Type parameters in generics indented incorrectly when formatted

[TRCYX]

Bug Report

🔎 Search Terms

generic indent indentation format type parameters

🕗 Version & Regression Information

• This is the behavior in every version I tried, and I reviewed the FAQ for entries about formatting & generics

⏯ Playground Link

Playground link with relevant code

Same as below.

💻 Code

export class C<E
    > {

    x: any;
    constructor<T,
        >(x: T) { this.x = x; }
}


declare function f<T,
    >(x: T): T;

const id = <
    C,
    >(x: C): C => { return x; }

type TYP<
    E
    > = E[];

interface INT<
    E, F
    > { }

export const x = class <E
    >{ };

🙁 Actual behavior

The above code is already formatted.

🙂 Expected behavior

All right angular brackets should be unindented. Note that under certain circumstances the trailing comma is necessary to reproduce the bug, while sometimes it does not matter.

Seems related to

• Type parameters and arguments not always treated as a list in src/service/formatting/formatting.ts in
  

  TypeScript/src/services/formatting/formatting.ts

  Line 1308 in ce85d64

  function getOpenTokenForList(node: Node, list: readonly Node[]) {

• After that, the condition that the trailing comma is recognized in a list only checks for call-like expressions:
  

  TypeScript/src/services/formatting/formatting.ts

  Line 838 in ce85d64

  if (tokenInfo.token.kind === SyntaxKind.CommaToken && isCallLikeExpression(parent)) {

Also related to PR #42341 which fixes a similar case in issue #15782, but only fixes the problem for instantiating a generic type, not for type parameters and arguments in general.

I've started trying to write a fix for this.

[TRCYX]

Note the generic constructor example is actually wrong, but the source code claims to be able to handle this as an error, so I kept it.