openArray views in VM and js give errors

[timotheecour]

--experimental:views don't seem to work well with VM and js:
toOpenArray errors in VM, while using it in js as below gives: Error: internal error: genTypeInfo(tyOpenArray)

Example 1: vm

when true:
  {.experimental: "views".}
  proc test(x: openArray[int]) =
    let y: openArray[int] = toOpenArray(x, 0, 2)
    echo (y[0],)
  template fn=
    test([0,1,2,3,4,5])
  fn() # ok
  static: fn() # Error: cannot generate code for: mSlice

Current Output

Error: cannot generate code for: mSlice

Expected Output

works

Example 2: js

nim r -b:js main
Error: internal error: genTypeInfo(tyOpenArray)

when true:
  {.experimental: "views".}
  proc test(x: openArray[int]) =
    echo (toOpenArray(x, 1, 3),) # ok
    let y: openArray[int] = toOpenArray(x, 1, 3) # Error: internal error: genTypeInfo(tyOpenArray)
    echo (y,)
  var a = [0,1,2,3,4,5]
  test(a)

Possible Solution

see proposal in #16305 (comment)
related: #15952

Additional Information

• devel 1.5.1 f344a70

[ringabout]

fixed by #21440