Type inference in conditional types doesn't work with overloads

[falsandtru]

cc @ahejlsberg

TypeScript Version: 2.7.0-dev.20180206

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Code

type Call<T extends () => any> = T extends () => infer R ? R : never;
type Cast<T> = Call<CastMap<T>>;
interface CastMap<T> {
  (this: ThisType<true>): true;
  (this: ThisType<false>): false;
  (this: ThisType<boolean>): boolean;
  (this: ThisType<void>): void;
}

type A = Cast<true>;

Expected behavior:

A is true.

Actual behavior:

A is void.

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