rollup merge of #18494 : nikomatsakis/issue-18453

src/test/run-pass/trait-where-clause-vs-impl.rs

@@ -0,0 +1,50 @@
+// 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.
+
+// Test that when there is a conditional (but blanket) impl and a
+// where clause, we don't get confused in trait resolution.
+//
+// Issue #18453.
+
+use std::rc::Rc;
+
+pub trait Foo<M> {
+    fn foo(&mut self, msg: M);
+}
+
+pub trait Bar<M> {
+    fn dummy(&self) -> M;
+}
+
+impl<M, F: Bar<M>> Foo<M> for F {
+    fn foo(&mut self, msg: M) {
+    }
+}
+
+pub struct Both<M, F> {
+    inner: Rc<(M, F)>,
+}
+
+impl<M, F: Foo<M>> Clone for Both<M, F> {
+    fn clone(&self) -> Both<M, F> {
+        Both { inner: self.inner.clone() }
+    }
+}
+
+fn repro1<M, F: Foo<M>>(_both: Both<M, F>) {
+}
+
+fn repro2<M, F: Foo<M>>(msg: M, foo: F) {
+    let both = Both { inner: Rc::new((msg, foo)) };
+    repro1(both.clone()); // <--- This clone causes problem
+}
+
+pub fn main() {
+}