Rollup merge of #135378 - compiler-errors:unnecessary-stashing, r=chenyukang

Remove a bunch of diagnostic stashing that doesn't do anything

#121669 removed a bunch of conditional diagnostic stashing/canceling, but left around the `steal` calls which just emitted the error eagerly instead of canceling the diagnostic. I think that these no-op `steal` calls don't do much and are confusing to encounter, so let's remove them.

The net effect is:
1. We emit more duplicated errors, since stashing has the side effect of duplicating diagnostics. This is not a big deal, since outside of `-Zdeduplicate-diagnostics=no`, the errors are already being deduplicated by the compiler.
2. It changes the order of diagnostics, since we're no longer stashing and then later stealing the errors. I don't think this matters much for the changes that the UI test suite manifests, and it makes these errors less order dependent.

3 files changed, 9 insertions, 16 deletions

diff --git a/compiler/rustc_hir_analysis/src/check/check.rs b/compiler/rustc_hir_analysis/src/check/check.rs
index 821829455d9..974a8648bc0 100644
--- a/compiler/rustc_hir_analysis/src/check/check.rs
+++ b/compiler/rustc_hir_analysis/src/check/check.rs
@@ -575,7 +575,7 @@ fn sanity_check_found_hidden_type<'tcx>(
     } else {
         let span = tcx.def_span(key.def_id);
         let other = ty::OpaqueHiddenType { ty: hidden_ty, span };
-        Err(ty.build_mismatch_error(&other, key.def_id, tcx)?.emit())
+        Err(ty.build_mismatch_error(&other, tcx)?.emit())
     }
 }
 
diff --git a/compiler/rustc_hir_analysis/src/collect/type_of/opaque.rs b/compiler/rustc_hir_analysis/src/collect/type_of/opaque.rs
index c933095fd3d..d1a1e36c1d5 100644
--- a/compiler/rustc_hir_analysis/src/collect/type_of/opaque.rs
+++ b/compiler/rustc_hir_analysis/src/collect/type_of/opaque.rs
@@ -1,4 +1,3 @@
-use rustc_errors::StashKey;
 use rustc_hir::def::DefKind;
 use rustc_hir::def_id::LocalDefId;
 use rustc_hir::intravisit::{self, Visitor};
@@ -45,7 +44,7 @@ pub(super) fn find_opaque_ty_constraints_for_impl_trait_in_assoc_type(
         if !hidden.ty.references_error() {
             for concrete_type in locator.typeck_types {
                 if concrete_type.ty != tcx.erase_regions(hidden.ty) {
-                    if let Ok(d) = hidden.build_mismatch_error(&concrete_type, def_id, tcx) {
+                    if let Ok(d) = hidden.build_mismatch_error(&concrete_type, tcx) {
                         d.emit();
                     }
                 }
@@ -121,7 +120,7 @@ pub(super) fn find_opaque_ty_constraints_for_tait(tcx: TyCtxt<'_>, def_id: Local
         if !hidden.ty.references_error() {
             for concrete_type in locator.typeck_types {
                 if concrete_type.ty != tcx.erase_regions(hidden.ty) {
-                    if let Ok(d) = hidden.build_mismatch_error(&concrete_type, def_id, tcx) {
+                    if let Ok(d) = hidden.build_mismatch_error(&concrete_type, tcx) {
                         d.emit();
                     }
                 }
@@ -285,9 +284,8 @@ impl TaitConstraintLocator<'_> {
             debug!(?concrete_type, "found constraint");
             if let Some(prev) = &mut self.found {
                 if concrete_type.ty != prev.ty {
-                    let (Ok(guar) | Err(guar)) = prev
-                        .build_mismatch_error(&concrete_type, self.def_id, self.tcx)
-                        .map(|d| d.emit());
+                    let (Ok(guar) | Err(guar)) =
+                        prev.build_mismatch_error(&concrete_type, self.tcx).map(|d| d.emit());
                     prev.ty = Ty::new_error(self.tcx, guar);
                 }
             } else {
@@ -361,11 +359,8 @@ pub(super) fn find_opaque_ty_constraints_for_rpit<'tcx>(
             );
             if let Some(prev) = &mut hir_opaque_ty {
                 if concrete_type.ty != prev.ty {
-                    if let Ok(d) = prev.build_mismatch_error(&concrete_type, def_id, tcx) {
-                        d.stash(
-                            tcx.def_span(opaque_type_key.def_id),
-                            StashKey::OpaqueHiddenTypeMismatch,
-                        );
+                    if let Ok(d) = prev.build_mismatch_error(&concrete_type, tcx) {
+                        d.emit();
                     }
                 }
             } else {
@@ -435,9 +430,7 @@ impl RpitConstraintChecker<'_> {
             debug!(?concrete_type, "found constraint");
 
             if concrete_type.ty != self.found.ty {
-                if let Ok(d) =
-                    self.found.build_mismatch_error(&concrete_type, self.def_id, self.tcx)
-                {
+                if let Ok(d) = self.found.build_mismatch_error(&concrete_type, self.tcx) {
                     d.emit();
                 }
             }
diff --git a/compiler/rustc_hir_analysis/src/hir_ty_lowering/lint.rs b/compiler/rustc_hir_analysis/src/hir_ty_lowering/lint.rs
index 0ec73a19475..a1f2b8c7594 100644
--- a/compiler/rustc_hir_analysis/src/hir_ty_lowering/lint.rs
+++ b/compiler/rustc_hir_analysis/src/hir_ty_lowering/lint.rs
@@ -103,7 +103,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                 s1.append(s2);
                 sugg.cancel();
             }
-            diag.stash(self_ty.span, StashKey::TraitMissingMethod)
+            Some(diag.emit())
         } else {
             tcx.node_span_lint(BARE_TRAIT_OBJECTS, self_ty.hir_id, self_ty.span, |lint| {
                 lint.primary_message("trait objects without an explicit `dyn` are deprecated");