Compiler internal error when using default value for a generic parameter.

[lscrd]

The following program causes an internal error in the compiler:

type MyObject[T] = object
  x: T

proc initMyObject[T](value = T.default): MyObject[T] =
  MyObject[T](x: value)

var obj = initMyObject[int]()

Current Output

Error: internal error: expr(skType); unknown symbol

Expected Output

Compilation successful.

Possible Solution

Explicitly specifying the type of the parameter solves the problem:

type MyObject[T] = object
  x: T

proc initMyObject[T](value: T = T.default): MyObject[T] =
  MyObject[T](x: value)

var obj = initMyObject[int]()

Additional Information

$ nim -v
Nim Compiler Version 1.4.2 [Linux: amd64]
Compiled at 2020-11-30
Copyright (c) 2006-2020 by Andreas Rumpf

git hash: 3fb5157ab1b666a5a5c34efde0f357a82d433d04
active boot switches: -d:release

Also present in development version.

[ringabout]

Another workaround:

type MyObject[T] = object
  x: T

proc initMyObject[T](value = default(T)): MyObject[T] =
  MyObject[T](x: value)

var obj = initMyObject[int]()