@brandon-b-miller it looks like the new code path in this test is not fully being exercised. If I had to guess, it's because the condition is short-circuiting so some of the later conditions are never being evaluated (i.e. you don't reach is_supported_cast if both is_fixed_width tests fail).

@brandon-b-miller it looks like the new code path in this test is not fully being exercised. If I had to guess, it's because the condition is short-circuiting so some of the later conditions are never being evaluated (i.e. you don't reach is_supported_cast if both is_fixed_width tests fail).

This was subtle but it came down to a failed StringFunction.Contains test:

• the plan inserting a cast to string on the argument passed to contains (in this case an int->string cast)
• the existing code failing to reject this cast when setting up the test data and allowing the test to proceed and hit the NotImplementedError in contains that coverage now complains we miss
• The code still raising NotImplementedError eventually causing the test to pass both ways

Nice find! That seems to have done the trick.

I'll leave this for @wence- to re-review and merge in the morning, but hopefully this is all set now.