Do less panicking in general

Author: jonas-schievink

src/librustc_driver/driver.rs

@@ -84,7 +84,13 @@ pub fn compile_input(sess: &Session,
     // possible to keep the peak memory usage low
     let (outputs, trans) = {
         let (outputs, expanded_crate, id) = {
-            let krate = panictry!(phase_1_parse_input(sess, cfg, input));
+            let krate = match phase_1_parse_input(sess, cfg, input) {
+                Ok(krate) => krate,
+                Err(mut parse_error) => {
+                    parse_error.emit();
+                    return Err(1);
+                }
+            };
 
             controller_entry_point!(after_parse,
                                     sess,

src/librustc_driver/lib.rs

@@ -529,7 +529,19 @@ impl RustcDefaultCalls {
             return Compilation::Continue;
         }
 
-        let attrs = input.map(|input| panictry!(parse_crate_attrs(sess, input)));
+        let attrs = match input {
+            None => None,
+            Some(input) => {
+                let result = parse_crate_attrs(sess, input);
+                match result {
+                    Ok(attrs) => Some(attrs),
+                    Err(mut parse_error) => {
+                        parse_error.emit();
+                        return Compilation::Stop;
+                    }
+                }
+            }
+        };
         for req in &sess.opts.prints {
             match *req {
                 PrintRequest::TargetList => {

src/libsyntax/parse/mod.rs

@@ -120,6 +120,10 @@ pub fn parse_expr_from_source_str<'a>(name: String,
     p.parse_expr()
 }
 
+/// Parses an item.
+///
+/// Returns `Ok(Some(item))` when successful, `Ok(None)` when no item was found, and`Err`
+/// when a syntax error occurred.
 pub fn parse_item_from_source_str<'a>(name: String,
                                       source: String,
                                       cfg: ast::CrateConfig,