diff --git a/gcc/rust/checks/errors/rust-ast-validation.cc b/gcc/rust/checks/errors/rust-ast-validation.cc
index aeae6035db8f..0604c5673964 100644
--- a/gcc/rust/checks/errors/rust-ast-validation.cc
+++ b/gcc/rust/checks/errors/rust-ast-validation.cc
@@ -109,6 +109,9 @@ ASTValidation::visit (AST::Trait &trait)
 	rust_error_at (trait.get_type_param_bounds ()[0]->get_locus (),
 		       ErrorCode::E0568,
 		       "auto traits cannot have super traits");
+      if (trait.has_trait_items ())
+	rust_error_at (trait.get_locus (), ErrorCode::E0380,
+		       "auto traits cannot have methods or associated items");
     }
 
   AST::ContextualASTVisitor::visit (trait);