* Don't show trace information by default (`--show-trace' to enable).

  NixOS evaluation errors in particular look intimidating and
  generally aren't very useful.  Ideally the builtins.throw messages
  should be self-contained.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/libutil/util.cc b/src/libutil/util.cc
index 1cb94215ee1b..b2fe7e627ef1 100644
--- a/src/libutil/util.cc
+++ b/src/libutil/util.cc
@@ -33,7 +33,7 @@ BaseError::BaseError(const format & f)
 
 BaseError & BaseError::addPrefix(const format & f)
 {
-    err = f.str() + err;
+    prefix_ = f.str() + prefix_;
     return *this;
 }