diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 6e249c3977d..81ea34b0510 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -574,7 +574,7 @@ namespace ts {
                 recordMergedSymbol(target, source);
             }
             else if (target.flags & SymbolFlags.NamespaceModule) {
-                error(source.valueDeclaration.name, Diagnostics.Cannot_augment_module_0_with_value_exports_because_it_resolves_to_a_non_module_entity, symbolToString(target));
+                error(source.declarations[0].name, Diagnostics.Cannot_augment_module_0_with_value_exports_because_it_resolves_to_a_non_module_entity, symbolToString(target));
             }
             else {
                 const message = target.flags & SymbolFlags.BlockScopedVariable || source.flags & SymbolFlags.BlockScopedVariable