Rollup merge of #134984 - compiler-errors:obligation-tweaks, r=lqd

`ObligationCause` construction tweaks in typeck

Mostly just consolidating the way we construct obligations in `FnCtxt`.

Author: matthiaskrgr

compiler/rustc_hir_typeck/src/callee.rs

@@ -7,7 +7,7 @@ use rustc_hir::def_id::DefId;
 use rustc_hir::{self as hir, HirId, LangItem};
 use rustc_hir_analysis::autoderef::Autoderef;
 use rustc_infer::infer;
-use rustc_infer::traits::{self, Obligation, ObligationCause, ObligationCauseCode};
+use rustc_infer::traits::{Obligation, ObligationCause, ObligationCauseCode};
 use rustc_middle::ty::adjustment::{
     Adjust, Adjustment, AllowTwoPhase, AutoBorrow, AutoBorrowMutability,
 };
@@ -512,7 +512,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 self.register_bound(
                     ty,
                     self.tcx.require_lang_item(hir::LangItem::Tuple, Some(sp)),
-                    traits::ObligationCause::new(sp, self.body_id, ObligationCauseCode::RustCall),
+                    self.cause(sp, ObligationCauseCode::RustCall),
                 );
                 self.require_type_is_sized(ty, sp, ObligationCauseCode::RustCall);
             } else {

compiler/rustc_hir_typeck/src/coercion.rs

@@ -580,11 +580,7 @@ impl<'f, 'tcx> Coerce<'f, 'tcx> {
         let mut selcx = traits::SelectionContext::new(self);
 
         // Create an obligation for `Source: CoerceUnsized<Target>`.
-        let cause =
-            ObligationCause::new(self.cause.span, self.body_id, ObligationCauseCode::Coercion {
-                source,
-                target,
-            });
+        let cause = self.cause(self.cause.span, ObligationCauseCode::Coercion { source, target });
 
         // Use a FIFO queue for this custom fulfillment procedure.
         //

compiler/rustc_hir_typeck/src/expr.rs

@@ -22,7 +22,6 @@ use rustc_hir::{ExprKind, HirId, QPath};
 use rustc_hir_analysis::hir_ty_lowering::{FeedConstTy, HirTyLowerer as _};
 use rustc_infer::infer;
 use rustc_infer::infer::{DefineOpaqueTypes, InferOk};
-use rustc_infer::traits::ObligationCause;
 use rustc_infer::traits::query::NoSolution;
 use rustc_middle::ty::adjustment::{Adjust, Adjustment, AllowTwoPhase};
 use rustc_middle::ty::error::{ExpectedFound, TypeError};
@@ -1174,9 +1173,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         for err in errors {
             let cause = &mut err.obligation.cause;
             if let ObligationCauseCode::OpaqueReturnType(None) = cause.code() {
-                let new_cause = ObligationCause::new(
+                let new_cause = self.cause(
                     cause.span,
-                    cause.body_id,
                     ObligationCauseCode::OpaqueReturnType(Some((return_expr_ty, hir_id))),
                 );
                 *cause = new_cause;
@@ -3856,7 +3854,15 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
                     // Enums are anyway always sized. But just to safeguard against future
                     // language extensions, let's double-check.
-                    self.require_type_is_sized(field_ty, expr.span, ObligationCauseCode::Misc);
+                    self.require_type_is_sized(
+                        field_ty,
+                        expr.span,
+                        ObligationCauseCode::FieldSized {
+                            adt_kind: AdtKind::Enum,
+                            span: self.tcx.def_span(field.did),
+                            last: false,
+                        },
+                    );
 
                     if field.vis.is_accessible_from(sub_def_scope, self.tcx) {
                         self.tcx.check_stability(field.did, Some(expr.hir_id), expr.span, None);
@@ -3884,11 +3890,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         let field_ty = self.field_ty(expr.span, field, args);
 
                         if self.tcx.features().offset_of_slice() {
-                            self.require_type_has_static_alignment(
-                                field_ty,
-                                expr.span,
-                                ObligationCauseCode::Misc,
-                            );
+                            self.require_type_has_static_alignment(field_ty, expr.span);
                         } else {
                             self.require_type_is_sized(
                                 field_ty,
@@ -3917,11 +3919,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     {
                         if let Some(&field_ty) = tys.get(index) {
                             if self.tcx.features().offset_of_slice() {
-                                self.require_type_has_static_alignment(
-                                    field_ty,
-                                    expr.span,
-                                    ObligationCauseCode::Misc,
-                                );
+                                self.require_type_has_static_alignment(field_ty, expr.span);
                             } else {
                                 self.require_type_is_sized(
                                     field_ty,

compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs

@@ -384,7 +384,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         code: traits::ObligationCauseCode<'tcx>,
         def_id: DefId,
     ) {
-        self.register_bound(ty, def_id, traits::ObligationCause::new(span, self.body_id, code));
+        self.register_bound(ty, def_id, self.cause(span, code));
     }
 
     pub(crate) fn require_type_is_sized(
@@ -410,12 +410,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         }
     }
 
-    pub(crate) fn require_type_has_static_alignment(
-        &self,
-        ty: Ty<'tcx>,
-        span: Span,
-        code: traits::ObligationCauseCode<'tcx>,
-    ) {
+    pub(crate) fn require_type_has_static_alignment(&self, ty: Ty<'tcx>, span: Span) {
         if !ty.references_error() {
             let tail = self.tcx.struct_tail_raw(
                 ty,
@@ -434,7 +429,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             } else {
                 // We can't be sure, let's required full `Sized`.
                 let lang_item = self.tcx.require_lang_item(LangItem::Sized, None);
-                self.require_type_meets(ty, span, code, lang_item);
+                self.require_type_meets(ty, span, ObligationCauseCode::Misc, lang_item);
             }
         }
     }
@@ -572,7 +567,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         code: traits::ObligationCauseCode<'tcx>,
     ) {
         // WF obligations never themselves fail, so no real need to give a detailed cause:
-        let cause = traits::ObligationCause::new(span, self.body_id, code);
+        let cause = self.cause(span, code);
         self.register_predicate(traits::Obligation::new(
             self.tcx,
             cause,
@@ -1426,9 +1421,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         let bounds = self.instantiate_bounds(span, def_id, args);
 
         for obligation in traits::predicates_for_generics(
-            |idx, predicate_span| {
-                traits::ObligationCause::new(span, self.body_id, code(idx, predicate_span))
-            },
+            |idx, predicate_span| self.cause(span, code(idx, predicate_span)),
             param_env,
             bounds,
         ) {
@@ -1561,7 +1554,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         query_result: &Canonical<'tcx, QueryResponse<'tcx, Ty<'tcx>>>,
     ) -> InferResult<'tcx, Ty<'tcx>> {
         self.instantiate_query_response_and_region_obligations(
-            &traits::ObligationCause::misc(span, self.body_id),
+            &self.misc(span),
             self.param_env,
             original_values,
             query_result,

compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs

@@ -207,7 +207,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             self.register_wf_obligation(
                 fn_input_ty.into(),
                 arg_expr.span,
-                ObligationCauseCode::Misc,
+                ObligationCauseCode::WellFormed(None),
             );
         }
 

compiler/rustc_hir_typeck/src/method/confirm.rs

@@ -601,7 +601,7 @@ impl<'a, 'tcx> ConfirmContext<'a, 'tcx> {
                     self.call_expr.hir_id,
                     idx,
                 );
-                traits::ObligationCause::new(self.span, self.body_id, code)
+                self.cause(self.span, code)
             },
             self.param_env,
             method_predicates,

compiler/rustc_hir_typeck/src/method/probe.rs

@@ -1739,8 +1739,8 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
         &self,
         trait_ref: ty::TraitRef<'tcx>,
     ) -> traits::SelectionResult<'tcx, traits::Selection<'tcx>> {
-        let cause = traits::ObligationCause::misc(self.span, self.body_id);
-        let obligation = traits::Obligation::new(self.tcx, cause, self.param_env, trait_ref);
+        let obligation =
+            traits::Obligation::new(self.tcx, self.misc(self.span), self.param_env, trait_ref);
         traits::SelectionContext::new(self).select(&obligation)
     }
 
@@ -1841,7 +1841,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
                                 self.scope_expr_id,
                                 idx,
                             );
-                            ObligationCause::new(self.span, self.body_id, code)
+                            self.cause(self.span, code)
                         },
                         self.param_env,
                         impl_bounds,

compiler/rustc_hir_typeck/src/method/suggest.rs

@@ -105,8 +105,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             return false;
         };
         let trait_ref = ty::TraitRef::new(self.tcx, into_iterator_trait, [ty]);
-        let cause = ObligationCause::new(span, self.body_id, ObligationCauseCode::Misc);
-        let obligation = Obligation::new(self.tcx, cause, self.param_env, trait_ref);
+        let obligation = Obligation::new(self.tcx, self.misc(span), self.param_env, trait_ref);
         if !self.predicate_must_hold_modulo_regions(&obligation) {
             return false;
         }
@@ -3489,7 +3488,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 let pred = ty::TraitRef::new(self.tcx, unpin_trait, [*rcvr_ty]);
                 let unpin = self.predicate_must_hold_considering_regions(&Obligation::new(
                     self.tcx,
-                    ObligationCause::misc(rcvr.span, self.body_id),
+                    self.misc(rcvr.span),
                     self.param_env,
                     pred,
                 ));