**TypeScript Version:** 2.5.2 / nightly (2.6.0-dev.20170910) **Code** ```ts interface MyInterface { exec(action: 'action_1'): void; exec(action: 'action_2'): void; exec(action: string): void; } const test: MyInterface = { exec(arg) { // `arg` type is `any` } }; ``` **Expected behavior:** I would expect `arg` type to be `"action1"|"action2"|string`. **Actual behavior:** `arg` type is `any`.