Remove SharedEmitterMessage::AbortIfErrors.

It's always paired wth `SharedEmitterMessage::Diagnostic`, so the two
can be merged.

Author: nnethercote

compiler/rustc_codegen_ssa/src/back/write.rs

@@ -1002,11 +1002,12 @@ pub struct CguMessage;
 // A cut-down version of `rustc_errors::Diagnostic` that impls `Send`, which
 // can be used to send diagnostics from codegen threads to the main thread.
 // It's missing the following fields from `rustc_errors::Diagnostic`.
-// - `span`: because `MultiSpan` doesn't impl `Send`.
-// - `suggestions`: because it doesn't impl `Send`, and is not worth the complexity.
-// - `sort_span`: because `Span` doesn't impl `Send`.
-// - `is_lint`: because lints aren't relevant during codegen.
-// - `emitted_at`: not worth the complexity.
+// - `span`: it doesn't impl `Send`.
+// - `suggestions`: it doesn't impl `Send`, and isn't used for codegen
+//   diagnostics.
+// - `sort_span`: it doesn't impl `Send`.
+// - `is_lint`: lints aren't relevant during codegen.
+// - `emitted_at`: not used for codegen diagnostics.
 struct Diagnostic {
     level: Level,
     messages: Vec<(DiagnosticMessage, Style)>,
@@ -1017,7 +1018,7 @@ struct Diagnostic {
 
 // A cut-down version of `rustc_errors::SubDiagnostic` that impls `Send`. It's
 // missing the following fields from `rustc_errors::SubDiagnostic`.
-// - `span`: because `MultiSpan` doesn't impl `Send`.
+// - `span`: it doesn't impl `Send`.
 pub struct Subdiagnostic {
     level: Level,
     messages: Vec<(DiagnosticMessage, Style)>,
@@ -1783,7 +1784,6 @@ fn spawn_work<'a, B: ExtraBackendMethods>(
 enum SharedEmitterMessage {
     Diagnostic(Diagnostic),
     InlineAsmError(u32, String, Level, Option<(String, Vec<InnerSpan>)>),
-    AbortIfErrors,
     Fatal(String),
 }
 
@@ -1852,7 +1852,6 @@ impl Emitter for SharedEmitter {
                 args,
             })),
         );
-        drop(self.sender.send(SharedEmitterMessage::AbortIfErrors));
     }
 
     fn source_map(&self) -> Option<&Lrc<SourceMap>> {
@@ -1894,6 +1893,7 @@ impl SharedEmitterMain {
                         .collect();
                     d.args = diag.args;
                     dcx.emit_diagnostic(d);
+                    sess.dcx().abort_if_errors();
                 }
                 Ok(SharedEmitterMessage::InlineAsmError(cookie, msg, level, source)) => {
                     assert!(matches!(level, Level::Error | Level::Warning | Level::Note));
@@ -1926,9 +1926,6 @@ impl SharedEmitterMain {
 
                     err.emit();
                 }
-                Ok(SharedEmitterMessage::AbortIfErrors) => {
-                    sess.dcx().abort_if_errors();
-                }
                 Ok(SharedEmitterMessage::Fatal(msg)) => {
                     sess.dcx().fatal(msg);
                 }