Nix/doc/manual/rl-next/with-error-reporting.md

synopsis	prs
Better error reporting for `with` expressions	9658

with expressions using non-attrset values to resolve variables are now reported with proper positions.

Previously an incorrect with expression would report no position at all, making it hard to determine where the error originated:

nix-repl> with 1; a
error:
       … <borked>

         at «none»:0: (source not available)

       error: value is an integer while a set was expected

Now position information is preserved and reported as with most other errors:

nix-repl> with 1; a
error:
       … while evaluating the first subexpression of a with expression
         at «string»:1:1:
            1| with 1; a
             | ^

       error: expected a set but found an integer