Remove `-Zdont-buffer-diagnostics`.

It was added in #54232. It seems like it was aimed at NLL development,
which is well in the past. Also, it looks like `-Ztreat-err-as-bug` can
be used to achieve the same effect. So it doesn't seem necessary.

1 files changed, 1 insertions, 2 deletions

diff --git a/compiler/rustc_errors/src/diagnostic_builder.rs b/compiler/rustc_errors/src/diagnostic_builder.rs
index e72791d89a2..3789cdaf354 100644
--- a/compiler/rustc_errors/src/diagnostic_builder.rs
+++ b/compiler/rustc_errors/src/diagnostic_builder.rs
@@ -266,8 +266,7 @@ impl<'a, G: EmissionGuarantee> DiagnosticBuilder<'a, G> {
     /// Converts the builder to a `Diagnostic` for later emission,
     /// unless dcx has disabled such buffering.
     pub fn into_diagnostic(mut self) -> Option<(Diagnostic, &'a DiagCtxt)> {
-        let flags = self.dcx.inner.lock().flags;
-        if flags.dont_buffer_diagnostics || flags.treat_err_as_bug.is_some() {
+        if self.dcx.inner.lock().flags.treat_err_as_bug.is_some() {
             self.emit();
             return None;
         }