Work towards a non-panicing parser (libsyntax)

- Functions in parser.rs return PResult<> rather than panicing
- Other functions in libsyntax call panic! explicitly for now if they rely on panicing behaviour.
- 'panictry!' macro added as scaffolding while converting panicing functions.
  (This does the same as 'unwrap()' but is easier to grep for and turn into try!())
- Leaves panicing wrappers for the following functions so that the
  quote_* macros behave the same:
  - parse_expr, parse_item, parse_pat, parse_arm, parse_ty, parse_stmt

1 files changed, 2 insertions, 2 deletions

diff --git a/src/libsyntax/parse/lexer/mod.rs b/src/libsyntax/parse/lexer/mod.rs
index 78470f00207..22b7d5c9f1d 100644
--- a/src/libsyntax/parse/lexer/mod.rs
+++ b/src/libsyntax/parse/lexer/mod.rs
@@ -116,7 +116,7 @@ impl<'a> Reader for TtReader<'a> {
         r
     }
     fn fatal(&self, m: &str) -> ! {
-        self.sp_diag.span_fatal(self.cur_span, m);
+        panic!(self.sp_diag.span_fatal(self.cur_span, m));
     }
     fn err(&self, m: &str) {
         self.sp_diag.span_err(self.cur_span, m);
@@ -181,7 +181,7 @@ impl<'a> StringReader<'a> {
 
     /// Report a fatal lexical error with a given span.
     pub fn fatal_span(&self, sp: Span, m: &str) -> ! {
-        self.span_diagnostic.span_fatal(sp, m)
+        panic!(self.span_diagnostic.span_fatal(sp, m))
     }
 
     /// Report a lexical error with a given span.