Oh, apparently I already did this one. Yes, it just goes to the default case. For the match to succed, c has to be the character in question AND if condition has to be true. If it already met the first part (i.e. it was a ')' then it won't match '}' or ']' and hit the default.

Ok. Since the kata has been retired it's prolly better to remove the mention in description too, though.

Resolved!

No random tests

The markdown link toward the part 1 kata is badly formatted.

No random tests.

Nice catch! My intention was that None should be returned if any overflow were to occur.

I'll update the description to specify this, and add test cases for add_mixed_narrowing() and add_mixed_signs() to test this case.

Edit: Kata has been updated.

Can the sum in add_mixed_narrowing overflow u32? It's not specified.