Add DiagCtxt::delayed_bug.

We have `span_delayed_bug` and often pass it a `DUMMY_SP`. This commit
adds `delayed_bug`, which matches pairs like `err`/`span_err` and
`warn`/`span_warn`.

Author: nnethercote

compiler/rustc_borrowck/src/diagnostics/region_errors.rs

@@ -27,7 +27,7 @@ use rustc_middle::ty::TypeVisitor;
 use rustc_middle::ty::{self, RegionVid, Ty};
 use rustc_middle::ty::{Region, TyCtxt};
 use rustc_span::symbol::{kw, Ident};
-use rustc_span::{Span, DUMMY_SP};
+use rustc_span::Span;
 
 use crate::borrowck_errors;
 use crate::session_diagnostics::{
@@ -84,7 +84,7 @@ impl<'tcx> RegionErrors<'tcx> {
     #[track_caller]
     pub fn push(&mut self, val: impl Into<RegionErrorKind<'tcx>>) {
         let val = val.into();
-        self.1.sess.dcx().span_delayed_bug(DUMMY_SP, format!("{val:?}"));
+        self.1.sess.dcx().delayed_bug(format!("{val:?}"));
         self.0.push(val);
     }
     pub fn is_empty(&self) -> bool {

compiler/rustc_const_eval/src/const_eval/machine.rs

@@ -391,10 +391,10 @@ impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for CompileTimeInterpreter<'mir,
                 if ecx.tcx.is_ctfe_mir_available(def) {
                     Ok(ecx.tcx.mir_for_ctfe(def))
                 } else if ecx.tcx.def_kind(def) == DefKind::AssocConst {
-                    let guar = ecx.tcx.dcx().span_delayed_bug(
-                        rustc_span::DUMMY_SP,
-                        "This is likely a const item that is missing from its impl",
-                    );
+                    let guar = ecx
+                        .tcx
+                        .dcx()
+                        .delayed_bug("This is likely a const item that is missing from its impl");
                     throw_inval!(AlreadyReported(guar.into()));
                 } else {
                     // `find_mir_or_eval_fn` checks that this is a const fn before even calling us,

compiler/rustc_errors/src/lib.rs

@@ -865,10 +865,16 @@ impl DiagCtxt {
     /// For example, it can be used to create an [`ErrorGuaranteed`]
     /// (but you should prefer threading through the [`ErrorGuaranteed`] from an error emission
     /// directly).
-    ///
-    /// If no span is available, use [`DUMMY_SP`].
-    ///
-    /// [`DUMMY_SP`]: rustc_span::DUMMY_SP
+    #[track_caller]
+    pub fn delayed_bug(&self, msg: impl Into<DiagnosticMessage>) -> ErrorGuaranteed {
+        let treat_next_err_as_bug = self.inner.borrow().treat_next_err_as_bug();
+        if treat_next_err_as_bug {
+            self.bug(msg);
+        }
+        DiagnosticBuilder::<ErrorGuaranteed>::new(self, DelayedBug, msg).emit()
+    }
+
+    /// Like `delayed_bug`, but takes an additional span.
     ///
     /// Note: this function used to be called `delay_span_bug`. It was renamed
     /// to match similar functions like `span_err`, `span_warn`, etc.
@@ -882,9 +888,7 @@ impl DiagCtxt {
         if treat_next_err_as_bug {
             self.span_bug(sp, msg);
         }
-        let mut diagnostic = Diagnostic::new(DelayedBug, msg);
-        diagnostic.span(sp);
-        self.emit_diagnostic(diagnostic).unwrap()
+        DiagnosticBuilder::<ErrorGuaranteed>::new(self, DelayedBug, msg).span_mv(sp).emit()
     }
 
     // FIXME(eddyb) note the comment inside `impl Drop for DiagCtxtInner`, that's

compiler/rustc_hir_analysis/src/check/check.rs

@@ -659,10 +659,7 @@ pub(super) fn check_specialization_validity<'tcx>(
         if !tcx.is_impl_trait_in_trait(impl_item) {
             report_forbidden_specialization(tcx, impl_item, parent_impl);
         } else {
-            tcx.dcx().span_delayed_bug(
-                DUMMY_SP,
-                format!("parent item: {parent_impl:?} not marked as default"),
-            );
+            tcx.dcx().delayed_bug(format!("parent item: {parent_impl:?} not marked as default"));
         }
     }
 }

compiler/rustc_hir_analysis/src/check/compare_impl_item.rs

@@ -19,7 +19,7 @@ use rustc_middle::ty::{
     self, GenericArgs, Ty, TypeFoldable, TypeFolder, TypeSuperFoldable, TypeVisitableExt,
 };
 use rustc_middle::ty::{GenericParamDefKind, TyCtxt};
-use rustc_span::{Span, DUMMY_SP};
+use rustc_span::Span;
 use rustc_trait_selection::traits::error_reporting::TypeErrCtxtExt;
 use rustc_trait_selection::traits::outlives_bounds::InferCtxtExt as _;
 use rustc_trait_selection::traits::{
@@ -942,9 +942,7 @@ impl<'tcx> ty::FallibleTypeFolder<TyCtxt<'tcx>> for RemapHiddenTyRegions<'tcx> {
                         .note_mv(format!("hidden type inferred to be `{}`", self.ty))
                         .emit()
                 }
-                _ => {
-                    self.tcx.dcx().span_delayed_bug(DUMMY_SP, "should've been able to remap region")
-                }
+                _ => self.tcx.dcx().delayed_bug("should've been able to remap region"),
             };
             return Err(guar);
         };
@@ -1303,8 +1301,7 @@ fn compare_number_of_generics<'tcx>(
     // inheriting the generics from will also have mismatched arguments, and
     // we'll report an error for that instead. Delay a bug for safety, though.
     if trait_.is_impl_trait_in_trait() {
-        return Err(tcx.dcx().span_delayed_bug(
-            rustc_span::DUMMY_SP,
+        return Err(tcx.dcx().delayed_bug(
             "errors comparing numbers of generics of trait/impl functions were not emitted",
         ));
     }

compiler/rustc_hir_analysis/src/check/compare_impl_item/refine.rs

@@ -7,7 +7,7 @@ use rustc_middle::traits::{ObligationCause, Reveal};
 use rustc_middle::ty::{
     self, Ty, TyCtxt, TypeFoldable, TypeFolder, TypeSuperVisitable, TypeVisitable, TypeVisitor,
 };
-use rustc_span::{Span, DUMMY_SP};
+use rustc_span::Span;
 use rustc_trait_selection::traits::{
     elaborate, normalize_param_env_or_error, outlives_bounds::InferCtxtExt, ObligationCtxt,
 };
@@ -153,10 +153,7 @@ pub(super) fn check_refining_return_position_impl_trait_in_trait<'tcx>(
         trait_m_sig.inputs_and_output,
     ));
     if !ocx.select_all_or_error().is_empty() {
-        tcx.dcx().span_delayed_bug(
-            DUMMY_SP,
-            "encountered errors when checking RPITIT refinement (selection)",
-        );
+        tcx.dcx().delayed_bug("encountered errors when checking RPITIT refinement (selection)");
         return;
     }
     let outlives_env = OutlivesEnvironment::with_bounds(
@@ -165,18 +162,12 @@ pub(super) fn check_refining_return_position_impl_trait_in_trait<'tcx>(
     );
     let errors = infcx.resolve_regions(&outlives_env);
     if !errors.is_empty() {
-        tcx.dcx().span_delayed_bug(
-            DUMMY_SP,
-            "encountered errors when checking RPITIT refinement (regions)",
-        );
+        tcx.dcx().delayed_bug("encountered errors when checking RPITIT refinement (regions)");
         return;
     }
     // Resolve any lifetime variables that may have been introduced during normalization.
     let Ok((trait_bounds, impl_bounds)) = infcx.fully_resolve((trait_bounds, impl_bounds)) else {
-        tcx.dcx().span_delayed_bug(
-            DUMMY_SP,
-            "encountered errors when checking RPITIT refinement (resolution)",
-        );
+        tcx.dcx().delayed_bug("encountered errors when checking RPITIT refinement (resolution)");
         return;
     };
 

compiler/rustc_hir_analysis/src/check/intrinsicck.rs

@@ -4,7 +4,7 @@ use rustc_hir as hir;
 use rustc_middle::ty::{self, Article, FloatTy, IntTy, Ty, TyCtxt, TypeVisitableExt, UintTy};
 use rustc_session::lint;
 use rustc_span::def_id::LocalDefId;
-use rustc_span::{Symbol, DUMMY_SP};
+use rustc_span::Symbol;
 use rustc_target::abi::FieldIdx;
 use rustc_target::asm::{InlineAsmReg, InlineAsmRegClass, InlineAsmRegOrRegClass, InlineAsmType};
 
@@ -294,7 +294,7 @@ impl<'a, 'tcx> InlineAsmCtxt<'a, 'tcx> {
     pub fn check_asm(&self, asm: &hir::InlineAsm<'tcx>, enclosing_id: LocalDefId) {
         let target_features = self.tcx.asm_target_features(enclosing_id.to_def_id());
         let Some(asm_arch) = self.tcx.sess.asm_arch else {
-            self.tcx.dcx().span_delayed_bug(DUMMY_SP, "target architecture does not support asm");
+            self.tcx.dcx().delayed_bug("target architecture does not support asm");
             return;
         };
         for (idx, (op, op_sp)) in asm.operands.iter().enumerate() {

compiler/rustc_hir_analysis/src/collect/resolve_bound_vars.rs

@@ -22,7 +22,7 @@ use rustc_middle::ty::{self, TyCtxt, TypeSuperVisitable, TypeVisitor};
 use rustc_session::lint;
 use rustc_span::def_id::DefId;
 use rustc_span::symbol::{sym, Ident};
-use rustc_span::{Span, DUMMY_SP};
+use rustc_span::Span;
 use std::fmt;
 
 use crate::errors;
@@ -335,13 +335,10 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> {
                     // though this may happen when we call `poly_trait_ref_binder_info` with
                     // an (erroneous, #113423) associated return type bound in an impl header.
                     if !supertrait_bound_vars.is_empty() {
-                        self.tcx.dcx().span_delayed_bug(
-                            DUMMY_SP,
-                            format!(
-                                "found supertrait lifetimes without a binder to append \
+                        self.tcx.dcx().delayed_bug(format!(
+                            "found supertrait lifetimes without a binder to append \
                                 them to: {supertrait_bound_vars:?}"
-                            ),
-                        );
+                        ));
                     }
                     break (vec![], BinderScopeType::Normal);
                 }

compiler/rustc_infer/src/infer/canonical/canonicalizer.rs

@@ -192,10 +192,10 @@ impl CanonicalizeMode for CanonicalizeQueryResponse {
                 // rust-lang/rust#57464: `impl Trait` can leak local
                 // scopes (in manner violating typeck). Therefore, use
                 // `span_delayed_bug` to allow type error over an ICE.
-                canonicalizer.tcx.dcx().span_delayed_bug(
-                    rustc_span::DUMMY_SP,
-                    format!("unexpected region in query response: `{r:?}`"),
-                );
+                canonicalizer
+                    .tcx
+                    .dcx()
+                    .delayed_bug(format!("unexpected region in query response: `{r:?}`"));
                 r
             }
         }

compiler/rustc_infer/src/infer/mod.rs

@@ -38,7 +38,7 @@ use rustc_middle::ty::{self, GenericParamDefKind, InferConst, InferTy, Ty, TyCtx
 use rustc_middle::ty::{ConstVid, EffectVid, FloatVid, IntVid, TyVid};
 use rustc_middle::ty::{GenericArg, GenericArgKind, GenericArgs, GenericArgsRef};
 use rustc_span::symbol::Symbol;
-use rustc_span::{Span, DUMMY_SP};
+use rustc_span::Span;
 
 use std::cell::{Cell, RefCell};
 use std::fmt;
@@ -1434,10 +1434,8 @@ impl<'tcx> InferCtxt<'tcx> {
                     bug!("`{value:?}` is not fully resolved");
                 }
                 if value.has_infer_regions() {
-                    let guar = self
-                        .tcx
-                        .dcx()
-                        .span_delayed_bug(DUMMY_SP, format!("`{value:?}` is not fully resolved"));
+                    let guar =
+                        self.tcx.dcx().delayed_bug(format!("`{value:?}` is not fully resolved"));
                     Ok(self.tcx.fold_regions(value, |re, _| {
                         if re.is_var() { ty::Region::new_error(self.tcx, guar) } else { re }
                     }))