1 files changed, 25 insertions, 0 deletions
diff --git a/src/test/ui/transmute/transmute-impl.rs b/src/test/ui/transmute/transmute-impl.rs
new file mode 100644
index 000000000..df422bda1
--- /dev/null
+++ b/src/test/ui/transmute/transmute-impl.rs
@@ -0,0 +1,25 @@
+// normalize-stderr-test "\d+ bits" -> "N bits"
+
+// Tests that are conservative around thin/fat pointer mismatches.
+
+#![allow(dead_code)]
+
+use std::mem::transmute;
+
+struct Foo<T: ?Sized> {
+    t: Box<T>
+}
+
+impl<T: ?Sized> Foo<T> {
+    fn m(x: &T) -> &isize where T : Sized {
+        // OK here, because T : Sized is in scope.
+        unsafe { transmute(x) }
+    }
+
+    fn n(x: &T) -> &isize {
+        // Not OK here, because T : Sized is not in scope.
+        unsafe { transmute(x) } //~ ERROR cannot transmute between types of different sizes
+    }
+}
+
+fn main() { }