Auto merge of #128041 - compiler-errors:uplift-errors-into-trait-sel, r=lcnr

Uplift most type-system related error reporting from `rustc_infer` to `rustc_trait_selection`

Completes the major part of #127492. The only cleanup that's needed afterwards is to actually use normalization in favor of the callback where needed, and deleting `can_eq_shallow`.

r? lcnr

Sorry for the large diff! Would prefer if comments can be handled in a follow-up (unless they're absolutely dealbreakers) because it seems bitrotty to let this sit.

compiler/rustc_hir_analysis/src/check/check.rs

@@ -26,7 +26,7 @@ use rustc_middle::ty::{
 use rustc_session::lint::builtin::{UNINHABITED_STATIC, UNSUPPORTED_CALLING_CONVENTIONS};
 use rustc_target::abi::FieldIdx;
 use rustc_trait_selection::error_reporting::traits::on_unimplemented::OnUnimplementedDirective;
-use rustc_trait_selection::error_reporting::traits::TypeErrCtxtExt as _;
+use rustc_trait_selection::error_reporting::InferCtxtErrorExt;
 use rustc_trait_selection::traits;
 use rustc_trait_selection::traits::outlives_bounds::InferCtxtExt as _;
 use rustc_type_ir::fold::TypeFoldable;

compiler/rustc_hir_analysis/src/check/compare_impl_item.rs

@@ -21,7 +21,7 @@ use rustc_middle::ty::{
 use rustc_middle::ty::{GenericParamDefKind, TyCtxt};
 use rustc_middle::{bug, span_bug};
 use rustc_span::Span;
-use rustc_trait_selection::error_reporting::traits::TypeErrCtxtExt;
+use rustc_trait_selection::error_reporting::InferCtxtErrorExt;
 use rustc_trait_selection::infer::InferCtxtExt;
 use rustc_trait_selection::regions::InferCtxtRegionExt;
 use rustc_trait_selection::traits::outlives_bounds::InferCtxtExt as _;

compiler/rustc_hir_analysis/src/check/entry.rs

@@ -7,7 +7,7 @@ use rustc_session::config::EntryFnType;
 use rustc_span::def_id::{DefId, LocalDefId, CRATE_DEF_ID};
 use rustc_span::{symbol::sym, Span};
 use rustc_target::spec::abi::Abi;
-use rustc_trait_selection::error_reporting::traits::TypeErrCtxtExt as _;
+use rustc_trait_selection::error_reporting::InferCtxtErrorExt;
 use rustc_trait_selection::traits::{self, ObligationCause, ObligationCauseCode};
 
 use std::ops::Not;

compiler/rustc_hir_analysis/src/check/mod.rs

@@ -82,7 +82,6 @@ use rustc_errors::{pluralize, struct_span_code_err, Diag};
 use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_hir::intravisit::Visitor;
 use rustc_index::bit_set::BitSet;
-use rustc_infer::error_reporting::infer::ObligationCauseExt as _;
 use rustc_infer::infer::outlives::env::OutlivesEnvironment;
 use rustc_infer::infer::{self, TyCtxtInferExt as _};
 use rustc_infer::traits::ObligationCause;
@@ -96,10 +95,9 @@ use rustc_span::symbol::{kw, sym, Ident};
 use rustc_span::{def_id::CRATE_DEF_ID, BytePos, Span, Symbol, DUMMY_SP};
 use rustc_target::abi::VariantIdx;
 use rustc_target::spec::abi::Abi;
-use rustc_trait_selection::error_reporting::traits::suggestions::{
-    ReturnsVisitor, TypeErrCtxtExt as _,
-};
-use rustc_trait_selection::error_reporting::traits::TypeErrCtxtExt as _;
+use rustc_trait_selection::error_reporting::infer::ObligationCauseExt as _;
+use rustc_trait_selection::error_reporting::traits::suggestions::ReturnsVisitor;
+use rustc_trait_selection::error_reporting::InferCtxtErrorExt;
 use rustc_trait_selection::traits::ObligationCtxt;
 
 use crate::errors;

compiler/rustc_hir_analysis/src/check/wfcheck.rs

@@ -29,7 +29,7 @@ use rustc_session::parse::feature_err;
 use rustc_span::symbol::{sym, Ident};
 use rustc_span::{Span, DUMMY_SP};
 use rustc_target::spec::abi::Abi;
-use rustc_trait_selection::error_reporting::traits::TypeErrCtxtExt;
+use rustc_trait_selection::error_reporting::InferCtxtErrorExt;
 use rustc_trait_selection::regions::InferCtxtRegionExt;
 use rustc_trait_selection::traits::misc::{
     type_allowed_to_implement_const_param_ty, ConstParamTyImplementationError,

compiler/rustc_hir_analysis/src/coherence/builtin.rs

@@ -17,7 +17,7 @@ use rustc_middle::ty::adjustment::CoerceUnsizedInfo;
 use rustc_middle::ty::print::PrintTraitRefExt as _;
 use rustc_middle::ty::{self, suggest_constraining_type_params, Ty, TyCtxt, TypeVisitableExt};
 use rustc_span::{Span, DUMMY_SP};
-use rustc_trait_selection::error_reporting::traits::TypeErrCtxtExt;
+use rustc_trait_selection::error_reporting::InferCtxtErrorExt;
 use rustc_trait_selection::traits::misc::{
     type_allowed_to_implement_const_param_ty, type_allowed_to_implement_copy,
     ConstParamTyImplementationError, CopyImplementationError, InfringingFieldsReason,

compiler/rustc_hir_analysis/src/coherence/orphan.rs

@@ -517,9 +517,10 @@ impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for UncoveredTyParamCollector<'_, 'tcx> {
         if !ty.has_type_flags(ty::TypeFlags::HAS_TY_INFER) {
             return;
         }
-        let Some(origin) = self.infcx.type_var_origin(ty) else {
+        let ty::Infer(ty::TyVar(vid)) = *ty.kind() else {
             return ty.super_visit_with(self);
         };
+        let origin = self.infcx.type_var_origin(vid);
         if let Some(def_id) = origin.param_def_id {
             self.uncovered_params.insert(def_id);
         }
@@ -546,9 +547,10 @@ impl<'cx, 'tcx> TypeFolder<TyCtxt<'tcx>> for TyVarReplacer<'cx, 'tcx> {
         if !ty.has_type_flags(ty::TypeFlags::HAS_TY_INFER) {
             return ty;
         }
-        let Some(origin) = self.infcx.type_var_origin(ty) else {
+        let ty::Infer(ty::TyVar(vid)) = *ty.kind() else {
             return ty.super_fold_with(self);
         };
+        let origin = self.infcx.type_var_origin(vid);
         if let Some(def_id) = origin.param_def_id {
             // The generics of an `impl` don't have a parent, we can index directly.
             let index = self.generics.param_def_id_to_index[&def_id];

compiler/rustc_hir_analysis/src/impl_wf_check/min_specialization.rs

@@ -78,7 +78,7 @@ use rustc_middle::ty::trait_def::TraitSpecializationKind;
 use rustc_middle::ty::{self, TyCtxt, TypeVisitableExt};
 use rustc_middle::ty::{GenericArg, GenericArgs, GenericArgsRef};
 use rustc_span::{ErrorGuaranteed, Span};
-use rustc_trait_selection::error_reporting::traits::TypeErrCtxtExt;
+use rustc_trait_selection::error_reporting::InferCtxtErrorExt;
 use rustc_trait_selection::traits::outlives_bounds::InferCtxtExt as _;
 use rustc_trait_selection::traits::{self, translate_args_with_cause, wf, ObligationCtxt};