diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index f8f63bfe0f7..9f4e3a60eb1 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -5821,7 +5821,7 @@ namespace ts {
                     prop.syntheticLiteralTypeOrigin = t as StringLiteralType;
                     members.set(propName, prop);
                 }
-                else if (t.flags & TypeFlags.String) {
+                else if (t.flags & (TypeFlags.Any | TypeFlags.String)) {
                     stringIndexInfo = createIndexInfo(propType, templateReadonly);
                 }
             }