Key Remapping in Mapped Types does not contribute to the reference of the original type

Bug Report

Key Remapping in Mapped Types does not contribute to the reference of the original type

🔎 Search Terms

Key Remapping in Mapped Types does not contribute to the reference of the original type

🕗 Version & Regression Information

• This changed between versions 4.1 and nightly 20210616

⏯ Playground Link

Playground link with relevant code

💻 Code

const x = {a: 1, b: 2}
x.a

declare const y: {
  [key in keyof typeof x]: boolean
}
y.a

declare const z: {
  [key in keyof typeof x as `get_${key}`]: boolean
}
z.get_a

🙁 Actual behavior

x.a has references on line 2 and line 7

🙂 Expected behavior

x.a has references on line 2, line 7, and line 12

Rename x.a to x.c should rename line 12 to get_c

[RyanCavanaugh]

This turns out to be way harder than just a bugfix. The find-all-references code depends on being able to quickly reduce the set of candidate positions to look for based on the identifier tokens in each source file, but we don’t have any way to know that get_a should be counted as a reference to a since this operation occurs syntactically before we have any type information.

[Jack-Works]

Note to self: Have GAB look at this in a couple weeks

Thanks, that’s very helpful!