gccrs: Add a regression test for super trait on auto trait

Add a new regression test to highlight the error behavior with a super
trait on an auto trait.

gcc/testsuite/ChangeLog:

	* rust/compile/auto_trait_super_trait.rs: New test.

Signed-off-by: Pierre-Emmanuel Patry <pierre-emmanuel.patry@embecosm.com>

diff --git a/gcc/testsuite/rust/compile/auto_trait_super_trait.rs b/gcc/testsuite/rust/compile/auto_trait_super_trait.rs
new file mode 100644 (file)
index 0000000..1080afb
--- /dev/null
+++ b/gcc/testsuite/rust/compile/auto_trait_super_trait.rs
@@ -0,0 +1,4 @@
+trait Cold {}
+
+auto trait IsCool: Cold {}
+// { dg-error "auto traits cannot have super traits .E0568." "" { target *-*-* } .-1 }