Auto merge of #126623 - oli-obk:do_not_count_errors, r=davidtwco

Replace all `&DiagCtxt` with a `DiagCtxtHandle<'_>` wrapper type

r? `@davidtwco`

This paves the way for tracking more state (e.g. error tainting) in the diagnostic context handle

Basically I will add a field to the `DiagCtxtHandle` that refers back to the `InferCtxt`'s (and others) `Option<ErrorHandled>`, allowing us to immediately taint these contexts when emitting an error and not needing manual tainting anymore (which is easy to forget and we don't do in general anyway)

Author: bors

compiler/rustc_ast_lowering/src/lib.rs

@@ -50,7 +50,7 @@ use rustc_data_structures::fx::FxIndexSet;
 use rustc_data_structures::sorted_map::SortedMap;
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
 use rustc_data_structures::sync::Lrc;
-use rustc_errors::{DiagArgFromDisplay, DiagCtxt, StashKey};
+use rustc_errors::{DiagArgFromDisplay, DiagCtxtHandle, StashKey};
 use rustc_hir::def::{DefKind, LifetimeRes, Namespace, PartialRes, PerNS, Res};
 use rustc_hir::def_id::{LocalDefId, LocalDefIdMap, CRATE_DEF_ID, LOCAL_CRATE};
 use rustc_hir::{self as hir};
@@ -188,7 +188,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         }
     }
 
-    pub(crate) fn dcx(&self) -> &'hir DiagCtxt {
+    pub(crate) fn dcx(&self) -> DiagCtxtHandle<'hir> {
         self.tcx.dcx()
     }
 }

compiler/rustc_ast_passes/src/ast_validation.rs

@@ -12,6 +12,7 @@ use rustc_ast::visit::{walk_list, AssocCtxt, BoundKind, FnCtxt, FnKind, Visitor}
 use rustc_ast::*;
 use rustc_ast_pretty::pprust::{self, State};
 use rustc_data_structures::fx::FxIndexMap;
+use rustc_errors::DiagCtxtHandle;
 use rustc_feature::Features;
 use rustc_parse::validate_attr;
 use rustc_session::lint::builtin::{
@@ -269,7 +270,7 @@ impl<'a> AstValidator<'a> {
         }
     }
 
-    fn dcx(&self) -> &rustc_errors::DiagCtxt {
+    fn dcx(&self) -> DiagCtxtHandle<'a> {
         self.session.dcx()
     }
 
@@ -809,11 +810,7 @@ impl<'a> AstValidator<'a> {
 
 /// Checks that generic parameters are in the correct order,
 /// which is lifetimes, then types and then consts. (`<'a, T, const N: usize>`)
-fn validate_generic_param_order(
-    dcx: &rustc_errors::DiagCtxt,
-    generics: &[GenericParam],
-    span: Span,
-) {
+fn validate_generic_param_order(dcx: DiagCtxtHandle<'_>, generics: &[GenericParam], span: Span) {
     let mut max_param: Option<ParamKindOrd> = None;
     let mut out_of_order = FxIndexMap::default();
     let mut param_idents = Vec::with_capacity(generics.len());