Remove -Zreport-delayed-bugs.

It's not used within the repository in any way (e.g. in tests), and
doesn't seem useful.

compiler/rustc_errors/src/lib.rs

@@ -525,9 +525,6 @@ pub struct DiagCtxtFlags {
     /// 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,
-    /// If true, immediately print bugs registered with `span_delayed_bug`.
-    /// (rustc: see `-Z report-delayed-bugs`)
-    pub report_delayed_bugs: bool,
     /// Show macro backtraces.
     /// (rustc: see `-Z macro-backtrace`)
     pub macro_backtrace: bool,
@@ -1004,7 +1001,6 @@ impl DiagCtxt {
     ) -> ErrorGuaranteed {
         let treat_next_err_as_bug = self.inner.borrow().treat_next_err_as_bug();
         if treat_next_err_as_bug {
-            // FIXME: don't abort here if report_delayed_bugs is off
             self.span_bug(sp, msg);
         }
         let mut diagnostic = Diagnostic::new(DelayedBug, msg);
@@ -1016,11 +1012,7 @@ impl DiagCtxt {
     // where the explanation of what "good path" is (also, it should be renamed).
     pub fn good_path_delayed_bug(&self, msg: impl Into<DiagnosticMessage>) {
         let mut inner = self.inner.borrow_mut();
-
-        let mut diagnostic = Diagnostic::new(DelayedBug, msg);
-        if inner.flags.report_delayed_bugs {
-            inner.emit_diagnostic_without_consuming(&mut diagnostic);
-        }
+        let diagnostic = Diagnostic::new(DelayedBug, msg);
         let backtrace = std::backtrace::Backtrace::capture();
         inner.good_path_delayed_bugs.push(DelayedDiagnostic::with_backtrace(diagnostic, backtrace));
     }
@@ -1430,10 +1422,8 @@ impl DiagCtxtInner {
             self.span_delayed_bugs
                 .push(DelayedDiagnostic::with_backtrace(diagnostic.clone(), backtrace));
 
-            if !self.flags.report_delayed_bugs {
-                #[allow(deprecated)]
-                return Some(ErrorGuaranteed::unchecked_claim_error_was_emitted());
-            }
+            #[allow(deprecated)]
+            return Some(ErrorGuaranteed::unchecked_claim_error_was_emitted());
         }
 
         if diagnostic.has_future_breakage() {

compiler/rustc_interface/src/tests.rs

@@ -806,7 +806,6 @@ fn test_unstable_options_tracking_hash() {
     tracked!(relax_elf_relocations, Some(true));
     tracked!(relro_level, Some(RelroLevel::Full));
     tracked!(remap_cwd_prefix, Some(PathBuf::from("abc")));
-    tracked!(report_delayed_bugs, true);
     tracked!(sanitizer, SanitizerSet::ADDRESS);
     tracked!(sanitizer_cfi_canonical_jump_tables, None);
     tracked!(sanitizer_cfi_generalize_pointers, Some(true));

compiler/rustc_session/src/config.rs

@@ -1162,7 +1162,6 @@ impl UnstableOptions {
             can_emit_warnings,
             treat_err_as_bug: self.treat_err_as_bug,
             dont_buffer_diagnostics: self.dont_buffer_diagnostics,
-            report_delayed_bugs: self.report_delayed_bugs,
             macro_backtrace: self.macro_backtrace,
             deduplicate_diagnostics: self.deduplicate_diagnostics,
             track_diagnostics: self.track_diagnostics,

compiler/rustc_session/src/options.rs

@@ -1841,8 +1841,6 @@ options! {
     remark_dir: Option<PathBuf> = (None, parse_opt_pathbuf, [UNTRACKED],
         "directory into which to write optimization remarks (if not specified, they will be \
 written to standard error output)"),
-    report_delayed_bugs: bool = (false, parse_bool, [TRACKED],
-        "immediately print bugs registered with `span_delayed_bug` (default: no)"),
     sanitizer: SanitizerSet = (SanitizerSet::empty(), parse_sanitizers, [TRACKED],
         "use a sanitizer"),
     sanitizer_cfi_canonical_jump_tables: Option<bool> = (Some(true), parse_opt_bool, [TRACKED],