No TNimNode generated for cimport object [--mm:refc]

[iacore]

This bug is very specific. I don't why it happens, but it happens. The Rectangle is a struct from C. Using the equivalent definition in Nim don't have this bug.

Example

(clone this with git)
https://gist.github.com/locriacyber/c797c39e5583745e13a4caed68a38453

Current Output

(disabled: false, shapepos: (x: 12.0, y: 34.0, width: 56.0, height: 78.0), inputs: @[(payload: 42)], outputs: @[], rails: @[])
@[(disabled: false, shapepos: (x: 0.0, y: 0.0, width: 0.0, height: 0.0), inputs: @[(payload: 42)], outputs: @[], rails: @[])]

Expected Output

The two output should be the same.

Additional Information

This issue exists in Nim version 1.2.0 too.

Nim Compiler Version 1.6.2 [Linux: amd64]
Compiled at 2021-12-17
Copyright (c) 2006-2021 by Andreas Rumpf

git hash: 9084d9bc02bcd983b81a4c76a05f27b9ce2707dd
active boot switches: -d:release

As Elegantbeef pointed out in #nim-lang:matrix.org that this bug only exists with --mm:refc, since other memory models don't need type info (TNimNode) at runtime for this example. Not sure if this will bite me back in the future, but I'll use --mm:orc for now.

[rightbrace]

Related, also discovered while using nimraylib_now: #19482

[iacore]

So, I found a manual fix.

I changed TNimKind of Rectangle from tyObject to 0. And it works now.

NTIrectangle__tVlkfxUbqhSfCIz2T9aInUA_.size = sizeof(Rectangle);
NTIrectangle__tVlkfxUbqhSfCIz2T9aInUA_.align = NIM_ALIGNOF(Rectangle);
NTIrectangle__tVlkfxUbqhSfCIz2T9aInUA_.kind = 0; // previously 18
NTIrectangle__tVlkfxUbqhSfCIz2T9aInUA_.base = 0;
NTIrectangle__tVlkfxUbqhSfCIz2T9aInUA_.flags = 1;
NTIrectangle__tVlkfxUbqhSfCIz2T9aInUA_.node = &TM__rmH9bpP9b3ZIjFP4QhigizlA_0[3];

[iacore]

The problem is, mt.node of the cimport type is not assigned (all zeros in most c compiler). There is no generated TNimNode for cimport types.
https://gist.github.com/locriacyber/34d546150949ab58f322246a412d4a92#file-mbug-nim-c-L1108
https://gist.github.com/locriacyber/34d546150949ab58f322246a412d4a92#file-assign-nim-L55