diff --git a/actionpack/lib/action_dispatch/middleware/templates/rescues/layout.erb b/actionpack/lib/action_dispatch/middleware/templates/rescues/layout.erb
index e0509f56f4..39ea25bdfc 100644
--- a/actionpack/lib/action_dispatch/middleware/templates/rescues/layout.erb
+++ b/actionpack/lib/action_dispatch/middleware/templates/rescues/layout.erb
@@ -106,6 +106,7 @@
 
     .line {
       padding-left: 10px;
+      white-space: pre;
     }
 
     .line:hover {