microsoft / microsoft/TypeScript

intellisense in static method suggests TypeParameter of outer class

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Description

TypeScript Version: 3.2.0-dev.20181101

Search Terms:

Code

class Outer<T> {
    doStuff() {
        class Inner<T> {
            static doStuff(param: /**/) {}
        }
    }
}

Expected behavior:

Intellisense does not suggest T as it will result in an error.
OR
T of Inner doesn't shadow the outer T in static members, which is therefore accessible.

Actual behavior:

Suggests T from Outer.

Playground Link: https://agentcooper.github.io/typescript-play/#code/MYGwhgzhAEDyCuAXApgJwDwBUB80DeAUNMdACYD2AyovAGa0AUAlPkSe6JDAJIB2vaLLkLtRJCIjCIAlsDJUa9BgAcwqMAFsAXNAD0AKn26WeAL5sx59udNA

Related Issues:
#28471

TypeChecker.getSymbolsInScope correctly excludes TypeParameters of the containing class for its static members. Because of that an outer scope can add a symbol with the same name.

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First steps

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  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by reproducing the nested generic static-member case from the issue or its Playground link, then inspect TypeChecker.getSymbolsInScope and the IntelliSense symbol collection around static members. Done means IntelliSense no longer suggests the inaccessible outer T, while the intended handling of Inner's T is preserved.

Written by the indexing model from the issue text.

Assessment

Tech stack
typescript
Domain
compilers, developer-experience
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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