Rollup merge of #120342 - oli-obk:track_errors6, r=nnethercote

Remove various `has_errors` or `err_count` uses

follow up to #119895

r? `@nnethercote` since you recently did something similar.

There are so many more of these, but I wanted to get a PR out instead of growing the commit list indefinitely. The commits all work on their own and can be reviewed commit by commit.

compiler/rustc_builtin_macros/src/format.rs

@@ -139,15 +139,15 @@ fn parse_args<'a>(ecx: &mut ExtCtxt<'a>, sp: Span, tts: TokenStream) -> PResult<
             _ => {
                 let expr = p.parse_expr()?;
                 if !args.named_args().is_empty() {
-                    ecx.dcx().emit_err(errors::PositionalAfterNamed {
+                    return Err(ecx.dcx().create_err(errors::PositionalAfterNamed {
                         span: expr.span,
                         args: args
                             .named_args()
                             .iter()
                             .filter_map(|a| a.kind.ident().map(|ident| (a, ident)))
                             .map(|(arg, n)| n.span.to(arg.expr.span))
                             .collect(),
-                    });
+                    }));
                 }
                 args.add(FormatArgument { kind: FormatArgumentKind::Normal, expr });
             }
@@ -313,6 +313,8 @@ fn make_format_args(
     }
     use ArgRef::*;
 
+    let mut unnamed_arg_after_named_arg = false;
+
     let mut lookup_arg = |arg: ArgRef<'_>,
                           span: Option<Span>,
                           used_as: PositionUsedAs,
@@ -352,6 +354,7 @@ fn make_format_args(
                         // For the moment capturing variables from format strings expanded from macros is
                         // disabled (see RFC #2795)
                         ecx.dcx().emit_err(errors::FormatNoArgNamed { span, name });
+                        unnamed_arg_after_named_arg = true;
                         DummyResult::raw_expr(span, true)
                     };
                     Ok(args.add(FormatArgument { kind: FormatArgumentKind::Captured(ident), expr }))
@@ -510,7 +513,8 @@ fn make_format_args(
         })
         .collect::<Vec<_>>();
 
-    if !unused.is_empty() {
+    let has_unused = !unused.is_empty();
+    if has_unused {
         // If there's a lot of unused arguments,
         // let's check if this format arguments looks like another syntax (printf / shell).
         let detect_foreign_fmt = unused.len() > args.explicit_args().len() / 2;
@@ -529,7 +533,7 @@ fn make_format_args(
 
     // Only check for unused named argument names if there are no other errors to avoid causing
     // too much noise in output errors, such as when a named argument is entirely unused.
-    if invalid_refs.is_empty() && ecx.dcx().has_errors().is_none() {
+    if invalid_refs.is_empty() && !has_unused && !unnamed_arg_after_named_arg {
         for &(index, span, used_as) in &numeric_refences_to_named_arg {
             let (position_sp_to_replace, position_sp_for_msg) = match used_as {
                 Placeholder(pspan) => (span, pspan),

compiler/rustc_expand/src/mbe/macro_rules.rs

@@ -485,7 +485,9 @@ pub fn compile_declarative_macro(
                     )
                     .pop()
                     .unwrap();
-                    valid &= check_lhs_nt_follows(sess, def, &tt);
+                    // We don't handle errors here, the driver will abort
+                    // after parsing/expansion. we can report every error in every macro this way.
+                    valid &= check_lhs_nt_follows(sess, def, &tt).is_ok();
                     return tt;
                 }
                 sess.dcx().span_bug(def.span, "wrong-structured lhs")
@@ -589,18 +591,19 @@ pub fn compile_declarative_macro(
     (mk_syn_ext(expander), rule_spans)
 }
 
-fn check_lhs_nt_follows(sess: &Session, def: &ast::Item, lhs: &mbe::TokenTree) -> bool {
+fn check_lhs_nt_follows(
+    sess: &Session,
+    def: &ast::Item,
+    lhs: &mbe::TokenTree,
+) -> Result<(), ErrorGuaranteed> {
     // lhs is going to be like TokenTree::Delimited(...), where the
     // entire lhs is those tts. Or, it can be a "bare sequence", not wrapped in parens.
     if let mbe::TokenTree::Delimited(.., delimited) = lhs {
         check_matcher(sess, def, &delimited.tts)
     } else {
         let msg = "invalid macro matcher; matchers must be contained in balanced delimiters";
-        sess.dcx().span_err(lhs.span(), msg);
-        false
+        Err(sess.dcx().span_err(lhs.span(), msg))
     }
-    // we don't abort on errors on rejection, the driver will do that for us
-    // after parsing/expansion. we can report every error in every macro this way.
 }
 
 fn is_empty_token_tree(sess: &Session, seq: &mbe::SequenceRepetition) -> bool {
@@ -675,12 +678,15 @@ fn check_rhs(sess: &Session, rhs: &mbe::TokenTree) -> bool {
     false
 }
 
-fn check_matcher(sess: &Session, def: &ast::Item, matcher: &[mbe::TokenTree]) -> bool {
+fn check_matcher(
+    sess: &Session,
+    def: &ast::Item,
+    matcher: &[mbe::TokenTree],
+) -> Result<(), ErrorGuaranteed> {
     let first_sets = FirstSets::new(matcher);
     let empty_suffix = TokenSet::empty();
-    let err = sess.dcx().err_count();
-    check_matcher_core(sess, def, &first_sets, matcher, &empty_suffix);
-    err == sess.dcx().err_count()
+    check_matcher_core(sess, def, &first_sets, matcher, &empty_suffix)?;
+    Ok(())
 }
 
 fn has_compile_error_macro(rhs: &mbe::TokenTree) -> bool {
@@ -1020,11 +1026,13 @@ fn check_matcher_core<'tt>(
     first_sets: &FirstSets<'tt>,
     matcher: &'tt [mbe::TokenTree],
     follow: &TokenSet<'tt>,
-) -> TokenSet<'tt> {
+) -> Result<TokenSet<'tt>, ErrorGuaranteed> {
     use mbe::TokenTree;
 
     let mut last = TokenSet::empty();
 
+    let mut errored = Ok(());
+
     // 2. For each token and suffix  [T, SUFFIX] in M:
     // ensure that T can be followed by SUFFIX, and if SUFFIX may be empty,
     // then ensure T can also be followed by any element of FOLLOW.
@@ -1068,7 +1076,7 @@ fn check_matcher_core<'tt>(
                     token::CloseDelim(d.delim),
                     span.close,
                 ));
-                check_matcher_core(sess, def, first_sets, &d.tts, &my_suffix);
+                check_matcher_core(sess, def, first_sets, &d.tts, &my_suffix)?;
                 // don't track non NT tokens
                 last.replace_with_irrelevant();
 
@@ -1100,7 +1108,7 @@ fn check_matcher_core<'tt>(
                 // At this point, `suffix_first` is built, and
                 // `my_suffix` is some TokenSet that we can use
                 // for checking the interior of `seq_rep`.
-                let next = check_matcher_core(sess, def, first_sets, &seq_rep.tts, my_suffix);
+                let next = check_matcher_core(sess, def, first_sets, &seq_rep.tts, my_suffix)?;
                 if next.maybe_empty {
                     last.add_all(&next);
                 } else {
@@ -1206,14 +1214,15 @@ fn check_matcher_core<'tt>(
                                     ));
                                 }
                             }
-                            err.emit();
+                            errored = Err(err.emit());
                         }
                     }
                 }
             }
         }
     }
-    last
+    errored?;
+    Ok(last)
 }
 
 fn token_can_be_followed_by_any(tok: &mbe::TokenTree) -> bool {

compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs

@@ -426,7 +426,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     .map(|vars| self.resolve_vars_if_possible(vars)),
             );
 
-            self.report_arg_errors(
+            self.set_tainted_by_errors(self.report_arg_errors(
                 compatibility_diagonal,
                 formal_and_expected_inputs,
                 provided_args,
@@ -435,7 +435,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 fn_def_id,
                 call_span,
                 call_expr,
-            );
+            ));
         }
     }
 
@@ -449,7 +449,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         fn_def_id: Option<DefId>,
         call_span: Span,
         call_expr: &'tcx hir::Expr<'tcx>,
-    ) {
+    ) -> ErrorGuaranteed {
         // Next, let's construct the error
         let (error_span, full_call_span, call_name, is_method) = match &call_expr.kind {
             hir::ExprKind::Call(
@@ -488,10 +488,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         }
 
         let tcx = self.tcx;
-        // FIXME: taint after emitting errors and pass through an `ErrorGuaranteed`
-        self.set_tainted_by_errors(
-            tcx.dcx().span_delayed_bug(call_span, "no errors reported for args"),
-        );
 
         // Get the argument span in the context of the call span so that
         // suggestions and labels are (more) correct when an arg is a
@@ -698,8 +694,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         Some(mismatch_idx),
                         is_method,
                     );
-                    err.emit();
-                    return;
+                    return err.emit();
                 }
             }
         }
@@ -723,11 +718,11 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             if cfg!(debug_assertions) {
                 span_bug!(error_span, "expected errors from argument matrix");
             } else {
-                tcx.dcx().emit_err(errors::ArgMismatchIndeterminate { span: error_span });
+                return tcx.dcx().emit_err(errors::ArgMismatchIndeterminate { span: error_span });
             }
-            return;
         }
 
+        let mut reported = None;
         errors.retain(|error| {
             let Error::Invalid(provided_idx, expected_idx, Compatibility::Incompatible(Some(e))) =
                 error
@@ -738,16 +733,18 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             let trace =
                 mk_trace(provided_span, formal_and_expected_inputs[*expected_idx], provided_ty);
             if !matches!(trace.cause.as_failure_code(*e), FailureCode::Error0308) {
-                self.err_ctxt().report_and_explain_type_error(trace, *e).emit();
+                reported = Some(self.err_ctxt().report_and_explain_type_error(trace, *e).emit());
                 return false;
             }
             true
         });
 
         // We're done if we found errors, but we already emitted them.
-        if errors.is_empty() {
-            return;
+        if let Some(reported) = reported {
+            assert!(errors.is_empty());
+            return reported;
         }
+        assert!(!errors.is_empty());
 
         // Okay, now that we've emitted the special errors separately, we
         // are only left missing/extra/swapped and mismatched arguments, both
@@ -804,8 +801,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 Some(expected_idx.as_usize()),
                 is_method,
             );
-            err.emit();
-            return;
+            return err.emit();
         }
 
         let mut err = if formal_and_expected_inputs.len() == provided_args.len() {
@@ -1253,7 +1249,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             );
         }
 
-        err.emit();
+        err.emit()
     }
 
     fn suggest_ptr_null_mut(

compiler/rustc_hir_typeck/src/fn_ctxt/mod.rs

@@ -45,14 +45,6 @@ pub struct FnCtxt<'a, 'tcx> {
     /// eventually).
     pub(super) param_env: ty::ParamEnv<'tcx>,
 
-    /// Number of errors that had been reported when we started
-    /// checking this function. On exit, if we find that *more* errors
-    /// have been reported, we will skip regionck and other work that
-    /// expects the types within the function to be consistent.
-    // FIXME(matthewjasper) This should not exist, and it's not correct
-    // if type checking is run in parallel.
-    err_count_on_creation: usize,
-
     /// If `Some`, this stores coercion information for returned
     /// expressions. If `None`, this is in a context where return is
     /// inappropriate, such as a const expression.
@@ -126,7 +118,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         FnCtxt {
             body_id,
             param_env,
-            err_count_on_creation: inh.tcx.dcx().err_count(),
             ret_coercion: None,
             ret_coercion_span: Cell::new(None),
             coroutine_types: None,
@@ -195,10 +186,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             }),
         }
     }
-
-    pub fn errors_reported_since_creation(&self) -> bool {
-        self.dcx().err_count() > self.err_count_on_creation
-    }
 }
 
 impl<'a, 'tcx> Deref for FnCtxt<'a, 'tcx> {

compiler/rustc_infer/src/infer/mod.rs

@@ -278,7 +278,8 @@ pub struct InferCtxt<'tcx> {
 
     /// The set of predicates on which errors have been reported, to
     /// avoid reporting the same error twice.
-    pub reported_trait_errors: RefCell<FxIndexMap<Span, Vec<ty::Predicate<'tcx>>>>,
+    pub reported_trait_errors:
+        RefCell<FxIndexMap<Span, (Vec<ty::Predicate<'tcx>>, ErrorGuaranteed)>>,
 
     pub reported_signature_mismatch: RefCell<FxHashSet<(Span, Option<Span>)>>,