nimsuggest: crash when analyzing code with generic closures

[ibb-dinosaur]

Description

Using the vscode-nim extension (version 1.2) with the language server (version 1.6), the nimsuggest extension crashes when analyzing specific Nim code. The code is valid and compiles without errors.

Minimal reproducible example:

import sugar

type
    Parser[T] = object
    
proc eatWhile[T](p: Parser[T], predicate: T -> bool): seq[T] =
    return @[]

proc skipWs(p: Parser[char]) =
    discard p.eatWhile((c: char) => c == 'a')

Nim Version

Nim Compiler Version 2.0.8 [Windows: amd64]
Compiled at 2024-07-03

Current Output

Server failed with lineinfos.nim(318)     raise RecoverableError
Error: unhandled exception: fatal error: command expects a filename [ERecoverableError]

Expected Output

No response

Known Workarounds

No response

Additional Information

No response

[metagn]

Guessing this causes the same issue

import sugar

type Parser[T] = T -> bool

[ibb-dinosaur]

Ok after looking into it I was actually wrong. It's something about the server being restarted (possibly the vscode extension issue).

When I click Restart under the single open file, everything's fine. But when I click Restart All nimsuggest the error appears, even on an empty file. Not sure if I should open a new issue for this?

[metagn]

I was able to reproduce a crash from the code, it segfaults the compiler, so there is an issue unrelated to the server restarting.