Auto merge of #64272 - Mark-Simulacrum:parallel-handler, r=estebank

Refactor librustc_errors::Handler API

This should be reviewed by-commit.

The last commit moves all fields into an inner struct behind a single lock; this is done to prevent possible deadlocks in a multi-threaded compiler, as well as inconsistent state observation.

7 files changed, 8 insertions, 13 deletions

diff --git a/src/libsyntax/parse/attr.rs b/src/libsyntax/parse/attr.rs
index bba70973631..cf6151d17b1 100644
--- a/src/libsyntax/parse/attr.rs
+++ b/src/libsyntax/parse/attr.rs
@@ -302,14 +302,14 @@ impl<'a> Parser<'a> {
             Ok(lit) => {
                 return Ok(ast::NestedMetaItem::Literal(lit))
             }
-            Err(ref mut err) => self.diagnostic().cancel(err)
+            Err(ref mut err) => err.cancel(),
         }
 
         match self.parse_meta_item() {
             Ok(mi) => {
                 return Ok(ast::NestedMetaItem::MetaItem(mi))
             }
-            Err(ref mut err) => self.diagnostic().cancel(err)
+            Err(ref mut err) => err.cancel(),
         }
 
         let found = self.this_token_to_string();
diff --git a/src/libsyntax/parse/diagnostics.rs b/src/libsyntax/parse/diagnostics.rs
index 2d7f4f71ca4..59de5f14123 100644
--- a/src/libsyntax/parse/diagnostics.rs
+++ b/src/libsyntax/parse/diagnostics.rs
@@ -197,10 +197,6 @@ impl<'a> Parser<'a> {
         self.sess.span_diagnostic.span_bug(sp, m)
     }
 
-    crate fn cancel(&self, err: &mut DiagnosticBuilder<'_>) {
-        self.sess.span_diagnostic.cancel(err)
-    }
-
     crate fn diagnostic(&self) -> &'a errors::Handler {
         &self.sess.span_diagnostic
     }
@@ -426,15 +422,13 @@ impl<'a> Parser<'a> {
     /// Eats and discards tokens until one of `kets` is encountered. Respects token trees,
     /// passes through any errors encountered. Used for error recovery.
     crate fn eat_to_tokens(&mut self, kets: &[&TokenKind]) {
-        let handler = self.diagnostic();
-
         if let Err(ref mut err) = self.parse_seq_to_before_tokens(
             kets,
             SeqSep::none(),
             TokenExpectType::Expect,
             |p| Ok(p.parse_token_tree()),
         ) {
-            handler.cancel(err);
+            err.cancel();
         }
     }
 
diff --git a/src/libsyntax/parse/lexer/tests.rs b/src/libsyntax/parse/lexer/tests.rs
index c1ec41902e2..de301b1fc49 100644
--- a/src/libsyntax/parse/lexer/tests.rs
+++ b/src/libsyntax/parse/lexer/tests.rs
@@ -18,6 +18,7 @@ fn mk_sess(sm: Lrc<SourceMap>) -> ParseSess {
         false,
         false,
         None,
+        false,
     );
     ParseSess::with_span_handler(Handler::with_emitter(true, None, Box::new(emitter)), sm)
 }
diff --git a/src/libsyntax/parse/mod.rs b/src/libsyntax/parse/mod.rs
index f7b87d154fe..fa4c1043122 100644
--- a/src/libsyntax/parse/mod.rs
+++ b/src/libsyntax/parse/mod.rs
@@ -304,7 +304,7 @@ fn file_to_source_file(sess: &ParseSess, path: &Path, spanopt: Option<Span>)
     match try_file_to_source_file(sess, path, spanopt) {
         Ok(source_file) => source_file,
         Err(d) => {
-            DiagnosticBuilder::new_diagnostic(&sess.span_diagnostic, d).emit();
+            sess.span_diagnostic.emit_diagnostic(&d);
             FatalError.raise();
         }
     }
diff --git a/src/libsyntax/parse/parser/expr.rs b/src/libsyntax/parse/parser/expr.rs
index 41c3747b950..d0c865a7b8e 100644
--- a/src/libsyntax/parse/parser/expr.rs
+++ b/src/libsyntax/parse/parser/expr.rs
@@ -777,7 +777,7 @@ impl<'a> Parser<'a> {
                         ex = ExprKind::Lit(literal);
                     }
                     Err(mut err) => {
-                        self.cancel(&mut err);
+                        err.cancel();
                         return Err(self.expected_expression_found());
                     }
                 }
diff --git a/src/libsyntax/parse/parser/pat.rs b/src/libsyntax/parse/parser/pat.rs
index 08ee3a6bd86..3c624959ead 100644
--- a/src/libsyntax/parse/parser/pat.rs
+++ b/src/libsyntax/parse/parser/pat.rs
@@ -537,7 +537,7 @@ impl<'a> Parser<'a> {
         mut err: DiagnosticBuilder<'a>,
         expected: Expected,
     ) -> PResult<'a, P<Pat>> {
-        self.cancel(&mut err);
+        err.cancel();
 
         let expected = expected.unwrap_or("pattern");
         let msg = format!("expected {}, found {}", expected, self.this_token_descr());
diff --git a/src/libsyntax/parse/parser/stmt.rs b/src/libsyntax/parse/parser/stmt.rs
index 04bd61a4cfb..02da56f6e35 100644
--- a/src/libsyntax/parse/parser/stmt.rs
+++ b/src/libsyntax/parse/parser/stmt.rs
@@ -361,7 +361,7 @@ impl<'a> Parser<'a> {
                 }
                 Err(mut e) => {
                     self.recover_stmt_(SemiColonMode::Break, BlockMode::Ignore);
-                    self.cancel(&mut e);
+                    e.cancel();
                 }
                 _ => ()
             }