Compiler crash with empty array and generic instantiation with int as parameter

[liquidev]

The compiler crashes with the following example, where FloatGen is defined as an alias to Gen[float, 8].

Example

type
  Gen[T; U: int] = object
    a: array[U, T]
 
proc initGen[T; U: int](): Gen[T, U] =
  result = Gen[T, U]()
  result.a = []

type
  FloatGen = Gen[float, 8] # this makes the compiler crash

var gen = initGen[float, 8]()
echo gen

Current Output

fatal.nim(39)            sysFatal
Error: unhandled exception: int128.nim(72, 11) `arg.sdata(2) == 0` out of range [AssertionError]

Expected Output

This is the output when the type alias is removed, it's also the expected error message.

/usercode/in.nim(9, 18) template/generic instantiation of `initGen` from here
/usercode/in.nim(7, 14) Error: type mismatch: got <array[0..-1, empty]> but expected 'array[int, float]'

Additional Information

$ nim -v
Nim Compiler Version 1.0.0 [Linux: amd64]
Compiled at 2019-09-23
Copyright (c) 2006-2019 by Andreas Rumpf

git hash: f7a8fc46c0012033917582eb740dc0343c093e35
active boot switches: -d:release