JS compiler error related to implicit return and return var type

[nitely]

Example

type
  TrackySeq[T] = object
    s: seq[T]
    pos: int

proc foobar(ls: var TrackySeq[seq[int]], i: int): var seq[int] =
  echo ls.pos  # removing this, or making the return explicit works
  ls.s[i]

var foo: TrackySeq[seq[int]]
foo.s.add(@[0])
foo.foobar(0).add(1)
echo foo.s

Current Output

foob.nim(8, 3) Error: internal error: genAddr: nkStmtListExpr

Expected Output

0
@[@[0, 1]]

$ nim -v
Nim Compiler Version 0.19.9 [Linux: amd64]
Compiled at 2019-05-18
Copyright (c) 2006-2019 by Andreas Rumpf

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