tests: add two new run-pass tests for method behavior after UFCS.

Author: eddyb

src/test/run-pass/impl-inherent-non-conflict.rs

@@ -0,0 +1,31 @@
+// 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.
+
+// Ensure that an user-defined type admits multiple inherent methods
+// with the same name, which can be called on values that have a
+// precise enough type to allow distinguishing between the methods.
+
+struct Foo<T>(T);
+
+impl Foo<usize> {
+    fn bar(&self) -> i32 { self.0 as i32 }
+}
+
+impl Foo<isize> {
+    fn bar(&self) -> i32 { -(self.0 as i32) }
+}
+
+fn main() {
+    let foo_u = Foo::<usize>(5);
+    assert_eq!(foo_u.bar(), 5);
+
+    let foo_i = Foo::<isize>(3);
+    assert_eq!(foo_i.bar(), -3);
+}

src/test/run-pass/impl-inherent-prefer-over-trait.rs

@@ -0,0 +1,38 @@
+// 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.
+
+struct Foo;
+
+trait Trait {
+    fn bar(&self);
+}
+
+// Inherent impls should be preferred over trait ones.
+impl Foo {
+    fn bar(&self) {}
+}
+
+impl Trait {
+    fn baz(_: &Foo) {}
+}
+
+impl Trait for Foo {
+    fn bar(&self) { panic!("wrong method called!") }
+}
+
+fn main() {
+    Foo.bar();
+    Foo::bar(&Foo);
+    <Foo>::bar(&Foo);
+
+    // Should work even if Trait::baz doesn't exist.
+    // N.B: `<Trait>::bar` would be ambiguous.
+    <Trait>::baz(&Foo);
+}