diff --git a/gcc/rust/checks/errors/rust-feature-gate.cc b/gcc/rust/checks/errors/rust-feature-gate.cc
index 37c0679c2fc9..a90944e45ab1 100644
--- a/gcc/rust/checks/errors/rust-feature-gate.cc
+++ b/gcc/rust/checks/errors/rust-feature-gate.cc
@@ -49,8 +49,8 @@ FeatureGate::check (AST::Crate &crate)
 		    }
 
 		  else
-		    rust_error_at (item->get_locus (), "unknown feature '%s'",
-				   name_str.c_str ());
+		    rust_error_at (item->get_locus (), ErrorCode::E0635,
+				   "unknown feature %qs", name_str.c_str ());
 		}
 	    }
 	}
diff --git a/gcc/testsuite/rust/compile/feature.rs b/gcc/testsuite/rust/compile/feature.rs
index 305d112b7c41..f743f9229b68 100644
--- a/gcc/testsuite/rust/compile/feature.rs
+++ b/gcc/testsuite/rust/compile/feature.rs
@@ -1,4 +1,6 @@
-#![feature(AA)] //{ dg-error "unknown feature 'AA'" }
-                   
+// ErrorCode - E0635
+#![feature(AA)] //{ dg-error "unknown feature .AA." }
+#![feature(iamcrabby)] // { dg-error "unknown feature .iamcrabby." }
+#![feature(nonexistent_gccrs_feature)] // { dg-error "unknown feature .nonexistent_gccrs_feature." }
 
-fn main(){}
\ No newline at end of file
+fn main() {}