1 files changed, 26 insertions, 0 deletions
diff --git a/src/test/ui/dst/dst-bad-coercions.rs b/src/test/ui/dst/dst-bad-coercions.rs
new file mode 100644
index 000000000..bffef378c
--- /dev/null
+++ b/src/test/ui/dst/dst-bad-coercions.rs
@@ -0,0 +1,26 @@
+// Test implicit coercions involving DSTs and raw pointers.
+
+struct S;
+trait T {}
+impl T for S {}
+
+struct Foo<T: ?Sized> {
+    f: T
+}
+
+pub fn main() {
+    // Test that we cannot convert from *-ptr to &S and &T
+    let x: *const S = &S;
+    let y: &S = x; //~ ERROR mismatched types
+    let y: &dyn T = x; //~ ERROR mismatched types
+
+    // Test that we cannot convert from *-ptr to &S and &T (mut version)
+    let x: *mut S = &mut S;
+    let y: &S = x; //~ ERROR mismatched types
+    let y: &dyn T = x; //~ ERROR mismatched types
+
+    // Test that we cannot convert an immutable ptr to a mutable one using *-ptrs
+    let x: &mut dyn T = &S; //~ ERROR mismatched types
+    let x: *mut dyn T = &S; //~ ERROR mismatched types
+    let x: *mut S = &S; //~ ERROR mismatched types
+}