fixes #8301; disallow typedesc being assigned to result

[ringabout]

fixes #8301

tyVoid matches tyAnthing; the same thing goes for fitNode;

# bug #8301
proc foo_1():auto=
  void

when true:
  # Error: internal error: expr: var not init result_115006
  foo_p1()

[metagn]

Why specialize for void? There is no mechanism that deals with this for any typedesc.

proc foo: auto = int

foo() # expr: var not init result_436207618

[ringabout]

Thank you! I'm gonna to do it for typedesc.

[ringabout]

It seems there are more discussion about it:

#16846
#11959
#16601
#16600

[juancarlospaco]

Whats useful for using typedesc as return type?, it is Ok for argument types, but for return types?.
Maybe just disallow typedesc as return type, or at least a warning. 🤔

[ringabout]

The Nim manual only mentions typedesc used as the return type of macros. I will work on disallowing typedesc being assigned to result (with typedesc/tyAnything). It should be an improvement compared to the compiler crash. We can remove the restriction when the time is ripe.

[ringabout]

It would be nice to have compile time procs return typedesc. But until then we should provide better error messages for what were compiler crashes.

[Araq]

Nothing is special about assignment here either:

proc foo(x: auto) = discard

foo(void)

This is already not allowed but then why is it for assignments?

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This pull request has been marked as stale and closed due to inactivity after 395 days.