Rollup merge of rust-lang#106173 - compiler-errors:deduplicate-op-methods, r=jackh726

Deduplicate `op` methods

There are some operator-checking flavored methods in `FnCtxt` that can be deduplicated.

Author: matthiaskrgr

compiler/rustc_hir_typeck/src/callee.rs

@@ -241,7 +241,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             });
 
             if let Some(ok) = self.lookup_method_in_trait(
-                call_expr.span,
+                self.misc(call_expr.span),
                 method_name,
                 trait_def_id,
                 adjusted_ty,

compiler/rustc_hir_typeck/src/method/mod.rs

@@ -11,7 +11,7 @@ pub use self::suggest::SelfSource;
 pub use self::MethodError::*;
 
 use crate::errors::OpMethodGenericParams;
-use crate::{Expectation, FnCtxt};
+use crate::FnCtxt;
 use rustc_data_structures::sync::Lrc;
 use rustc_errors::{Applicability, Diagnostic};
 use rustc_hir as hir;
@@ -264,7 +264,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
     pub(super) fn obligation_for_method(
         &self,
-        span: Span,
+        cause: ObligationCause<'tcx>,
         trait_def_id: DefId,
         self_ty: Ty<'tcx>,
         opt_input_types: Option<&[Ty<'tcx>]>,
@@ -282,71 +282,19 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     }
                 }
             }
-            self.var_for_def(span, param)
-        });
-
-        let trait_ref = self.tcx.mk_trait_ref(trait_def_id, substs);
-
-        // Construct an obligation
-        let poly_trait_ref = ty::Binder::dummy(trait_ref);
-        (
-            traits::Obligation::misc(
-                self.tcx,
-                span,
-                self.body_id,
-                self.param_env,
-                poly_trait_ref.without_const(),
-            ),
-            substs,
-        )
-    }
-
-    pub(super) fn obligation_for_op_method(
-        &self,
-        span: Span,
-        trait_def_id: DefId,
-        self_ty: Ty<'tcx>,
-        opt_input_type: Option<Ty<'tcx>>,
-        opt_input_expr: Option<&'tcx hir::Expr<'tcx>>,
-        expected: Expectation<'tcx>,
-    ) -> (traits::Obligation<'tcx, ty::Predicate<'tcx>>, &'tcx ty::List<ty::subst::GenericArg<'tcx>>)
-    {
-        // Construct a trait-reference `self_ty : Trait<input_tys>`
-        let substs = InternalSubsts::for_item(self.tcx, trait_def_id, |param, _| {
-            match param.kind {
-                GenericParamDefKind::Lifetime | GenericParamDefKind::Const { .. } => {}
-                GenericParamDefKind::Type { .. } => {
-                    if param.index == 0 {
-                        return self_ty.into();
-                    } else if let Some(input_type) = opt_input_type {
-                        return input_type.into();
-                    }
-                }
-            }
-            self.var_for_def(span, param)
+            self.var_for_def(cause.span, param)
         });
 
         let trait_ref = self.tcx.mk_trait_ref(trait_def_id, substs);
 
         // Construct an obligation
         let poly_trait_ref = ty::Binder::dummy(trait_ref);
-        let output_ty = expected.only_has_type(self).and_then(|ty| (!ty.needs_infer()).then(|| ty));
-
         (
             traits::Obligation::new(
                 self.tcx,
-                traits::ObligationCause::new(
-                    span,
-                    self.body_id,
-                    traits::BinOp {
-                        rhs_span: opt_input_expr.map(|expr| expr.span),
-                        is_lit: opt_input_expr
-                            .map_or(false, |expr| matches!(expr.kind, hir::ExprKind::Lit(_))),
-                        output_ty,
-                    },
-                ),
+                cause,
                 self.param_env,
-                poly_trait_ref,
+                poly_trait_ref.without_const(),
             ),
             substs,
         )
@@ -357,69 +305,29 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     /// In particular, it doesn't really do any probing: it simply constructs
     /// an obligation for a particular trait with the given self type and checks
     /// whether that trait is implemented.
-    #[instrument(level = "debug", skip(self, span))]
+    #[instrument(level = "debug", skip(self))]
     pub(super) fn lookup_method_in_trait(
         &self,
-        span: Span,
+        cause: ObligationCause<'tcx>,
         m_name: Ident,
         trait_def_id: DefId,
         self_ty: Ty<'tcx>,
         opt_input_types: Option<&[Ty<'tcx>]>,
     ) -> Option<InferOk<'tcx, MethodCallee<'tcx>>> {
         let (obligation, substs) =
-            self.obligation_for_method(span, trait_def_id, self_ty, opt_input_types);
-        self.construct_obligation_for_trait(
-            span,
-            m_name,
-            trait_def_id,
-            obligation,
-            substs,
-            None,
-            false,
-        )
-    }
-
-    pub(super) fn lookup_op_method_in_trait(
-        &self,
-        span: Span,
-        m_name: Ident,
-        trait_def_id: DefId,
-        self_ty: Ty<'tcx>,
-        opt_input_type: Option<Ty<'tcx>>,
-        opt_input_expr: Option<&'tcx hir::Expr<'tcx>>,
-        expected: Expectation<'tcx>,
-    ) -> Option<InferOk<'tcx, MethodCallee<'tcx>>> {
-        let (obligation, substs) = self.obligation_for_op_method(
-            span,
-            trait_def_id,
-            self_ty,
-            opt_input_type,
-            opt_input_expr,
-            expected,
-        );
-        self.construct_obligation_for_trait(
-            span,
-            m_name,
-            trait_def_id,
-            obligation,
-            substs,
-            opt_input_expr,
-            true,
-        )
+            self.obligation_for_method(cause, trait_def_id, self_ty, opt_input_types);
+        self.construct_obligation_for_trait(m_name, trait_def_id, obligation, substs)
     }
 
     // FIXME(#18741): it seems likely that we can consolidate some of this
     // code with the other method-lookup code. In particular, the second half
     // of this method is basically the same as confirmation.
     fn construct_obligation_for_trait(
         &self,
-        span: Span,
         m_name: Ident,
         trait_def_id: DefId,
         obligation: traits::PredicateObligation<'tcx>,
         substs: &'tcx ty::List<ty::subst::GenericArg<'tcx>>,
-        opt_input_expr: Option<&'tcx hir::Expr<'tcx>>,
-        is_op: bool,
     ) -> Option<InferOk<'tcx, MethodCallee<'tcx>>> {
         debug!(?obligation);
 
@@ -435,7 +343,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         let tcx = self.tcx;
         let Some(method_item) = self.associated_value(trait_def_id, m_name) else {
             tcx.sess.delay_span_bug(
-                span,
+                obligation.cause.span,
                 "operator trait does not have corresponding operator method",
             );
             return None;
@@ -461,24 +369,11 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         // with bound regions.
         let fn_sig = tcx.bound_fn_sig(def_id);
         let fn_sig = fn_sig.subst(self.tcx, substs);
-        let fn_sig = self.replace_bound_vars_with_fresh_vars(span, infer::FnCall, fn_sig);
-
-        let cause = if is_op {
-            ObligationCause::new(
-                span,
-                self.body_id,
-                traits::BinOp {
-                    rhs_span: opt_input_expr.map(|expr| expr.span),
-                    is_lit: opt_input_expr
-                        .map_or(false, |expr| matches!(expr.kind, hir::ExprKind::Lit(_))),
-                    output_ty: None,
-                },
-            )
-        } else {
-            traits::ObligationCause::misc(span, self.body_id)
-        };
+        let fn_sig =
+            self.replace_bound_vars_with_fresh_vars(obligation.cause.span, infer::FnCall, fn_sig);
 
-        let InferOk { value, obligations: o } = self.at(&cause, self.param_env).normalize(fn_sig);
+        let InferOk { value, obligations: o } =
+            self.at(&obligation.cause, self.param_env).normalize(fn_sig);
         let fn_sig = {
             obligations.extend(o);
             value
@@ -494,15 +389,16 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         // any late-bound regions appearing in its bounds.
         let bounds = self.tcx.predicates_of(def_id).instantiate(self.tcx, substs);
 
-        let InferOk { value, obligations: o } = self.at(&cause, self.param_env).normalize(bounds);
+        let InferOk { value, obligations: o } =
+            self.at(&obligation.cause, self.param_env).normalize(bounds);
         let bounds = {
             obligations.extend(o);
             value
         };
 
         assert!(!bounds.has_escaping_bound_vars());
 
-        let predicates_cause = cause.clone();
+        let predicates_cause = obligation.cause.clone();
         obligations.extend(traits::predicates_for_generics(
             move |_, _| predicates_cause.clone(),
             self.param_env,
@@ -517,7 +413,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         );
         obligations.push(traits::Obligation::new(
             tcx,
-            cause,
+            obligation.cause,
             self.param_env,
             ty::Binder::dummy(ty::PredicateKind::WellFormed(method_ty.into())),
         ));