error:
       … while calling the 'substring' builtin
         at /pwd/eval-fail-over-coercive-builtins-with-xp-feature.nix:1:1:
            1| builtins.substring 0 1 42 == "4"
             | ^
            2|

       … while evaluating the third argument (the string) passed to builtins.substring

       error: cannot coerce an integer to a string: 42
