From 6c2933a8d72f9328a2931a8166439bed96b80f24 Mon Sep 17 00:00:00 2001 From: Ben Burdette Date: Mon, 9 Nov 2020 17:04:52 -0700 Subject: [PATCH] add position --- src/libexpr/eval.cc | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc index e52e8dcf2..11f2e31ce 100644 --- a/src/libexpr/eval.cc +++ b/src/libexpr/eval.cc @@ -1370,11 +1370,11 @@ void EvalState::autoCallFunction(Bindings & args, Value & fun, Value & res) if (j != args.end()) { actualArgs->attrs->push_back(*j); } else if (!i.def) { - throwUndefinedVarError(R"(cannot auto-call a function that has an argument without a default value ('%1%') + throwUndefinedVarError(i.pos, R"(cannot auto-call a function that has an argument without a default value ('%1%') An 'auto-call' is when a nix expression is evaluated without any external arguments. If that nix expression is a function, and that function's arguments all have default values, then all is well. - But if the function arguments don't have default values, then evaluation fails. + But if the function arguments don't have default values, evaluation fails. The classic case for this error is evaluating a nix file with nix-build that expects to be evaluated by callPackage. # in 'callPackage' format: expression is a function that takes an argument 'stdenv'.