Merge from rustc

Author: The Miri Cronjob Bot

tests/fail/dyn-upcast-trait-mismatch.rs

@@ -59,8 +59,10 @@ impl Baz for i32 {
 }
 
 fn main() {
-    let baz: &dyn Baz = &1;
-    let baz_fake: *const dyn Bar = unsafe { std::mem::transmute(baz) };
-    let _err = baz_fake as *const dyn Foo;
-    //~^ERROR: using vtable for trait `Baz` but trait `Bar` was expected
+    unsafe {
+        let baz: &dyn Baz = &1;
+        let baz_fake: *const dyn Bar = std::mem::transmute(baz);
+        let _err = baz_fake as *const dyn Foo;
+        //~^ERROR: using vtable for trait `Baz` but trait `Bar` was expected
+    }
 }

tests/fail/dyn-upcast-trait-mismatch.stderr

@@ -1,8 +1,8 @@
 error: Undefined Behavior: using vtable for trait `Baz` but trait `Bar` was expected
   --> $DIR/dyn-upcast-trait-mismatch.rs:LL:CC
    |
-LL |     let _err = baz_fake as *const dyn Foo;
-   |                ^^^^^^^^ using vtable for trait `Baz` but trait `Bar` was expected
+LL |         let _err = baz_fake as *const dyn Foo;
+   |                    ^^^^^^^^ using vtable for trait `Baz` but trait `Bar` was expected
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information