Tests

src/test/compile-fail/where-for-self-2.rs

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+// 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.
+
+// Test that we can quantify lifetimes outside a constraint (i.e., including
+// the self type) in a where clause. Specifically, test that implementing for a
+// specific lifetime is not enough to satisify the `for<'a> ...` constraint, which
+// should require *all* lifetimes.
+
+static X: &'static u32 = &42;
+
+trait Bar {
+    fn bar(&self);
+}
+
+impl Bar for &'static u32 {
+    fn bar(&self) {}
+}
+
+fn foo<T>(x: &T)
+    where for<'a> &'a T: Bar
+{}
+
+fn main() {
+    foo(&X);
+    //~^ error: `for<'a> Bar` is not implemented
+}

src/test/compile-fail/where-for-self.rs

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+// 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.
+
+// Test that we can quantify lifetimes outside a constraint (i.e., including
+// the self type) in a where clause. Specifically, test that we cannot nest
+// quantification in constraints (to be clear, there is no reason this should not
+// we're testing we don't crash or do something stupid).
+
+trait Bar<'a> {
+    fn bar(&self);
+}
+
+impl<'a, 'b> Bar<'b> for &'a u32 {
+    fn bar(&self) {}
+}
+
+fn foo<T>(x: &T)
+    where for<'a> &'a T: for<'b> Bar<'b>
+    //~^ error: nested quantification of lifetimes
+{}
+
+fn main() {}

src/test/run-pass/where-for-self.rs

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+// 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.
+
+// Test that we can quantify lifetimes outside a constraint (i.e., including
+// the self type) in a where clause.
+
+static mut COUNT: u32 = 1;
+
+trait Bar<'a> {
+    fn bar(&self);
+}
+
+trait Baz<'a> {
+    fn baz(&self);
+}
+
+impl<'a, 'b> Bar<'b> for &'a u32 {
+    fn bar(&self) {
+        unsafe { COUNT *= 2; }
+    }
+}
+
+impl<'a, 'b> Baz<'b> for &'a u32 {
+    fn baz(&self) {
+        unsafe { COUNT *= 3; }
+    }
+}
+
+// Test we can use the syntax for HRL including the self type.
+fn foo1<T>(x: &T)
+    where for<'a, 'b> &'a T: Bar<'b>
+{
+    x.bar()
+}
+
+// Test we can quantify multiple bounds (i.e., the precedence is sensible).
+fn foo2<T>(x: &T)
+    where for<'a, 'b> &'a T: Bar<'b> + Baz<'b>
+{
+    x.baz();
+    x.bar()
+}
+
+fn main() {
+    let x = 42u32;
+    foo1(&x);
+    foo2(&x);
+    unsafe {
+        assert!(COUNT == 12);
+    }
+}
+