Auto merge of #124952 - compiler-errors:no-error, r=lcnr

Rename some `FulfillmentErrorCode`/`ObligationCauseCode` variants to be less redundant

1. Rename some `FulfillmentErrorCode` variants.
2. Always use `ObligationCauseCode::` to prefix a code, rather than using a glob import and naming them through `traits::`.
3. Rename some `ObligationCauseCode` variants -- I wasn't particularly thorough with thinking of a new names for these, so could workshop them if necessary.
4. Misc stuff from renaming.

r? lcnr

compiler/rustc_hir_analysis/src/check/compare_impl_item.rs

@@ -175,7 +175,7 @@ fn compare_method_predicate_entailment<'tcx>(
     let cause = ObligationCause::new(
         impl_m_span,
         impl_m_def_id,
-        ObligationCauseCode::CompareImplItemObligation {
+        ObligationCauseCode::CompareImplItem {
             impl_item_def_id: impl_m_def_id,
             trait_item_def_id: trait_m.def_id,
             kind: impl_m.kind,
@@ -236,7 +236,7 @@ fn compare_method_predicate_entailment<'tcx>(
         let cause = ObligationCause::new(
             span,
             impl_m_def_id,
-            ObligationCauseCode::CompareImplItemObligation {
+            ObligationCauseCode::CompareImplItem {
                 impl_item_def_id: impl_m_def_id,
                 trait_item_def_id: trait_m.def_id,
                 kind: impl_m.kind,
@@ -464,7 +464,7 @@ pub(super) fn collect_return_position_impl_trait_in_trait_tys<'tcx>(
     let cause = ObligationCause::new(
         return_span,
         impl_m_def_id,
-        ObligationCauseCode::CompareImplItemObligation {
+        ObligationCauseCode::CompareImplItem {
             impl_item_def_id: impl_m_def_id,
             trait_item_def_id: trait_m.def_id,
             kind: impl_m.kind,
@@ -819,7 +819,7 @@ impl<'tcx> TypeFolder<TyCtxt<'tcx>> for ImplTraitInTraitCollector<'_, 'tcx> {
                     ObligationCause::new(
                         self.span,
                         self.body_id,
-                        ObligationCauseCode::BindingObligation(proj.def_id, pred_span),
+                        ObligationCauseCode::SpannedWhereClause(proj.def_id, pred_span),
                     ),
                     self.param_env,
                     pred,
@@ -1752,7 +1752,7 @@ fn compare_const_predicate_entailment<'tcx>(
     let impl_ty = tcx.type_of(impl_ct_def_id).instantiate_identity();
 
     let trait_ty = tcx.type_of(trait_ct.def_id).instantiate(tcx, trait_to_impl_args);
-    let code = ObligationCauseCode::CompareImplItemObligation {
+    let code = ObligationCauseCode::CompareImplItem {
         impl_item_def_id: impl_ct_def_id,
         trait_item_def_id: trait_ct.def_id,
         kind: impl_ct.kind,
@@ -1924,7 +1924,7 @@ fn compare_type_predicate_entailment<'tcx>(
         let cause = ObligationCause::new(
             span,
             impl_ty_def_id,
-            ObligationCauseCode::CompareImplItemObligation {
+            ObligationCauseCode::CompareImplItem {
                 impl_item_def_id: impl_ty.def_id.expect_local(),
                 trait_item_def_id: trait_ty.def_id,
                 kind: impl_ty.kind,
@@ -2012,9 +2012,9 @@ pub(super) fn check_type_bounds<'tcx>(
     );
     let mk_cause = |span: Span| {
         let code = if span.is_dummy() {
-            traits::ItemObligation(trait_ty.def_id)
+            ObligationCauseCode::WhereClause(trait_ty.def_id)
         } else {
-            traits::BindingObligation(trait_ty.def_id, span)
+            ObligationCauseCode::SpannedWhereClause(trait_ty.def_id, span)
         };
         ObligationCause::new(impl_ty_span, impl_ty_def_id, code)
     };
@@ -2251,7 +2251,8 @@ fn try_report_async_mismatch<'tcx>(
     };
 
     for error in errors {
-        if let traits::BindingObligation(def_id, _) = *error.root_obligation.cause.code()
+        if let ObligationCauseCode::SpannedWhereClause(def_id, _) =
+            *error.root_obligation.cause.code()
             && def_id == async_future_def_id
             && let Some(proj) = error.root_obligation.predicate.to_opt_poly_projection_pred()
             && let Some(proj) = proj.no_bound_vars()

compiler/rustc_hir_analysis/src/check/dropck.rs

@@ -5,6 +5,7 @@ use rustc_data_structures::fx::FxHashSet;
 use rustc_errors::{codes::*, struct_span_code_err, ErrorGuaranteed};
 use rustc_infer::infer::outlives::env::OutlivesEnvironment;
 use rustc_infer::infer::{RegionResolutionError, TyCtxtInferExt};
+use rustc_infer::traits::ObligationCauseCode;
 use rustc_middle::ty::util::CheckRegions;
 use rustc_middle::ty::GenericArgsRef;
 use rustc_middle::ty::{self, TyCtxt};
@@ -139,7 +140,7 @@ fn ensure_drop_predicates_are_implied_by_item_defn<'tcx>(
     for (pred, span) in tcx.predicates_of(drop_impl_def_id).instantiate_identity(tcx) {
         let normalize_cause = traits::ObligationCause::misc(span, adt_def_id);
         let pred = ocx.normalize(&normalize_cause, param_env, pred);
-        let cause = traits::ObligationCause::new(span, adt_def_id, traits::DropImpl);
+        let cause = traits::ObligationCause::new(span, adt_def_id, ObligationCauseCode::DropImpl);
         ocx.register_obligation(traits::Obligation::new(tcx, cause, param_env, pred));
     }
 

compiler/rustc_hir_analysis/src/check/wfcheck.rs

@@ -1136,7 +1136,7 @@ fn check_type_defn<'tcx>(
                     traits::ObligationCause::new(
                         hir_ty.span,
                         wfcx.body_def_id,
-                        traits::FieldSized {
+                        ObligationCauseCode::FieldSized {
                             adt_kind: match &item.kind {
                                 ItemKind::Struct(..) => AdtKind::Struct,
                                 ItemKind::Union(..) => AdtKind::Union,
@@ -1161,7 +1161,7 @@ fn check_type_defn<'tcx>(
                 let cause = traits::ObligationCause::new(
                     tcx.def_span(discr_def_id),
                     wfcx.body_def_id,
-                    traits::MiscObligation,
+                    ObligationCauseCode::Misc,
                 );
                 wfcx.register_obligation(traits::Obligation::new(
                     tcx,
@@ -1278,7 +1278,11 @@ fn check_item_type(
         wfcx.register_wf_obligation(ty_span, Some(WellFormedLoc::Ty(item_id)), item_ty.into());
         if forbid_unsized {
             wfcx.register_bound(
-                traits::ObligationCause::new(ty_span, wfcx.body_def_id, traits::WellFormed(None)),
+                traits::ObligationCause::new(
+                    ty_span,
+                    wfcx.body_def_id,
+                    ObligationCauseCode::WellFormed(None),
+                ),
                 wfcx.param_env,
                 item_ty,
                 tcx.require_lang_item(LangItem::Sized, None),
@@ -1293,7 +1297,11 @@ fn check_item_type(
 
         if should_check_for_sync {
             wfcx.register_bound(
-                traits::ObligationCause::new(ty_span, wfcx.body_def_id, traits::SharedStatic),
+                traits::ObligationCause::new(
+                    ty_span,
+                    wfcx.body_def_id,
+                    ObligationCauseCode::SharedStatic,
+                ),
                 wfcx.param_env,
                 item_ty,
                 tcx.require_lang_item(LangItem::Sync, Some(ty_span)),
@@ -1542,7 +1550,7 @@ fn check_where_clauses<'tcx>(wfcx: &WfCheckingCtxt<'_, 'tcx>, span: Span, def_id
             let cause = traits::ObligationCause::new(
                 sp,
                 wfcx.body_def_id,
-                traits::ItemObligation(def_id.to_def_id()),
+                ObligationCauseCode::WhereClause(def_id.to_def_id()),
             );
             traits::Obligation::new(tcx, cause, wfcx.param_env, pred)
         });
@@ -1982,7 +1990,11 @@ impl<'tcx> WfCheckingCtxt<'_, 'tcx> {
 
                 let obligation = traits::Obligation::new(
                     tcx,
-                    traits::ObligationCause::new(span, self.body_def_id, traits::TrivialBound),
+                    traits::ObligationCause::new(
+                        span,
+                        self.body_def_id,
+                        ObligationCauseCode::TrivialBound,
+                    ),
                     empty_env,
                     pred,
                 );

compiler/rustc_hir_analysis/src/impl_wf_check/min_specialization.rs

@@ -212,7 +212,7 @@ fn get_impl_args(
             traits::ObligationCause::new(
                 impl1_span,
                 impl1_def_id,
-                traits::ObligationCauseCode::BindingObligation(impl2_node.def_id(), span),
+                traits::ObligationCauseCode::SpannedWhereClause(impl2_node.def_id(), span),
             )
         },
     );