Rollup merge of rust-lang#140498 - compiler-errors:check-fn-tweaks, r=oli-obk

matthiaskrgr · web-flow · commit 21df9db1f633 · 2025-04-30T17:28:00.000+02:00
Misc tweaks to HIR typeck (mostly w.r.t. checking calls)

Just some cleanups.

r? oli-obk
diff --git a/compiler/rustc_hir_typeck/src/callee.rs b/compiler/rustc_hir_typeck/src/callee.rs
@@ -14,7 +14,7 @@ use rustc_middle::ty::adjustment::{
 use rustc_middle::ty::{self, GenericArgsRef, Ty, TyCtxt, TypeVisitableExt};
 use rustc_middle::{bug, span_bug};
 use rustc_span::def_id::LocalDefId;
-use rustc_span::{Ident, Span, sym};
+use rustc_span::{Span, sym};
 use rustc_trait_selection::error_reporting::traits::DefIdOrName;
 use rustc_trait_selection::infer::InferCtxtExt as _;
 use rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt as _;
@@ -87,14 +87,29 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
         let output = match result {
             None => {
-                // this will report an error since original_callee_ty is not a fn
-                self.confirm_builtin_call(
-                    call_expr,
-                    callee_expr,
-                    original_callee_ty,
-                    arg_exprs,
-                    expected,
-                )
+                // Check all of the arg expressions, but with no expectations
+                // since we don't have a signature to compare them to.
+                for arg in arg_exprs {
+                    self.check_expr(arg);
+                }
+
+                if let hir::ExprKind::Path(hir::QPath::Resolved(_, path)) = &callee_expr.kind
+                    && let [segment] = path.segments
+                {
+                    self.dcx().try_steal_modify_and_emit_err(
+                        segment.ident.span,
+                        StashKey::CallIntoMethod,
+                        |err| {
+                            // Try suggesting `foo(a)` -> `a.foo()` if possible.
+                            self.suggest_call_as_method(
+                                err, segment, arg_exprs, call_expr, expected,
+                            );
+                        },
+                    );
+                }
+
+                let guar = self.report_invalid_callee(call_expr, callee_expr, expr_ty, arg_exprs);
+                Ty::new_error(self.tcx, guar)
             }
 
             Some(CallStep::Builtin(callee_ty)) => {
@@ -296,9 +311,9 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 Ty::new_tup_from_iter(self.tcx, arg_exprs.iter().map(|e| self.next_ty_var(e.span)))
             });
 
-            if let Some(ok) = self.lookup_method_in_trait(
+            if let Some(ok) = self.lookup_method_for_operator(
                 self.misc(call_expr.span),
-                Ident::with_dummy_span(method_name),
+                method_name,
                 trait_def_id,
                 adjusted_ty,
                 opt_input_type,
@@ -461,32 +476,11 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 }
                 (fn_sig, Some(def_id))
             }
+
             // FIXME(const_trait_impl): these arms should error because we can't enforce them
             ty::FnPtr(sig_tys, hdr) => (sig_tys.with(hdr), None),
-            _ => {
-                for arg in arg_exprs {
-                    self.check_expr(arg);
-                }
 
-                if let hir::ExprKind::Path(hir::QPath::Resolved(_, path)) = &callee_expr.kind
-                    && let [segment] = path.segments
-                {
-                    self.dcx().try_steal_modify_and_emit_err(
-                        segment.ident.span,
-                        StashKey::CallIntoMethod,
-                        |err| {
-                            // Try suggesting `foo(a)` -> `a.foo()` if possible.
-                            self.suggest_call_as_method(
-                                err, segment, arg_exprs, call_expr, expected,
-                            );
-                        },
-                    );
-                }
-
-                let err = self.report_invalid_callee(call_expr, callee_expr, callee_ty, arg_exprs);
-
-                return Ty::new_error(self.tcx, err);
-            }
+            _ => unreachable!(),
         };
 
         // Replace any late-bound regions that appear in the function
@@ -908,19 +902,23 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         call_expr: &'tcx hir::Expr<'tcx>,
         arg_exprs: &'tcx [hir::Expr<'tcx>],
         expected: Expectation<'tcx>,
-        method_callee: MethodCallee<'tcx>,
+        method: MethodCallee<'tcx>,
     ) -> Ty<'tcx> {
-        let output_type = self.check_method_argument_types(
+        self.check_argument_types(
             call_expr.span,
             call_expr,
-            Ok(method_callee),
+            &method.sig.inputs()[1..],
+            method.sig.output(),
+            expected,
             arg_exprs,
+            method.sig.c_variadic,
             TupleArgumentsFlag::TupleArguments,
-            expected,
+            Some(method.def_id),
         );
 
-        self.write_method_call_and_enforce_effects(call_expr.hir_id, call_expr.span, method_callee);
-        output_type
+        self.write_method_call_and_enforce_effects(call_expr.hir_id, call_expr.span, method);
+
+        method.sig.output()
     }
 }
 
diff --git a/compiler/rustc_hir_typeck/src/expr.rs b/compiler/rustc_hir_typeck/src/expr.rs
@@ -40,7 +40,6 @@ use tracing::{debug, instrument, trace};
 use {rustc_ast as ast, rustc_hir as hir};
 
 use crate::Expectation::{self, ExpectCastableToType, ExpectHasType, NoExpectation};
-use crate::TupleArgumentsFlag::DontTupleArguments;
 use crate::coercion::{CoerceMany, DynamicCoerceMany};
 use crate::errors::{
     AddressOfTemporaryTaken, BaseExpressionDoubleDot, BaseExpressionDoubleDotAddExpr,
@@ -51,8 +50,8 @@ use crate::errors::{
     YieldExprOutsideOfCoroutine,
 };
 use crate::{
-    BreakableCtxt, CoroutineTypes, Diverges, FnCtxt, Needs, cast, fatally_break_rust,
-    report_unexpected_variant_res, type_error_struct,
+    BreakableCtxt, CoroutineTypes, Diverges, FnCtxt, Needs, TupleArgumentsFlag, cast,
+    fatally_break_rust, report_unexpected_variant_res, type_error_struct,
 };
 
 impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
@@ -1591,28 +1590,45 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         // no need to check for bot/err -- callee does that
         let rcvr_t = self.structurally_resolve_type(rcvr.span, rcvr_t);
 
-        let method = match self.lookup_method(rcvr_t, segment, segment.ident.span, expr, rcvr, args)
-        {
+        match self.lookup_method(rcvr_t, segment, segment.ident.span, expr, rcvr, args) {
             Ok(method) => {
-                // We could add a "consider `foo::<params>`" suggestion here, but I wasn't able to
-                // trigger this codepath causing `structurally_resolve_type` to emit an error.
                 self.write_method_call_and_enforce_effects(expr.hir_id, expr.span, method);
-                Ok(method)
+
+                self.check_argument_types(
+                    segment.ident.span,
+                    expr,
+                    &method.sig.inputs()[1..],
+                    method.sig.output(),
+                    expected,
+                    args,
+                    method.sig.c_variadic,
+                    TupleArgumentsFlag::DontTupleArguments,
+                    Some(method.def_id),
+                );
+
+                method.sig.output()
             }
             Err(error) => {
-                Err(self.report_method_error(expr.hir_id, rcvr_t, error, expected, false))
-            }
-        };
+                let guar = self.report_method_error(expr.hir_id, rcvr_t, error, expected, false);
 
-        // Call the generic checker.
-        self.check_method_argument_types(
-            segment.ident.span,
-            expr,
-            method,
-            args,
-            DontTupleArguments,
-            expected,
-        )
+                let err_inputs = self.err_args(args.len(), guar);
+                let err_output = Ty::new_error(self.tcx, guar);
+
+                self.check_argument_types(
+                    segment.ident.span,
+                    expr,
+                    &err_inputs,
+                    err_output,
+                    NoExpectation,
+                    args,
+                    false,
+                    TupleArgumentsFlag::DontTupleArguments,
+                    None,
+                );
+
+                err_output
+            }
+        }
     }
 
     /// Checks use `x.use`.
diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs
@@ -33,7 +33,6 @@ use crate::fn_ctxt::arg_matrix::{ArgMatrix, Compatibility, Error, ExpectedIdx, P
 use crate::fn_ctxt::infer::FnCall;
 use crate::gather_locals::Declaration;
 use crate::inline_asm::InlineAsmCtxt;
-use crate::method::MethodCallee;
 use crate::method::probe::IsSuggestion;
 use crate::method::probe::Mode::MethodCall;
 use crate::method::probe::ProbeScope::TraitsInScope;
@@ -127,61 +126,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         }
     }
 
-    pub(in super::super) fn check_method_argument_types(
-        &self,
-        sp: Span,
-        expr: &'tcx hir::Expr<'tcx>,
-        method: Result<MethodCallee<'tcx>, ErrorGuaranteed>,
-        args_no_rcvr: &'tcx [hir::Expr<'tcx>],
-        tuple_arguments: TupleArgumentsFlag,
-        expected: Expectation<'tcx>,
-    ) -> Ty<'tcx> {
-        let has_error = match method {
-            Ok(method) => method.args.error_reported().and(method.sig.error_reported()),
-            Err(guar) => Err(guar),
-        };
-        if let Err(guar) = has_error {
-            let err_inputs = self.err_args(
-                method.map_or(args_no_rcvr.len(), |method| method.sig.inputs().len() - 1),
-                guar,
-            );
-            let err_output = Ty::new_error(self.tcx, guar);
-
-            let err_inputs = match tuple_arguments {
-                DontTupleArguments => err_inputs,
-                TupleArguments => vec![Ty::new_tup(self.tcx, &err_inputs)],
-            };
-
-            self.check_argument_types(
-                sp,
-                expr,
-                &err_inputs,
-                err_output,
-                NoExpectation,
-                args_no_rcvr,
-                false,
-                tuple_arguments,
-                method.ok().map(|method| method.def_id),
-            );
-            return err_output;
-        }
-
-        let method = method.unwrap();
-        self.check_argument_types(
-            sp,
-            expr,
-            &method.sig.inputs()[1..],
-            method.sig.output(),
-            expected,
-            args_no_rcvr,
-            method.sig.c_variadic,
-            tuple_arguments,
-            Some(method.def_id),
-        );
-
-        method.sig.output()
-    }
-
     /// Generic function that factors out common logic from function calls,
     /// method calls and overloaded operators.
     pub(in super::super) fn check_argument_types(
diff --git a/compiler/rustc_hir_typeck/src/method/mod.rs b/compiler/rustc_hir_typeck/src/method/mod.rs
@@ -19,7 +19,7 @@ use rustc_middle::ty::{
     self, GenericArgs, GenericArgsRef, GenericParamDefKind, Ty, TypeVisitableExt,
 };
 use rustc_middle::{bug, span_bug};
-use rustc_span::{ErrorGuaranteed, Ident, Span};
+use rustc_span::{ErrorGuaranteed, Ident, Span, Symbol};
 use rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt;
 use rustc_trait_selection::traits::{self, NormalizeExt};
 use tracing::{debug, instrument};
@@ -329,10 +329,10 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     /// an obligation for a particular trait with the given self type and checks
     /// whether that trait is implemented.
     #[instrument(level = "debug", skip(self))]
-    pub(super) fn lookup_method_in_trait(
+    pub(super) fn lookup_method_for_operator(
         &self,
         cause: ObligationCause<'tcx>,
-        m_name: Ident,
+        method_name: Symbol,
         trait_def_id: DefId,
         self_ty: Ty<'tcx>,
         opt_rhs_ty: Option<Ty<'tcx>>,
@@ -374,13 +374,20 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         // Trait must have a method named `m_name` and it should not have
         // type parameters or early-bound regions.
         let tcx = self.tcx;
-        let Some(method_item) = self.associated_value(trait_def_id, m_name) else {
+        // We use `Ident::with_dummy_span` since no built-in operator methods have
+        // any macro-specific hygeine, so the span's context doesn't really matter.
+        let Some(method_item) =
+            self.associated_value(trait_def_id, Ident::with_dummy_span(method_name))
+        else {
             bug!("expected associated item for operator trait")
         };
 
         let def_id = method_item.def_id;
         if !method_item.is_fn() {
-            span_bug!(tcx.def_span(def_id), "expected `{m_name}` to be an associated function");
+            span_bug!(
+                tcx.def_span(def_id),
+                "expected `{method_name}` to be an associated function"
+            );
         }
 
         debug!("lookup_in_trait_adjusted: method_item={:?}", method_item);
diff --git a/compiler/rustc_hir_typeck/src/op.rs b/compiler/rustc_hir_typeck/src/op.rs
@@ -12,7 +12,7 @@ use rustc_middle::ty::print::with_no_trimmed_paths;
 use rustc_middle::ty::{self, IsSuggestable, Ty, TyCtxt, TypeVisitableExt};
 use rustc_session::errors::ExprParenthesesNeeded;
 use rustc_span::source_map::Spanned;
-use rustc_span::{Ident, Span, Symbol, sym};
+use rustc_span::{Span, Symbol, sym};
 use rustc_trait_selection::infer::InferCtxtExt;
 use rustc_trait_selection::traits::{FulfillmentError, Obligation, ObligationCtxt};
 use tracing::debug;
@@ -975,7 +975,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             lhs_ty, opname, trait_did
         );
 
-        let opname = Ident::with_dummy_span(opname);
         let (opt_rhs_expr, opt_rhs_ty) = opt_rhs.unzip();
         let cause = self.cause(
             span,
@@ -990,7 +989,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         );
 
         let method =
-            self.lookup_method_in_trait(cause.clone(), opname, trait_did, lhs_ty, opt_rhs_ty);
+            self.lookup_method_for_operator(cause.clone(), opname, trait_did, lhs_ty, opt_rhs_ty);
         match method {
             Some(ok) => {
                 let method = self.register_infer_ok_obligations(ok);
diff --git a/compiler/rustc_hir_typeck/src/place_op.rs b/compiler/rustc_hir_typeck/src/place_op.rs
@@ -8,7 +8,7 @@ use rustc_middle::ty::adjustment::{
     PointerCoercion,
 };
 use rustc_middle::ty::{self, Ty};
-use rustc_span::{Ident, Span, sym};
+use rustc_span::{Span, sym};
 use tracing::debug;
 use {rustc_ast as ast, rustc_hir as hir};
 
@@ -211,13 +211,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             return None;
         };
 
-        self.lookup_method_in_trait(
-            self.misc(span),
-            Ident::with_dummy_span(imm_op),
-            imm_tr,
-            base_ty,
-            opt_rhs_ty,
-        )
+        self.lookup_method_for_operator(self.misc(span), imm_op, imm_tr, base_ty, opt_rhs_ty)
     }
 
     fn try_mutable_overloaded_place_op(
@@ -237,13 +231,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             return None;
         };
 
-        self.lookup_method_in_trait(
-            self.misc(span),
-            Ident::with_dummy_span(mut_op),
-            mut_tr,
-            base_ty,
-            opt_rhs_ty,
-        )
+        self.lookup_method_for_operator(self.misc(span), mut_op, mut_tr, base_ty, opt_rhs_ty)
     }
 
     /// Convert auto-derefs, indices, etc of an expression from `Deref` and `Index`
