[TODO] fix #13524: magics with untyped params (eg astToStr) now work inside generics

[timotheecour]

• fix astToStr doesn't work inside generics #13524: magics with untyped params (eg astToStr) now work inside generics
• if the tyUntyped trick i used isn't acceptable for some reason, I can simply change the logic to:

mixinContext = s.magic in {mDefined, mDefinedInScope, mCompiles, mAstToStr}

[Araq]

This is a breaking change though, for example, now astToStr(2 + 3) produces something different. Arguably something better, but ... breaking change!

[timotheecour]

not sure what you mean; both before and after PR I get:

echo 'echo astToStr(2+3)' | nim c -r -f -
2 + 3

(where the -f is needed until #13506 gets merged)

x is really untyped, not typed, so the previous declaration didn't make sense (in particular, T is meaningless); it only worked because of the way magics currently work, but hopefully one day this would be an error

[krux02]

if the tyUntyped trick i used isn't acceptable for some reason, I can simply change the logic to:

mixinContext = s.magic in {mDefined, mDefinedInScope, mCompiles, mAstToStr}

Yes, please do that.

[timotheecour]

Yes, please do that.

did so in #13681 so #13524 can be fixed soon; but keeping this PR open as it provides a more general fix

[krux02]

closing in favor of #13681