Inline obligation_for_method

compiler/rustc_hir_typeck/src/method/mod.rs

@@ -324,35 +324,6 @@ pub(crate) fn lookup_probe_for_diagnostic(
         Ok(pick)
     }
 
-    pub(super) fn obligation_for_method(
-        &self,
-        cause: ObligationCause<'tcx>,
-        trait_def_id: DefId,
-        self_ty: Ty<'tcx>,
-        opt_input_types: Option<&[Ty<'tcx>]>,
-    ) -> (traits::PredicateObligation<'tcx>, ty::GenericArgsRef<'tcx>) {
-        // Construct a trait-reference `self_ty : Trait<input_tys>`
-        let args = GenericArgs::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_types) = opt_input_types {
-                        return input_types[param.index as usize - 1].into();
-                    }
-                }
-            }
-            self.var_for_def(cause.span, param)
-        });
-
-        let trait_ref = ty::TraitRef::new_from_args(self.tcx, trait_def_id, args);
-
-        // Construct an obligation
-        let poly_trait_ref = ty::Binder::dummy(trait_ref);
-        (traits::Obligation::new(self.tcx, cause, self.param_env, poly_trait_ref), args)
-    }
-
     /// `lookup_method_in_trait` is used for overloaded operators.
     /// It does a very narrow slice of what the normal probe/confirm path does.
     /// In particular, it doesn't really do any probing: it simply constructs
@@ -367,8 +338,24 @@ pub(super) fn lookup_method_in_trait(
         self_ty: Ty<'tcx>,
         opt_input_types: Option<&[Ty<'tcx>]>,
     ) -> Option<InferOk<'tcx, MethodCallee<'tcx>>> {
-        let (obligation, args) =
+        // Construct a trait-reference `self_ty : Trait<input_tys>`
-            self.obligation_for_method(cause, trait_def_id, self_ty, opt_input_types);
+        let args = GenericArgs::for_item(self.tcx, trait_def_id, |param, _| match param.kind {
+            GenericParamDefKind::Lifetime | GenericParamDefKind::Const { .. } => {
+                unreachable!("did not expect operator trait to have lifetime/const")
+            }
+            GenericParamDefKind::Type { .. } => {
+                if param.index == 0 {
+                    self_ty.into()
+                } else if let Some(input_types) = opt_input_types {
+                    input_types[param.index as usize - 1].into()
+                } else {
+                    self.var_for_def(cause.span, param)
+                }
+            }
+        });
+
+        let trait_ref = ty::TraitRef::new_from_args(self.tcx, trait_def_id, args);
+        let obligation = traits::Obligation::new(self.tcx, cause, self.param_env, trait_ref);
         self.construct_obligation_for_trait(m_name, trait_def_id, obligation, args)
     }
 

compiler/rustc_hir_typeck/src/op.rs

@@ -15,7 +15,7 @@
 use rustc_span::source_map::Spanned;
 use rustc_span::symbol::{Ident, sym};
 use rustc_trait_selection::infer::InferCtxtExt;
-use rustc_trait_selection::traits::{FulfillmentError, ObligationCtxt};
+use rustc_trait_selection::traits::{FulfillmentError, Obligation, ObligationCtxt};
 use rustc_type_ir::TyKind::*;
 use tracing::debug;
 use {rustc_ast as ast, rustc_hir as hir};
@@ -931,9 +931,27 @@ fn lookup_op_method(
                     self.check_expr_coercible_to_type(rhs_expr, rhs_ty, None);
                 }
 
-                let (obligation, _) =
+                // Construct an obligation `self_ty : Trait<input_tys>`
-                    self.obligation_for_method(cause, trait_did, lhs_ty, Some(input_types));
+                let args =
-                // FIXME: This should potentially just add the obligation to the `FnCtxt`
+                    ty::GenericArgs::for_item(self.tcx, trait_did, |param, _| match param.kind {
+                        ty::GenericParamDefKind::Lifetime
+                        | ty::GenericParamDefKind::Const { .. } => {
+                            unreachable!("did not expect operand trait to have lifetime/const args")
+                        }
+                        ty::GenericParamDefKind::Type { .. } => {
+                            if param.index == 0 {
+                                lhs_ty.into()
+                            } else {
+                                input_types[param.index as usize - 1].into()
+                            }
+                        }
+                    });
+                let obligation = Obligation::new(
+                    self.tcx,
+                    cause,
+                    self.param_env,
+                    ty::TraitRef::new_from_args(self.tcx, trait_did, args),
+                );
                 let ocx = ObligationCtxt::new_with_diagnostics(&self.infcx);
                 ocx.register_obligation(obligation);
                 Err(ocx.select_all_or_error())