nimforum mirror - Typedesc error with 2.2.0

drkameleon (orginal) [2024-10-08T17:16:39+02:00] view original

I've been experimenting with upgrading to the latest Nim 2.2.0 and while the last ones (including 2.0.10) have been working fine for us, there is an issue in two similar with 2.2.0.

Code:

One of the spots is here: https://github.com/arturo-lang/arturo/blob/master/src/helpers/objects.nim#L282


    # perform initialization
    # using the available constructor
    if (let constructor = magicMethods.getOrDefault(ConstructorM, nil); not constructor.isNil):
        args.insert(result)
        constructor(args)

MagicMethods, MagicMethodInternal, etc are all defined here: https://github.com/arturo-lang/arturo/blob/master/src/vm/values/types.nim#L152-L198

The error:


../arturo/src/vm/values/comparison.nim(179, 23) template/generic instantiation of `fetch` from here
../arturo/src/vm/values/types.nim(497, 20) template/generic instantiation of `getOrDefault` from here
/Users/drkameleon/.choosenim/toolchains/nim-2.2.0/lib/pure/collections/tables.nim(437, 19) Error: type mismatch: got <typedesc[MagicMethodInternal]>
but expected one of:
MagicMethodInternal = proc (values: ValueArray){.closure.}
stack trace: (most recent call last)

Can you please shed some light as to what is going on here? I've been experimenting a bit and I cannot say I know what to fix.

Any help is more than welcome! :)

drkameleon (orginal) [2024-10-08T17:34:54+02:00] view original

Could be relevant?

https://github.com/nim-lang/Nim/issues/23587

drkameleon (orginal) [2024-10-08T17:58:58+02:00] view original

Apparently, I got it to work by using:


magicMethods.getOrDefault(ConstructorM)

instead of:


magicMethods.getOrDefault(ConstructorM, nil)

Could there be an issue with converting nil to the expected default value?

metagngn (orginal) [2024-10-08T19:45:24+02:00] view original

Described it in https://github.com/nim-lang/Nim/issues/23587, it's a trivial issue with the code in tables but a weird language edge case as well, the error message is misleading. The issue is triggered by calling getOrDefault with a specified default value which has a proc type.

catswhiskers (orginal) [2025-11-24T20:05:34+01:00] view original

Could this be something to do with building Arturo from sources fails with /usr/lib/nim/lib/system/nimscript.nim(264, 7) Error: unhandled exception: FAILED: nim c --define:GMP --define:useOpenssl3 --define:ssl -o:bin/arturo src/arturo.nim [OSError] This is on void linux with musl libc.

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12547 :: Typedesc error with 2.2.0