Nim Version

Nim Compiler Version 2.3.1 [Windows: amd64]
Compiled at 2025-11-01
Copyright (c) 2006-2025 by Andreas Rumpf

git hash: 5079074
active boot switches: -d:release

Description

type
  Thing = object
    a: int = 100 # this is fine
    b = 100 # this is not

proc overloaded[T: SomeSignedInt](x: T) = discard
proc overloaded[T: SomeUnsignedInt](x: T) = discard
proc overloaded[T: object](x: T) =
  for val in fields(x):
    var v: typeof(val)
    overloaded(v)

overloaded(Thing())

Current Output

/repro.nim(13, 11) template/generic instantiation of `overloaded` from here
/repro.nim(11, 15) Error: ambiguous call; both repro.overloaded(x: T: SomeSignedInt) [proc declared in /repro.nim(6, 6)] and repro.overloaded(x: T: SomeUnsignedInt) [proc declared in /repro.nim(7, 6)] match for: (int literal(100))

Expected Output

Known Workarounds

• Change b = 100 to b: int = 100.
• Change var v: typeof(val) to var v = default typeof(val)

Additional Information

• Requires all three overloaded to be generic.