1 files changed, 1 insertions, 2 deletions
diff --git a/third_party/nix/src/libexpr/json-to-value.cc b/third_party/nix/src/libexpr/json-to-value.cc
index e7c7794d1181..8d84a5ac6901 100644
--- a/third_party/nix/src/libexpr/json-to-value.cc
+++ b/third_party/nix/src/libexpr/json-to-value.cc
@@ -42,9 +42,8 @@ static string parseJSONString(const char*& s) {
         throw JSONParseError("invalid escaped character in JSON string");
       s++;
     } else {
-      res
+      res += *s++;
     }
-    += *s++;
   }
   s++;
   return res;