This typing for callbacks typed as any

[tinganho]

I don't quite understand why below code is typed as any(I'm using nightly with --noImplicitThis)?

interface A {
    a: string;
}
declare function test(callback: (this: A) => void): void;
test(function() {
    this.a;// typed as any?
});

[sandersn]

This works for me when I paste this into a VS Code instance running on a branch that I merged from master on Thursday. Let me try the current master...do you have another repro besides this snippet?

[sandersn]

Never mind, I was actually running code from July. It's broken once I point VS to the Thursday-updated branch.

[sandersn]

In case I want to git bisect later, July 6 was the time that the "works-for-me" branch was last merged from master.

[sandersn]

I suspect this PR: #9746
I'll investigate later.

[sandersn]

So, interestingly, this is a bug only in quick info and listing members. Change the callback to return A and you will see that errors are still caught:

interface A {
    a: string;
}
declare function noThis(callback: (this: A) => A): A;
noThis(function() { // error, 'string' is not assignable to 'A'
    return this.a + this.nope; // error, 'nope' does not exist on 'A'
});

I still suspect #9746.