diff --git a/gcc/rust/util/rust-attributes.cc b/gcc/rust/util/rust-attributes.cc
index bd91fdd5d03..a95249159d9 100644
--- a/gcc/rust/util/rust-attributes.cc
+++ b/gcc/rust/util/rust-attributes.cc
@@ -240,8 +240,8 @@ check_doc_attribute (const AST::Attribute &attribute)
     {
       rust_error_at (
 	attribute.get_locus (),
-	// FIXME: Improve error message here. Rustc has a very good one
-	"%<#[doc]%> cannot be an empty attribute");
+	"valid forms for the attribute are "
+	"%<#[doc(hidden|inline|...)]%> and %<#[doc = \" string \"]%>");
       return;
     }
 
@@ -807,6 +807,7 @@ void
 AttributeChecker::visit (AST::Trait &trait)
 {
   check_proc_macro_non_function (trait.get_outer_attrs ());
+  check_attributes (trait.get_outer_attrs ());
 }
 
 void
diff --git a/gcc/testsuite/rust/compile/attr_malformed_doc.rs b/gcc/testsuite/rust/compile/attr_malformed_doc.rs
new file mode 100644
index 00000000000..6b9ef6174df
--- /dev/null
+++ b/gcc/testsuite/rust/compile/attr_malformed_doc.rs
@@ -0,0 +1,3 @@
+// { dg-error "valid forms for the attribute are ...doc.hidden.inline....... and ...doc = . string ..." "" { target *-*-* } .+1 }
+#[doc]
+trait MyTrait {}