Teach -Z treat-err-as-bug to take a number of errors to emit

src/librustc/session/config.rs

@@ -816,6 +816,8 @@ macro_rules! options {
             Some("crate=integer");
         pub const parse_unpretty: Option<&str> =
             Some("`string` or `string=string`");
+        pub const parse_treat_err_as_bug: Option<&str> =
+            Some("either no value or a number bigger than 0");
         pub const parse_lto: Option<&str> =
             Some("either a boolean (`yes`, `no`, `on`, `off`, etc), `thin`, \
                   `fat`, or omitted");
@@ -1022,6 +1024,13 @@ macro_rules! options {
             }
         }
 
+        fn parse_treat_err_as_bug(slot: &mut Option<usize>, v: Option<&str>) -> bool {
+            match v {
+                Some(s) => { *slot = s.parse().ok().filter(|&x| x != 0); slot.unwrap_or(0) != 0 }
+                None => { *slot = Some(1); true }
+            }
+        }
+
         fn parse_lto(slot: &mut LtoCli, v: Option<&str>) -> bool {
             if v.is_some() {
                 let mut bool_arg = None;
@@ -1234,8 +1243,8 @@ options! {DebuggingOptions, DebuggingSetter, basic_debugging_options,
         "parse only; do not compile, assemble, or link"),
     no_codegen: bool = (false, parse_bool, [TRACKED],
         "run all passes except codegen; no output"),
-    treat_err_as_bug: bool = (false, parse_bool, [TRACKED],
-        "treat all errors that occur as bugs"),
+    treat_err_as_bug: Option<usize> = (None, parse_treat_err_as_bug, [TRACKED],
+        "treat error number `val` that occurs as bug"),
     report_delayed_bugs: bool = (false, parse_bool, [TRACKED],
         "immediately print bugs registered with `delay_span_bug`"),
     external_macro_backtrace: bool = (false, parse_bool, [UNTRACKED],
@@ -3212,7 +3221,7 @@ mod tests {
         assert!(reference.dep_tracking_hash() != opts.dep_tracking_hash());
 
         opts = reference.clone();
-        opts.debugging_opts.treat_err_as_bug = true;
+        opts.debugging_opts.treat_err_as_bug = Some(1);
         assert!(reference.dep_tracking_hash() != opts.dep_tracking_hash());
 
         opts = reference.clone();

src/librustc/session/mod.rs

@@ -1315,7 +1315,7 @@ pub fn early_error(output: config::ErrorOutputType, msg: &str) -> ! {
             Box::new(EmitterWriter::stderr(color_config, None, true, false))
         }
     };
-    let handler = errors::Handler::with_emitter(true, false, emitter);
+    let handler = errors::Handler::with_emitter(true, None, emitter);
     handler.emit(&MultiSpan::new(), msg, errors::Level::Fatal);
     errors::FatalError.raise();
 }
@@ -1330,7 +1330,7 @@ pub fn early_warn(output: config::ErrorOutputType, msg: &str) {
             Box::new(EmitterWriter::stderr(color_config, None, true, false))
         }
     };
-    let handler = errors::Handler::with_emitter(true, false, emitter);
+    let handler = errors::Handler::with_emitter(true, None, emitter);
     handler.emit(&MultiSpan::new(), msg, errors::Level::Warning);
 }
 

src/librustc_codegen_ssa/back/write.rs

@@ -247,7 +247,7 @@ pub struct CodegenContext<B: WriteBackendMethods> {
 
 impl<B: WriteBackendMethods> CodegenContext<B> {
     pub fn create_diag_handler(&self) -> Handler {
-        Handler::with_emitter(true, false, Box::new(self.diag_emitter.clone()))
+        Handler::with_emitter(true, None, Box::new(self.diag_emitter.clone()))
     }
 
     pub fn config(&self, kind: ModuleKind) -> &ModuleConfig {

src/librustc_driver/lib.rs

@@ -148,7 +148,7 @@ pub fn run<F>(run_compiler: F) -> isize
                                 true,
                                 false
                             );
-                        let handler = errors::Handler::with_emitter(true, false, Box::new(emitter));
+                        let handler = errors::Handler::with_emitter(true, None, Box::new(emitter));
                         handler.emit(&MultiSpan::new(),
                                      "aborting due to previous error(s)",
                                      errors::Level::Fatal);
@@ -1327,7 +1327,7 @@ pub fn monitor<F: FnOnce() + Send + 'static>(f: F) -> Result<(), CompilationFail
                                                                 None,
                                                                 false,
                                                                 false));
-            let handler = errors::Handler::with_emitter(true, false, emitter);
+            let handler = errors::Handler::with_emitter(true, None, emitter);
 
             // a .span_bug or .bug call has already printed what
             // it wants to print.

src/librustc_driver/test.rs

@@ -113,7 +113,7 @@ fn test_env_with_pool<F>(
 ) where
     F: FnOnce(Env),
 {
-    let diagnostic_handler = errors::Handler::with_emitter(true, false, emitter);
+    let diagnostic_handler = errors::Handler::with_emitter(true, None, emitter);
     let sess = session::build_session_(
         options,
         None,

src/librustc_errors/diagnostic_builder.rs

@@ -103,7 +103,9 @@ impl<'a> DiagnosticBuilder<'a> {
     /// Buffers the diagnostic for later emission, unless handler
     /// has disabled such buffering.
     pub fn buffer(mut self, buffered_diagnostics: &mut Vec<Diagnostic>) {
-        if self.handler.flags.dont_buffer_diagnostics || self.handler.flags.treat_err_as_bug {
+        if self.handler.flags.dont_buffer_diagnostics ||
+            self.handler.flags.treat_err_as_bug.is_some()
+        {
             self.emit();
             return;
         }

src/librustc_errors/lib.rs

@@ -330,7 +330,7 @@ pub struct HandlerFlags {
     pub can_emit_warnings: bool,
     /// If true, error-level diagnostics are upgraded to bug-level.
     /// (rustc: see `-Z treat-err-as-bug`)
-    pub treat_err_as_bug: bool,
+    pub treat_err_as_bug: Option<usize>,
     /// If true, immediately emit diagnostics that would otherwise be buffered.
     /// (rustc: see `-Z dont-buffer-diagnostics` and `-Z treat-err-as-bug`)
     pub dont_buffer_diagnostics: bool,
@@ -360,7 +360,7 @@ impl Drop for Handler {
 impl Handler {
     pub fn with_tty_emitter(color_config: ColorConfig,
                             can_emit_warnings: bool,
-                            treat_err_as_bug: bool,
+                            treat_err_as_bug: Option<usize>,
                             cm: Option<Lrc<SourceMapperDyn>>)
                             -> Handler {
         Handler::with_tty_emitter_and_flags(
@@ -382,7 +382,7 @@ impl Handler {
     }
 
     pub fn with_emitter(can_emit_warnings: bool,
-                        treat_err_as_bug: bool,
+                        treat_err_as_bug: Option<usize>,
                         e: Box<dyn Emitter + sync::Send>)
                         -> Handler {
         Handler::with_emitter_and_flags(
@@ -516,8 +516,20 @@ impl Handler {
     }
 
     fn panic_if_treat_err_as_bug(&self) {
-        if self.flags.treat_err_as_bug {
-            panic!("encountered error with `-Z treat_err_as_bug");
+        if self.treat_err_as_bug() {
+            let s = match (self.err_count(), self.flags.treat_err_as_bug.unwrap_or(0)) {
+                (0, _) => return,
+                (1, 1) => "aborting due to `-Z treat-err-as-bug=1`".to_string(),
+                (1, _) => return,
+                (count, as_bug) => {
+                    format!(
+                        "aborting after {} errors due to `-Z treat-err-as-bug={}`",
+                        count,
+                        as_bug,
+                    )
+                }
+            };
+            panic!(s);
         }
     }
 
@@ -558,7 +570,7 @@ impl Handler {
         panic!(ExplicitBug);
     }
     pub fn delay_span_bug<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
-        if self.flags.treat_err_as_bug {
+        if self.treat_err_as_bug() {
             // FIXME: don't abort here if report_delayed_bugs is off
             self.span_bug(sp, msg);
         }
@@ -593,14 +605,14 @@ impl Handler {
         DiagnosticBuilder::new(self, FailureNote, msg).emit()
     }
     pub fn fatal(&self, msg: &str) -> FatalError {
-        if self.flags.treat_err_as_bug {
+        if self.treat_err_as_bug() {
             self.bug(msg);
         }
         DiagnosticBuilder::new(self, Fatal, msg).emit();
         FatalError
     }
     pub fn err(&self, msg: &str) {
-        if self.flags.treat_err_as_bug {
+        if self.treat_err_as_bug() {
             self.bug(msg);
         }
         let mut db = DiagnosticBuilder::new(self, Error, msg);
@@ -610,6 +622,9 @@ impl Handler {
         let mut db = DiagnosticBuilder::new(self, Warning, msg);
         db.emit();
     }
+    fn treat_err_as_bug(&self) -> bool {
+        self.flags.treat_err_as_bug.map(|c| self.err_count() >= c).unwrap_or(false)
+    }
     pub fn note_without_error(&self, msg: &str) {
         let mut db = DiagnosticBuilder::new(self, Note, msg);
         db.emit();
@@ -624,8 +639,8 @@ impl Handler {
     }
 
     fn bump_err_count(&self) {
-        self.panic_if_treat_err_as_bug();
         self.err_count.fetch_add(1, SeqCst);
+        self.panic_if_treat_err_as_bug();
     }
 
     pub fn err_count(&self) -> usize {
@@ -642,6 +657,9 @@ impl Handler {
             1 => "aborting due to previous error".to_string(),
             _ => format!("aborting due to {} previous errors", self.err_count())
         };
+        if self.treat_err_as_bug() {
+            return;
+        }
 
         let _ = self.fatal(&s);
 

src/librustdoc/core.rs

@@ -266,7 +266,7 @@ impl DocAccessLevels for AccessLevels<DefId> {
 /// will be created for the handler.
 pub fn new_handler(error_format: ErrorOutputType,
                    source_map: Option<Lrc<source_map::SourceMap>>,
-                   treat_err_as_bug: bool,
+                   treat_err_as_bug: Option<usize>,
                    ui_testing: bool,
 ) -> errors::Handler {
     // rustdoc doesn't override (or allow to override) anything from this that is relevant here, so

src/librustdoc/test.rs

@@ -67,7 +67,7 @@ pub fn run(mut options: Options) -> isize {
         let source_map = Lrc::new(SourceMap::new(sessopts.file_path_mapping()));
         let handler =
             errors::Handler::with_tty_emitter(ColorConfig::Auto,
-                                            true, false,
+                                            true, None,
                                             Some(source_map.clone()));
 
         let mut sess = session::build_session_(
@@ -272,7 +272,7 @@ fn run_test(test: &str, cratename: &str, filename: &FileName, line: usize,
                                                         false);
 
         // Compile the code
-        let diagnostic_handler = errors::Handler::with_emitter(true, false, box emitter);
+        let diagnostic_handler = errors::Handler::with_emitter(true, None, box emitter);
 
         let mut sess = session::build_session_(
             sessopts, None, diagnostic_handler, source_map, Default::default(),
@@ -424,7 +424,7 @@ pub fn make_test(s: &str,
         // send all the errors that libsyntax emits directly into a `Sink` instead of stderr.
         let cm = Lrc::new(SourceMap::new(FilePathMapping::empty()));
         let emitter = EmitterWriter::new(box io::sink(), None, false, false);
-        let handler = Handler::with_emitter(false, false, box emitter);
+        let handler = Handler::with_emitter(false, None, box emitter);
         let sess = ParseSess::with_span_handler(handler, cm);
 
         let mut found_main = false;

src/libsyntax/parse/lexer/mod.rs

@@ -1920,7 +1920,7 @@ mod tests {
                                                           false,
                                                           false);
         ParseSess {
-            span_diagnostic: errors::Handler::with_emitter(true, false, Box::new(emitter)),
+            span_diagnostic: errors::Handler::with_emitter(true, None, Box::new(emitter)),
             unstable_features: UnstableFeatures::from_environment(),
             config: CrateConfig::default(),
             included_mod_stack: Lock::new(Vec::new()),

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)
     }

src/libsyntax/test_snippet.rs

@@ -58,7 +58,7 @@ fn test_harness(file_text: &str, span_labels: Vec<SpanLabel>, expected_output: &
                                         Some(source_map.clone()),
                                         false,
                                         false);
-        let handler = Handler::with_emitter(true, false, Box::new(emitter));
+        let handler = Handler::with_emitter(true, None, Box::new(emitter));
         handler.span_err(msp, "foo");
 
         assert!(expected_output.chars().next() == Some('\n'),

src/test/run-make-fulldeps/treat-err-as-bug/Makefile

@@ -2,4 +2,4 @@
 
 all:
 	$(RUSTC) err.rs -Z treat-err-as-bug 2>&1 \
-	    | $(CGREP) "panicked at 'encountered error with \`-Z treat_err_as_bug'"
+	    | $(CGREP) "panicked at 'aborting due to \`-Z treat-err-as-bug=1\`'"