Repro for #3140

testcase_3140.nim

iterator doStuff*(str: string, endpos = int.high): int =
  # let strlen = if endpos == int.high: str.len else: endpos+1
  # yield strlen
  if endpos == int.high:
   yield str.len
  else:
   yield endpos+1 #ERROR - Will not compile
  
for num in doStuff("HEY"):
 echo num
  
proc doStuff2(str: string, endpos = int.high): int =
 if endpos == int.high:
   return str.len
 else:
   return endpos+1

echo doStuff2("HEY")