Compiler API: Expose `signature.thisParameter`

[Gerrit0]

Suggestion

Remove @internal for the thisParameter on the Signature interface.

TypeScript/src/compiler/types.ts

Lines 5771 to 5772 in 20c93d3

	/* @internal */
	thisParameter?: Symbol; // symbol of this-type parameter

🔍 Search Terms

compiler api, thisParameter

✅ Viability Checklist

My suggestion meets these guidelines:

• This wouldn't be a breaking change in existing TypeScript/JavaScript code
• This wouldn't change the runtime behavior of existing JavaScript code
• This could be implemented without emitting different JS based on the types of the expressions
• This isn't a runtime feature (e.g. library functionality, non-ECMAScript syntax with JavaScript output, new syntax sugar for JS, etc.)
• This feature would agree with the rest of TypeScript's Design Goals.

⭐ Suggestion

As above.

📃 Motivating Example

TypeDoc needs to access the this parameter to properly document functions via their signature rather than relying on nodes. Today, I plan to add this to a declaration file to expose it manually. TypeStrong/typedoc#1875

[RyanCavanaugh]

@ahejlsberg any concerns? I'm inclined to approve

[sandersn]

It's just another parameter, so I think it should be public just like parameters.

[isc-aray]

Is there a way to turn this off? It just feels off to me to document "this" as if it were a normal parameter, since it can't be passed that way, and in the course of normal use, most users won't be thinking about the type of "this" when they call a method.

[RyanCavanaugh]

Turn what off, exactly? This issue is about API availability of this parameters

[isc-aray]

Ah! Sorry, I followed the wrong link from another page. Never mind.