for actual occurrences of
+// that lifetime in type expressions.
+
+trait HasLife<'a> { }
+
+trait UseLife01 {
+    fn refs<'a, H: HasLife<'a>>(&'a self) -> H;
+}
+
+trait UseLife02 {
+    fn refs<'a, T, H: HasType<&'a T>>(&'a self) -> H;
+}
+
+
+trait HasType<T> { }
+
+trait UseLife03<T> {
+    fn refs<'a, H: HasType<&'a T>>(&'a self) -> H;
+}
+
+
+// (The functions below were not actually a problem observed during
+// fixing of #12856; they just seem like natural tests to put in to
+// cover a couple more points in the testing space)
+
+pub fn top_refs_1<'a, H: HasLife<'a>>(_s: &'a ()) -> H {
+    unimplemented!()
+}
+
+pub fn top_refs_2<'a, T, H: HasType<&'a T>>(_s: &'a ()) -> H {
+    unimplemented!()
+}
+
+pub fn main() {}