diff --git a/src/libexpr/parser.y b/src/libexpr/parser.y
index df55986f6..afa1fd439 100644
--- a/src/libexpr/parser.y
+++ b/src/libexpr/parser.y
@@ -584,9 +584,9 @@ Path resolveExprPath(Path path)
     while (true) {
         // Basic cycle/depth limit to avoid infinite loops.
         if (++followCount >= maxFollow)
-          throw Error(format("can't resolve expression. infinite symlink recursion in path '%1%'") % path);
+            throw Error("too many symbolic links encountered while traversing the path '%s'", path);
         if (lstat(path.c_str(), &st))
-            throw SysError(format("getting status of '%1%'") % path);
+            throw SysError("getting status of '%s'", path);
         if (!S_ISLNK(st.st_mode)) break;
         path = absPath(readLink(path), dirOf(path));
     }