diff --git a/mlir/test/Dialect/EmitC/invalid_types.mlir b/mlir/test/Dialect/EmitC/invalid_types.mlir
new file mode 100644
--- /dev/null
+++ b/mlir/test/Dialect/EmitC/invalid_types.mlir
@@ -0,0 +1,6 @@
+// RUN: mlir-opt %s -split-input-file -verify-diagnostics
+
+func @illegal_opaque_type_1() {
+    // expected-error @+1 {{expected non empty string}}
+    %1 = "emitc.variable"(){value = "" : !emitc.opaque<"">} : () -> !emitc.opaque<"">
+}