Replace unnecessary abort_if_errors.

Replace `abort_if_errors` calls that are certain to abort -- because
we emit an error immediately beforehand -- with `FatalErro.raise()`.

Author: nnethercote

compiler/rustc_codegen_ssa/src/back/link.rs

@@ -3,7 +3,7 @@ use rustc_ast::CRATE_NODE_ID;
 use rustc_data_structures::fx::{FxIndexMap, FxIndexSet};
 use rustc_data_structures::memmap::Mmap;
 use rustc_data_structures::temp_dir::MaybeTempDir;
-use rustc_errors::{DiagCtxt, ErrorGuaranteed};
+use rustc_errors::{DiagCtxt, ErrorGuaranteed, FatalError};
 use rustc_fs_util::{fix_windows_verbatim_for_gcc, try_canonicalize};
 use rustc_hir::def_id::{CrateNum, LOCAL_CRATE};
 use rustc_metadata::find_native_static_library;
@@ -724,7 +724,7 @@ fn link_dwarf_object<'a>(
         Ok(()) => {}
         Err(e) => {
             sess.dcx().emit_err(errors::ThorinErrorWrapper(e));
-            sess.dcx().abort_if_errors();
+            FatalError.raise();
         }
     }
 }
@@ -1001,7 +1001,7 @@ fn link_natively<'a>(
                 sess.dcx().emit_note(errors::CheckInstalledVisualStudio);
                 sess.dcx().emit_note(errors::InsufficientVSCodeProduct);
             }
-            sess.dcx().abort_if_errors();
+            FatalError.raise();
         }
     }
 

compiler/rustc_codegen_ssa/src/base.rs

@@ -20,6 +20,7 @@ use rustc_data_structures::fx::{FxHashMap, FxIndexSet};
 use rustc_data_structures::profiling::{get_resident_set_size, print_time_passes_entry};
 use rustc_data_structures::sync::par_map;
 use rustc_data_structures::unord::UnordMap;
+use rustc_errors::FatalError;
 use rustc_hir as hir;
 use rustc_hir::def_id::{DefId, LOCAL_CRATE};
 use rustc_hir::lang_items::LangItem;
@@ -451,8 +452,7 @@ pub fn maybe_create_entry_wrapper<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
             let span = cx.tcx().def_span(rust_main_def_id);
             let dcx = cx.tcx().dcx();
             dcx.emit_err(errors::MultipleMainFunctions { span });
-            dcx.abort_if_errors();
-            bug!();
+            FatalError.raise();
         };
 
         // `main` should respect same config for frame pointer elimination as rest of code

compiler/rustc_errors/src/lib.rs

@@ -877,6 +877,10 @@ impl DiagCtxt {
         }
     }
 
+    /// This excludes delayed bugs and stashed errors. Used for early aborts
+    /// after errors occurred -- e.g. because continuing in the face of errors is
+    /// likely to lead to bad results, such as spurious/uninteresting
+    /// additional errors -- when returning an error `Result` is difficult.
     pub fn abort_if_errors(&self) {
         if self.has_errors().is_some() {
             FatalError.raise();

compiler/rustc_interface/src/passes.rs

@@ -9,7 +9,7 @@ use rustc_codegen_ssa::traits::CodegenBackend;
 use rustc_data_structures::parallel;
 use rustc_data_structures::steal::Steal;
 use rustc_data_structures::sync::{Lrc, OnceLock, WorkerLocal};
-use rustc_errors::PResult;
+use rustc_errors::{FatalError, PResult};
 use rustc_expand::base::{ExtCtxt, LintStoreExpand};
 use rustc_feature::Features;
 use rustc_fs_util::try_canonicalize;
@@ -938,7 +938,7 @@ pub fn start_codegen<'tcx>(
         if let Err(error) = rustc_mir_transform::dump_mir::emit_mir(tcx) {
             let dcx = tcx.dcx();
             dcx.emit_err(errors::CantEmitMIR { error });
-            dcx.abort_if_errors();
+            FatalError.raise();
         }
     }
 

compiler/rustc_session/src/output.rs

@@ -6,6 +6,7 @@ use crate::errors::{
 };
 use crate::Session;
 use rustc_ast::{self as ast, attr};
+use rustc_errors::FatalError;
 use rustc_span::symbol::sym;
 use rustc_span::{Span, Symbol};
 use std::path::Path;
@@ -115,7 +116,7 @@ pub fn validate_crate_name(sess: &Session, s: Symbol, sp: Option<Span>) {
     }
 
     if err_count > 0 {
-        sess.dcx().abort_if_errors();
+        FatalError.raise();
     }
 }
 

compiler/rustc_trait_selection/src/traits/error_reporting/type_err_ctxt_ext.rs

@@ -22,7 +22,7 @@ use crate::traits::{
 use rustc_data_structures::fx::{FxHashMap, FxIndexMap};
 use rustc_errors::{
     codes::*, pluralize, struct_span_code_err, Applicability, Diagnostic, DiagnosticBuilder,
-    ErrorGuaranteed, MultiSpan, StashKey, StringPart,
+    ErrorGuaranteed, FatalError, MultiSpan, StashKey, StringPart,
 };
 use rustc_hir as hir;
 use rustc_hir::def::{DefKind, Namespace, Res};
@@ -193,14 +193,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
         let mut err = self.build_overflow_error(predicate, span, suggest_increasing_limit);
         mutate(&mut err);
         err.emit();
-
-        self.dcx().abort_if_errors();
-        // FIXME: this should be something like `build_overflow_error_fatal`, which returns
-        // `DiagnosticBuilder<', !>`. Then we don't even need anything after that `emit()`.
-        unreachable!(
-            "did not expect compilation to continue after `abort_if_errors`, \
-            since an error was definitely emitted!"
-        );
+        FatalError.raise();
     }
 
     fn build_overflow_error<T>(