Add comments suggested by Niko

1 files changed, 6 insertions, 2 deletions

diff --git a/src/libsyntax/lib.rs b/src/libsyntax/lib.rs
index a8b6dae06b9..bf95daf8755 100644
--- a/src/libsyntax/lib.rs
+++ b/src/libsyntax/lib.rs
@@ -50,13 +50,17 @@ extern crate libc;
 
 extern crate serialize as rustc_serialize; // used by deriving
 
+// A variant of 'try!' that panics on Err(FatalError). This is used as a
+// crutch on the way towards a non-panic!-prone parser. It should be used
+// for fatal parsing errors; eventually we plan to convert all code using
+// panictry to just use normal try
 macro_rules! panictry {
     ($e:expr) => ({
         use std::result::Result::{Ok, Err};
-
+        use diagnostic::FatalError;
         match $e {
             Ok(e) => e,
-            Err(e) => panic!(e)
+            Err(FatalError) => panic!(FatalError)
         }
     })
 }