CallableFunction inference does not match runtime behavior

[karol-majewski]

TypeScript Version: 3.4.0-dev.20190309

Search Terms: CallableFunction, call, bind, inference

Code

Promise.resolve.call(1)           // Compiles without error, throws in runtime
Promise.resolve.call(Promise, 1); // Compile-time error, works fine in runtime

Expected behavior:

• Promise.resolve.call(1) should trigger a compile-time error
• Promise.resolve.call(Promise, 1) should compile

Actual behavior:

The situation is reversed. The one that works in runtime does not compile. The one that does compile throws a runtime error.

• Promise.resolve.call(1) compiles without error, throws Uncaught TypeError: PromiseResolve called on non-object in runtime
• Promise.resolve.call(Promise, 1) gives a compile-time error (Expected 1 arguments, but got 2.), works fine in runtime (returns a Promise<number>)

I'm using "lib": ["dom", "esnext"], "target: "es2015". Tested on Chrome 72.0.3626.121, V8 7.2.502.28.

Playground Link: The compile-time error is not there, but the runtime exception can be observed

[RyanCavanaugh]

@rbuckton bug or no?

[rbuckton]

@RyanCavanaugh: This is likely due to overload resolution related to --strictBindCallApply, as we see the same error in this case:

declare class C {
  static x(y: number): number;
  static x(): number;
}
C.x.call(C, 1); // error, but should be ok
C.x.call(C); // ok
C.x.call(1); // ok (not an error because the `this` type of `x` is not constrained)

[rbuckton]

Note that if you switch the order of the overloads, you get the exact opposite results (C.x.call(C, 1) works but C.x.call(C) and C.x.call(1) fail).

[rbuckton]

@RyanCavanaugh: Not a bug per se, as we have documented this is the expected behavior, however it does result in a poor user experience.