x/tools/cmd/guru: no way to find functions which are assignable to (match the signature of) a function type

[a-h]

If I define a function type:

type Printer func(s string)

And a function which accepts a Printer:

type Print(s string, p Printer) {
  p(s)
}

I'd like to be able to use guru to find methods which satisfy the Printer type's signature. I'd also be able to find any matching functions for an anonymous function signature too (e.g. var x func(s string)).

guru is often used to provide text editor features. Having the ability to discover implementations would allow being able to place a caret on p Printer, select Find implementations from the text editor options, then view a list of possible implementations to use.

I've put together an example of how this might work at https://gist.github.com/a-h/dd48a97aba7c07f988aac8e529dadf6d

(See Stackoverflow question at https://stackoverflow.com/questions/50059956/how-do-i-find-implementations-of-a-function-type/50086309#50086309)

[bcmills]

CC: @stamblerre @alandonovan

[stamblerre]

This would be a nice feature and could probably become part of the existing "implements" query. If you'd like to contribute the code you wrote, feel free to send out a review. Otherwise, I'd be happy to look into adding this.

[a-h]

Does anyone have any interest in reviewing this on Gerrit? https://go-review.googlesource.com/c/tools/+/114800