lix/tests/functional2/repl_characterization/repl_basics/error.md

Errors at the top of an expression are printed normally:

builtins.throw "Evil puppy detected!!!"

error:
       … caused by explicit throw
         at «string»:1:1:
            1| builtins.throw "Evil puppy detected!!!"
             | ^

       error: Evil puppy detected!!!

Errors in attribute values are printed inline, to make it easier to explore values like nixpkgs where some parts of the value fail to evaluate:

{ puppy = builtins.throw "This puppy is EVIL!!!"; puppy2 = "This puppy is GOOD :)"; }

{
  puppy = «error: This puppy is EVIL!!!»;
  puppy2 = "This puppy is GOOD :)";
}

Same for list values:

[ (builtins.throw "This puppy is EVIL!!!") ("This puppy is GOOD :)") ]

[
  «error: This puppy is EVIL!!!»
  "This puppy is GOOD :)"
]