Make `-Z treat-err-as-bug` take a number of errors to be emitted

`-Z treat-err-as-bug=0` will cause `rustc` to panic after the first
error is reported. `-Z treat-err-as-bug=2` will cause `rustc` to
panic after 3 errors have been reported.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/libsyntax/parse/mod.rs b/src/libsyntax/parse/mod.rs
index b2d4d97d57d..9cfcfcd6241 100644
--- a/src/libsyntax/parse/mod.rs
+++ b/src/libsyntax/parse/mod.rs
@@ -53,7 +53,7 @@ impl ParseSess {
         let cm = Lrc::new(SourceMap::new(file_path_mapping));
         let handler = Handler::with_tty_emitter(ColorConfig::Auto,
                                                 true,
-                                                false,
+                                                None,
                                                 Some(cm.clone()));
         ParseSess::with_span_handler(handler, cm)
     }