Obscure message for UnimplementedException

[matiasbattocchia]

Version Information

• vyper Version (output of vyper --version): 0.3.3
• OS: linux
• Python Version (output of python --version): 3.9.12

What's your issue about?

Arithmetic operator are only implemented for uint8 and uint256 but the compiler could not tell it when using the addition assignment (+=).

sum: uint16 = 0
equities: uint16[3] = [1, 2, 3]

for equity in equities:
    sum += equity

$ brownie compile

vyper.exceptions.UnimplementedException: <exception str() failed>

Then changed code to

sum: uint16 = 0
equities: uint16[3] = [1, 2, 3]

for equity in equities:
    sum = sum + equity

and finally could spot the problem.

$ brownie compile

vyper.exceptions.UnimplementedException: Not implemented: uint16 + uint16
  contract "contracts/DaiCell.vy", function "__init__", line 25:14 
       24     for equity in equities:
  ---> 25         sum = sum + equity

[charles-cooper]

well, the solution is to implement it :)

tracking in #2786