Improve code formatting for inferred type signatures on hover in VSC

Suggestion

🔍 Search Terms

VSC, code formatting, prettier, type signature, hover, inferred types

✅ 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

In VSC when hovering over a code element (e.g. a function call) it displays the definition of the code element (e.g. the function signature) combined with the inferred types.

Problem

For simple code elements (e.g. variables) the displayed result is usually easy to read but for more complex code elements (e.g. complex function definitions) the displayed definition gets hard to read.

e.g. here's what I see when hovering over T.catchAllCause (see source)

For reference this is the corresponding source code (when I jump to definition) which is properly formatted:

/**
 * Recovers from all errors with provided cause.
 *
 * @dataFirst catchAllCause_
 */
export declare function catchAllCause<R2, E2, A2, R, E, A>(
  f: (_: Cause<E2>) => Effect<R, E, A>,
  __trace?: string
): (effect: Effect<R2, E2, A2>) => Effect<R2 & R, E, A2 | A>

Solution suggestion

It would be great if the rendered code definition were formatted/pretty printed to make it easier to read (or apply the original code formatting of the definition).

Here's an annotated version of my suggestion based on what I'm seeing when holding down the CMD key.

Start with the VSC hover output described in the issue and compare it with the properly formatted TypeScript source example from Effect-TS. Trace how inferred type signatures are rendered for hover results. Done means complex definitions are consistently formatted and remain readable in VSC.