rollup merge of #20325: nick29581/obj-safety-static

Closes #19949 and rust-lang/rfcs#428

[breaking change]

If you have traits used with objects with static methods, you'll need to move
the static methods to a different trait.

r? @cmr

2 files changed, 31 insertions, 6 deletions

diff --git a/src/test/compile-fail/trait-object-safety.rs b/src/test/compile-fail/trait-object-safety.rs
new file mode 100644
index 00000000000..d594e3e1747
--- /dev/null
+++ b/src/test/compile-fail/trait-object-safety.rs
@@ -0,0 +1,26 @@
+// 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.
+
+// Check that static methods are not object-safe.
+
+trait Tr {
+    fn foo();
+}
+
+struct St;
+
+impl Tr for St {
+    fn foo() {}
+}
+
+fn main() {
+    let _: &Tr = &St; //~ ERROR cannot convert to a trait object because trait `Tr` is not
+    //~^ NOTE cannot call a static method (`foo`) through a trait object
+}
diff --git a/src/test/run-pass/trait-object-safety.rs b/src/test/run-pass/trait-object-safety.rs
index 929cb9e7f17..ed7284a8353 100644
--- a/src/test/run-pass/trait-object-safety.rs
+++ b/src/test/run-pass/trait-object-safety.rs
@@ -8,20 +8,19 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// Check that object-safe methods are identified as such.  Also
-// acts as a regression test for #18490
+// Check that object-safe methods are identified as such.
 
 trait Tr {
-    // Static methods are always safe regardless of other rules
-    fn new() -> Self;
+    fn foo(&self);
 }
 
 struct St;
 
 impl Tr for St {
-    fn new() -> St { St }
+    fn foo(&self) {}
 }
 
 fn main() {
-    &St as &Tr;
+    let s: &Tr = &St;
+    s.foo();
 }