Rollup of 4 pull requests

compiler/rustc_lint/src/unused.rs

@@ -240,17 +240,17 @@ impl<'tcx> LateLintPass<'tcx> for UnusedResults {
                 }
                 ty::Tuple(ref tys) => {
                     let mut has_emitted = false;
-                    let spans = if let hir::ExprKind::Tup(comps) = &expr.kind {
+                    let comps = if let hir::ExprKind::Tup(comps) = expr.kind {
                         debug_assert_eq!(comps.len(), tys.len());
-                        comps.iter().map(|e| e.span).collect()
+                        comps
                     } else {
-                        vec![]
+                        &[]
                     };
                     for (i, ty) in tys.iter().enumerate() {
                         let descr_post = &format!(" in tuple element {}", i);
-                        let span = *spans.get(i).unwrap_or(&span);
-                        if check_must_use_ty(cx, ty, expr, span, descr_pre, descr_post, plural_len)
-                        {
+                        let e = comps.get(i).unwrap_or(expr);
+                        let span = e.span;
+                        if check_must_use_ty(cx, ty, e, span, descr_pre, descr_post, plural_len) {
                             has_emitted = true;
                         }
                     }

compiler/rustc_middle/src/traits/mod.rs

@@ -368,6 +368,11 @@ pub enum ObligationCauseCode<'tcx> {
 
     /// From `match_impl`. The cause for us having to match an impl, and the DefId we are matching against.
     MatchImpl(ObligationCause<'tcx>, DefId),
+
+    BinOp {
+        rhs_span: Option<Span>,
+        is_lit: bool,
+    },
 }
 
 /// The 'location' at which we try to perform HIR-based wf checking.

compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs

@@ -501,6 +501,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
                             err.span_label(enclosing_scope_span, s.as_str());
                         }
 
+                        self.suggest_floating_point_literal(&obligation, &mut err, &trait_ref);
                         self.suggest_dereferences(&obligation, &mut err, trait_predicate);
                         self.suggest_fn_call(&obligation, &mut err, trait_predicate);
                         self.suggest_remove_reference(&obligation, &mut err, trait_predicate);

compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs

@@ -174,6 +174,13 @@ pub trait InferCtxtExt<'tcx> {
         trait_pred: ty::PolyTraitPredicate<'tcx>,
         span: Span,
     );
+
+    fn suggest_floating_point_literal(
+        &self,
+        obligation: &PredicateObligation<'tcx>,
+        err: &mut DiagnosticBuilder<'_>,
+        trait_ref: &ty::PolyTraitRef<'tcx>,
+    );
 }
 
 fn predicate_constraint(generics: &hir::Generics<'_>, pred: String) -> (Span, String) {
@@ -1910,8 +1917,9 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
             | ObligationCauseCode::AwaitableExpr(_)
             | ObligationCauseCode::ForLoopIterator
             | ObligationCauseCode::QuestionMark
+            | ObligationCauseCode::CheckAssociatedTypeBounds { .. }
             | ObligationCauseCode::LetElse
-            | ObligationCauseCode::CheckAssociatedTypeBounds { .. } => {}
+            | ObligationCauseCode::BinOp { .. } => {}
             ObligationCauseCode::SliceOrArrayElem => {
                 err.note("slice and array elements must have `Sized` type");
             }
@@ -2497,6 +2505,32 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
             }
         }
     }
+
+    fn suggest_floating_point_literal(
+        &self,
+        obligation: &PredicateObligation<'tcx>,
+        err: &mut DiagnosticBuilder<'_>,
+        trait_ref: &ty::PolyTraitRef<'tcx>,
+    ) {
+        let rhs_span = match obligation.cause.code() {
+            ObligationCauseCode::BinOp { rhs_span: Some(span), is_lit } if *is_lit => span,
+            _ => return,
+        };
+        match (
+            trait_ref.skip_binder().self_ty().kind(),
+            trait_ref.skip_binder().substs.type_at(1).kind(),
+        ) {
+            (ty::Float(_), ty::Infer(InferTy::IntVar(_))) => {
+                err.span_suggestion_verbose(
+                    rhs_span.shrink_to_hi(),
+                    "consider using a floating-point literal by writing it with `.0`",
+                    String::from(".0"),
+                    Applicability::MaybeIncorrect,
+                );
+            }
+            _ => {}
+        }
+    }
 }
 
 /// Collect all the returned expressions within the input expression.

compiler/rustc_typeck/src/check/check.rs

@@ -14,7 +14,7 @@ use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKi
 use rustc_infer::infer::{RegionVariableOrigin, TyCtxtInferExt};
 use rustc_middle::hir::nested_filter;
 use rustc_middle::ty::fold::TypeFoldable;
-use rustc_middle::ty::layout::MAX_SIMD_LANES;
+use rustc_middle::ty::layout::{LayoutError, MAX_SIMD_LANES};
 use rustc_middle::ty::subst::GenericArgKind;
 use rustc_middle::ty::util::{Discr, IntTypeExt};
 use rustc_middle::ty::{self, OpaqueTypeKey, ParamEnv, Ty, TyCtxt};
@@ -417,10 +417,31 @@ fn check_static_inhabited<'tcx>(tcx: TyCtxt<'tcx>, def_id: LocalDefId, span: Spa
     // have UB during initialization if they are uninhabited, but there also seems to be no good
     // reason to allow any statics to be uninhabited.
     let ty = tcx.type_of(def_id);
-    let Ok(layout) = tcx.layout_of(ParamEnv::reveal_all().and(ty)) else {
+    let layout = match tcx.layout_of(ParamEnv::reveal_all().and(ty)) {
+        Ok(l) => l,
+        // Foreign statics that overflow their allowed size should emit an error
+        Err(LayoutError::SizeOverflow(_))
+            if {
+                let node = tcx.hir().get_by_def_id(def_id);
+                matches!(
+                    node,
+                    hir::Node::ForeignItem(hir::ForeignItem {
+                        kind: hir::ForeignItemKind::Static(..),
+                        ..
+                    })
+                )
+            } =>
+        {
+            tcx.sess
+                .struct_span_err(span, "extern static is too large for the current architecture")
+                .emit();
+            return;
+        }
         // Generic statics are rejected, but we still reach this case.
-        tcx.sess.delay_span_bug(span, "generic static must be rejected");
-        return;
+        Err(e) => {
+            tcx.sess.delay_span_bug(span, &e.to_string());
+            return;
+        }
     };
     if layout.abi.is_uninhabited() {
         tcx.struct_span_lint_hir(

compiler/rustc_typeck/src/check/fn_ctxt/_impl.rs

@@ -429,6 +429,30 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         )
     }
 
+    pub(in super::super) fn normalize_op_associated_types_in_as_infer_ok<T>(
+        &self,
+        span: Span,
+        value: T,
+        opt_input_expr: Option<&hir::Expr<'_>>,
+    ) -> InferOk<'tcx, T>
+    where
+        T: TypeFoldable<'tcx>,
+    {
+        self.inh.partially_normalize_associated_types_in(
+            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, ExprKind::Lit(_))),
+                },
+            ),
+            self.param_env,
+            value,
+        )
+    }
+
     pub fn require_type_meets(
         &self,
         ty: Ty<'tcx>,

compiler/rustc_typeck/src/check/method/mod.rs

@@ -333,15 +333,57 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         )
     }
 
+    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>>,
+    ) -> (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)
+        });
+
+        let trait_ref = ty::TraitRef::new(trait_def_id, substs);
+
+        // Construct an obligation
+        let poly_trait_ref = ty::Binder::dummy(trait_ref);
+        (
+            traits::Obligation::new(
+                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(_))),
+                    },
+                ),
+                self.param_env,
+                poly_trait_ref.without_const().to_predicate(self.tcx),
+            ),
+            substs,
+        )
+    }
+
     /// `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
     /// an obligation for a particular trait with the given self type and checks
     /// whether that trait is implemented.
-    //
-    // 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.
     #[instrument(level = "debug", skip(self, span, opt_input_types))]
     pub(super) fn lookup_method_in_trait(
         &self,
@@ -358,7 +400,57 @@ impl<'a, 'tcx> FnCtxt<'a, '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>>,
+    ) -> 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,
+        );
+        self.construct_obligation_for_trait(
+            span,
+            m_name,
+            trait_def_id,
+            obligation,
+            substs,
+            opt_input_expr,
+            true,
+        )
+    }
+
+    // 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);
 
         // Now we want to know if this can be matched
@@ -395,8 +487,11 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         let fn_sig = self.replace_bound_vars_with_fresh_vars(span, infer::FnCall, fn_sig).0;
         let fn_sig = fn_sig.subst(self.tcx, substs);
 
-        let InferOk { value, obligations: o } =
-            self.normalize_associated_types_in_as_infer_ok(span, fn_sig);
+        let InferOk { value, obligations: o } = if is_op {
+            self.normalize_op_associated_types_in_as_infer_ok(span, fn_sig, opt_input_expr)
+        } else {
+            self.normalize_associated_types_in_as_infer_ok(span, fn_sig)
+        };
         let fn_sig = {
             obligations.extend(o);
             value
@@ -412,16 +507,31 @@ 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.normalize_associated_types_in_as_infer_ok(span, bounds);
+        let InferOk { value, obligations: o } = if is_op {
+            self.normalize_op_associated_types_in_as_infer_ok(span, bounds, opt_input_expr)
+        } else {
+            self.normalize_associated_types_in_as_infer_ok(span, bounds)
+        };
         let bounds = {
             obligations.extend(o);
             value
         };
 
         assert!(!bounds.has_escaping_bound_vars());
 
-        let cause = traits::ObligationCause::misc(span, self.body_id);
+        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(_))),
+                },
+            )
+        } else {
+            traits::ObligationCause::misc(span, self.body_id)
+        };
         obligations.extend(traits::predicates_for_generics(cause.clone(), self.param_env, bounds));
 
         // Also add an obligation for the method type being well-formed.