1 files changed, 5 insertions, 2 deletions
diff --git a/src/libexpr/nixexpr.cc b/src/libexpr/nixexpr.cc
index 63cbef1dd..b4b65883d 100644
--- a/src/libexpr/nixexpr.cc
+++ b/src/libexpr/nixexpr.cc
@@ -267,8 +267,11 @@ void ExprVar::bindVars(const StaticEnv & env)
     /* Otherwise, the variable must be obtained from the nearest
        enclosing `with'.  If there is no `with', then we can issue an
        "undefined variable" error now. */
-    if (withLevel == -1) throw UndefinedVarError(format("undefined variable '%1%' at %2%") % name % pos);
-
+    if (withLevel == -1)
+        throw UndefinedVarError({
+            .hint = hintfmt("undefined variable '%1%'", name),
+            .nixCode = NixCode { .errPos = pos }
+        });
     fromWith = true;
     this->level = withLevel;
 }