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Diffstat (limited to '')
| -rw-r--r-- | compiler/rustc_typeck/src/check/op.rs | 1076 |
1 files changed, 0 insertions, 1076 deletions
diff --git a/compiler/rustc_typeck/src/check/op.rs b/compiler/rustc_typeck/src/check/op.rs deleted file mode 100644 index 920b3e688..000000000 --- a/compiler/rustc_typeck/src/check/op.rs +++ /dev/null @@ -1,1076 +0,0 @@ -//! Code related to processing overloaded binary and unary operators. - -use super::method::MethodCallee; -use super::{has_expected_num_generic_args, FnCtxt}; -use crate::check::Expectation; -use rustc_ast as ast; -use rustc_errors::{self, struct_span_err, Applicability, Diagnostic}; -use rustc_hir as hir; -use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind}; -use rustc_infer::traits::ObligationCauseCode; -use rustc_middle::ty::adjustment::{ - Adjust, Adjustment, AllowTwoPhase, AutoBorrow, AutoBorrowMutability, -}; -use rustc_middle::ty::{ - self, Ty, TyCtxt, TypeFolder, TypeSuperFoldable, TypeSuperVisitable, TypeVisitable, TypeVisitor, -}; -use rustc_span::source_map::Spanned; -use rustc_span::symbol::{sym, Ident}; -use rustc_span::Span; -use rustc_trait_selection::infer::InferCtxtExt; -use rustc_trait_selection::traits::error_reporting::suggestions::InferCtxtExt as _; -use rustc_trait_selection::traits::{FulfillmentError, TraitEngine, TraitEngineExt}; -use rustc_type_ir::sty::TyKind::*; - -use std::ops::ControlFlow; - -impl<'a, 'tcx> FnCtxt<'a, 'tcx> { - /// Checks a `a <op>= b` - pub fn check_binop_assign( - &self, - expr: &'tcx hir::Expr<'tcx>, - op: hir::BinOp, - lhs: &'tcx hir::Expr<'tcx>, - rhs: &'tcx hir::Expr<'tcx>, - expected: Expectation<'tcx>, - ) -> Ty<'tcx> { - let (lhs_ty, rhs_ty, return_ty) = - self.check_overloaded_binop(expr, lhs, rhs, op, IsAssign::Yes, expected); - - let ty = - if !lhs_ty.is_ty_var() && !rhs_ty.is_ty_var() && is_builtin_binop(lhs_ty, rhs_ty, op) { - self.enforce_builtin_binop_types(lhs.span, lhs_ty, rhs.span, rhs_ty, op); - self.tcx.mk_unit() - } else { - return_ty - }; - - self.check_lhs_assignable(lhs, "E0067", op.span, |err| { - if let Some(lhs_deref_ty) = self.deref_once_mutably_for_diagnostic(lhs_ty) { - if self - .lookup_op_method( - lhs_deref_ty, - Some(rhs_ty), - Some(rhs), - Op::Binary(op, IsAssign::Yes), - expected, - ) - .is_ok() - { - // Suppress this error, since we already emitted - // a deref suggestion in check_overloaded_binop - err.delay_as_bug(); - } - } - }); - - ty - } - - /// Checks a potentially overloaded binary operator. - pub fn check_binop( - &self, - expr: &'tcx hir::Expr<'tcx>, - op: hir::BinOp, - lhs_expr: &'tcx hir::Expr<'tcx>, - rhs_expr: &'tcx hir::Expr<'tcx>, - expected: Expectation<'tcx>, - ) -> Ty<'tcx> { - let tcx = self.tcx; - - debug!( - "check_binop(expr.hir_id={}, expr={:?}, op={:?}, lhs_expr={:?}, rhs_expr={:?})", - expr.hir_id, expr, op, lhs_expr, rhs_expr - ); - - match BinOpCategory::from(op) { - BinOpCategory::Shortcircuit => { - // && and || are a simple case. - self.check_expr_coercable_to_type(lhs_expr, tcx.types.bool, None); - let lhs_diverges = self.diverges.get(); - self.check_expr_coercable_to_type(rhs_expr, tcx.types.bool, None); - - // Depending on the LHS' value, the RHS can never execute. - self.diverges.set(lhs_diverges); - - tcx.types.bool - } - _ => { - // Otherwise, we always treat operators as if they are - // overloaded. This is the way to be most flexible w/r/t - // types that get inferred. - let (lhs_ty, rhs_ty, return_ty) = self.check_overloaded_binop( - expr, - lhs_expr, - rhs_expr, - op, - IsAssign::No, - expected, - ); - - // Supply type inference hints if relevant. Probably these - // hints should be enforced during select as part of the - // `consider_unification_despite_ambiguity` routine, but this - // more convenient for now. - // - // The basic idea is to help type inference by taking - // advantage of things we know about how the impls for - // scalar types are arranged. This is important in a - // scenario like `1_u32 << 2`, because it lets us quickly - // deduce that the result type should be `u32`, even - // though we don't know yet what type 2 has and hence - // can't pin this down to a specific impl. - if !lhs_ty.is_ty_var() - && !rhs_ty.is_ty_var() - && is_builtin_binop(lhs_ty, rhs_ty, op) - { - let builtin_return_ty = self.enforce_builtin_binop_types( - lhs_expr.span, - lhs_ty, - rhs_expr.span, - rhs_ty, - op, - ); - self.demand_suptype(expr.span, builtin_return_ty, return_ty); - } - - return_ty - } - } - } - - fn enforce_builtin_binop_types( - &self, - lhs_span: Span, - lhs_ty: Ty<'tcx>, - rhs_span: Span, - rhs_ty: Ty<'tcx>, - op: hir::BinOp, - ) -> Ty<'tcx> { - debug_assert!(is_builtin_binop(lhs_ty, rhs_ty, op)); - - // Special-case a single layer of referencing, so that things like `5.0 + &6.0f32` work. - // (See https://github.com/rust-lang/rust/issues/57447.) - let (lhs_ty, rhs_ty) = (deref_ty_if_possible(lhs_ty), deref_ty_if_possible(rhs_ty)); - - let tcx = self.tcx; - match BinOpCategory::from(op) { - BinOpCategory::Shortcircuit => { - self.demand_suptype(lhs_span, tcx.types.bool, lhs_ty); - self.demand_suptype(rhs_span, tcx.types.bool, rhs_ty); - tcx.types.bool - } - - BinOpCategory::Shift => { - // result type is same as LHS always - lhs_ty - } - - BinOpCategory::Math | BinOpCategory::Bitwise => { - // both LHS and RHS and result will have the same type - self.demand_suptype(rhs_span, lhs_ty, rhs_ty); - lhs_ty - } - - BinOpCategory::Comparison => { - // both LHS and RHS and result will have the same type - self.demand_suptype(rhs_span, lhs_ty, rhs_ty); - tcx.types.bool - } - } - } - - fn check_overloaded_binop( - &self, - expr: &'tcx hir::Expr<'tcx>, - lhs_expr: &'tcx hir::Expr<'tcx>, - rhs_expr: &'tcx hir::Expr<'tcx>, - op: hir::BinOp, - is_assign: IsAssign, - expected: Expectation<'tcx>, - ) -> (Ty<'tcx>, Ty<'tcx>, Ty<'tcx>) { - debug!( - "check_overloaded_binop(expr.hir_id={}, op={:?}, is_assign={:?})", - expr.hir_id, op, is_assign - ); - - let lhs_ty = match is_assign { - IsAssign::No => { - // Find a suitable supertype of the LHS expression's type, by coercing to - // a type variable, to pass as the `Self` to the trait, avoiding invariant - // trait matching creating lifetime constraints that are too strict. - // e.g., adding `&'a T` and `&'b T`, given `&'x T: Add<&'x T>`, will result - // in `&'a T <: &'x T` and `&'b T <: &'x T`, instead of `'a = 'b = 'x`. - let lhs_ty = self.check_expr(lhs_expr); - let fresh_var = self.next_ty_var(TypeVariableOrigin { - kind: TypeVariableOriginKind::MiscVariable, - span: lhs_expr.span, - }); - self.demand_coerce(lhs_expr, lhs_ty, fresh_var, Some(rhs_expr), AllowTwoPhase::No) - } - IsAssign::Yes => { - // rust-lang/rust#52126: We have to use strict - // equivalence on the LHS of an assign-op like `+=`; - // overwritten or mutably-borrowed places cannot be - // coerced to a supertype. - self.check_expr(lhs_expr) - } - }; - let lhs_ty = self.resolve_vars_with_obligations(lhs_ty); - - // N.B., as we have not yet type-checked the RHS, we don't have the - // type at hand. Make a variable to represent it. The whole reason - // for this indirection is so that, below, we can check the expr - // using this variable as the expected type, which sometimes lets - // us do better coercions than we would be able to do otherwise, - // particularly for things like `String + &String`. - let rhs_ty_var = self.next_ty_var(TypeVariableOrigin { - kind: TypeVariableOriginKind::MiscVariable, - span: rhs_expr.span, - }); - - let result = self.lookup_op_method( - lhs_ty, - Some(rhs_ty_var), - Some(rhs_expr), - Op::Binary(op, is_assign), - expected, - ); - - // see `NB` above - let rhs_ty = self.check_expr_coercable_to_type(rhs_expr, rhs_ty_var, Some(lhs_expr)); - let rhs_ty = self.resolve_vars_with_obligations(rhs_ty); - - let return_ty = match result { - Ok(method) => { - let by_ref_binop = !op.node.is_by_value(); - if is_assign == IsAssign::Yes || by_ref_binop { - if let ty::Ref(region, _, mutbl) = method.sig.inputs()[0].kind() { - let mutbl = match mutbl { - hir::Mutability::Not => AutoBorrowMutability::Not, - hir::Mutability::Mut => AutoBorrowMutability::Mut { - // Allow two-phase borrows for binops in initial deployment - // since they desugar to methods - allow_two_phase_borrow: AllowTwoPhase::Yes, - }, - }; - let autoref = Adjustment { - kind: Adjust::Borrow(AutoBorrow::Ref(*region, mutbl)), - target: method.sig.inputs()[0], - }; - self.apply_adjustments(lhs_expr, vec![autoref]); - } - } - if by_ref_binop { - if let ty::Ref(region, _, mutbl) = method.sig.inputs()[1].kind() { - let mutbl = match mutbl { - hir::Mutability::Not => AutoBorrowMutability::Not, - hir::Mutability::Mut => AutoBorrowMutability::Mut { - // Allow two-phase borrows for binops in initial deployment - // since they desugar to methods - allow_two_phase_borrow: AllowTwoPhase::Yes, - }, - }; - let autoref = Adjustment { - kind: Adjust::Borrow(AutoBorrow::Ref(*region, mutbl)), - target: method.sig.inputs()[1], - }; - // HACK(eddyb) Bypass checks due to reborrows being in - // some cases applied on the RHS, on top of which we need - // to autoref, which is not allowed by apply_adjustments. - // self.apply_adjustments(rhs_expr, vec![autoref]); - self.typeck_results - .borrow_mut() - .adjustments_mut() - .entry(rhs_expr.hir_id) - .or_default() - .push(autoref); - } - } - self.write_method_call(expr.hir_id, method); - - method.sig.output() - } - // error types are considered "builtin" - Err(_) if lhs_ty.references_error() || rhs_ty.references_error() => self.tcx.ty_error(), - Err(errors) => { - let source_map = self.tcx.sess.source_map(); - let (mut err, missing_trait, use_output) = match is_assign { - IsAssign::Yes => { - let mut err = struct_span_err!( - self.tcx.sess, - expr.span, - E0368, - "binary assignment operation `{}=` cannot be applied to type `{}`", - op.node.as_str(), - lhs_ty, - ); - err.span_label( - lhs_expr.span, - format!("cannot use `{}=` on type `{}`", op.node.as_str(), lhs_ty), - ); - let missing_trait = match op.node { - hir::BinOpKind::Add => Some("std::ops::AddAssign"), - hir::BinOpKind::Sub => Some("std::ops::SubAssign"), - hir::BinOpKind::Mul => Some("std::ops::MulAssign"), - hir::BinOpKind::Div => Some("std::ops::DivAssign"), - hir::BinOpKind::Rem => Some("std::ops::RemAssign"), - hir::BinOpKind::BitAnd => Some("std::ops::BitAndAssign"), - hir::BinOpKind::BitXor => Some("std::ops::BitXorAssign"), - hir::BinOpKind::BitOr => Some("std::ops::BitOrAssign"), - hir::BinOpKind::Shl => Some("std::ops::ShlAssign"), - hir::BinOpKind::Shr => Some("std::ops::ShrAssign"), - _ => None, - }; - self.note_unmet_impls_on_type(&mut err, errors); - (err, missing_trait, false) - } - IsAssign::No => { - let (message, missing_trait, use_output) = match op.node { - hir::BinOpKind::Add => ( - format!("cannot add `{rhs_ty}` to `{lhs_ty}`"), - Some("std::ops::Add"), - true, - ), - hir::BinOpKind::Sub => ( - format!("cannot subtract `{rhs_ty}` from `{lhs_ty}`"), - Some("std::ops::Sub"), - true, - ), - hir::BinOpKind::Mul => ( - format!("cannot multiply `{lhs_ty}` by `{rhs_ty}`"), - Some("std::ops::Mul"), - true, - ), - hir::BinOpKind::Div => ( - format!("cannot divide `{lhs_ty}` by `{rhs_ty}`"), - Some("std::ops::Div"), - true, - ), - hir::BinOpKind::Rem => ( - format!("cannot mod `{lhs_ty}` by `{rhs_ty}`"), - Some("std::ops::Rem"), - true, - ), - hir::BinOpKind::BitAnd => ( - format!("no implementation for `{lhs_ty} & {rhs_ty}`"), - Some("std::ops::BitAnd"), - true, - ), - hir::BinOpKind::BitXor => ( - format!("no implementation for `{lhs_ty} ^ {rhs_ty}`"), - Some("std::ops::BitXor"), - true, - ), - hir::BinOpKind::BitOr => ( - format!("no implementation for `{lhs_ty} | {rhs_ty}`"), - Some("std::ops::BitOr"), - true, - ), - hir::BinOpKind::Shl => ( - format!("no implementation for `{lhs_ty} << {rhs_ty}`"), - Some("std::ops::Shl"), - true, - ), - hir::BinOpKind::Shr => ( - format!("no implementation for `{lhs_ty} >> {rhs_ty}`"), - Some("std::ops::Shr"), - true, - ), - hir::BinOpKind::Eq | hir::BinOpKind::Ne => ( - format!( - "binary operation `{}` cannot be applied to type `{}`", - op.node.as_str(), - lhs_ty - ), - Some("std::cmp::PartialEq"), - false, - ), - hir::BinOpKind::Lt - | hir::BinOpKind::Le - | hir::BinOpKind::Gt - | hir::BinOpKind::Ge => ( - format!( - "binary operation `{}` cannot be applied to type `{}`", - op.node.as_str(), - lhs_ty - ), - Some("std::cmp::PartialOrd"), - false, - ), - _ => ( - format!( - "binary operation `{}` cannot be applied to type `{}`", - op.node.as_str(), - lhs_ty - ), - None, - false, - ), - }; - let mut err = struct_span_err!(self.tcx.sess, op.span, E0369, "{message}"); - if !lhs_expr.span.eq(&rhs_expr.span) { - self.add_type_neq_err_label( - &mut err, - lhs_expr.span, - lhs_ty, - rhs_ty, - rhs_expr, - op, - is_assign, - expected, - ); - self.add_type_neq_err_label( - &mut err, - rhs_expr.span, - rhs_ty, - lhs_ty, - lhs_expr, - op, - is_assign, - expected, - ); - } - self.note_unmet_impls_on_type(&mut err, errors); - (err, missing_trait, use_output) - } - }; - - let mut suggest_deref_binop = |lhs_deref_ty: Ty<'tcx>| { - if self - .lookup_op_method( - lhs_deref_ty, - Some(rhs_ty), - Some(rhs_expr), - Op::Binary(op, is_assign), - expected, - ) - .is_ok() - { - if let Ok(lstring) = source_map.span_to_snippet(lhs_expr.span) { - let msg = &format!( - "`{}{}` can be used on `{}`, you can dereference `{}`", - op.node.as_str(), - match is_assign { - IsAssign::Yes => "=", - IsAssign::No => "", - }, - lhs_deref_ty.peel_refs(), - lstring, - ); - err.span_suggestion_verbose( - lhs_expr.span.shrink_to_lo(), - msg, - "*", - rustc_errors::Applicability::MachineApplicable, - ); - } - } - }; - - // We should suggest `a + b` => `*a + b` if `a` is copy, and suggest - // `a += b` => `*a += b` if a is a mut ref. - if is_assign == IsAssign::Yes - && let Some(lhs_deref_ty) = self.deref_once_mutably_for_diagnostic(lhs_ty) { - suggest_deref_binop(lhs_deref_ty); - } else if is_assign == IsAssign::No - && let Ref(_, lhs_deref_ty, _) = lhs_ty.kind() { - if self.type_is_copy_modulo_regions(self.param_env, *lhs_deref_ty, lhs_expr.span) { - suggest_deref_binop(*lhs_deref_ty); - } - } - if let Some(missing_trait) = missing_trait { - let mut visitor = TypeParamVisitor(vec![]); - visitor.visit_ty(lhs_ty); - - if op.node == hir::BinOpKind::Add - && self.check_str_addition( - lhs_expr, rhs_expr, lhs_ty, rhs_ty, &mut err, is_assign, op, - ) - { - // This has nothing here because it means we did string - // concatenation (e.g., "Hello " + "World!"). This means - // we don't want the note in the else clause to be emitted - } else if let [ty] = &visitor.0[..] { - // Look for a TraitPredicate in the Fulfillment errors, - // and use it to generate a suggestion. - // - // Note that lookup_op_method must be called again but - // with a specific rhs_ty instead of a placeholder so - // the resulting predicate generates a more specific - // suggestion for the user. - let errors = self - .lookup_op_method( - lhs_ty, - Some(rhs_ty), - Some(rhs_expr), - Op::Binary(op, is_assign), - expected, - ) - .unwrap_err(); - if !errors.is_empty() { - for error in errors { - if let Some(trait_pred) = - error.obligation.predicate.to_opt_poly_trait_pred() - { - let proj_pred = match error.obligation.cause.code() { - ObligationCauseCode::BinOp { - output_pred: Some(output_pred), - .. - } if use_output => { - output_pred.to_opt_poly_projection_pred() - } - _ => None, - }; - - self.suggest_restricting_param_bound( - &mut err, - trait_pred, - proj_pred, - self.body_id, - ); - } - } - } else if *ty != lhs_ty { - // When we know that a missing bound is responsible, we don't show - // this note as it is redundant. - err.note(&format!( - "the trait `{missing_trait}` is not implemented for `{lhs_ty}`" - )); - } - } - } - err.emit(); - self.tcx.ty_error() - } - }; - - (lhs_ty, rhs_ty, return_ty) - } - - /// If one of the types is an uncalled function and calling it would yield the other type, - /// suggest calling the function. Returns `true` if suggestion would apply (even if not given). - fn add_type_neq_err_label( - &self, - err: &mut Diagnostic, - span: Span, - ty: Ty<'tcx>, - other_ty: Ty<'tcx>, - other_expr: &'tcx hir::Expr<'tcx>, - op: hir::BinOp, - is_assign: IsAssign, - expected: Expectation<'tcx>, - ) -> bool /* did we suggest to call a function because of missing parentheses? */ { - err.span_label(span, ty.to_string()); - if let FnDef(def_id, _) = *ty.kind() { - if !self.tcx.has_typeck_results(def_id) { - return false; - } - // FIXME: Instead of exiting early when encountering bound vars in - // the function signature, consider keeping the binder here and - // propagating it downwards. - let Some(fn_sig) = self.tcx.fn_sig(def_id).no_bound_vars() else { - return false; - }; - - let other_ty = if let FnDef(def_id, _) = *other_ty.kind() { - if !self.tcx.has_typeck_results(def_id) { - return false; - } - // We're emitting a suggestion, so we can just ignore regions - self.tcx.fn_sig(def_id).skip_binder().output() - } else { - other_ty - }; - - if self - .lookup_op_method( - fn_sig.output(), - Some(other_ty), - Some(other_expr), - Op::Binary(op, is_assign), - expected, - ) - .is_ok() - { - let (variable_snippet, applicability) = if !fn_sig.inputs().is_empty() { - ("( /* arguments */ )", Applicability::HasPlaceholders) - } else { - ("()", Applicability::MaybeIncorrect) - }; - - err.span_suggestion_verbose( - span.shrink_to_hi(), - "you might have forgotten to call this function", - variable_snippet, - applicability, - ); - return true; - } - } - false - } - - /// Provide actionable suggestions when trying to add two strings with incorrect types, - /// like `&str + &str`, `String + String` and `&str + &String`. - /// - /// If this function returns `true` it means a note was printed, so we don't need - /// to print the normal "implementation of `std::ops::Add` might be missing" note - fn check_str_addition( - &self, - lhs_expr: &'tcx hir::Expr<'tcx>, - rhs_expr: &'tcx hir::Expr<'tcx>, - lhs_ty: Ty<'tcx>, - rhs_ty: Ty<'tcx>, - err: &mut Diagnostic, - is_assign: IsAssign, - op: hir::BinOp, - ) -> bool { - let str_concat_note = "string concatenation requires an owned `String` on the left"; - let rm_borrow_msg = "remove the borrow to obtain an owned `String`"; - let to_owned_msg = "create an owned `String` from a string reference"; - - let is_std_string = |ty: Ty<'tcx>| { - ty.ty_adt_def() - .map_or(false, |ty_def| self.tcx.is_diagnostic_item(sym::String, ty_def.did())) - }; - - match (lhs_ty.kind(), rhs_ty.kind()) { - (&Ref(_, l_ty, _), &Ref(_, r_ty, _)) // &str or &String + &str, &String or &&str - if (*l_ty.kind() == Str || is_std_string(l_ty)) - && (*r_ty.kind() == Str - || is_std_string(r_ty) - || matches!( - r_ty.kind(), Ref(_, inner_ty, _) if *inner_ty.kind() == Str - )) => - { - if let IsAssign::No = is_assign { // Do not supply this message if `&str += &str` - err.span_label(op.span, "`+` cannot be used to concatenate two `&str` strings"); - err.note(str_concat_note); - if let hir::ExprKind::AddrOf(_, _, lhs_inner_expr) = lhs_expr.kind { - err.span_suggestion_verbose( - lhs_expr.span.until(lhs_inner_expr.span), - rm_borrow_msg, - "", - Applicability::MachineApplicable - ); - } else { - err.span_suggestion_verbose( - lhs_expr.span.shrink_to_hi(), - to_owned_msg, - ".to_owned()", - Applicability::MachineApplicable - ); - } - } - true - } - (&Ref(_, l_ty, _), &Adt(..)) // Handle `&str` & `&String` + `String` - if (*l_ty.kind() == Str || is_std_string(l_ty)) && is_std_string(rhs_ty) => - { - err.span_label( - op.span, - "`+` cannot be used to concatenate a `&str` with a `String`", - ); - match is_assign { - IsAssign::No => { - let sugg_msg; - let lhs_sugg = if let hir::ExprKind::AddrOf(_, _, lhs_inner_expr) = lhs_expr.kind { - sugg_msg = "remove the borrow on the left and add one on the right"; - (lhs_expr.span.until(lhs_inner_expr.span), "".to_owned()) - } else { - sugg_msg = "create an owned `String` on the left and add a borrow on the right"; - (lhs_expr.span.shrink_to_hi(), ".to_owned()".to_owned()) - }; - let suggestions = vec![ - lhs_sugg, - (rhs_expr.span.shrink_to_lo(), "&".to_owned()), - ]; - err.multipart_suggestion_verbose( - sugg_msg, - suggestions, - Applicability::MachineApplicable, - ); - } - IsAssign::Yes => { - err.note(str_concat_note); - } - } - true - } - _ => false, - } - } - - pub fn check_user_unop( - &self, - ex: &'tcx hir::Expr<'tcx>, - operand_ty: Ty<'tcx>, - op: hir::UnOp, - expected: Expectation<'tcx>, - ) -> Ty<'tcx> { - assert!(op.is_by_value()); - match self.lookup_op_method(operand_ty, None, None, Op::Unary(op, ex.span), expected) { - Ok(method) => { - self.write_method_call(ex.hir_id, method); - method.sig.output() - } - Err(errors) => { - let actual = self.resolve_vars_if_possible(operand_ty); - if !actual.references_error() { - let mut err = struct_span_err!( - self.tcx.sess, - ex.span, - E0600, - "cannot apply unary operator `{}` to type `{}`", - op.as_str(), - actual - ); - err.span_label( - ex.span, - format!("cannot apply unary operator `{}`", op.as_str()), - ); - - let mut visitor = TypeParamVisitor(vec![]); - visitor.visit_ty(operand_ty); - if let [_] = &visitor.0[..] && let ty::Param(_) = *operand_ty.kind() { - let predicates = errors - .iter() - .filter_map(|error| { - error.obligation.predicate.to_opt_poly_trait_pred() - }); - for pred in predicates { - self.suggest_restricting_param_bound( - &mut err, - pred, - None, - self.body_id, - ); - } - } - - let sp = self.tcx.sess.source_map().start_point(ex.span); - if let Some(sp) = - self.tcx.sess.parse_sess.ambiguous_block_expr_parse.borrow().get(&sp) - { - // If the previous expression was a block expression, suggest parentheses - // (turning this into a binary subtraction operation instead.) - // for example, `{2} - 2` -> `({2}) - 2` (see src\test\ui\parser\expr-as-stmt.rs) - self.tcx.sess.parse_sess.expr_parentheses_needed(&mut err, *sp); - } else { - match actual.kind() { - Uint(_) if op == hir::UnOp::Neg => { - err.note("unsigned values cannot be negated"); - - if let hir::ExprKind::Unary( - _, - hir::Expr { - kind: - hir::ExprKind::Lit(Spanned { - node: ast::LitKind::Int(1, _), - .. - }), - .. - }, - ) = ex.kind - { - err.span_suggestion( - ex.span, - &format!( - "you may have meant the maximum value of `{actual}`", - ), - format!("{actual}::MAX"), - Applicability::MaybeIncorrect, - ); - } - } - Str | Never | Char | Tuple(_) | Array(_, _) => {} - Ref(_, lty, _) if *lty.kind() == Str => {} - _ => { - self.note_unmet_impls_on_type(&mut err, errors); - } - } - } - err.emit(); - } - self.tcx.ty_error() - } - } - } - - fn lookup_op_method( - &self, - lhs_ty: Ty<'tcx>, - other_ty: Option<Ty<'tcx>>, - other_ty_expr: Option<&'tcx hir::Expr<'tcx>>, - op: Op, - expected: Expectation<'tcx>, - ) -> Result<MethodCallee<'tcx>, Vec<FulfillmentError<'tcx>>> { - let lang = self.tcx.lang_items(); - - let span = match op { - Op::Binary(op, _) => op.span, - Op::Unary(_, span) => span, - }; - let (opname, trait_did) = if let Op::Binary(op, IsAssign::Yes) = op { - match op.node { - hir::BinOpKind::Add => (sym::add_assign, lang.add_assign_trait()), - hir::BinOpKind::Sub => (sym::sub_assign, lang.sub_assign_trait()), - hir::BinOpKind::Mul => (sym::mul_assign, lang.mul_assign_trait()), - hir::BinOpKind::Div => (sym::div_assign, lang.div_assign_trait()), - hir::BinOpKind::Rem => (sym::rem_assign, lang.rem_assign_trait()), - hir::BinOpKind::BitXor => (sym::bitxor_assign, lang.bitxor_assign_trait()), - hir::BinOpKind::BitAnd => (sym::bitand_assign, lang.bitand_assign_trait()), - hir::BinOpKind::BitOr => (sym::bitor_assign, lang.bitor_assign_trait()), - hir::BinOpKind::Shl => (sym::shl_assign, lang.shl_assign_trait()), - hir::BinOpKind::Shr => (sym::shr_assign, lang.shr_assign_trait()), - hir::BinOpKind::Lt - | hir::BinOpKind::Le - | hir::BinOpKind::Ge - | hir::BinOpKind::Gt - | hir::BinOpKind::Eq - | hir::BinOpKind::Ne - | hir::BinOpKind::And - | hir::BinOpKind::Or => { - span_bug!(span, "impossible assignment operation: {}=", op.node.as_str()) - } - } - } else if let Op::Binary(op, IsAssign::No) = op { - match op.node { - hir::BinOpKind::Add => (sym::add, lang.add_trait()), - hir::BinOpKind::Sub => (sym::sub, lang.sub_trait()), - hir::BinOpKind::Mul => (sym::mul, lang.mul_trait()), - hir::BinOpKind::Div => (sym::div, lang.div_trait()), - hir::BinOpKind::Rem => (sym::rem, lang.rem_trait()), - hir::BinOpKind::BitXor => (sym::bitxor, lang.bitxor_trait()), - hir::BinOpKind::BitAnd => (sym::bitand, lang.bitand_trait()), - hir::BinOpKind::BitOr => (sym::bitor, lang.bitor_trait()), - hir::BinOpKind::Shl => (sym::shl, lang.shl_trait()), - hir::BinOpKind::Shr => (sym::shr, lang.shr_trait()), - hir::BinOpKind::Lt => (sym::lt, lang.partial_ord_trait()), - hir::BinOpKind::Le => (sym::le, lang.partial_ord_trait()), - hir::BinOpKind::Ge => (sym::ge, lang.partial_ord_trait()), - hir::BinOpKind::Gt => (sym::gt, lang.partial_ord_trait()), - hir::BinOpKind::Eq => (sym::eq, lang.eq_trait()), - hir::BinOpKind::Ne => (sym::ne, lang.eq_trait()), - hir::BinOpKind::And | hir::BinOpKind::Or => { - span_bug!(span, "&& and || are not overloadable") - } - } - } else if let Op::Unary(hir::UnOp::Not, _) = op { - (sym::not, lang.not_trait()) - } else if let Op::Unary(hir::UnOp::Neg, _) = op { - (sym::neg, lang.neg_trait()) - } else { - bug!("lookup_op_method: op not supported: {:?}", op) - }; - - debug!( - "lookup_op_method(lhs_ty={:?}, op={:?}, opname={:?}, trait_did={:?})", - lhs_ty, op, opname, trait_did - ); - - // Catches cases like #83893, where a lang item is declared with the - // wrong number of generic arguments. Should have yielded an error - // elsewhere by now, but we have to catch it here so that we do not - // index `other_tys` out of bounds (if the lang item has too many - // generic arguments, `other_tys` is too short). - if !has_expected_num_generic_args( - self.tcx, - trait_did, - match op { - // Binary ops have a generic right-hand side, unary ops don't - Op::Binary(..) => 1, - Op::Unary(..) => 0, - }, - ) { - return Err(vec![]); - } - - let opname = Ident::with_dummy_span(opname); - let method = trait_did.and_then(|trait_did| { - self.lookup_op_method_in_trait( - span, - opname, - trait_did, - lhs_ty, - other_ty, - other_ty_expr, - expected, - ) - }); - - match (method, trait_did) { - (Some(ok), _) => { - let method = self.register_infer_ok_obligations(ok); - self.select_obligations_where_possible(false, |_| {}); - Ok(method) - } - (None, None) => Err(vec![]), - (None, Some(trait_did)) => { - let (obligation, _) = self.obligation_for_op_method( - span, - trait_did, - lhs_ty, - other_ty, - other_ty_expr, - expected, - ); - let mut fulfill = <dyn TraitEngine<'_>>::new(self.tcx); - fulfill.register_predicate_obligation(self, obligation); - Err(fulfill.select_where_possible(&self.infcx)) - } - } - } -} - -// Binary operator categories. These categories summarize the behavior -// with respect to the builtin operations supported. -enum BinOpCategory { - /// &&, || -- cannot be overridden - Shortcircuit, - - /// <<, >> -- when shifting a single integer, rhs can be any - /// integer type. For simd, types must match. - Shift, - - /// +, -, etc -- takes equal types, produces same type as input, - /// applicable to ints/floats/simd - Math, - - /// &, |, ^ -- takes equal types, produces same type as input, - /// applicable to ints/floats/simd/bool - Bitwise, - - /// ==, !=, etc -- takes equal types, produces bools, except for simd, - /// which produce the input type - Comparison, -} - -impl BinOpCategory { - fn from(op: hir::BinOp) -> BinOpCategory { - match op.node { - hir::BinOpKind::Shl | hir::BinOpKind::Shr => BinOpCategory::Shift, - - hir::BinOpKind::Add - | hir::BinOpKind::Sub - | hir::BinOpKind::Mul - | hir::BinOpKind::Div - | hir::BinOpKind::Rem => BinOpCategory::Math, - - hir::BinOpKind::BitXor | hir::BinOpKind::BitAnd | hir::BinOpKind::BitOr => { - BinOpCategory::Bitwise - } - - hir::BinOpKind::Eq - | hir::BinOpKind::Ne - | hir::BinOpKind::Lt - | hir::BinOpKind::Le - | hir::BinOpKind::Ge - | hir::BinOpKind::Gt => BinOpCategory::Comparison, - - hir::BinOpKind::And | hir::BinOpKind::Or => BinOpCategory::Shortcircuit, - } - } -} - -/// Whether the binary operation is an assignment (`a += b`), or not (`a + b`) -#[derive(Clone, Copy, Debug, PartialEq)] -enum IsAssign { - No, - Yes, -} - -#[derive(Clone, Copy, Debug)] -enum Op { - Binary(hir::BinOp, IsAssign), - Unary(hir::UnOp, Span), -} - -/// Dereferences a single level of immutable referencing. -fn deref_ty_if_possible<'tcx>(ty: Ty<'tcx>) -> Ty<'tcx> { - match ty.kind() { - ty::Ref(_, ty, hir::Mutability::Not) => *ty, - _ => ty, - } -} - -/// Returns `true` if this is a built-in arithmetic operation (e.g., u32 -/// + u32, i16x4 == i16x4) and false if these types would have to be -/// overloaded to be legal. There are two reasons that we distinguish -/// builtin operations from overloaded ones (vs trying to drive -/// everything uniformly through the trait system and intrinsics or -/// something like that): -/// -/// 1. Builtin operations can trivially be evaluated in constants. -/// 2. For comparison operators applied to SIMD types the result is -/// not of type `bool`. For example, `i16x4 == i16x4` yields a -/// type like `i16x4`. This means that the overloaded trait -/// `PartialEq` is not applicable. -/// -/// Reason #2 is the killer. I tried for a while to always use -/// overloaded logic and just check the types in constants/codegen after -/// the fact, and it worked fine, except for SIMD types. -nmatsakis -fn is_builtin_binop<'tcx>(lhs: Ty<'tcx>, rhs: Ty<'tcx>, op: hir::BinOp) -> bool { - // Special-case a single layer of referencing, so that things like `5.0 + &6.0f32` work. - // (See https://github.com/rust-lang/rust/issues/57447.) - let (lhs, rhs) = (deref_ty_if_possible(lhs), deref_ty_if_possible(rhs)); - - match BinOpCategory::from(op) { - BinOpCategory::Shortcircuit => true, - - BinOpCategory::Shift => { - lhs.references_error() - || rhs.references_error() - || lhs.is_integral() && rhs.is_integral() - } - - BinOpCategory::Math => { - lhs.references_error() - || rhs.references_error() - || lhs.is_integral() && rhs.is_integral() - || lhs.is_floating_point() && rhs.is_floating_point() - } - - BinOpCategory::Bitwise => { - lhs.references_error() - || rhs.references_error() - || lhs.is_integral() && rhs.is_integral() - || lhs.is_floating_point() && rhs.is_floating_point() - || lhs.is_bool() && rhs.is_bool() - } - - BinOpCategory::Comparison => { - lhs.references_error() || rhs.references_error() || lhs.is_scalar() && rhs.is_scalar() - } - } -} - -struct TypeParamVisitor<'tcx>(Vec<Ty<'tcx>>); - -impl<'tcx> TypeVisitor<'tcx> for TypeParamVisitor<'tcx> { - fn visit_ty(&mut self, ty: Ty<'tcx>) -> ControlFlow<Self::BreakTy> { - if let ty::Param(_) = ty.kind() { - self.0.push(ty); - } - ty.super_visit_with(self) - } -} - -struct TypeParamEraser<'a, 'tcx>(&'a FnCtxt<'a, 'tcx>, Span); - -impl<'tcx> TypeFolder<'tcx> for TypeParamEraser<'_, 'tcx> { - fn tcx(&self) -> TyCtxt<'tcx> { - self.0.tcx - } - - fn fold_ty(&mut self, ty: Ty<'tcx>) -> Ty<'tcx> { - match ty.kind() { - ty::Param(_) => self.0.next_ty_var(TypeVariableOrigin { - kind: TypeVariableOriginKind::MiscVariable, - span: self.1, - }), - _ => ty.super_fold_with(self), - } - } -} |