Overflow in loop

[FranciscoDomingues]

Version Information

Tested on Remix

What's your issue about?

It appears there is no overflow checking for the loop variables. For example, the code

@public
def test_for() -> int128:
  a: int128 = 0
  for i in range(MAX_INT128, MAX_INT128+2):
        a = i
  return a

returns -2**127.

[fubuloubu]

Good catch!

[jacqueswww]

Looking at this.

[fubuloubu]

Fixed in #2029

Error:

E           vyper.exceptions.TypeMismatch: Given reference has type uint256, expected int128
E           function 'test_for', line 6:12 
E                5     for i in range(MAX_INT128, MAX_INT128+2):
E           ---> 6         a = i
E           -------------------^
E                7     return a

Added this test case in #2067