fix(40609): Crash on extract to type alias

[a-tarasyuk]

Fixes #40609

[jessetrinity]

Why were duplicate type parameters causing the crash?

[a-tarasyuk]

The visitor checks all parameters and adds each parameter type to the result. for the following example

type Foo<T> = {
    fn: (a: T, b: T, c: T) => void;
}

ExtractType tries to create a type type NewType<T, T, T> which causes the error. @jessetrinity does that make sense?

[jessetrinity]

Yes, that makes sense. Thanks for the explanation and the PR!

[DanielRosenwasser]

I'm still not clear on why it crashes but this seems to fix another future bug.

[andrewbranch]

At some point it would be good to add a variety of tests that pump template and pattern literal types through codefixes/refactors. When @jessetrinity and I were debugging this, we definitely saw the formatting scanner get tripped up on that node. I still think there might be a missing condition to reScan something. I’m surprised this fixes that crash based on the behavior we saw, but the formatter works in mysterious ways 🤷

[a-tarasyuk]

@andrewbranch I'm ok to revert these changes, in favor of adding changes to formatter.

[jessetrinity]

Strictly speaking it doesn't fix the template type bug, #40738 did.

Previous to that, extract type on

type a = `${a}` 

would cause a crash.

You should actually be able to remove the string templates from the tests in this PR and still get the crash previous to this change.

[andrewbranch]

I'm ok to revert these changes, in favor of adding changes to formatter.

Oh no, these changes are clearly correct, I was just surprised they fixed the bug.

Strictly speaking it doesn't fix the template type bug, #40738 did.

Ah, that makes more sense 👍

[a-tarasyuk]

#40738 did

@jessetrinity Yep, I was waiting for the merging of this PR., because my first PR contained changes related to missing nodes and duplicated type references.

[a-tarasyuk]

@andrewbranch @jessetrinity Does that make sense to drop the test tests/cases/fourslash/refactorExtractType69.ts?

[jessetrinity]

I thought it was good to have a test on the code that surfaced the bug, but maybe it's a little confusing since there were two bugs..?

If anything, we might want a more minimal test for the template string issue covering with span:

type a = \*a*\`${extractMe}`\*b*\