supportsCopyMem can fail from macro context with tuples

[Vindaar]

Description

I just noticed helping someone with a problem with my https://github.com/Vindaar/forked syntax sugar library that in some cases std/typetraits supportsCopyMem can fail in a macro context.

The following code illustrates the problem

import std / [macros, typetraits]

macro forked*(body: typed): untyped = # typed or untyped does not matter
  result = quote do:
    type WIn = typeof(`body`)
    echo "Type? ", Win, " supportsCopyMem? ", Win.supportsCopyMem
    echo "Type? ", (int, Win), " supportsCopyMem? ", (int, Win).supportsCopyMem

forked:
  "foobar"

Note that the straightforward version without a macro:

type
  WIn = typeof("foo")
echo "Type? ", Win, " supportsCopyMem? ", Win.supportsCopyMem
echo "Type? ", (int, Win), " supportsCopyMem? ", (int, Win).supportsCopyMem

yields the correct output.

Nim Version

Nim Compiler Version 2.2.1 [Linux: amd64]
Compiled at 2024-10-28
Copyright (c) 2006-2024 by Andreas Rumpf

git hash: 15271dba2f4772a193f027d36c05b838dfff5bd4
active boot switches: -d:release -d:danger

(previously tested on a devel compiler from 2024/10/13 with the same behavior)

Current Output

Type? string supportsCopyMem? false
Type? (int, string) supportsCopyMem? true

Expected Output

Type? string supportsCopyMem? false
Type? (int, string) supportsCopyMem? false

Known Workarounds

No response

Additional Information

No response