diff --git a/flang/include/flang/Evaluate/expression.h b/flang/include/flang/Evaluate/expression.h
--- a/flang/include/flang/Evaluate/expression.h
+++ b/flang/include/flang/Evaluate/expression.h
@@ -745,7 +745,7 @@
   using Result = SomeKind<CAT>;
   EVALUATE_UNION_CLASS_BOILERPLATE(Expr)
   int GetKind() const;
-  common::MapTemplate<Expr, CategoryTypes<CAT>> u;
+  common::MapTemplate<evaluate::Expr, CategoryTypes<CAT>> u;
 };
 
 template <> class Expr<SomeCharacter> : public ExpressionBase<SomeCharacter> {