| //! Type checking expressions. |
| //! |
| //! See `mod.rs` for more context on type checking in general. |
| |
| use crate::cast; |
| use crate::coercion::CoerceMany; |
| use crate::coercion::DynamicCoerceMany; |
| use crate::errors::TypeMismatchFruTypo; |
| use crate::errors::{AddressOfTemporaryTaken, ReturnStmtOutsideOfFnBody, StructExprNonExhaustive}; |
| use crate::errors::{ |
| FieldMultiplySpecifiedInInitializer, FunctionalRecordUpdateOnNonStruct, HelpUseLatestEdition, |
| YieldExprOutsideOfGenerator, |
| }; |
| use crate::fatally_break_rust; |
| use crate::method::SelfSource; |
| use crate::type_error_struct; |
| use crate::Expectation::{self, ExpectCastableToType, ExpectHasType, NoExpectation}; |
| use crate::{ |
| report_unexpected_variant_res, BreakableCtxt, Diverges, FnCtxt, Needs, |
| TupleArgumentsFlag::DontTupleArguments, |
| }; |
| use rustc_ast as ast; |
| use rustc_data_structures::fx::FxHashMap; |
| use rustc_data_structures::stack::ensure_sufficient_stack; |
| use rustc_errors::{ |
| pluralize, struct_span_err, AddToDiagnostic, Applicability, Diagnostic, DiagnosticBuilder, |
| DiagnosticId, ErrorGuaranteed, StashKey, |
| }; |
| use rustc_hir as hir; |
| use rustc_hir::def::{CtorKind, DefKind, Res}; |
| use rustc_hir::def_id::DefId; |
| use rustc_hir::intravisit::Visitor; |
| use rustc_hir::lang_items::LangItem; |
| use rustc_hir::{ExprKind, HirId, QPath}; |
| use rustc_hir_analysis::astconv::AstConv as _; |
| use rustc_hir_analysis::check::ty_kind_suggestion; |
| use rustc_infer::infer; |
| use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind}; |
| use rustc_infer::infer::InferOk; |
| use rustc_infer::traits::ObligationCause; |
| use rustc_middle::middle::stability; |
| use rustc_middle::ty::adjustment::{Adjust, Adjustment, AllowTwoPhase}; |
| use rustc_middle::ty::error::TypeError::FieldMisMatch; |
| use rustc_middle::ty::subst::SubstsRef; |
| use rustc_middle::ty::{self, AdtKind, Ty, TypeVisitableExt}; |
| use rustc_session::errors::ExprParenthesesNeeded; |
| use rustc_session::parse::feature_err; |
| use rustc_span::edit_distance::find_best_match_for_name; |
| use rustc_span::hygiene::DesugaringKind; |
| use rustc_span::source_map::{Span, Spanned}; |
| use rustc_span::symbol::{kw, sym, Ident, Symbol}; |
| use rustc_target::spec::abi::Abi::RustIntrinsic; |
| use rustc_trait_selection::infer::InferCtxtExt; |
| use rustc_trait_selection::traits::{self, ObligationCauseCode}; |
| |
| impl<'a, 'tcx> FnCtxt<'a, 'tcx> { |
| fn check_expr_eq_type(&self, expr: &'tcx hir::Expr<'tcx>, expected: Ty<'tcx>) { |
| let ty = self.check_expr_with_hint(expr, expected); |
| self.demand_eqtype(expr.span, expected, ty); |
| } |
| |
| pub fn check_expr_has_type_or_error( |
| &self, |
| expr: &'tcx hir::Expr<'tcx>, |
| expected: Ty<'tcx>, |
| extend_err: impl FnMut(&mut Diagnostic), |
| ) -> Ty<'tcx> { |
| self.check_expr_meets_expectation_or_error(expr, ExpectHasType(expected), extend_err) |
| } |
| |
| fn check_expr_meets_expectation_or_error( |
| &self, |
| expr: &'tcx hir::Expr<'tcx>, |
| expected: Expectation<'tcx>, |
| mut extend_err: impl FnMut(&mut Diagnostic), |
| ) -> Ty<'tcx> { |
| let expected_ty = expected.to_option(&self).unwrap_or(self.tcx.types.bool); |
| let mut ty = self.check_expr_with_expectation(expr, expected); |
| |
| // While we don't allow *arbitrary* coercions here, we *do* allow |
| // coercions from ! to `expected`. |
| if ty.is_never() { |
| if let Some(adjustments) = self.typeck_results.borrow().adjustments().get(expr.hir_id) { |
| let reported = self.tcx().sess.delay_span_bug( |
| expr.span, |
| "expression with never type wound up being adjusted", |
| ); |
| return if let [Adjustment { kind: Adjust::NeverToAny, target }] = &adjustments[..] { |
| target.to_owned() |
| } else { |
| self.tcx().ty_error(reported) |
| }; |
| } |
| |
| let adj_ty = self.next_ty_var(TypeVariableOrigin { |
| kind: TypeVariableOriginKind::AdjustmentType, |
| span: expr.span, |
| }); |
| self.apply_adjustments( |
| expr, |
| vec![Adjustment { kind: Adjust::NeverToAny, target: adj_ty }], |
| ); |
| ty = adj_ty; |
| } |
| |
| if let Some(mut err) = self.demand_suptype_diag(expr.span, expected_ty, ty) { |
| let _ = self.emit_type_mismatch_suggestions( |
| &mut err, |
| expr.peel_drop_temps(), |
| ty, |
| expected_ty, |
| None, |
| None, |
| ); |
| extend_err(&mut err); |
| err.emit(); |
| } |
| ty |
| } |
| |
| pub(super) fn check_expr_coercable_to_type( |
| &self, |
| expr: &'tcx hir::Expr<'tcx>, |
| expected: Ty<'tcx>, |
| expected_ty_expr: Option<&'tcx hir::Expr<'tcx>>, |
| ) -> Ty<'tcx> { |
| let ty = self.check_expr_with_hint(expr, expected); |
| // checks don't need two phase |
| self.demand_coerce(expr, ty, expected, expected_ty_expr, AllowTwoPhase::No) |
| } |
| |
| pub(super) fn check_expr_with_hint( |
| &self, |
| expr: &'tcx hir::Expr<'tcx>, |
| expected: Ty<'tcx>, |
| ) -> Ty<'tcx> { |
| self.check_expr_with_expectation(expr, ExpectHasType(expected)) |
| } |
| |
| fn check_expr_with_expectation_and_needs( |
| &self, |
| expr: &'tcx hir::Expr<'tcx>, |
| expected: Expectation<'tcx>, |
| needs: Needs, |
| ) -> Ty<'tcx> { |
| let ty = self.check_expr_with_expectation(expr, expected); |
| |
| // If the expression is used in a place whether mutable place is required |
| // e.g. LHS of assignment, perform the conversion. |
| if let Needs::MutPlace = needs { |
| self.convert_place_derefs_to_mutable(expr); |
| } |
| |
| ty |
| } |
| |
| pub(super) fn check_expr(&self, expr: &'tcx hir::Expr<'tcx>) -> Ty<'tcx> { |
| self.check_expr_with_expectation(expr, NoExpectation) |
| } |
| |
| pub(super) fn check_expr_with_needs( |
| &self, |
| expr: &'tcx hir::Expr<'tcx>, |
| needs: Needs, |
| ) -> Ty<'tcx> { |
| self.check_expr_with_expectation_and_needs(expr, NoExpectation, needs) |
| } |
| |
| /// Invariant: |
| /// If an expression has any sub-expressions that result in a type error, |
| /// inspecting that expression's type with `ty.references_error()` will return |
| /// true. Likewise, if an expression is known to diverge, inspecting its |
| /// type with `ty::type_is_bot` will return true (n.b.: since Rust is |
| /// strict, _|_ can appear in the type of an expression that does not, |
| /// itself, diverge: for example, fn() -> _|_.) |
| /// Note that inspecting a type's structure *directly* may expose the fact |
| /// that there are actually multiple representations for `Error`, so avoid |
| /// that when err needs to be handled differently. |
| #[instrument(skip(self, expr), level = "debug")] |
| pub(super) fn check_expr_with_expectation( |
| &self, |
| expr: &'tcx hir::Expr<'tcx>, |
| expected: Expectation<'tcx>, |
| ) -> Ty<'tcx> { |
| self.check_expr_with_expectation_and_args(expr, expected, &[]) |
| } |
| |
| /// Same as `check_expr_with_expectation`, but allows us to pass in the arguments of a |
| /// `ExprKind::Call` when evaluating its callee when it is an `ExprKind::Path`. |
| pub(super) fn check_expr_with_expectation_and_args( |
| &self, |
| expr: &'tcx hir::Expr<'tcx>, |
| expected: Expectation<'tcx>, |
| args: &'tcx [hir::Expr<'tcx>], |
| ) -> Ty<'tcx> { |
| if self.tcx().sess.verbose() { |
| // make this code only run with -Zverbose because it is probably slow |
| if let Ok(lint_str) = self.tcx.sess.source_map().span_to_snippet(expr.span) { |
| if !lint_str.contains('\n') { |
| debug!("expr text: {lint_str}"); |
| } else { |
| let mut lines = lint_str.lines(); |
| if let Some(line0) = lines.next() { |
| let remaining_lines = lines.count(); |
| debug!("expr text: {line0}"); |
| debug!("expr text: ...(and {remaining_lines} more lines)"); |
| } |
| } |
| } |
| } |
| |
| // True if `expr` is a `Try::from_ok(())` that is a result of desugaring a try block |
| // without the final expr (e.g. `try { return; }`). We don't want to generate an |
| // unreachable_code lint for it since warnings for autogenerated code are confusing. |
| let is_try_block_generated_unit_expr = match expr.kind { |
| ExprKind::Call(_, args) if expr.span.is_desugaring(DesugaringKind::TryBlock) => { |
| args.len() == 1 && args[0].span.is_desugaring(DesugaringKind::TryBlock) |
| } |
| |
| _ => false, |
| }; |
| |
| // Warn for expressions after diverging siblings. |
| if !is_try_block_generated_unit_expr { |
| self.warn_if_unreachable(expr.hir_id, expr.span, "expression"); |
| } |
| |
| // Hide the outer diverging and has_errors flags. |
| let old_diverges = self.diverges.replace(Diverges::Maybe); |
| |
| let ty = ensure_sufficient_stack(|| match &expr.kind { |
| hir::ExprKind::Path( |
| qpath @ hir::QPath::Resolved(..) | qpath @ hir::QPath::TypeRelative(..), |
| ) => self.check_expr_path(qpath, expr, args), |
| _ => self.check_expr_kind(expr, expected), |
| }); |
| let ty = self.resolve_vars_if_possible(ty); |
| |
| // Warn for non-block expressions with diverging children. |
| match expr.kind { |
| ExprKind::Block(..) |
| | ExprKind::If(..) |
| | ExprKind::Let(..) |
| | ExprKind::Loop(..) |
| | ExprKind::Match(..) => {} |
| // If `expr` is a result of desugaring the try block and is an ok-wrapped |
| // diverging expression (e.g. it arose from desugaring of `try { return }`), |
| // we skip issuing a warning because it is autogenerated code. |
| ExprKind::Call(..) if expr.span.is_desugaring(DesugaringKind::TryBlock) => {} |
| ExprKind::Call(callee, _) => self.warn_if_unreachable(expr.hir_id, callee.span, "call"), |
| ExprKind::MethodCall(segment, ..) => { |
| self.warn_if_unreachable(expr.hir_id, segment.ident.span, "call") |
| } |
| _ => self.warn_if_unreachable(expr.hir_id, expr.span, "expression"), |
| } |
| |
| // Any expression that produces a value of type `!` must have diverged |
| if ty.is_never() { |
| self.diverges.set(self.diverges.get() | Diverges::always(expr.span)); |
| } |
| |
| // Record the type, which applies it effects. |
| // We need to do this after the warning above, so that |
| // we don't warn for the diverging expression itself. |
| self.write_ty(expr.hir_id, ty); |
| |
| // Combine the diverging and has_error flags. |
| self.diverges.set(self.diverges.get() | old_diverges); |
| |
| debug!("type of {} is...", self.tcx.hir().node_to_string(expr.hir_id)); |
| debug!("... {:?}, expected is {:?}", ty, expected); |
| |
| ty |
| } |
| |
| #[instrument(skip(self, expr), level = "debug")] |
| fn check_expr_kind( |
| &self, |
| expr: &'tcx hir::Expr<'tcx>, |
| expected: Expectation<'tcx>, |
| ) -> Ty<'tcx> { |
| trace!("expr={:#?}", expr); |
| |
| let tcx = self.tcx; |
| match expr.kind { |
| ExprKind::Box(subexpr) => self.check_expr_box(subexpr, expected), |
| ExprKind::Lit(ref lit) => self.check_lit(&lit, expected), |
| ExprKind::Binary(op, lhs, rhs) => self.check_binop(expr, op, lhs, rhs, expected), |
| ExprKind::Assign(lhs, rhs, span) => { |
| self.check_expr_assign(expr, expected, lhs, rhs, span) |
| } |
| ExprKind::AssignOp(op, lhs, rhs) => { |
| self.check_binop_assign(expr, op, lhs, rhs, expected) |
| } |
| ExprKind::Unary(unop, oprnd) => self.check_expr_unary(unop, oprnd, expected, expr), |
| ExprKind::AddrOf(kind, mutbl, oprnd) => { |
| self.check_expr_addr_of(kind, mutbl, oprnd, expected, expr) |
| } |
| ExprKind::Path(QPath::LangItem(lang_item, _, hir_id)) => { |
| self.check_lang_item_path(lang_item, expr, hir_id) |
| } |
| ExprKind::Path(ref qpath) => self.check_expr_path(qpath, expr, &[]), |
| ExprKind::InlineAsm(asm) => { |
| // We defer some asm checks as we may not have resolved the input and output types yet (they may still be infer vars). |
| self.deferred_asm_checks.borrow_mut().push((asm, expr.hir_id)); |
| self.check_expr_asm(asm) |
| } |
| ExprKind::Break(destination, ref expr_opt) => { |
| self.check_expr_break(destination, expr_opt.as_deref(), expr) |
| } |
| ExprKind::Continue(destination) => { |
| if destination.target_id.is_ok() { |
| tcx.types.never |
| } else { |
| // There was an error; make type-check fail. |
| tcx.ty_error_misc() |
| } |
| } |
| ExprKind::Ret(ref expr_opt) => self.check_expr_return(expr_opt.as_deref(), expr), |
| ExprKind::Let(let_expr) => self.check_expr_let(let_expr), |
| ExprKind::Loop(body, _, source, _) => { |
| self.check_expr_loop(body, source, expected, expr) |
| } |
| ExprKind::Match(discrim, arms, match_src) => { |
| self.check_match(expr, &discrim, arms, expected, match_src) |
| } |
| ExprKind::Closure(closure) => self.check_expr_closure(closure, expr.span, expected), |
| ExprKind::Block(body, _) => self.check_block_with_expected(&body, expected), |
| ExprKind::Call(callee, args) => self.check_call(expr, &callee, args, expected), |
| ExprKind::MethodCall(segment, receiver, args, _) => { |
| self.check_method_call(expr, segment, receiver, args, expected) |
| } |
| ExprKind::Cast(e, t) => self.check_expr_cast(e, t, expr), |
| ExprKind::Type(e, t) => { |
| let ty = self.to_ty_saving_user_provided_ty(&t); |
| self.check_expr_eq_type(&e, ty); |
| ty |
| } |
| ExprKind::If(cond, then_expr, opt_else_expr) => { |
| self.check_then_else(cond, then_expr, opt_else_expr, expr.span, expected) |
| } |
| ExprKind::DropTemps(e) => self.check_expr_with_expectation(e, expected), |
| ExprKind::Array(args) => self.check_expr_array(args, expected, expr), |
| ExprKind::ConstBlock(ref anon_const) => { |
| self.check_expr_const_block(anon_const, expected, expr) |
| } |
| ExprKind::Repeat(element, ref count) => { |
| self.check_expr_repeat(element, count, expected, expr) |
| } |
| ExprKind::Tup(elts) => self.check_expr_tuple(elts, expected, expr), |
| ExprKind::Struct(qpath, fields, ref base_expr) => { |
| self.check_expr_struct(expr, expected, qpath, fields, base_expr) |
| } |
| ExprKind::Field(base, field) => self.check_field(expr, &base, field, expected), |
| ExprKind::Index(base, idx) => self.check_expr_index(base, idx, expr), |
| ExprKind::Yield(value, ref src) => self.check_expr_yield(value, expr, src), |
| hir::ExprKind::Err(guar) => tcx.ty_error(guar), |
| } |
| } |
| |
| fn check_expr_box(&self, expr: &'tcx hir::Expr<'tcx>, expected: Expectation<'tcx>) -> Ty<'tcx> { |
| let expected_inner = expected.to_option(self).map_or(NoExpectation, |ty| match ty.kind() { |
| ty::Adt(def, _) if def.is_box() => Expectation::rvalue_hint(self, ty.boxed_ty()), |
| _ => NoExpectation, |
| }); |
| let referent_ty = self.check_expr_with_expectation(expr, expected_inner); |
| self.require_type_is_sized(referent_ty, expr.span, traits::SizedBoxType); |
| self.tcx.mk_box(referent_ty) |
| } |
| |
| fn check_expr_unary( |
| &self, |
| unop: hir::UnOp, |
| oprnd: &'tcx hir::Expr<'tcx>, |
| expected: Expectation<'tcx>, |
| expr: &'tcx hir::Expr<'tcx>, |
| ) -> Ty<'tcx> { |
| let tcx = self.tcx; |
| let expected_inner = match unop { |
| hir::UnOp::Not | hir::UnOp::Neg => expected, |
| hir::UnOp::Deref => NoExpectation, |
| }; |
| let mut oprnd_t = self.check_expr_with_expectation(&oprnd, expected_inner); |
| |
| if !oprnd_t.references_error() { |
| oprnd_t = self.structurally_resolved_type(expr.span, oprnd_t); |
| match unop { |
| hir::UnOp::Deref => { |
| if let Some(ty) = self.lookup_derefing(expr, oprnd, oprnd_t) { |
| oprnd_t = ty; |
| } else { |
| let mut err = type_error_struct!( |
| tcx.sess, |
| expr.span, |
| oprnd_t, |
| E0614, |
| "type `{oprnd_t}` cannot be dereferenced", |
| ); |
| let sp = tcx.sess.source_map().start_point(expr.span).with_parent(None); |
| if let Some(sp) = |
| tcx.sess.parse_sess.ambiguous_block_expr_parse.borrow().get(&sp) |
| { |
| err.subdiagnostic(ExprParenthesesNeeded::surrounding(*sp)); |
| } |
| oprnd_t = tcx.ty_error(err.emit()); |
| } |
| } |
| hir::UnOp::Not => { |
| let result = self.check_user_unop(expr, oprnd_t, unop, expected_inner); |
| // If it's builtin, we can reuse the type, this helps inference. |
| if !(oprnd_t.is_integral() || *oprnd_t.kind() == ty::Bool) { |
| oprnd_t = result; |
| } |
| } |
| hir::UnOp::Neg => { |
| let result = self.check_user_unop(expr, oprnd_t, unop, expected_inner); |
| // If it's builtin, we can reuse the type, this helps inference. |
| if !oprnd_t.is_numeric() { |
| oprnd_t = result; |
| } |
| } |
| } |
| } |
| oprnd_t |
| } |
| |
| fn check_expr_addr_of( |
| &self, |
| kind: hir::BorrowKind, |
| mutbl: hir::Mutability, |
| oprnd: &'tcx hir::Expr<'tcx>, |
| expected: Expectation<'tcx>, |
| expr: &'tcx hir::Expr<'tcx>, |
| ) -> Ty<'tcx> { |
| let hint = expected.only_has_type(self).map_or(NoExpectation, |ty| { |
| match ty.kind() { |
| ty::Ref(_, ty, _) | ty::RawPtr(ty::TypeAndMut { ty, .. }) => { |
| if oprnd.is_syntactic_place_expr() { |
| // Places may legitimately have unsized types. |
| // For example, dereferences of a fat pointer and |
| // the last field of a struct can be unsized. |
| ExpectHasType(*ty) |
| } else { |
| Expectation::rvalue_hint(self, *ty) |
| } |
| } |
| _ => NoExpectation, |
| } |
| }); |
| let ty = |
| self.check_expr_with_expectation_and_needs(&oprnd, hint, Needs::maybe_mut_place(mutbl)); |
| |
| let tm = ty::TypeAndMut { ty, mutbl }; |
| match kind { |
| _ if tm.ty.references_error() => self.tcx.ty_error_misc(), |
| hir::BorrowKind::Raw => { |
| self.check_named_place_expr(oprnd); |
| self.tcx.mk_ptr(tm) |
| } |
| hir::BorrowKind::Ref => { |
| // Note: at this point, we cannot say what the best lifetime |
| // is to use for resulting pointer. We want to use the |
| // shortest lifetime possible so as to avoid spurious borrowck |
| // errors. Moreover, the longest lifetime will depend on the |
| // precise details of the value whose address is being taken |
| // (and how long it is valid), which we don't know yet until |
| // type inference is complete. |
| // |
| // Therefore, here we simply generate a region variable. The |
| // region inferencer will then select a suitable value. |
| // Finally, borrowck will infer the value of the region again, |
| // this time with enough precision to check that the value |
| // whose address was taken can actually be made to live as long |
| // as it needs to live. |
| let region = self.next_region_var(infer::AddrOfRegion(expr.span)); |
| self.tcx.mk_ref(region, tm) |
| } |
| } |
| } |
| |
| /// Does this expression refer to a place that either: |
| /// * Is based on a local or static. |
| /// * Contains a dereference |
| /// Note that the adjustments for the children of `expr` should already |
| /// have been resolved. |
| fn check_named_place_expr(&self, oprnd: &'tcx hir::Expr<'tcx>) { |
| let is_named = oprnd.is_place_expr(|base| { |
| // Allow raw borrows if there are any deref adjustments. |
| // |
| // const VAL: (i32,) = (0,); |
| // const REF: &(i32,) = &(0,); |
| // |
| // &raw const VAL.0; // ERROR |
| // &raw const REF.0; // OK, same as &raw const (*REF).0; |
| // |
| // This is maybe too permissive, since it allows |
| // `let u = &raw const Box::new((1,)).0`, which creates an |
| // immediately dangling raw pointer. |
| self.typeck_results |
| .borrow() |
| .adjustments() |
| .get(base.hir_id) |
| .map_or(false, |x| x.iter().any(|adj| matches!(adj.kind, Adjust::Deref(_)))) |
| }); |
| if !is_named { |
| self.tcx.sess.emit_err(AddressOfTemporaryTaken { span: oprnd.span }); |
| } |
| } |
| |
| fn check_lang_item_path( |
| &self, |
| lang_item: hir::LangItem, |
| expr: &'tcx hir::Expr<'tcx>, |
| hir_id: Option<hir::HirId>, |
| ) -> Ty<'tcx> { |
| self.resolve_lang_item_path(lang_item, expr.span, expr.hir_id, hir_id).1 |
| } |
| |
| pub(crate) fn check_expr_path( |
| &self, |
| qpath: &'tcx hir::QPath<'tcx>, |
| expr: &'tcx hir::Expr<'tcx>, |
| args: &'tcx [hir::Expr<'tcx>], |
| ) -> Ty<'tcx> { |
| let tcx = self.tcx; |
| let (res, opt_ty, segs) = |
| self.resolve_ty_and_res_fully_qualified_call(qpath, expr.hir_id, expr.span); |
| let ty = match res { |
| Res::Err => { |
| self.suggest_assoc_method_call(segs); |
| let e = |
| self.tcx.sess.delay_span_bug(qpath.span(), "`Res::Err` but no error emitted"); |
| self.set_tainted_by_errors(e); |
| tcx.ty_error(e) |
| } |
| Res::Def(DefKind::Variant, _) => { |
| let e = report_unexpected_variant_res(tcx, res, qpath, expr.span, "E0533", "value"); |
| tcx.ty_error(e) |
| } |
| _ => self.instantiate_value_path(segs, opt_ty, res, expr.span, expr.hir_id).0, |
| }; |
| |
| if let ty::FnDef(did, ..) = *ty.kind() { |
| let fn_sig = ty.fn_sig(tcx); |
| if tcx.fn_sig(did).skip_binder().abi() == RustIntrinsic |
| && tcx.item_name(did) == sym::transmute |
| { |
| let from = fn_sig.inputs().skip_binder()[0]; |
| let to = fn_sig.output().skip_binder(); |
| // We defer the transmute to the end of typeck, once all inference vars have |
| // been resolved or we errored. This is important as we can only check transmute |
| // on concrete types, but the output type may not be known yet (it would only |
| // be known if explicitly specified via turbofish). |
| self.deferred_transmute_checks.borrow_mut().push((from, to, expr.hir_id)); |
| } |
| if !tcx.features().unsized_fn_params { |
| // We want to remove some Sized bounds from std functions, |
| // but don't want to expose the removal to stable Rust. |
| // i.e., we don't want to allow |
| // |
| // ```rust |
| // drop as fn(str); |
| // ``` |
| // |
| // to work in stable even if the Sized bound on `drop` is relaxed. |
| for i in 0..fn_sig.inputs().skip_binder().len() { |
| // We just want to check sizedness, so instead of introducing |
| // placeholder lifetimes with probing, we just replace higher lifetimes |
| // with fresh vars. |
| let span = args.get(i).map(|a| a.span).unwrap_or(expr.span); |
| let input = self.instantiate_binder_with_fresh_vars( |
| span, |
| infer::LateBoundRegionConversionTime::FnCall, |
| fn_sig.input(i), |
| ); |
| self.require_type_is_sized_deferred( |
| input, |
| span, |
| traits::SizedArgumentType(None), |
| ); |
| } |
| } |
| // Here we want to prevent struct constructors from returning unsized types. |
| // There were two cases this happened: fn pointer coercion in stable |
| // and usual function call in presence of unsized_locals. |
| // Also, as we just want to check sizedness, instead of introducing |
| // placeholder lifetimes with probing, we just replace higher lifetimes |
| // with fresh vars. |
| let output = self.instantiate_binder_with_fresh_vars( |
| expr.span, |
| infer::LateBoundRegionConversionTime::FnCall, |
| fn_sig.output(), |
| ); |
| self.require_type_is_sized_deferred(output, expr.span, traits::SizedReturnType); |
| } |
| |
| // We always require that the type provided as the value for |
| // a type parameter outlives the moment of instantiation. |
| let substs = self.typeck_results.borrow().node_substs(expr.hir_id); |
| self.add_wf_bounds(substs, expr); |
| |
| ty |
| } |
| |
| fn check_expr_break( |
| &self, |
| destination: hir::Destination, |
| expr_opt: Option<&'tcx hir::Expr<'tcx>>, |
| expr: &'tcx hir::Expr<'tcx>, |
| ) -> Ty<'tcx> { |
| let tcx = self.tcx; |
| if let Ok(target_id) = destination.target_id { |
| let (e_ty, cause); |
| if let Some(e) = expr_opt { |
| // If this is a break with a value, we need to type-check |
| // the expression. Get an expected type from the loop context. |
| let opt_coerce_to = { |
| // We should release `enclosing_breakables` before the `check_expr_with_hint` |
| // below, so can't move this block of code to the enclosing scope and share |
| // `ctxt` with the second `enclosing_breakables` borrow below. |
| let mut enclosing_breakables = self.enclosing_breakables.borrow_mut(); |
| match enclosing_breakables.opt_find_breakable(target_id) { |
| Some(ctxt) => ctxt.coerce.as_ref().map(|coerce| coerce.expected_ty()), |
| None => { |
| // Avoid ICE when `break` is inside a closure (#65383). |
| return tcx.ty_error_with_message( |
| expr.span, |
| "break was outside loop, but no error was emitted", |
| ); |
| } |
| } |
| }; |
| |
| // If the loop context is not a `loop { }`, then break with |
| // a value is illegal, and `opt_coerce_to` will be `None`. |
| // Just set expectation to error in that case. |
| let coerce_to = opt_coerce_to.unwrap_or_else(|| tcx.ty_error_misc()); |
| |
| // Recurse without `enclosing_breakables` borrowed. |
| e_ty = self.check_expr_with_hint(e, coerce_to); |
| cause = self.misc(e.span); |
| } else { |
| // Otherwise, this is a break *without* a value. That's |
| // always legal, and is equivalent to `break ()`. |
| e_ty = tcx.mk_unit(); |
| cause = self.misc(expr.span); |
| } |
| |
| // Now that we have type-checked `expr_opt`, borrow |
| // the `enclosing_loops` field and let's coerce the |
| // type of `expr_opt` into what is expected. |
| let mut enclosing_breakables = self.enclosing_breakables.borrow_mut(); |
| let Some(ctxt) = enclosing_breakables.opt_find_breakable(target_id) else { |
| // Avoid ICE when `break` is inside a closure (#65383). |
| return tcx.ty_error_with_message( |
| expr.span, |
| "break was outside loop, but no error was emitted", |
| ); |
| }; |
| |
| if let Some(ref mut coerce) = ctxt.coerce { |
| if let Some(ref e) = expr_opt { |
| coerce.coerce(self, &cause, e, e_ty); |
| } else { |
| assert!(e_ty.is_unit()); |
| let ty = coerce.expected_ty(); |
| coerce.coerce_forced_unit( |
| self, |
| &cause, |
| &mut |mut err| { |
| self.suggest_mismatched_types_on_tail( |
| &mut err, expr, ty, e_ty, target_id, |
| ); |
| if let Some(val) = ty_kind_suggestion(ty) { |
| let label = destination |
| .label |
| .map(|l| format!(" {}", l.ident)) |
| .unwrap_or_else(String::new); |
| err.span_suggestion( |
| expr.span, |
| "give it a value of the expected type", |
| format!("break{label} {val}"), |
| Applicability::HasPlaceholders, |
| ); |
| } |
| }, |
| false, |
| ); |
| } |
| } else { |
| // If `ctxt.coerce` is `None`, we can just ignore |
| // the type of the expression. This is because |
| // either this was a break *without* a value, in |
| // which case it is always a legal type (`()`), or |
| // else an error would have been flagged by the |
| // `loops` pass for using break with an expression |
| // where you are not supposed to. |
| assert!(expr_opt.is_none() || self.tcx.sess.has_errors().is_some()); |
| } |
| |
| // If we encountered a `break`, then (no surprise) it may be possible to break from the |
| // loop... unless the value being returned from the loop diverges itself, e.g. |
| // `break return 5` or `break loop {}`. |
| ctxt.may_break |= !self.diverges.get().is_always(); |
| |
| // the type of a `break` is always `!`, since it diverges |
| tcx.types.never |
| } else { |
| // Otherwise, we failed to find the enclosing loop; |
| // this can only happen if the `break` was not |
| // inside a loop at all, which is caught by the |
| // loop-checking pass. |
| let err = self.tcx.ty_error_with_message( |
| expr.span, |
| "break was outside loop, but no error was emitted", |
| ); |
| |
| // We still need to assign a type to the inner expression to |
| // prevent the ICE in #43162. |
| if let Some(e) = expr_opt { |
| self.check_expr_with_hint(e, err); |
| |
| // ... except when we try to 'break rust;'. |
| // ICE this expression in particular (see #43162). |
| if let ExprKind::Path(QPath::Resolved(_, path)) = e.kind { |
| if path.segments.len() == 1 && path.segments[0].ident.name == sym::rust { |
| fatally_break_rust(self.tcx.sess); |
| } |
| } |
| } |
| |
| // There was an error; make type-check fail. |
| err |
| } |
| } |
| |
| fn check_expr_return( |
| &self, |
| expr_opt: Option<&'tcx hir::Expr<'tcx>>, |
| expr: &'tcx hir::Expr<'tcx>, |
| ) -> Ty<'tcx> { |
| if self.ret_coercion.is_none() { |
| let mut err = ReturnStmtOutsideOfFnBody { |
| span: expr.span, |
| encl_body_span: None, |
| encl_fn_span: None, |
| }; |
| |
| let encl_item_id = self.tcx.hir().get_parent_item(expr.hir_id); |
| |
| if let Some(hir::Node::Item(hir::Item { |
| kind: hir::ItemKind::Fn(..), |
| span: encl_fn_span, |
| .. |
| })) |
| | Some(hir::Node::TraitItem(hir::TraitItem { |
| kind: hir::TraitItemKind::Fn(_, hir::TraitFn::Provided(_)), |
| span: encl_fn_span, |
| .. |
| })) |
| | Some(hir::Node::ImplItem(hir::ImplItem { |
| kind: hir::ImplItemKind::Fn(..), |
| span: encl_fn_span, |
| .. |
| })) = self.tcx.hir().find_by_def_id(encl_item_id.def_id) |
| { |
| // We are inside a function body, so reporting "return statement |
| // outside of function body" needs an explanation. |
| |
| let encl_body_owner_id = self.tcx.hir().enclosing_body_owner(expr.hir_id); |
| |
| // If this didn't hold, we would not have to report an error in |
| // the first place. |
| assert_ne!(encl_item_id.def_id, encl_body_owner_id); |
| |
| let encl_body_id = self.tcx.hir().body_owned_by(encl_body_owner_id); |
| let encl_body = self.tcx.hir().body(encl_body_id); |
| |
| err.encl_body_span = Some(encl_body.value.span); |
| err.encl_fn_span = Some(*encl_fn_span); |
| } |
| |
| self.tcx.sess.emit_err(err); |
| |
| if let Some(e) = expr_opt { |
| // We still have to type-check `e` (issue #86188), but calling |
| // `check_return_expr` only works inside fn bodies. |
| self.check_expr(e); |
| } |
| } else if let Some(e) = expr_opt { |
| if self.ret_coercion_span.get().is_none() { |
| self.ret_coercion_span.set(Some(e.span)); |
| } |
| self.check_return_expr(e, true); |
| } else { |
| let mut coercion = self.ret_coercion.as_ref().unwrap().borrow_mut(); |
| if self.ret_coercion_span.get().is_none() { |
| self.ret_coercion_span.set(Some(expr.span)); |
| } |
| let cause = self.cause(expr.span, ObligationCauseCode::ReturnNoExpression); |
| if let Some((fn_decl, _)) = self.get_fn_decl(expr.hir_id) { |
| coercion.coerce_forced_unit( |
| self, |
| &cause, |
| &mut |db| { |
| let span = fn_decl.output.span(); |
| if let Ok(snippet) = self.tcx.sess.source_map().span_to_snippet(span) { |
| db.span_label( |
| span, |
| format!("expected `{snippet}` because of this return type"), |
| ); |
| } |
| }, |
| true, |
| ); |
| } else { |
| coercion.coerce_forced_unit(self, &cause, &mut |_| (), true); |
| } |
| } |
| self.tcx.types.never |
| } |
| |
| /// `explicit_return` is `true` if we're checking an explicit `return expr`, |
| /// and `false` if we're checking a trailing expression. |
| pub(super) fn check_return_expr( |
| &self, |
| return_expr: &'tcx hir::Expr<'tcx>, |
| explicit_return: bool, |
| ) { |
| let ret_coercion = self.ret_coercion.as_ref().unwrap_or_else(|| { |
| span_bug!(return_expr.span, "check_return_expr called outside fn body") |
| }); |
| |
| let ret_ty = ret_coercion.borrow().expected_ty(); |
| let return_expr_ty = self.check_expr_with_hint(return_expr, ret_ty); |
| let mut span = return_expr.span; |
| // Use the span of the trailing expression for our cause, |
| // not the span of the entire function |
| if !explicit_return { |
| if let ExprKind::Block(body, _) = return_expr.kind && let Some(last_expr) = body.expr { |
| span = last_expr.span; |
| } |
| } |
| ret_coercion.borrow_mut().coerce( |
| self, |
| &self.cause(span, ObligationCauseCode::ReturnValue(return_expr.hir_id)), |
| return_expr, |
| return_expr_ty, |
| ); |
| |
| if let Some(fn_sig) = self.body_fn_sig() |
| && fn_sig.output().has_opaque_types() |
| { |
| // Point any obligations that were registered due to opaque type |
| // inference at the return expression. |
| self.select_obligations_where_possible(|errors| { |
| self.point_at_return_for_opaque_ty_error(errors, span, return_expr_ty, return_expr.span); |
| }); |
| } |
| } |
| |
| fn point_at_return_for_opaque_ty_error( |
| &self, |
| errors: &mut Vec<traits::FulfillmentError<'tcx>>, |
| span: Span, |
| return_expr_ty: Ty<'tcx>, |
| return_span: Span, |
| ) { |
| // Don't point at the whole block if it's empty |
| if span == return_span { |
| return; |
| } |
| for err in errors { |
| let cause = &mut err.obligation.cause; |
| if let ObligationCauseCode::OpaqueReturnType(None) = cause.code() { |
| let new_cause = ObligationCause::new( |
| cause.span, |
| cause.body_id, |
| ObligationCauseCode::OpaqueReturnType(Some((return_expr_ty, span))), |
| ); |
| *cause = new_cause; |
| } |
| } |
| } |
| |
| pub(crate) fn check_lhs_assignable( |
| &self, |
| lhs: &'tcx hir::Expr<'tcx>, |
| err_code: &'static str, |
| op_span: Span, |
| adjust_err: impl FnOnce(&mut Diagnostic), |
| ) { |
| if lhs.is_syntactic_place_expr() { |
| return; |
| } |
| |
| // FIXME: Make this use Diagnostic once error codes can be dynamically set. |
| let mut err = self.tcx.sess.struct_span_err_with_code( |
| op_span, |
| "invalid left-hand side of assignment", |
| DiagnosticId::Error(err_code.into()), |
| ); |
| err.span_label(lhs.span, "cannot assign to this expression"); |
| |
| self.comes_from_while_condition(lhs.hir_id, |expr| { |
| err.span_suggestion_verbose( |
| expr.span.shrink_to_lo(), |
| "you might have meant to use pattern destructuring", |
| "let ", |
| Applicability::MachineApplicable, |
| ); |
| }); |
| |
| adjust_err(&mut err); |
| |
| err.emit(); |
| } |
| |
| // Check if an expression `original_expr_id` comes from the condition of a while loop, |
| /// as opposed from the body of a while loop, which we can naively check by iterating |
| /// parents until we find a loop... |
| pub(super) fn comes_from_while_condition( |
| &self, |
| original_expr_id: HirId, |
| then: impl FnOnce(&hir::Expr<'_>), |
| ) { |
| let mut parent = self.tcx.hir().parent_id(original_expr_id); |
| while let Some(node) = self.tcx.hir().find(parent) { |
| match node { |
| hir::Node::Expr(hir::Expr { |
| kind: |
| hir::ExprKind::Loop( |
| hir::Block { |
| expr: |
| Some(hir::Expr { |
| kind: |
| hir::ExprKind::Match(expr, ..) | hir::ExprKind::If(expr, ..), |
| .. |
| }), |
| .. |
| }, |
| _, |
| hir::LoopSource::While, |
| _, |
| ), |
| .. |
| }) => { |
| // Check if our original expression is a child of the condition of a while loop |
| let expr_is_ancestor = std::iter::successors(Some(original_expr_id), |id| { |
| self.tcx.hir().opt_parent_id(*id) |
| }) |
| .take_while(|id| *id != parent) |
| .any(|id| id == expr.hir_id); |
| // if it is, then we have a situation like `while Some(0) = value.get(0) {`, |
| // where `while let` was more likely intended. |
| if expr_is_ancestor { |
| then(expr); |
| } |
| break; |
| } |
| hir::Node::Item(_) |
| | hir::Node::ImplItem(_) |
| | hir::Node::TraitItem(_) |
| | hir::Node::Crate(_) => break, |
| _ => { |
| parent = self.tcx.hir().parent_id(parent); |
| } |
| } |
| } |
| } |
| |
| // A generic function for checking the 'then' and 'else' clauses in an 'if' |
| // or 'if-else' expression. |
| fn check_then_else( |
| &self, |
| cond_expr: &'tcx hir::Expr<'tcx>, |
| then_expr: &'tcx hir::Expr<'tcx>, |
| opt_else_expr: Option<&'tcx hir::Expr<'tcx>>, |
| sp: Span, |
| orig_expected: Expectation<'tcx>, |
| ) -> Ty<'tcx> { |
| let cond_ty = self.check_expr_has_type_or_error(cond_expr, self.tcx.types.bool, |_| {}); |
| |
| self.warn_if_unreachable( |
| cond_expr.hir_id, |
| then_expr.span, |
| "block in `if` or `while` expression", |
| ); |
| |
| let cond_diverges = self.diverges.get(); |
| self.diverges.set(Diverges::Maybe); |
| |
| let expected = orig_expected.adjust_for_branches(self); |
| let then_ty = self.check_expr_with_expectation(then_expr, expected); |
| let then_diverges = self.diverges.get(); |
| self.diverges.set(Diverges::Maybe); |
| |
| // We've already taken the expected type's preferences |
| // into account when typing the `then` branch. To figure |
| // out the initial shot at a LUB, we thus only consider |
| // `expected` if it represents a *hard* constraint |
| // (`only_has_type`); otherwise, we just go with a |
| // fresh type variable. |
| let coerce_to_ty = expected.coercion_target_type(self, sp); |
| let mut coerce: DynamicCoerceMany<'_> = CoerceMany::new(coerce_to_ty); |
| |
| coerce.coerce(self, &self.misc(sp), then_expr, then_ty); |
| |
| if let Some(else_expr) = opt_else_expr { |
| let else_ty = self.check_expr_with_expectation(else_expr, expected); |
| let else_diverges = self.diverges.get(); |
| |
| let opt_suggest_box_span = self.opt_suggest_box_span(then_ty, else_ty, orig_expected); |
| let if_cause = self.if_cause( |
| sp, |
| cond_expr.span, |
| then_expr, |
| else_expr, |
| then_ty, |
| else_ty, |
| opt_suggest_box_span, |
| ); |
| |
| coerce.coerce(self, &if_cause, else_expr, else_ty); |
| |
| // We won't diverge unless both branches do (or the condition does). |
| self.diverges.set(cond_diverges | then_diverges & else_diverges); |
| } else { |
| self.if_fallback_coercion(sp, then_expr, &mut coerce); |
| |
| // If the condition is false we can't diverge. |
| self.diverges.set(cond_diverges); |
| } |
| |
| let result_ty = coerce.complete(self); |
| if let Err(guar) = cond_ty.error_reported() { self.tcx.ty_error(guar) } else { result_ty } |
| } |
| |
| /// Type check assignment expression `expr` of form `lhs = rhs`. |
| /// The expected type is `()` and is passed to the function for the purposes of diagnostics. |
| fn check_expr_assign( |
| &self, |
| expr: &'tcx hir::Expr<'tcx>, |
| expected: Expectation<'tcx>, |
| lhs: &'tcx hir::Expr<'tcx>, |
| rhs: &'tcx hir::Expr<'tcx>, |
| span: Span, |
| ) -> Ty<'tcx> { |
| let expected_ty = expected.coercion_target_type(self, expr.span); |
| if expected_ty == self.tcx.types.bool { |
| // The expected type is `bool` but this will result in `()` so we can reasonably |
| // say that the user intended to write `lhs == rhs` instead of `lhs = rhs`. |
| // The likely cause of this is `if foo = bar { .. }`. |
| let actual_ty = self.tcx.mk_unit(); |
| let mut err = self.demand_suptype_diag(expr.span, expected_ty, actual_ty).unwrap(); |
| let lhs_ty = self.check_expr(&lhs); |
| let rhs_ty = self.check_expr(&rhs); |
| let (applicability, eq) = if self.can_coerce(rhs_ty, lhs_ty) { |
| (Applicability::MachineApplicable, true) |
| } else if let ExprKind::Binary( |
| Spanned { node: hir::BinOpKind::And | hir::BinOpKind::Or, .. }, |
| _, |
| rhs_expr, |
| ) = lhs.kind |
| { |
| // if x == 1 && y == 2 { .. } |
| // + |
| let actual_lhs_ty = self.check_expr(&rhs_expr); |
| (Applicability::MaybeIncorrect, self.can_coerce(rhs_ty, actual_lhs_ty)) |
| } else if let ExprKind::Binary( |
| Spanned { node: hir::BinOpKind::And | hir::BinOpKind::Or, .. }, |
| lhs_expr, |
| _, |
| ) = rhs.kind |
| { |
| // if x == 1 && y == 2 { .. } |
| // + |
| let actual_rhs_ty = self.check_expr(&lhs_expr); |
| (Applicability::MaybeIncorrect, self.can_coerce(actual_rhs_ty, lhs_ty)) |
| } else { |
| (Applicability::MaybeIncorrect, false) |
| }; |
| if !lhs.is_syntactic_place_expr() |
| && lhs.is_approximately_pattern() |
| && !matches!(lhs.kind, hir::ExprKind::Lit(_)) |
| { |
| // Do not suggest `if let x = y` as `==` is way more likely to be the intention. |
| let hir = self.tcx.hir(); |
| if let hir::Node::Expr(hir::Expr { kind: ExprKind::If { .. }, .. }) = |
| hir.get_parent(hir.parent_id(expr.hir_id)) |
| { |
| err.span_suggestion_verbose( |
| expr.span.shrink_to_lo(), |
| "you might have meant to use pattern matching", |
| "let ", |
| applicability, |
| ); |
| }; |
| } |
| if eq { |
| err.span_suggestion_verbose( |
| span.shrink_to_hi(), |
| "you might have meant to compare for equality", |
| '=', |
| applicability, |
| ); |
| } |
| |
| // If the assignment expression itself is ill-formed, don't |
| // bother emitting another error |
| let reported = err.emit_unless(lhs_ty.references_error() || rhs_ty.references_error()); |
| return self.tcx.ty_error(reported); |
| } |
| |
| let lhs_ty = self.check_expr_with_needs(&lhs, Needs::MutPlace); |
| |
| let suggest_deref_binop = |err: &mut Diagnostic, rhs_ty: Ty<'tcx>| { |
| if let Some(lhs_deref_ty) = self.deref_once_mutably_for_diagnostic(lhs_ty) { |
| // Can only assign if the type is sized, so if `DerefMut` yields a type that is |
| // unsized, do not suggest dereferencing it. |
| let lhs_deref_ty_is_sized = self |
| .infcx |
| .type_implements_trait( |
| self.tcx.require_lang_item(LangItem::Sized, None), |
| [lhs_deref_ty], |
| self.param_env, |
| ) |
| .may_apply(); |
| if lhs_deref_ty_is_sized && self.can_coerce(rhs_ty, lhs_deref_ty) { |
| err.span_suggestion_verbose( |
| lhs.span.shrink_to_lo(), |
| "consider dereferencing here to assign to the mutably borrowed value", |
| "*", |
| Applicability::MachineApplicable, |
| ); |
| } |
| } |
| }; |
| |
| // This is (basically) inlined `check_expr_coercable_to_type`, but we want |
| // to suggest an additional fixup here in `suggest_deref_binop`. |
| let rhs_ty = self.check_expr_with_hint(&rhs, lhs_ty); |
| if let (_, Some(mut diag)) = |
| self.demand_coerce_diag(rhs, rhs_ty, lhs_ty, Some(lhs), AllowTwoPhase::No) |
| { |
| suggest_deref_binop(&mut diag, rhs_ty); |
| diag.emit(); |
| } |
| |
| self.check_lhs_assignable(lhs, "E0070", span, |err| { |
| if let Some(rhs_ty) = self.typeck_results.borrow().expr_ty_opt(rhs) { |
| suggest_deref_binop(err, rhs_ty); |
| } |
| }); |
| |
| self.require_type_is_sized(lhs_ty, lhs.span, traits::AssignmentLhsSized); |
| |
| if let Err(guar) = (lhs_ty, rhs_ty).error_reported() { |
| self.tcx.ty_error(guar) |
| } else { |
| self.tcx.mk_unit() |
| } |
| } |
| |
| pub(super) fn check_expr_let(&self, let_expr: &'tcx hir::Let<'tcx>) -> Ty<'tcx> { |
| // for let statements, this is done in check_stmt |
| let init = let_expr.init; |
| self.warn_if_unreachable(init.hir_id, init.span, "block in `let` expression"); |
| // otherwise check exactly as a let statement |
| self.check_decl(let_expr.into()); |
| // but return a bool, for this is a boolean expression |
| self.tcx.types.bool |
| } |
| |
| fn check_expr_loop( |
| &self, |
| body: &'tcx hir::Block<'tcx>, |
| source: hir::LoopSource, |
| expected: Expectation<'tcx>, |
| expr: &'tcx hir::Expr<'tcx>, |
| ) -> Ty<'tcx> { |
| let coerce = match source { |
| // you can only use break with a value from a normal `loop { }` |
| hir::LoopSource::Loop => { |
| let coerce_to = expected.coercion_target_type(self, body.span); |
| Some(CoerceMany::new(coerce_to)) |
| } |
| |
| hir::LoopSource::While | hir::LoopSource::ForLoop => None, |
| }; |
| |
| let ctxt = BreakableCtxt { |
| coerce, |
| may_break: false, // Will get updated if/when we find a `break`. |
| }; |
| |
| let (ctxt, ()) = self.with_breakable_ctxt(expr.hir_id, ctxt, || { |
| self.check_block_no_value(&body); |
| }); |
| |
| if ctxt.may_break { |
| // No way to know whether it's diverging because |
| // of a `break` or an outer `break` or `return`. |
| self.diverges.set(Diverges::Maybe); |
| } |
| |
| // If we permit break with a value, then result type is |
| // the LUB of the breaks (possibly ! if none); else, it |
| // is nil. This makes sense because infinite loops |
| // (which would have type !) are only possible iff we |
| // permit break with a value [1]. |
| if ctxt.coerce.is_none() && !ctxt.may_break { |
| // [1] |
| self.tcx.sess.delay_span_bug(body.span, "no coercion, but loop may not break"); |
| } |
| ctxt.coerce.map(|c| c.complete(self)).unwrap_or_else(|| self.tcx.mk_unit()) |
| } |
| |
| /// Checks a method call. |
| fn check_method_call( |
| &self, |
| expr: &'tcx hir::Expr<'tcx>, |
| segment: &hir::PathSegment<'_>, |
| rcvr: &'tcx hir::Expr<'tcx>, |
| args: &'tcx [hir::Expr<'tcx>], |
| expected: Expectation<'tcx>, |
| ) -> Ty<'tcx> { |
| let rcvr_t = self.check_expr(&rcvr); |
| // no need to check for bot/err -- callee does that |
| let rcvr_t = self.structurally_resolved_type(rcvr.span, rcvr_t); |
| let span = segment.ident.span; |
| |
| let method = match self.lookup_method(rcvr_t, segment, 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_resolved_type` to emit an error. |
| |
| self.write_method_call(expr.hir_id, method); |
| Ok(method) |
| } |
| Err(error) => { |
| if segment.ident.name != kw::Empty { |
| if let Some(mut err) = self.report_method_error( |
| span, |
| rcvr_t, |
| segment.ident, |
| SelfSource::MethodCall(rcvr), |
| error, |
| Some((rcvr, args)), |
| expected, |
| ) { |
| err.emit(); |
| } |
| } |
| Err(()) |
| } |
| }; |
| |
| // Call the generic checker. |
| self.check_method_argument_types(span, expr, method, &args, DontTupleArguments, expected) |
| } |
| |
| fn check_expr_cast( |
| &self, |
| e: &'tcx hir::Expr<'tcx>, |
| t: &'tcx hir::Ty<'tcx>, |
| expr: &'tcx hir::Expr<'tcx>, |
| ) -> Ty<'tcx> { |
| // Find the type of `e`. Supply hints based on the type we are casting to, |
| // if appropriate. |
| let t_cast = self.to_ty_saving_user_provided_ty(t); |
| let t_cast = self.resolve_vars_if_possible(t_cast); |
| let t_expr = self.check_expr_with_expectation(e, ExpectCastableToType(t_cast)); |
| let t_expr = self.resolve_vars_if_possible(t_expr); |
| |
| // Eagerly check for some obvious errors. |
| if let Err(guar) = (t_expr, t_cast).error_reported() { |
| self.tcx.ty_error(guar) |
| } else { |
| // Defer other checks until we're done type checking. |
| let mut deferred_cast_checks = self.deferred_cast_checks.borrow_mut(); |
| match cast::CastCheck::new( |
| self, |
| e, |
| t_expr, |
| t_cast, |
| t.span, |
| expr.span, |
| self.param_env.constness(), |
| ) { |
| Ok(cast_check) => { |
| debug!( |
| "check_expr_cast: deferring cast from {:?} to {:?}: {:?}", |
| t_cast, t_expr, cast_check, |
| ); |
| deferred_cast_checks.push(cast_check); |
| t_cast |
| } |
| Err(guar) => self.tcx.ty_error(guar), |
| } |
| } |
| } |
| |
| fn check_expr_array( |
| &self, |
| args: &'tcx [hir::Expr<'tcx>], |
| expected: Expectation<'tcx>, |
| expr: &'tcx hir::Expr<'tcx>, |
| ) -> Ty<'tcx> { |
| let element_ty = if !args.is_empty() { |
| let coerce_to = expected |
| .to_option(self) |
| .and_then(|uty| match *uty.kind() { |
| ty::Array(ty, _) | ty::Slice(ty) => Some(ty), |
| _ => None, |
| }) |
| .unwrap_or_else(|| { |
| self.next_ty_var(TypeVariableOrigin { |
| kind: TypeVariableOriginKind::TypeInference, |
| span: expr.span, |
| }) |
| }); |
| let mut coerce = CoerceMany::with_coercion_sites(coerce_to, args); |
| assert_eq!(self.diverges.get(), Diverges::Maybe); |
| for e in args { |
| let e_ty = self.check_expr_with_hint(e, coerce_to); |
| let cause = self.misc(e.span); |
| coerce.coerce(self, &cause, e, e_ty); |
| } |
| coerce.complete(self) |
| } else { |
| self.next_ty_var(TypeVariableOrigin { |
| kind: TypeVariableOriginKind::TypeInference, |
| span: expr.span, |
| }) |
| }; |
| let array_len = args.len() as u64; |
| self.suggest_array_len(expr, array_len); |
| self.tcx.mk_array(element_ty, array_len) |
| } |
| |
| fn suggest_array_len(&self, expr: &'tcx hir::Expr<'tcx>, array_len: u64) { |
| let parent_node = self.tcx.hir().parent_iter(expr.hir_id).find(|(_, node)| { |
| !matches!(node, hir::Node::Expr(hir::Expr { kind: hir::ExprKind::AddrOf(..), .. })) |
| }); |
| let Some((_, |
| hir::Node::Local(hir::Local { ty: Some(ty), .. }) |
| | hir::Node::Item(hir::Item { kind: hir::ItemKind::Const(ty, _), .. })) |
| ) = parent_node else { |
| return |
| }; |
| if let hir::TyKind::Array(_, length) = ty.peel_refs().kind |
| && let hir::ArrayLen::Body(hir::AnonConst { hir_id, .. }) = length |
| && let Some(span) = self.tcx.hir().opt_span(hir_id) |
| { |
| match self.tcx.sess.diagnostic().steal_diagnostic(span, StashKey::UnderscoreForArrayLengths) { |
| Some(mut err) => { |
| err.span_suggestion( |
| span, |
| "consider specifying the array length", |
| array_len, |
| Applicability::MaybeIncorrect, |
| ); |
| err.emit(); |
| } |
| None => () |
| } |
| } |
| } |
| |
| fn check_expr_const_block( |
| &self, |
| anon_const: &'tcx hir::AnonConst, |
| expected: Expectation<'tcx>, |
| _expr: &'tcx hir::Expr<'tcx>, |
| ) -> Ty<'tcx> { |
| let body = self.tcx.hir().body(anon_const.body); |
| |
| // Create a new function context. |
| let def_id = anon_const.def_id; |
| let fcx = FnCtxt::new(self, self.param_env.with_const(), def_id); |
| crate::GatherLocalsVisitor::new(&fcx).visit_body(body); |
| |
| let ty = fcx.check_expr_with_expectation(&body.value, expected); |
| fcx.require_type_is_sized(ty, body.value.span, traits::ConstSized); |
| fcx.write_ty(anon_const.hir_id, ty); |
| ty |
| } |
| |
| fn check_expr_repeat( |
| &self, |
| element: &'tcx hir::Expr<'tcx>, |
| count: &'tcx hir::ArrayLen, |
| expected: Expectation<'tcx>, |
| expr: &'tcx hir::Expr<'tcx>, |
| ) -> Ty<'tcx> { |
| let tcx = self.tcx; |
| let count = self.array_length_to_const(count); |
| if let Some(count) = count.try_eval_target_usize(tcx, self.param_env) { |
| self.suggest_array_len(expr, count); |
| } |
| |
| let uty = match expected { |
| ExpectHasType(uty) => match *uty.kind() { |
| ty::Array(ty, _) | ty::Slice(ty) => Some(ty), |
| _ => None, |
| }, |
| _ => None, |
| }; |
| |
| let (element_ty, t) = match uty { |
| Some(uty) => { |
| self.check_expr_coercable_to_type(&element, uty, None); |
| (uty, uty) |
| } |
| None => { |
| let ty = self.next_ty_var(TypeVariableOrigin { |
| kind: TypeVariableOriginKind::MiscVariable, |
| span: element.span, |
| }); |
| let element_ty = self.check_expr_has_type_or_error(&element, ty, |_| {}); |
| (element_ty, ty) |
| } |
| }; |
| |
| if let Err(guar) = element_ty.error_reported() { |
| return tcx.ty_error(guar); |
| } |
| |
| self.check_repeat_element_needs_copy_bound(element, count, element_ty); |
| |
| tcx.mk_array_with_const_len(t, count) |
| } |
| |
| fn check_repeat_element_needs_copy_bound( |
| &self, |
| element: &hir::Expr<'_>, |
| count: ty::Const<'tcx>, |
| element_ty: Ty<'tcx>, |
| ) { |
| let tcx = self.tcx; |
| // Actual constants as the repeat element get inserted repeatedly instead of getting copied via Copy. |
| match &element.kind { |
| hir::ExprKind::ConstBlock(..) => return, |
| hir::ExprKind::Path(qpath) => { |
| let res = self.typeck_results.borrow().qpath_res(qpath, element.hir_id); |
| if let Res::Def(DefKind::Const | DefKind::AssocConst | DefKind::AnonConst, _) = res |
| { |
| return; |
| } |
| } |
| _ => {} |
| } |
| // If someone calls a const fn, they can extract that call out into a separate constant (or a const |
| // block in the future), so we check that to tell them that in the diagnostic. Does not affect typeck. |
| let is_const_fn = match element.kind { |
| hir::ExprKind::Call(func, _args) => match *self.node_ty(func.hir_id).kind() { |
| ty::FnDef(def_id, _) => tcx.is_const_fn(def_id), |
| _ => false, |
| }, |
| _ => false, |
| }; |
| |
| // If the length is 0, we don't create any elements, so we don't copy any. If the length is 1, we |
| // don't copy that one element, we move it. Only check for Copy if the length is larger. |
| if count.try_eval_target_usize(tcx, self.param_env).map_or(true, |len| len > 1) { |
| let lang_item = self.tcx.require_lang_item(LangItem::Copy, None); |
| let code = traits::ObligationCauseCode::RepeatElementCopy { is_const_fn }; |
| self.require_type_meets(element_ty, element.span, code, lang_item); |
| } |
| } |
| |
| fn check_expr_tuple( |
| &self, |
| elts: &'tcx [hir::Expr<'tcx>], |
| expected: Expectation<'tcx>, |
| expr: &'tcx hir::Expr<'tcx>, |
| ) -> Ty<'tcx> { |
| let flds = expected.only_has_type(self).and_then(|ty| { |
| let ty = self.resolve_vars_with_obligations(ty); |
| match ty.kind() { |
| ty::Tuple(flds) => Some(&flds[..]), |
| _ => None, |
| } |
| }); |
| |
| let elt_ts_iter = elts.iter().enumerate().map(|(i, e)| match flds { |
| Some(fs) if i < fs.len() => { |
| let ety = fs[i]; |
| self.check_expr_coercable_to_type(&e, ety, None); |
| ety |
| } |
| _ => self.check_expr_with_expectation(&e, NoExpectation), |
| }); |
| let tuple = self.tcx.mk_tup_from_iter(elt_ts_iter); |
| if let Err(guar) = tuple.error_reported() { |
| self.tcx.ty_error(guar) |
| } else { |
| self.require_type_is_sized(tuple, expr.span, traits::TupleInitializerSized); |
| tuple |
| } |
| } |
| |
| fn check_expr_struct( |
| &self, |
| expr: &hir::Expr<'_>, |
| expected: Expectation<'tcx>, |
| qpath: &QPath<'_>, |
| fields: &'tcx [hir::ExprField<'tcx>], |
| base_expr: &'tcx Option<&'tcx hir::Expr<'tcx>>, |
| ) -> Ty<'tcx> { |
| // Find the relevant variant |
| let (variant, adt_ty) = match self.check_struct_path(qpath, expr.hir_id) { |
| Ok(data) => data, |
| Err(guar) => { |
| self.check_struct_fields_on_error(fields, base_expr); |
| return self.tcx.ty_error(guar); |
| } |
| }; |
| |
| // Prohibit struct expressions when non-exhaustive flag is set. |
| let adt = adt_ty.ty_adt_def().expect("`check_struct_path` returned non-ADT type"); |
| if !adt.did().is_local() && variant.is_field_list_non_exhaustive() { |
| self.tcx |
| .sess |
| .emit_err(StructExprNonExhaustive { span: expr.span, what: adt.variant_descr() }); |
| } |
| |
| self.check_expr_struct_fields( |
| adt_ty, |
| expected, |
| expr.hir_id, |
| qpath.span(), |
| variant, |
| fields, |
| base_expr, |
| expr.span, |
| ); |
| |
| self.require_type_is_sized(adt_ty, expr.span, traits::StructInitializerSized); |
| adt_ty |
| } |
| |
| fn check_expr_struct_fields( |
| &self, |
| adt_ty: Ty<'tcx>, |
| expected: Expectation<'tcx>, |
| expr_id: hir::HirId, |
| span: Span, |
| variant: &'tcx ty::VariantDef, |
| ast_fields: &'tcx [hir::ExprField<'tcx>], |
| base_expr: &'tcx Option<&'tcx hir::Expr<'tcx>>, |
| expr_span: Span, |
| ) { |
| let tcx = self.tcx; |
| |
| let expected_inputs = |
| self.expected_inputs_for_expected_output(span, expected, adt_ty, &[adt_ty]); |
| let adt_ty_hint = if let Some(expected_inputs) = expected_inputs { |
| expected_inputs.get(0).cloned().unwrap_or(adt_ty) |
| } else { |
| adt_ty |
| }; |
| // re-link the regions that EIfEO can erase. |
| self.demand_eqtype(span, adt_ty_hint, adt_ty); |
| |
| let ty::Adt(adt, substs) = adt_ty.kind() else { |
| span_bug!(span, "non-ADT passed to check_expr_struct_fields"); |
| }; |
| let adt_kind = adt.adt_kind(); |
| |
| let mut remaining_fields = variant |
| .fields |
| .iter() |
| .enumerate() |
| .map(|(i, field)| (field.ident(tcx).normalize_to_macros_2_0(), (i, field))) |
| .collect::<FxHashMap<_, _>>(); |
| |
| let mut seen_fields = FxHashMap::default(); |
| |
| let mut error_happened = false; |
| |
| // Type-check each field. |
| for (idx, field) in ast_fields.iter().enumerate() { |
| let ident = tcx.adjust_ident(field.ident, variant.def_id); |
| let field_type = if let Some((i, v_field)) = remaining_fields.remove(&ident) { |
| seen_fields.insert(ident, field.span); |
| self.write_field_index(field.hir_id, i); |
| |
| // We don't look at stability attributes on |
| // struct-like enums (yet...), but it's definitely not |
| // a bug to have constructed one. |
| if adt_kind != AdtKind::Enum { |
| tcx.check_stability(v_field.did, Some(expr_id), field.span, None); |
| } |
| |
| self.field_ty(field.span, v_field, substs) |
| } else { |
| error_happened = true; |
| let guar = if let Some(prev_span) = seen_fields.get(&ident) { |
| tcx.sess.emit_err(FieldMultiplySpecifiedInInitializer { |
| span: field.ident.span, |
| prev_span: *prev_span, |
| ident, |
| }) |
| } else { |
| self.report_unknown_field( |
| adt_ty, |
| variant, |
| field, |
| ast_fields, |
| adt.variant_descr(), |
| expr_span, |
| ) |
| }; |
| |
| tcx.ty_error(guar) |
| }; |
| |
| // Make sure to give a type to the field even if there's |
| // an error, so we can continue type-checking. |
| let ty = self.check_expr_with_hint(&field.expr, field_type); |
| let (_, diag) = |
| self.demand_coerce_diag(&field.expr, ty, field_type, None, AllowTwoPhase::No); |
| |
| if let Some(mut diag) = diag { |
| if idx == ast_fields.len() - 1 { |
| if remaining_fields.is_empty() { |
| self.suggest_fru_from_range(field, variant, substs, &mut diag); |
| diag.emit(); |
| } else { |
| diag.stash(field.span, StashKey::MaybeFruTypo); |
| } |
| } else { |
| diag.emit(); |
| } |
| } |
| } |
| |
| // Make sure the programmer specified correct number of fields. |
| if adt_kind == AdtKind::Union { |
| if ast_fields.len() != 1 { |
| struct_span_err!( |
| tcx.sess, |
| span, |
| E0784, |
| "union expressions should have exactly one field", |
| ) |
| .emit(); |
| } |
| } |
| |
| // If check_expr_struct_fields hit an error, do not attempt to populate |
| // the fields with the base_expr. This could cause us to hit errors later |
| // when certain fields are assumed to exist that in fact do not. |
| if error_happened { |
| if let Some(base_expr) = base_expr { |
| self.check_expr(base_expr); |
| } |
| return; |
| } |
| |
| if let Some(base_expr) = base_expr { |
| // FIXME: We are currently creating two branches here in order to maintain |
| // consistency. But they should be merged as much as possible. |
| let fru_tys = if self.tcx.features().type_changing_struct_update { |
| if adt.is_struct() { |
| // Make some fresh substitutions for our ADT type. |
| let fresh_substs = self.fresh_substs_for_item(base_expr.span, adt.did()); |
| // We do subtyping on the FRU fields first, so we can |
| // learn exactly what types we expect the base expr |
| // needs constrained to be compatible with the struct |
| // type we expect from the expectation value. |
| let fru_tys = variant |
| .fields |
| .iter() |
| .map(|f| { |
| let fru_ty = self.normalize( |
| expr_span, |
| self.field_ty(base_expr.span, f, fresh_substs), |
| ); |
| let ident = self.tcx.adjust_ident(f.ident(self.tcx), variant.def_id); |
| if let Some(_) = remaining_fields.remove(&ident) { |
| let target_ty = self.field_ty(base_expr.span, f, substs); |
| let cause = self.misc(base_expr.span); |
| match self.at(&cause, self.param_env).sup(target_ty, fru_ty) { |
| Ok(InferOk { obligations, value: () }) => { |
| self.register_predicates(obligations) |
| } |
| Err(_) => { |
| // This should never happen, since we're just subtyping the |
| // remaining_fields, but it's fine to emit this, I guess. |
| self.err_ctxt() |
| .report_mismatched_types( |
| &cause, |
| target_ty, |
| fru_ty, |
| FieldMisMatch(variant.name, ident.name), |
| ) |
| .emit(); |
| } |
| } |
| } |
| self.resolve_vars_if_possible(fru_ty) |
| }) |
| .collect(); |
| // The use of fresh substs that we have subtyped against |
| // our base ADT type's fields allows us to guide inference |
| // along so that, e.g. |
| // ``` |
| // MyStruct<'a, F1, F2, const C: usize> { |
| // f: F1, |
| // // Other fields that reference `'a`, `F2`, and `C` |
| // } |
| // |
| // let x = MyStruct { |
| // f: 1usize, |
| // ..other_struct |
| // }; |
| // ``` |
| // will have the `other_struct` expression constrained to |
| // `MyStruct<'a, _, F2, C>`, as opposed to just `_`... |
| // This is important to allow coercions to happen in |
| // `other_struct` itself. See `coerce-in-base-expr.rs`. |
| let fresh_base_ty = self.tcx.mk_adt(*adt, fresh_substs); |
| self.check_expr_has_type_or_error( |
| base_expr, |
| self.resolve_vars_if_possible(fresh_base_ty), |
| |_| {}, |
| ); |
| fru_tys |
| } else { |
| // Check the base_expr, regardless of a bad expected adt_ty, so we can get |
| // type errors on that expression, too. |
| self.check_expr(base_expr); |
| self.tcx |
| .sess |
| .emit_err(FunctionalRecordUpdateOnNonStruct { span: base_expr.span }); |
| return; |
| } |
| } else { |
| self.check_expr_has_type_or_error(base_expr, adt_ty, |_| { |
| let base_ty = self.typeck_results.borrow().expr_ty(*base_expr); |
| let same_adt = match (adt_ty.kind(), base_ty.kind()) { |
| (ty::Adt(adt, _), ty::Adt(base_adt, _)) if adt == base_adt => true, |
| _ => false, |
| }; |
| if self.tcx.sess.is_nightly_build() && same_adt { |
| feature_err( |
| &self.tcx.sess.parse_sess, |
| sym::type_changing_struct_update, |
| base_expr.span, |
| "type changing struct updating is experimental", |
| ) |
| .emit(); |
| } |
| }); |
| match adt_ty.kind() { |
| ty::Adt(adt, substs) if adt.is_struct() => variant |
| .fields |
| .iter() |
| .map(|f| self.normalize(expr_span, f.ty(self.tcx, substs))) |
| .collect(), |
| _ => { |
| self.tcx |
| .sess |
| .emit_err(FunctionalRecordUpdateOnNonStruct { span: base_expr.span }); |
| return; |
| } |
| } |
| }; |
| self.typeck_results.borrow_mut().fru_field_types_mut().insert(expr_id, fru_tys); |
| } else if adt_kind != AdtKind::Union && !remaining_fields.is_empty() { |
| debug!(?remaining_fields); |
| let private_fields: Vec<&ty::FieldDef> = variant |
| .fields |
| .iter() |
| .filter(|field| !field.vis.is_accessible_from(tcx.parent_module(expr_id), tcx)) |
| .collect(); |
| |
| if !private_fields.is_empty() { |
| self.report_private_fields(adt_ty, span, private_fields, ast_fields); |
| } else { |
| self.report_missing_fields( |
| adt_ty, |
| span, |
| remaining_fields, |
| variant, |
| ast_fields, |
| substs, |
| ); |
| } |
| } |
| } |
| |
| fn check_struct_fields_on_error( |
| &self, |
| fields: &'tcx [hir::ExprField<'tcx>], |
| base_expr: &'tcx Option<&'tcx hir::Expr<'tcx>>, |
| ) { |
| for field in fields { |
| self.check_expr(&field.expr); |
| } |
| if let Some(base) = *base_expr { |
| self.check_expr(&base); |
| } |
| } |
| |
| /// Report an error for a struct field expression when there are fields which aren't provided. |
| /// |
| /// ```text |
| /// error: missing field `you_can_use_this_field` in initializer of `foo::Foo` |
| /// --> src/main.rs:8:5 |
| /// | |
| /// 8 | foo::Foo {}; |
| /// | ^^^^^^^^ missing `you_can_use_this_field` |
| /// |
| /// error: aborting due to previous error |
| /// ``` |
| fn report_missing_fields( |
| &self, |
| adt_ty: Ty<'tcx>, |
| span: Span, |
| remaining_fields: FxHashMap<Ident, (usize, &ty::FieldDef)>, |
| variant: &'tcx ty::VariantDef, |
| ast_fields: &'tcx [hir::ExprField<'tcx>], |
| substs: SubstsRef<'tcx>, |
| ) { |
| let len = remaining_fields.len(); |
| |
| let mut displayable_field_names: Vec<&str> = |
| remaining_fields.keys().map(|ident| ident.as_str()).collect(); |
| // sorting &str primitives here, sort_unstable is ok |
| displayable_field_names.sort_unstable(); |
| |
| let mut truncated_fields_error = String::new(); |
| let remaining_fields_names = match &displayable_field_names[..] { |
| [field1] => format!("`{}`", field1), |
| [field1, field2] => format!("`{field1}` and `{field2}`"), |
| [field1, field2, field3] => format!("`{field1}`, `{field2}` and `{field3}`"), |
| _ => { |
| truncated_fields_error = |
| format!(" and {} other field{}", len - 3, pluralize!(len - 3)); |
| displayable_field_names |
| .iter() |
| .take(3) |
| .map(|n| format!("`{n}`")) |
| .collect::<Vec<_>>() |
| .join(", ") |
| } |
| }; |
| |
| let mut err = struct_span_err!( |
| self.tcx.sess, |
| span, |
| E0063, |
| "missing field{} {}{} in initializer of `{}`", |
| pluralize!(len), |
| remaining_fields_names, |
| truncated_fields_error, |
| adt_ty |
| ); |
| err.span_label(span, format!("missing {remaining_fields_names}{truncated_fields_error}")); |
| |
| if let Some(last) = ast_fields.last() { |
| self.suggest_fru_from_range(last, variant, substs, &mut err); |
| } |
| |
| err.emit(); |
| } |
| |
| /// If the last field is a range literal, but it isn't supposed to be, then they probably |
| /// meant to use functional update syntax. |
| fn suggest_fru_from_range( |
| &self, |
| last_expr_field: &hir::ExprField<'tcx>, |
| variant: &ty::VariantDef, |
| substs: SubstsRef<'tcx>, |
| err: &mut Diagnostic, |
| ) { |
| // I don't use 'is_range_literal' because only double-sided, half-open ranges count. |
| if let ExprKind::Struct( |
| QPath::LangItem(LangItem::Range, ..), |
| [range_start, range_end], |
| _, |
| ) = last_expr_field.expr.kind |
| && let variant_field = |
| variant.fields.iter().find(|field| field.ident(self.tcx) == last_expr_field.ident) |
| && let range_def_id = self.tcx.lang_items().range_struct() |
| && variant_field |
| .and_then(|field| field.ty(self.tcx, substs).ty_adt_def()) |
| .map(|adt| adt.did()) |
| != range_def_id |
| { |
| // Suppress any range expr type mismatches |
| if let Some(mut diag) = self |
| .tcx |
| .sess |
| .diagnostic() |
| .steal_diagnostic(last_expr_field.span, StashKey::MaybeFruTypo) |
| { |
| diag.delay_as_bug(); |
| } |
| |
| // Use a (somewhat arbitrary) filtering heuristic to avoid printing |
| // expressions that are either too long, or have control character |
| //such as newlines in them. |
| let expr = self |
| .tcx |
| .sess |
| .source_map() |
| .span_to_snippet(range_end.expr.span) |
| .ok() |
| .filter(|s| s.len() < 25 && !s.contains(|c: char| c.is_control())); |
| |
| let fru_span = self |
| .tcx |
| .sess |
| .source_map() |
| .span_extend_while(range_start.span, |c| c.is_whitespace()) |
| .unwrap_or(range_start.span).shrink_to_hi().to(range_end.span); |
| |
| err.subdiagnostic(TypeMismatchFruTypo { |
| expr_span: range_start.span, |
| fru_span, |
| expr, |
| }); |
| } |
| } |
| |
| /// Report an error for a struct field expression when there are invisible fields. |
| /// |
| /// ```text |
| /// error: cannot construct `Foo` with struct literal syntax due to private fields |
| /// --> src/main.rs:8:5 |
| /// | |
| /// 8 | foo::Foo {}; |
| /// | ^^^^^^^^ |
| /// |
| /// error: aborting due to previous error |
| /// ``` |
| fn report_private_fields( |
| &self, |
| adt_ty: Ty<'tcx>, |
| span: Span, |
| private_fields: Vec<&ty::FieldDef>, |
| used_fields: &'tcx [hir::ExprField<'tcx>], |
| ) { |
| let mut err = self.tcx.sess.struct_span_err( |
| span, |
| &format!( |
| "cannot construct `{adt_ty}` with struct literal syntax due to private fields", |
| ), |
| ); |
| let (used_private_fields, remaining_private_fields): ( |
| Vec<(Symbol, Span, bool)>, |
| Vec<(Symbol, Span, bool)>, |
| ) = private_fields |
| .iter() |
| .map(|field| { |
| match used_fields.iter().find(|used_field| field.name == used_field.ident.name) { |
| Some(used_field) => (field.name, used_field.span, true), |
| None => (field.name, self.tcx.def_span(field.did), false), |
| } |
| }) |
| .partition(|field| field.2); |
| err.span_labels(used_private_fields.iter().map(|(_, span, _)| *span), "private field"); |
| if !remaining_private_fields.is_empty() { |
| let remaining_private_fields_len = remaining_private_fields.len(); |
| let names = match &remaining_private_fields |
| .iter() |
| .map(|(name, _, _)| name) |
| .collect::<Vec<_>>()[..] |
| { |
| _ if remaining_private_fields_len > 6 => String::new(), |
| [name] => format!("`{name}` "), |
| [names @ .., last] => { |
| let names = names.iter().map(|name| format!("`{name}`")).collect::<Vec<_>>(); |
| format!("{} and `{last}` ", names.join(", ")) |
| } |
| [] => unreachable!(), |
| }; |
| err.note(format!( |
| "... and other private field{s} {names}that {were} not provided", |
| s = pluralize!(remaining_private_fields_len), |
| were = pluralize!("was", remaining_private_fields_len), |
| )); |
| } |
| err.emit(); |
| } |
| |
| fn report_unknown_field( |
| &self, |
| ty: Ty<'tcx>, |
| variant: &'tcx ty::VariantDef, |
| field: &hir::ExprField<'_>, |
| skip_fields: &[hir::ExprField<'_>], |
| kind_name: &str, |
| expr_span: Span, |
| ) -> ErrorGuaranteed { |
| if variant.is_recovered() { |
| let guar = self |
| .tcx |
| .sess |
| .delay_span_bug(expr_span, "parser recovered but no error was emitted"); |
| self.set_tainted_by_errors(guar); |
| return guar; |
| } |
| let mut err = self.err_ctxt().type_error_struct_with_diag( |
| field.ident.span, |
| |actual| match ty.kind() { |
| ty::Adt(adt, ..) if adt.is_enum() => struct_span_err!( |
| self.tcx.sess, |
| field.ident.span, |
| E0559, |
| "{} `{}::{}` has no field named `{}`", |
| kind_name, |
| actual, |
| variant.name, |
| field.ident |
| ), |
| _ => struct_span_err!( |
| self.tcx.sess, |
| field.ident.span, |
| E0560, |
| "{} `{}` has no field named `{}`", |
| kind_name, |
| actual, |
| field.ident |
| ), |
| }, |
| ty, |
| ); |
| |
| let variant_ident_span = self.tcx.def_ident_span(variant.def_id).unwrap(); |
| match variant.ctor_kind() { |
| Some(CtorKind::Fn) => match ty.kind() { |
| ty::Adt(adt, ..) if adt.is_enum() => { |
| err.span_label( |
| variant_ident_span, |
| format!( |
| "`{adt}::{variant}` defined here", |
| adt = ty, |
| variant = variant.name, |
| ), |
| ); |
| err.span_label(field.ident.span, "field does not exist"); |
| err.span_suggestion_verbose( |
| expr_span, |
| &format!( |
| "`{adt}::{variant}` is a tuple {kind_name}, use the appropriate syntax", |
| adt = ty, |
| variant = variant.name, |
| ), |
| format!( |
| "{adt}::{variant}(/* fields */)", |
| adt = ty, |
| variant = variant.name, |
| ), |
| Applicability::HasPlaceholders, |
| ); |
| } |
| _ => { |
| err.span_label(variant_ident_span, format!("`{adt}` defined here", adt = ty)); |
| err.span_label(field.ident.span, "field does not exist"); |
| err.span_suggestion_verbose( |
| expr_span, |
| &format!( |
| "`{adt}` is a tuple {kind_name}, use the appropriate syntax", |
| adt = ty, |
| kind_name = kind_name, |
| ), |
| format!("{adt}(/* fields */)", adt = ty), |
| Applicability::HasPlaceholders, |
| ); |
| } |
| }, |
| _ => { |
| // prevent all specified fields from being suggested |
| let skip_fields = skip_fields.iter().map(|x| x.ident.name); |
| if let Some(field_name) = self.suggest_field_name( |
| variant, |
| field.ident.name, |
| skip_fields.collect(), |
| expr_span, |
| ) { |
| err.span_suggestion( |
| field.ident.span, |
| "a field with a similar name exists", |
| field_name, |
| Applicability::MaybeIncorrect, |
| ); |
| } else { |
| match ty.kind() { |
| ty::Adt(adt, ..) => { |
| if adt.is_enum() { |
| err.span_label( |
| field.ident.span, |
| format!("`{}::{}` does not have this field", ty, variant.name), |
| ); |
| } else { |
| err.span_label( |
| field.ident.span, |
| format!("`{ty}` does not have this field"), |
| ); |
| } |
| let available_field_names = |
| self.available_field_names(variant, expr_span); |
| if !available_field_names.is_empty() { |
| err.note(&format!( |
| "available fields are: {}", |
| self.name_series_display(available_field_names) |
| )); |
| } |
| } |
| _ => bug!("non-ADT passed to report_unknown_field"), |
| } |
| }; |
| } |
| } |
| err.emit() |
| } |
| |
| // Return a hint about the closest match in field names |
| fn suggest_field_name( |
| &self, |
| variant: &'tcx ty::VariantDef, |
| field: Symbol, |
| skip: Vec<Symbol>, |
| // The span where stability will be checked |
| span: Span, |
| ) -> Option<Symbol> { |
| let names = variant |
| .fields |
| .iter() |
| .filter_map(|field| { |
| // ignore already set fields and private fields from non-local crates |
| // and unstable fields. |
| if skip.iter().any(|&x| x == field.name) |
| || (!variant.def_id.is_local() && !field.vis.is_public()) |
| || matches!( |
| self.tcx.eval_stability(field.did, None, span, None), |
| stability::EvalResult::Deny { .. } |
| ) |
| { |
| None |
| } else { |
| Some(field.name) |
| } |
| }) |
| .collect::<Vec<Symbol>>(); |
| |
| find_best_match_for_name(&names, field, None) |
| } |
| |
| fn available_field_names( |
| &self, |
| variant: &'tcx ty::VariantDef, |
| access_span: Span, |
| ) -> Vec<Symbol> { |
| let body_owner_hir_id = self.tcx.hir().local_def_id_to_hir_id(self.body_id); |
| variant |
| .fields |
| .iter() |
| .filter(|field| { |
| let def_scope = self |
| .tcx |
| .adjust_ident_and_get_scope( |
| field.ident(self.tcx), |
| variant.def_id, |
| body_owner_hir_id, |
| ) |
| .1; |
| field.vis.is_accessible_from(def_scope, self.tcx) |
| && !matches!( |
| self.tcx.eval_stability(field.did, None, access_span, None), |
| stability::EvalResult::Deny { .. } |
| ) |
| }) |
| .filter(|field| !self.tcx.is_doc_hidden(field.did)) |
| .map(|field| field.name) |
| .collect() |
| } |
| |
| fn name_series_display(&self, names: Vec<Symbol>) -> String { |
| // dynamic limit, to never omit just one field |
| let limit = if names.len() == 6 { 6 } else { 5 }; |
| let mut display = |
| names.iter().take(limit).map(|n| format!("`{}`", n)).collect::<Vec<_>>().join(", "); |
| if names.len() > limit { |
| display = format!("{} ... and {} others", display, names.len() - limit); |
| } |
| display |
| } |
| |
| // Check field access expressions |
| fn check_field( |
| &self, |
| expr: &'tcx hir::Expr<'tcx>, |
| base: &'tcx hir::Expr<'tcx>, |
| field: Ident, |
| expected: Expectation<'tcx>, |
| ) -> Ty<'tcx> { |
| debug!("check_field(expr: {:?}, base: {:?}, field: {:?})", expr, base, field); |
| let base_ty = self.check_expr(base); |
| let base_ty = self.structurally_resolved_type(base.span, base_ty); |
| let mut private_candidate = None; |
| let mut autoderef = self.autoderef(expr.span, base_ty); |
| while let Some((deref_base_ty, _)) = autoderef.next() { |
| debug!("deref_base_ty: {:?}", deref_base_ty); |
| match deref_base_ty.kind() { |
| ty::Adt(base_def, substs) if !base_def.is_enum() => { |
| debug!("struct named {:?}", deref_base_ty); |
| let body_hir_id = self.tcx.hir().local_def_id_to_hir_id(self.body_id); |
| let (ident, def_scope) = |
| self.tcx.adjust_ident_and_get_scope(field, base_def.did(), body_hir_id); |
| let fields = &base_def.non_enum_variant().fields; |
| if let Some(index) = fields |
| .iter() |
| .position(|f| f.ident(self.tcx).normalize_to_macros_2_0() == ident) |
| { |
| let field = &fields[index]; |
| let field_ty = self.field_ty(expr.span, field, substs); |
| // Save the index of all fields regardless of their visibility in case |
| // of error recovery. |
| self.write_field_index(expr.hir_id, index); |
| let adjustments = self.adjust_steps(&autoderef); |
| if field.vis.is_accessible_from(def_scope, self.tcx) { |
| self.apply_adjustments(base, adjustments); |
| self.register_predicates(autoderef.into_obligations()); |
| |
| self.tcx.check_stability(field.did, Some(expr.hir_id), expr.span, None); |
| return field_ty; |
| } |
| private_candidate = Some((adjustments, base_def.did())); |
| } |
| } |
| ty::Tuple(tys) => { |
| let fstr = field.as_str(); |
| if let Ok(index) = fstr.parse::<usize>() { |
| if fstr == index.to_string() { |
| if let Some(&field_ty) = tys.get(index) { |
| let adjustments = self.adjust_steps(&autoderef); |
| self.apply_adjustments(base, adjustments); |
| self.register_predicates(autoderef.into_obligations()); |
| |
| self.write_field_index(expr.hir_id, index); |
| return field_ty; |
| } |
| } |
| } |
| } |
| _ => {} |
| } |
| } |
| self.structurally_resolved_type(autoderef.span(), autoderef.final_ty(false)); |
| |
| if let Some((adjustments, did)) = private_candidate { |
| // (#90483) apply adjustments to avoid ExprUseVisitor from |
| // creating erroneous projection. |
| self.apply_adjustments(base, adjustments); |
| let guar = self.ban_private_field_access( |
| expr, |
| base_ty, |
| field, |
| did, |
| expected.only_has_type(self), |
| ); |
| return self.tcx().ty_error(guar); |
| } |
| |
| let guar = if field.name == kw::Empty { |
| self.tcx.sess.delay_span_bug(field.span, "field name with no name") |
| } else if self.method_exists( |
| field, |
| base_ty, |
| expr.hir_id, |
| true, |
| expected.only_has_type(self), |
| ) { |
| self.ban_take_value_of_method(expr, base_ty, field) |
| } else if !base_ty.is_primitive_ty() { |
| self.ban_nonexisting_field(field, base, expr, base_ty) |
| } else { |
| let field_name = field.to_string(); |
| let mut err = type_error_struct!( |
| self.tcx().sess, |
| field.span, |
| base_ty, |
| E0610, |
| "`{base_ty}` is a primitive type and therefore doesn't have fields", |
| ); |
| let is_valid_suffix = |field: &str| { |
| if field == "f32" || field == "f64" { |
| return true; |
| } |
| let mut chars = field.chars().peekable(); |
| match chars.peek() { |
| Some('e') | Some('E') => { |
| chars.next(); |
| if let Some(c) = chars.peek() |
| && !c.is_numeric() && *c != '-' && *c != '+' |
| { |
| return false; |
| } |
| while let Some(c) = chars.peek() { |
| if !c.is_numeric() { |
| break; |
| } |
| chars.next(); |
| } |
| } |
| _ => (), |
| } |
| let suffix = chars.collect::<String>(); |
| suffix.is_empty() || suffix == "f32" || suffix == "f64" |
| }; |
| let maybe_partial_suffix = |field: &str| -> Option<&str> { |
| let first_chars = ['f', 'l']; |
| if field.len() >= 1 |
| && field.to_lowercase().starts_with(first_chars) |
| && field[1..].chars().all(|c| c.is_ascii_digit()) |
| { |
| if field.to_lowercase().starts_with(['f']) { Some("f32") } else { Some("f64") } |
| } else { |
| None |
| } |
| }; |
| if let ty::Infer(ty::IntVar(_)) = base_ty.kind() |
| && let ExprKind::Lit(Spanned { |
| node: ast::LitKind::Int(_, ast::LitIntType::Unsuffixed), |
| .. |
| }) = base.kind |
| && !base.span.from_expansion() |
| { |
| if is_valid_suffix(&field_name) { |
| err.span_suggestion_verbose( |
| field.span.shrink_to_lo(), |
| "if intended to be a floating point literal, consider adding a `0` after the period", |
| '0', |
| Applicability::MaybeIncorrect, |
| ); |
| } else if let Some(correct_suffix) = maybe_partial_suffix(&field_name) { |
| err.span_suggestion_verbose( |
| field.span, |
| format!("if intended to be a floating point literal, consider adding a `0` after the period and a `{correct_suffix}` suffix"), |
| format!("0{correct_suffix}"), |
| Applicability::MaybeIncorrect, |
| ); |
| } |
| } |
| err.emit() |
| }; |
| |
| self.tcx().ty_error(guar) |
| } |
| |
| fn suggest_await_on_field_access( |
| &self, |
| err: &mut Diagnostic, |
| field_ident: Ident, |
| base: &'tcx hir::Expr<'tcx>, |
| ty: Ty<'tcx>, |
| ) { |
| let Some(output_ty) = self.get_impl_future_output_ty(ty) else { return; }; |
| let mut add_label = true; |
| if let ty::Adt(def, _) = output_ty.kind() { |
| // no field access on enum type |
| if !def.is_enum() { |
| if def |
| .non_enum_variant() |
| .fields |
| .iter() |
| .any(|field| field.ident(self.tcx) == field_ident) |
| { |
| add_label = false; |
| err.span_label( |
| field_ident.span, |
| "field not available in `impl Future`, but it is available in its `Output`", |
| ); |
| err.span_suggestion_verbose( |
| base.span.shrink_to_hi(), |
| "consider `await`ing on the `Future` and access the field of its `Output`", |
| ".await", |
| Applicability::MaybeIncorrect, |
| ); |
| } |
| } |
| } |
| if add_label { |
| err.span_label(field_ident.span, &format!("field not found in `{ty}`")); |
| } |
| } |
| |
| fn ban_nonexisting_field( |
| &self, |
| ident: Ident, |
| base: &'tcx hir::Expr<'tcx>, |
| expr: &'tcx hir::Expr<'tcx>, |
| base_ty: Ty<'tcx>, |
| ) -> ErrorGuaranteed { |
| debug!( |
| "ban_nonexisting_field: field={:?}, base={:?}, expr={:?}, base_ty={:?}", |
| ident, base, expr, base_ty |
| ); |
| let mut err = self.no_such_field_err(ident, base_ty, base.hir_id); |
| |
| match *base_ty.peel_refs().kind() { |
| ty::Array(_, len) => { |
| self.maybe_suggest_array_indexing(&mut err, expr, base, ident, len); |
| } |
| ty::RawPtr(..) => { |
| self.suggest_first_deref_field(&mut err, expr, base, ident); |
| } |
| ty::Adt(def, _) if !def.is_enum() => { |
| self.suggest_fields_on_recordish(&mut err, def, ident, expr.span); |
| } |
| ty::Param(param_ty) => { |
| self.point_at_param_definition(&mut err, param_ty); |
| } |
| ty::Alias(ty::Opaque, _) => { |
| self.suggest_await_on_field_access(&mut err, ident, base, base_ty.peel_refs()); |
| } |
| _ => {} |
| } |
| |
| self.suggest_fn_call(&mut err, base, base_ty, |output_ty| { |
| if let ty::Adt(def, _) = output_ty.kind() && !def.is_enum() { |
| def.non_enum_variant().fields.iter().any(|field| { |
| field.ident(self.tcx) == ident |
| && field.vis.is_accessible_from(expr.hir_id.owner.def_id, self.tcx) |
| }) |
| } else if let ty::Tuple(tys) = output_ty.kind() |
| && let Ok(idx) = ident.as_str().parse::<usize>() |
| { |
| idx < tys.len() |
| } else { |
| false |
| } |
| }); |
| |
| if ident.name == kw::Await { |
| // We know by construction that `<expr>.await` is either on Rust 2015 |
| // or results in `ExprKind::Await`. Suggest switching the edition to 2018. |
| err.note("to `.await` a `Future`, switch to Rust 2018 or later"); |
| HelpUseLatestEdition::new().add_to_diagnostic(&mut err); |
| } |
| |
| err.emit() |
| } |
| |
| fn ban_private_field_access( |
| &self, |
| expr: &hir::Expr<'tcx>, |
| expr_t: Ty<'tcx>, |
| field: Ident, |
| base_did: DefId, |
| return_ty: Option<Ty<'tcx>>, |
| ) -> ErrorGuaranteed { |
| let struct_path = self.tcx().def_path_str(base_did); |
| let kind_name = self.tcx().def_descr(base_did); |
| let mut err = struct_span_err!( |
| self.tcx().sess, |
| field.span, |
| E0616, |
| "field `{field}` of {kind_name} `{struct_path}` is private", |
| ); |
| err.span_label(field.span, "private field"); |
| // Also check if an accessible method exists, which is often what is meant. |
| if self.method_exists(field, expr_t, expr.hir_id, false, return_ty) |
| && !self.expr_in_place(expr.hir_id) |
| { |
| self.suggest_method_call( |
| &mut err, |
| &format!("a method `{field}` also exists, call it with parentheses"), |
| field, |
| expr_t, |
| expr, |
| None, |
| ); |
| } |
| err.emit() |
| } |
| |
| fn ban_take_value_of_method( |
| &self, |
| expr: &hir::Expr<'tcx>, |
| expr_t: Ty<'tcx>, |
| field: Ident, |
| ) -> ErrorGuaranteed { |
| let mut err = type_error_struct!( |
| self.tcx().sess, |
| field.span, |
| expr_t, |
| E0615, |
| "attempted to take value of method `{field}` on type `{expr_t}`", |
| ); |
| err.span_label(field.span, "method, not a field"); |
| let expr_is_call = |
| if let hir::Node::Expr(hir::Expr { kind: ExprKind::Call(callee, _args), .. }) = |
| self.tcx.hir().get_parent(expr.hir_id) |
| { |
| expr.hir_id == callee.hir_id |
| } else { |
| false |
| }; |
| let expr_snippet = |
| self.tcx.sess.source_map().span_to_snippet(expr.span).unwrap_or_default(); |
| let is_wrapped = expr_snippet.starts_with('(') && expr_snippet.ends_with(')'); |
| let after_open = expr.span.lo() + rustc_span::BytePos(1); |
| let before_close = expr.span.hi() - rustc_span::BytePos(1); |
| |
| if expr_is_call && is_wrapped { |
| err.multipart_suggestion( |
| "remove wrapping parentheses to call the method", |
| vec![ |
| (expr.span.with_hi(after_open), String::new()), |
| (expr.span.with_lo(before_close), String::new()), |
| ], |
| Applicability::MachineApplicable, |
| ); |
| } else if !self.expr_in_place(expr.hir_id) { |
| // Suggest call parentheses inside the wrapping parentheses |
| let span = if is_wrapped { |
| expr.span.with_lo(after_open).with_hi(before_close) |
| } else { |
| expr.span |
| }; |
| self.suggest_method_call( |
| &mut err, |
| "use parentheses to call the method", |
| field, |
| expr_t, |
| expr, |
| Some(span), |
| ); |
| } else if let ty::RawPtr(ty_and_mut) = expr_t.kind() |
| && let ty::Adt(adt_def, _) = ty_and_mut.ty.kind() |
| && let ExprKind::Field(base_expr, _) = expr.kind |
| && adt_def.variants().len() == 1 |
| && adt_def |
| .variants() |
| .iter() |
| .next() |
| .unwrap() |
| .fields |
| .iter() |
| .any(|f| f.ident(self.tcx) == field) |
| { |
| err.multipart_suggestion( |
| "to access the field, dereference first", |
| vec![ |
| (base_expr.span.shrink_to_lo(), "(*".to_string()), |
| (base_expr.span.shrink_to_hi(), ")".to_string()), |
| ], |
| Applicability::MaybeIncorrect, |
| ); |
| } else { |
| err.help("methods are immutable and cannot be assigned to"); |
| } |
| |
| err.emit() |
| } |
| |
| fn point_at_param_definition(&self, err: &mut Diagnostic, param: ty::ParamTy) { |
| let generics = self.tcx.generics_of(self.body_id); |
| let generic_param = generics.type_param(¶m, self.tcx); |
| if let ty::GenericParamDefKind::Type { synthetic: true, .. } = generic_param.kind { |
| return; |
| } |
| let param_def_id = generic_param.def_id; |
| let param_hir_id = match param_def_id.as_local() { |
| Some(x) => self.tcx.hir().local_def_id_to_hir_id(x), |
| None => return, |
| }; |
| let param_span = self.tcx.hir().span(param_hir_id); |
| let param_name = self.tcx.hir().ty_param_name(param_def_id.expect_local()); |
| |
| err.span_label(param_span, &format!("type parameter '{param_name}' declared here")); |
| } |
| |
| fn suggest_fields_on_recordish( |
| &self, |
| err: &mut Diagnostic, |
| def: ty::AdtDef<'tcx>, |
| field: Ident, |
| access_span: Span, |
| ) { |
| if let Some(suggested_field_name) = |
| self.suggest_field_name(def.non_enum_variant(), field.name, vec![], access_span) |
| { |
| err.span_suggestion( |
| field.span, |
| "a field with a similar name exists", |
| suggested_field_name, |
| Applicability::MaybeIncorrect, |
| ); |
| } else { |
| err.span_label(field.span, "unknown field"); |
| let struct_variant_def = def.non_enum_variant(); |
| let field_names = self.available_field_names(struct_variant_def, access_span); |
| if !field_names.is_empty() { |
| err.note(&format!( |
| "available fields are: {}", |
| self.name_series_display(field_names), |
| )); |
| } |
| } |
| } |
| |
| fn maybe_suggest_array_indexing( |
| &self, |
| err: &mut Diagnostic, |
| expr: &hir::Expr<'_>, |
| base: &hir::Expr<'_>, |
| field: Ident, |
| len: ty::Const<'tcx>, |
| ) { |
| if let (Some(len), Ok(user_index)) = |
| (len.try_eval_target_usize(self.tcx, self.param_env), field.as_str().parse::<u64>()) |
| && let Ok(base) = self.tcx.sess.source_map().span_to_snippet(base.span) |
| { |
| let help = "instead of using tuple indexing, use array indexing"; |
| let suggestion = format!("{base}[{field}]"); |
| let applicability = if len < user_index { |
| Applicability::MachineApplicable |
| } else { |
| Applicability::MaybeIncorrect |
| }; |
| err.span_suggestion(expr.span, help, suggestion, applicability); |
| } |
| } |
| |
| fn suggest_first_deref_field( |
| &self, |
| err: &mut Diagnostic, |
| expr: &hir::Expr<'_>, |
| base: &hir::Expr<'_>, |
| field: Ident, |
| ) { |
| if let Ok(base) = self.tcx.sess.source_map().span_to_snippet(base.span) { |
| let msg = format!("`{base}` is a raw pointer; try dereferencing it"); |
| let suggestion = format!("(*{base}).{field}"); |
| err.span_suggestion(expr.span, &msg, suggestion, Applicability::MaybeIncorrect); |
| } |
| } |
| |
| fn no_such_field_err( |
| &self, |
| field: Ident, |
| expr_t: Ty<'tcx>, |
| id: HirId, |
| ) -> DiagnosticBuilder<'_, ErrorGuaranteed> { |
| let span = field.span; |
| debug!("no_such_field_err(span: {:?}, field: {:?}, expr_t: {:?})", span, field, expr_t); |
| |
| let mut err = type_error_struct!( |
| self.tcx().sess, |
| field.span, |
| expr_t, |
| E0609, |
| "no field `{field}` on type `{expr_t}`", |
| ); |
| |
| // try to add a suggestion in case the field is a nested field of a field of the Adt |
| let mod_id = self.tcx.parent_module(id).to_def_id(); |
| if let Some((fields, substs)) = |
| self.get_field_candidates_considering_privacy(span, expr_t, mod_id) |
| { |
| let candidate_fields: Vec<_> = fields |
| .filter_map(|candidate_field| { |
| self.check_for_nested_field_satisfying( |
| span, |
| &|candidate_field, _| candidate_field.ident(self.tcx()) == field, |
| candidate_field, |
| substs, |
| vec![], |
| mod_id, |
| ) |
| }) |
| .map(|mut field_path| { |
| field_path.pop(); |
| field_path |
| .iter() |
| .map(|id| id.name.to_ident_string()) |
| .collect::<Vec<String>>() |
| .join(".") |
| }) |
| .collect::<Vec<_>>(); |
| |
| let len = candidate_fields.len(); |
| if len > 0 { |
| err.span_suggestions( |
| field.span.shrink_to_lo(), |
| format!( |
| "{} of the expressions' fields {} a field of the same name", |
| if len > 1 { "some" } else { "one" }, |
| if len > 1 { "have" } else { "has" }, |
| ), |
| candidate_fields.iter().map(|path| format!("{path}.")), |
| Applicability::MaybeIncorrect, |
| ); |
| } |
| } |
| err |
| } |
| |
| pub(crate) fn get_field_candidates_considering_privacy( |
| &self, |
| span: Span, |
| base_ty: Ty<'tcx>, |
| mod_id: DefId, |
| ) -> Option<(impl Iterator<Item = &'tcx ty::FieldDef> + 'tcx, SubstsRef<'tcx>)> { |
| debug!("get_field_candidates(span: {:?}, base_t: {:?}", span, base_ty); |
| |
| for (base_t, _) in self.autoderef(span, base_ty) { |
| match base_t.kind() { |
| ty::Adt(base_def, substs) if !base_def.is_enum() => { |
| let tcx = self.tcx; |
| let fields = &base_def.non_enum_variant().fields; |
| // Some struct, e.g. some that impl `Deref`, have all private fields |
| // because you're expected to deref them to access the _real_ fields. |
| // This, for example, will help us suggest accessing a field through a `Box<T>`. |
| if fields.iter().all(|field| !field.vis.is_accessible_from(mod_id, tcx)) { |
| continue; |
| } |
| return Some(( |
| fields |
| .iter() |
| .filter(move |field| field.vis.is_accessible_from(mod_id, tcx)) |
| // For compile-time reasons put a limit on number of fields we search |
| .take(100), |
| substs, |
| )); |
| } |
| _ => {} |
| } |
| } |
| None |
| } |
| |
| /// This method is called after we have encountered a missing field error to recursively |
| /// search for the field |
| pub(crate) fn check_for_nested_field_satisfying( |
| &self, |
| span: Span, |
| matches: &impl Fn(&ty::FieldDef, Ty<'tcx>) -> bool, |
| candidate_field: &ty::FieldDef, |
| subst: SubstsRef<'tcx>, |
| mut field_path: Vec<Ident>, |
| mod_id: DefId, |
| ) -> Option<Vec<Ident>> { |
| debug!( |
| "check_for_nested_field_satisfying(span: {:?}, candidate_field: {:?}, field_path: {:?}", |
| span, candidate_field, field_path |
| ); |
| |
| if field_path.len() > 3 { |
| // For compile-time reasons and to avoid infinite recursion we only check for fields |
| // up to a depth of three |
| None |
| } else { |
| field_path.push(candidate_field.ident(self.tcx).normalize_to_macros_2_0()); |
| let field_ty = candidate_field.ty(self.tcx, subst); |
| if matches(candidate_field, field_ty) { |
| return Some(field_path); |
| } else if let Some((nested_fields, subst)) = |
| self.get_field_candidates_considering_privacy(span, field_ty, mod_id) |
| { |
| // recursively search fields of `candidate_field` if it's a ty::Adt |
| for field in nested_fields { |
| if let Some(field_path) = self.check_for_nested_field_satisfying( |
| span, |
| matches, |
| field, |
| subst, |
| field_path.clone(), |
| mod_id, |
| ) { |
| return Some(field_path); |
| } |
| } |
| } |
| None |
| } |
| } |
| |
| fn check_expr_index( |
| &self, |
| base: &'tcx hir::Expr<'tcx>, |
| idx: &'tcx hir::Expr<'tcx>, |
| expr: &'tcx hir::Expr<'tcx>, |
| ) -> Ty<'tcx> { |
| let base_t = self.check_expr(&base); |
| let idx_t = self.check_expr(&idx); |
| |
| if base_t.references_error() { |
| base_t |
| } else if idx_t.references_error() { |
| idx_t |
| } else { |
| let base_t = self.structurally_resolved_type(base.span, base_t); |
| match self.lookup_indexing(expr, base, base_t, idx, idx_t) { |
| Some((index_ty, element_ty)) => { |
| // two-phase not needed because index_ty is never mutable |
| self.demand_coerce(idx, idx_t, index_ty, None, AllowTwoPhase::No); |
| self.select_obligations_where_possible(|errors| { |
| self.point_at_index_if_possible(errors, idx.span) |
| }); |
| element_ty |
| } |
| None => { |
| let mut err = type_error_struct!( |
| self.tcx.sess, |
| expr.span, |
| base_t, |
| E0608, |
| "cannot index into a value of type `{base_t}`", |
| ); |
| // Try to give some advice about indexing tuples. |
| if let ty::Tuple(..) = base_t.kind() { |
| let mut needs_note = true; |
| // If the index is an integer, we can show the actual |
| // fixed expression: |
| if let ExprKind::Lit(ref lit) = idx.kind { |
| if let ast::LitKind::Int(i, ast::LitIntType::Unsuffixed) = lit.node { |
| let snip = self.tcx.sess.source_map().span_to_snippet(base.span); |
| if let Ok(snip) = snip { |
| err.span_suggestion( |
| expr.span, |
| "to access tuple elements, use", |
| format!("{snip}.{i}"), |
| Applicability::MachineApplicable, |
| ); |
| needs_note = false; |
| } |
| } |
| } |
| if needs_note { |
| err.help( |
| "to access tuple elements, use tuple indexing \ |
| syntax (e.g., `tuple.0`)", |
| ); |
| } |
| } |
| let reported = err.emit(); |
| self.tcx.ty_error(reported) |
| } |
| } |
| } |
| } |
| |
| fn point_at_index_if_possible( |
| &self, |
| errors: &mut Vec<traits::FulfillmentError<'tcx>>, |
| span: Span, |
| ) { |
| for error in errors { |
| match error.obligation.predicate.kind().skip_binder() { |
| ty::PredicateKind::Clause(ty::Clause::Trait(predicate)) |
| if self.tcx.is_diagnostic_item(sym::SliceIndex, predicate.trait_ref.def_id) => { |
| } |
| _ => continue, |
| } |
| error.obligation.cause.span = span; |
| } |
| } |
| |
| fn check_expr_yield( |
| &self, |
| value: &'tcx hir::Expr<'tcx>, |
| expr: &'tcx hir::Expr<'tcx>, |
| src: &'tcx hir::YieldSource, |
| ) -> Ty<'tcx> { |
| match self.resume_yield_tys { |
| Some((resume_ty, yield_ty)) => { |
| self.check_expr_coercable_to_type(&value, yield_ty, None); |
| |
| resume_ty |
| } |
| // Given that this `yield` expression was generated as a result of lowering a `.await`, |
| // we know that the yield type must be `()`; however, the context won't contain this |
| // information. Hence, we check the source of the yield expression here and check its |
| // value's type against `()` (this check should always hold). |
| None if src.is_await() => { |
| self.check_expr_coercable_to_type(&value, self.tcx.mk_unit(), None); |
| self.tcx.mk_unit() |
| } |
| _ => { |
| self.tcx.sess.emit_err(YieldExprOutsideOfGenerator { span: expr.span }); |
| // Avoid expressions without types during writeback (#78653). |
| self.check_expr(value); |
| self.tcx.mk_unit() |
| } |
| } |
| } |
| |
| fn check_expr_asm_operand(&self, expr: &'tcx hir::Expr<'tcx>, is_input: bool) { |
| let needs = if is_input { Needs::None } else { Needs::MutPlace }; |
| let ty = self.check_expr_with_needs(expr, needs); |
| self.require_type_is_sized(ty, expr.span, traits::InlineAsmSized); |
| |
| if !is_input && !expr.is_syntactic_place_expr() { |
| let mut err = self.tcx.sess.struct_span_err(expr.span, "invalid asm output"); |
| err.span_label(expr.span, "cannot assign to this expression"); |
| err.emit(); |
| } |
| |
| // If this is an input value, we require its type to be fully resolved |
| // at this point. This allows us to provide helpful coercions which help |
| // pass the type candidate list in a later pass. |
| // |
| // We don't require output types to be resolved at this point, which |
| // allows them to be inferred based on how they are used later in the |
| // function. |
| if is_input { |
| let ty = self.structurally_resolved_type(expr.span, ty); |
| match *ty.kind() { |
| ty::FnDef(..) => { |
| let fnptr_ty = self.tcx.mk_fn_ptr(ty.fn_sig(self.tcx)); |
| self.demand_coerce(expr, ty, fnptr_ty, None, AllowTwoPhase::No); |
| } |
| ty::Ref(_, base_ty, mutbl) => { |
| let ptr_ty = self.tcx.mk_ptr(ty::TypeAndMut { ty: base_ty, mutbl }); |
| self.demand_coerce(expr, ty, ptr_ty, None, AllowTwoPhase::No); |
| } |
| _ => {} |
| } |
| } |
| } |
| |
| fn check_expr_asm(&self, asm: &'tcx hir::InlineAsm<'tcx>) -> Ty<'tcx> { |
| for (op, _op_sp) in asm.operands { |
| match op { |
| hir::InlineAsmOperand::In { expr, .. } => { |
| self.check_expr_asm_operand(expr, true); |
| } |
| hir::InlineAsmOperand::Out { expr: Some(expr), .. } |
| | hir::InlineAsmOperand::InOut { expr, .. } => { |
| self.check_expr_asm_operand(expr, false); |
| } |
| hir::InlineAsmOperand::Out { expr: None, .. } => {} |
| hir::InlineAsmOperand::SplitInOut { in_expr, out_expr, .. } => { |
| self.check_expr_asm_operand(in_expr, true); |
| if let Some(out_expr) = out_expr { |
| self.check_expr_asm_operand(out_expr, false); |
| } |
| } |
| // `AnonConst`s have their own body and is type-checked separately. |
| // As they don't flow into the type system we don't need them to |
| // be well-formed. |
| hir::InlineAsmOperand::Const { .. } | hir::InlineAsmOperand::SymFn { .. } => {} |
| hir::InlineAsmOperand::SymStatic { .. } => {} |
| } |
| } |
| if asm.options.contains(ast::InlineAsmOptions::NORETURN) { |
| self.tcx.types.never |
| } else { |
| self.tcx.mk_unit() |
| } |
| } |
| } |