diff --git a/src/compiler/transformers/declarations/diagnostics.ts b/src/compiler/transformers/declarations/diagnostics.ts
index eb12f695b2ffb..873f23cbf7987 100644
--- a/src/compiler/transformers/declarations/diagnostics.ts
+++ b/src/compiler/transformers/declarations/diagnostics.ts
@@ -767,7 +767,7 @@ export function createGetIsolatedDeclarationErrors(resolver: EmitResolver): (nod
         if (isSetAccessor(node.parent)) {
             return createAccessorTypeError(node.parent);
         }
-        const addUndefined = resolver.requiresAddingImplicitUndefined(node, findAncestor(node, isFunctionLikeDeclaration));
+        const addUndefined = resolver.requiresAddingImplicitUndefined(node, node.parent);
         if (!addUndefined && node.initializer) {
             return createExpressionError(node.initializer);
         }