2899 lines
116 KiB
Rust
2899 lines
116 KiB
Rust
//! Type checking expressions.
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//!
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//! See `mod.rs` for more context on type checking in general.
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use crate::astconv::AstConv as _;
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use crate::check::cast;
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use crate::check::coercion::CoerceMany;
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use crate::check::fatally_break_rust;
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use crate::check::method::SelfSource;
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use crate::check::Expectation::{self, ExpectCastableToType, ExpectHasType, NoExpectation};
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use crate::check::{
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report_unexpected_variant_res, BreakableCtxt, Diverges, DynamicCoerceMany, FnCtxt, Needs,
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TupleArgumentsFlag::DontTupleArguments,
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};
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use crate::errors::{
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FieldMultiplySpecifiedInInitializer, FunctionalRecordUpdateOnNonStruct,
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YieldExprOutsideOfGenerator,
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};
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use crate::type_error_struct;
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use crate::errors::{AddressOfTemporaryTaken, ReturnStmtOutsideOfFnBody, StructExprNonExhaustive};
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use rustc_ast as ast;
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use rustc_data_structures::fx::FxHashMap;
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use rustc_data_structures::stack::ensure_sufficient_stack;
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use rustc_errors::{
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pluralize, struct_span_err, Applicability, Diagnostic, DiagnosticBuilder, DiagnosticId,
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ErrorGuaranteed, StashKey,
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};
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use rustc_hir as hir;
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use rustc_hir::def::{CtorKind, DefKind, Res};
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use rustc_hir::def_id::DefId;
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use rustc_hir::intravisit::Visitor;
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use rustc_hir::lang_items::LangItem;
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use rustc_hir::{Closure, ExprKind, HirId, QPath};
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use rustc_infer::infer;
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use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
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use rustc_infer::infer::InferOk;
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use rustc_infer::traits::ObligationCause;
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use rustc_middle::middle::stability;
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use rustc_middle::ty::adjustment::{Adjust, Adjustment, AllowTwoPhase};
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use rustc_middle::ty::error::TypeError::FieldMisMatch;
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use rustc_middle::ty::subst::SubstsRef;
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use rustc_middle::ty::{self, AdtKind, Ty, TypeVisitable};
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use rustc_session::errors::ExprParenthesesNeeded;
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use rustc_session::parse::feature_err;
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use rustc_span::hygiene::DesugaringKind;
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use rustc_span::lev_distance::find_best_match_for_name;
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use rustc_span::source_map::{Span, Spanned};
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use rustc_span::symbol::{kw, sym, Ident, Symbol};
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use rustc_target::spec::abi::Abi::RustIntrinsic;
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use rustc_trait_selection::infer::InferCtxtExt;
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use rustc_trait_selection::traits::{self, ObligationCauseCode};
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impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
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fn check_expr_eq_type(&self, expr: &'tcx hir::Expr<'tcx>, expected: Ty<'tcx>) {
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let ty = self.check_expr_with_hint(expr, expected);
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self.demand_eqtype(expr.span, expected, ty);
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}
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pub fn check_expr_has_type_or_error(
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&self,
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expr: &'tcx hir::Expr<'tcx>,
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expected: Ty<'tcx>,
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extend_err: impl FnMut(&mut Diagnostic),
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) -> Ty<'tcx> {
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self.check_expr_meets_expectation_or_error(expr, ExpectHasType(expected), extend_err)
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}
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fn check_expr_meets_expectation_or_error(
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&self,
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expr: &'tcx hir::Expr<'tcx>,
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expected: Expectation<'tcx>,
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mut extend_err: impl FnMut(&mut Diagnostic),
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) -> Ty<'tcx> {
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let expected_ty = expected.to_option(&self).unwrap_or(self.tcx.types.bool);
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let mut ty = self.check_expr_with_expectation(expr, expected);
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// While we don't allow *arbitrary* coercions here, we *do* allow
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// coercions from ! to `expected`.
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if ty.is_never() {
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if let Some(adjustments) = self.typeck_results.borrow().adjustments().get(expr.hir_id) {
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self.tcx().sess.delay_span_bug(
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expr.span,
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"expression with never type wound up being adjusted",
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);
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return if let [Adjustment { kind: Adjust::NeverToAny, target }] = &adjustments[..] {
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target.to_owned()
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} else {
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self.tcx().ty_error()
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};
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}
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let adj_ty = self.next_ty_var(TypeVariableOrigin {
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kind: TypeVariableOriginKind::AdjustmentType,
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span: expr.span,
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});
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self.apply_adjustments(
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expr,
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vec![Adjustment { kind: Adjust::NeverToAny, target: adj_ty }],
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);
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ty = adj_ty;
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}
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if let Some(mut err) = self.demand_suptype_diag(expr.span, expected_ty, ty) {
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let expr = expr.peel_drop_temps();
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self.suggest_deref_ref_or_into(&mut err, expr, expected_ty, ty, None);
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extend_err(&mut err);
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err.emit();
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}
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ty
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}
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pub(super) fn check_expr_coercable_to_type(
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&self,
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expr: &'tcx hir::Expr<'tcx>,
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expected: Ty<'tcx>,
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expected_ty_expr: Option<&'tcx hir::Expr<'tcx>>,
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) -> Ty<'tcx> {
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let ty = self.check_expr_with_hint(expr, expected);
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// checks don't need two phase
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self.demand_coerce(expr, ty, expected, expected_ty_expr, AllowTwoPhase::No)
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}
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pub(super) fn check_expr_with_hint(
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&self,
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expr: &'tcx hir::Expr<'tcx>,
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expected: Ty<'tcx>,
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) -> Ty<'tcx> {
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self.check_expr_with_expectation(expr, ExpectHasType(expected))
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}
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fn check_expr_with_expectation_and_needs(
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&self,
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expr: &'tcx hir::Expr<'tcx>,
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expected: Expectation<'tcx>,
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needs: Needs,
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) -> Ty<'tcx> {
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let ty = self.check_expr_with_expectation(expr, expected);
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// If the expression is used in a place whether mutable place is required
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// e.g. LHS of assignment, perform the conversion.
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if let Needs::MutPlace = needs {
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self.convert_place_derefs_to_mutable(expr);
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}
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ty
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}
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pub(super) fn check_expr(&self, expr: &'tcx hir::Expr<'tcx>) -> Ty<'tcx> {
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self.check_expr_with_expectation(expr, NoExpectation)
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}
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pub(super) fn check_expr_with_needs(
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&self,
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expr: &'tcx hir::Expr<'tcx>,
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needs: Needs,
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) -> Ty<'tcx> {
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self.check_expr_with_expectation_and_needs(expr, NoExpectation, needs)
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}
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/// Invariant:
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/// If an expression has any sub-expressions that result in a type error,
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/// inspecting that expression's type with `ty.references_error()` will return
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/// true. Likewise, if an expression is known to diverge, inspecting its
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/// type with `ty::type_is_bot` will return true (n.b.: since Rust is
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/// strict, _|_ can appear in the type of an expression that does not,
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/// itself, diverge: for example, fn() -> _|_.)
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/// Note that inspecting a type's structure *directly* may expose the fact
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/// that there are actually multiple representations for `Error`, so avoid
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/// that when err needs to be handled differently.
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#[instrument(skip(self, expr), level = "debug")]
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pub(super) fn check_expr_with_expectation(
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&self,
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expr: &'tcx hir::Expr<'tcx>,
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expected: Expectation<'tcx>,
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) -> Ty<'tcx> {
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self.check_expr_with_expectation_and_args(expr, expected, &[])
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}
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/// Same as `check_expr_with_expectation`, but allows us to pass in the arguments of a
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/// `ExprKind::Call` when evaluating its callee when it is an `ExprKind::Path`.
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pub(super) fn check_expr_with_expectation_and_args(
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&self,
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expr: &'tcx hir::Expr<'tcx>,
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expected: Expectation<'tcx>,
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args: &'tcx [hir::Expr<'tcx>],
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) -> Ty<'tcx> {
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if self.tcx().sess.verbose() {
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// make this code only run with -Zverbose because it is probably slow
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if let Ok(lint_str) = self.tcx.sess.source_map().span_to_snippet(expr.span) {
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if !lint_str.contains('\n') {
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debug!("expr text: {lint_str}");
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} else {
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let mut lines = lint_str.lines();
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if let Some(line0) = lines.next() {
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let remaining_lines = lines.count();
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debug!("expr text: {line0}");
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debug!("expr text: ...(and {remaining_lines} more lines)");
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}
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}
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}
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}
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// True if `expr` is a `Try::from_ok(())` that is a result of desugaring a try block
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// without the final expr (e.g. `try { return; }`). We don't want to generate an
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// unreachable_code lint for it since warnings for autogenerated code are confusing.
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let is_try_block_generated_unit_expr = match expr.kind {
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ExprKind::Call(_, args) if expr.span.is_desugaring(DesugaringKind::TryBlock) => {
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args.len() == 1 && args[0].span.is_desugaring(DesugaringKind::TryBlock)
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}
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_ => false,
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};
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// Warn for expressions after diverging siblings.
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if !is_try_block_generated_unit_expr {
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self.warn_if_unreachable(expr.hir_id, expr.span, "expression");
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}
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// Hide the outer diverging and has_errors flags.
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let old_diverges = self.diverges.replace(Diverges::Maybe);
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let old_has_errors = self.has_errors.replace(false);
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let ty = ensure_sufficient_stack(|| match &expr.kind {
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hir::ExprKind::Path(
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qpath @ hir::QPath::Resolved(..) | qpath @ hir::QPath::TypeRelative(..),
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) => self.check_expr_path(qpath, expr, args),
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_ => self.check_expr_kind(expr, expected),
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});
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// Warn for non-block expressions with diverging children.
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match expr.kind {
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ExprKind::Block(..)
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| ExprKind::If(..)
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| ExprKind::Let(..)
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| ExprKind::Loop(..)
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| ExprKind::Match(..) => {}
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// If `expr` is a result of desugaring the try block and is an ok-wrapped
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// diverging expression (e.g. it arose from desugaring of `try { return }`),
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// we skip issuing a warning because it is autogenerated code.
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ExprKind::Call(..) if expr.span.is_desugaring(DesugaringKind::TryBlock) => {}
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ExprKind::Call(callee, _) => self.warn_if_unreachable(expr.hir_id, callee.span, "call"),
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ExprKind::MethodCall(segment, ..) => {
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self.warn_if_unreachable(expr.hir_id, segment.ident.span, "call")
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}
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_ => self.warn_if_unreachable(expr.hir_id, expr.span, "expression"),
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}
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// Any expression that produces a value of type `!` must have diverged
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if ty.is_never() {
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self.diverges.set(self.diverges.get() | Diverges::always(expr.span));
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}
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// Record the type, which applies it effects.
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// We need to do this after the warning above, so that
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// we don't warn for the diverging expression itself.
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self.write_ty(expr.hir_id, ty);
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// Combine the diverging and has_error flags.
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self.diverges.set(self.diverges.get() | old_diverges);
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self.has_errors.set(self.has_errors.get() | old_has_errors);
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debug!("type of {} is...", self.tcx.hir().node_to_string(expr.hir_id));
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debug!("... {:?}, expected is {:?}", ty, expected);
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ty
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}
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#[instrument(skip(self, expr), level = "debug")]
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fn check_expr_kind(
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&self,
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expr: &'tcx hir::Expr<'tcx>,
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expected: Expectation<'tcx>,
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) -> Ty<'tcx> {
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trace!("expr={:#?}", expr);
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let tcx = self.tcx;
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match expr.kind {
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ExprKind::Box(subexpr) => self.check_expr_box(subexpr, expected),
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ExprKind::Lit(ref lit) => self.check_lit(&lit, expected),
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ExprKind::Binary(op, lhs, rhs) => self.check_binop(expr, op, lhs, rhs, expected),
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ExprKind::Assign(lhs, rhs, span) => {
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self.check_expr_assign(expr, expected, lhs, rhs, span)
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}
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ExprKind::AssignOp(op, lhs, rhs) => {
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self.check_binop_assign(expr, op, lhs, rhs, expected)
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}
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ExprKind::Unary(unop, oprnd) => self.check_expr_unary(unop, oprnd, expected, expr),
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ExprKind::AddrOf(kind, mutbl, oprnd) => {
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self.check_expr_addr_of(kind, mutbl, oprnd, expected, expr)
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}
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ExprKind::Path(QPath::LangItem(lang_item, _, hir_id)) => {
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self.check_lang_item_path(lang_item, expr, hir_id)
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}
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ExprKind::Path(ref qpath) => self.check_expr_path(qpath, expr, &[]),
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ExprKind::InlineAsm(asm) => {
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// We defer some asm checks as we may not have resolved the input and output types yet (they may still be infer vars).
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self.deferred_asm_checks.borrow_mut().push((asm, expr.hir_id));
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self.check_expr_asm(asm)
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}
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ExprKind::Break(destination, ref expr_opt) => {
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self.check_expr_break(destination, expr_opt.as_deref(), expr)
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}
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ExprKind::Continue(destination) => {
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if destination.target_id.is_ok() {
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tcx.types.never
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} else {
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// There was an error; make type-check fail.
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tcx.ty_error()
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}
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}
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ExprKind::Ret(ref expr_opt) => self.check_expr_return(expr_opt.as_deref(), expr),
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ExprKind::Let(let_expr) => self.check_expr_let(let_expr),
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ExprKind::Loop(body, _, source, _) => {
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self.check_expr_loop(body, source, expected, expr)
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}
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ExprKind::Match(discrim, arms, match_src) => {
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self.check_match(expr, &discrim, arms, expected, match_src)
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}
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ExprKind::Closure(&Closure { capture_clause, fn_decl, body, movability, .. }) => {
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self.check_expr_closure(expr, capture_clause, &fn_decl, body, movability, expected)
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}
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ExprKind::Block(body, _) => self.check_block_with_expected(&body, expected),
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ExprKind::Call(callee, args) => self.check_call(expr, &callee, args, expected),
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ExprKind::MethodCall(segment, receiver, args, _) => {
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self.check_method_call(expr, segment, receiver, args, expected)
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}
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ExprKind::Cast(e, t) => self.check_expr_cast(e, t, expr),
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ExprKind::Type(e, t) => {
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let ty = self.to_ty_saving_user_provided_ty(&t);
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self.check_expr_eq_type(&e, ty);
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ty
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}
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ExprKind::If(cond, then_expr, opt_else_expr) => {
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self.check_then_else(cond, then_expr, opt_else_expr, expr.span, expected)
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}
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ExprKind::DropTemps(e) => self.check_expr_with_expectation(e, expected),
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ExprKind::Array(args) => self.check_expr_array(args, expected, expr),
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ExprKind::ConstBlock(ref anon_const) => {
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self.check_expr_const_block(anon_const, expected, expr)
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}
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ExprKind::Repeat(element, ref count) => {
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self.check_expr_repeat(element, count, expected, expr)
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}
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ExprKind::Tup(elts) => self.check_expr_tuple(elts, expected, expr),
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ExprKind::Struct(qpath, fields, ref base_expr) => {
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self.check_expr_struct(expr, expected, qpath, fields, base_expr)
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}
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ExprKind::Field(base, field) => self.check_field(expr, &base, field),
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ExprKind::Index(base, idx) => self.check_expr_index(base, idx, expr),
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ExprKind::Yield(value, ref src) => self.check_expr_yield(value, expr, src),
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hir::ExprKind::Err => tcx.ty_error(),
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}
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}
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fn check_expr_box(&self, expr: &'tcx hir::Expr<'tcx>, expected: Expectation<'tcx>) -> Ty<'tcx> {
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let expected_inner = expected.to_option(self).map_or(NoExpectation, |ty| match ty.kind() {
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ty::Adt(def, _) if def.is_box() => Expectation::rvalue_hint(self, ty.boxed_ty()),
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_ => NoExpectation,
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});
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let referent_ty = self.check_expr_with_expectation(expr, expected_inner);
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self.require_type_is_sized(referent_ty, expr.span, traits::SizedBoxType);
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self.tcx.mk_box(referent_ty)
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}
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fn check_expr_unary(
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&self,
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unop: hir::UnOp,
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oprnd: &'tcx hir::Expr<'tcx>,
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expected: Expectation<'tcx>,
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expr: &'tcx hir::Expr<'tcx>,
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) -> Ty<'tcx> {
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let tcx = self.tcx;
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let expected_inner = match unop {
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hir::UnOp::Not | hir::UnOp::Neg => expected,
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hir::UnOp::Deref => NoExpectation,
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};
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let mut oprnd_t = self.check_expr_with_expectation(&oprnd, expected_inner);
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if !oprnd_t.references_error() {
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oprnd_t = self.structurally_resolved_type(expr.span, oprnd_t);
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match unop {
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hir::UnOp::Deref => {
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if let Some(ty) = self.lookup_derefing(expr, oprnd, oprnd_t) {
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oprnd_t = ty;
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} else {
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let mut err = type_error_struct!(
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tcx.sess,
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expr.span,
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oprnd_t,
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E0614,
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"type `{oprnd_t}` cannot be dereferenced",
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);
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let sp = tcx.sess.source_map().start_point(expr.span);
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if let Some(sp) =
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tcx.sess.parse_sess.ambiguous_block_expr_parse.borrow().get(&sp)
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{
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err.subdiagnostic(ExprParenthesesNeeded::surrounding(*sp));
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}
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err.emit();
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oprnd_t = tcx.ty_error();
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}
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}
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hir::UnOp::Not => {
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let result = self.check_user_unop(expr, oprnd_t, unop, expected_inner);
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// If it's builtin, we can reuse the type, this helps inference.
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if !(oprnd_t.is_integral() || *oprnd_t.kind() == ty::Bool) {
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oprnd_t = result;
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}
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}
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hir::UnOp::Neg => {
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let result = self.check_user_unop(expr, oprnd_t, unop, expected_inner);
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// If it's builtin, we can reuse the type, this helps inference.
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if !oprnd_t.is_numeric() {
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oprnd_t = result;
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}
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}
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}
|
|
}
|
|
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(),
|
|
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.set_tainted_by_errors();
|
|
tcx.ty_error()
|
|
}
|
|
Res::Def(DefKind::Ctor(_, CtorKind::Fictive), _) => {
|
|
report_unexpected_variant_res(tcx, res, qpath, expr.span);
|
|
tcx.ty_error()
|
|
}
|
|
_ => 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).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.replace_bound_vars_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.replace_bound_vars_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());
|
|
|
|
// 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 self.return_type_has_opaque {
|
|
// Point any obligations that were registered due to opaque type
|
|
// inference at the return expression.
|
|
self.select_obligations_where_possible(false, |errors| {
|
|
self.point_at_return_for_opaque_ty_error(errors, span, return_expr_ty);
|
|
});
|
|
}
|
|
}
|
|
|
|
fn point_at_return_for_opaque_ty_error(
|
|
&self,
|
|
errors: &mut Vec<traits::FulfillmentError<'tcx>>,
|
|
span: Span,
|
|
return_expr_ty: Ty<'tcx>,
|
|
) {
|
|
// Don't point at the whole block if it's empty
|
|
if span == self.tcx.hir().span(self.body_id) {
|
|
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().get_parent_node(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().find_parent_node(*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().get_parent_node(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 cond_ty.references_error() { self.tcx.ty_error() } 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(hir.get_parent_node(hir.get_parent_node(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
|
|
if lhs_ty.references_error() || rhs_ty.references_error() {
|
|
err.delay_as_bug()
|
|
} else {
|
|
err.emit();
|
|
}
|
|
return self.tcx.ty_error();
|
|
}
|
|
|
|
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.lang_items().sized_trait().unwrap(),
|
|
lhs_deref_ty,
|
|
ty::List::empty(),
|
|
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 lhs_ty.references_error() || rhs_ty.references_error() {
|
|
self.tcx.ty_error()
|
|
} 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)),
|
|
) {
|
|
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 t_expr.references_error() || t_cast.references_error() {
|
|
self.tcx.ty_error()
|
|
} 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) {
|
|
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(_) => self.tcx.ty_error(),
|
|
}
|
|
}
|
|
}
|
|
|
|
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 fcx = FnCtxt::new(self, self.param_env.with_const(), body.value.hir_id);
|
|
crate::check::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_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 element_ty.references_error() {
|
|
return tcx.ty_error();
|
|
}
|
|
|
|
self.check_repeat_element_needs_copy_bound(element, count, element_ty);
|
|
|
|
tcx.mk_ty(ty::Array(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_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(elt_ts_iter);
|
|
if tuple.references_error() {
|
|
self.tcx.ty_error()
|
|
} 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 Some((variant, adt_ty)) = self.check_struct_path(qpath, expr.hir_id) else {
|
|
self.check_struct_fields_on_error(fields, base_expr);
|
|
return self.tcx.ty_error();
|
|
};
|
|
|
|
// 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;
|
|
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()
|
|
};
|
|
|
|
// 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 && remaining_fields.is_empty() {
|
|
self.suggest_fru_from_range(field, variant, substs, &mut diag);
|
|
}
|
|
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 {
|
|
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_associated_types_in(
|
|
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_associated_types_in(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, ..),
|
|
&[ref range_start, ref 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
|
|
{
|
|
let instead = self
|
|
.tcx
|
|
.sess
|
|
.source_map()
|
|
.span_to_snippet(range_end.expr.span)
|
|
.map(|s| format!(" from `{s}`"))
|
|
.unwrap_or_default();
|
|
err.span_suggestion(
|
|
range_start.span.shrink_to_hi(),
|
|
&format!("to set the remaining fields{instead}, separate the last named field with a comma"),
|
|
",",
|
|
Applicability::MaybeIncorrect,
|
|
);
|
|
}
|
|
}
|
|
|
|
/// 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,
|
|
) {
|
|
if variant.is_recovered() {
|
|
self.set_tainted_by_errors();
|
|
return;
|
|
}
|
|
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 {
|
|
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> {
|
|
variant
|
|
.fields
|
|
.iter()
|
|
.filter(|field| {
|
|
let def_scope = self
|
|
.tcx
|
|
.adjust_ident_and_get_scope(field.ident(self.tcx), variant.def_id, self.body_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,
|
|
) -> 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 (ident, def_scope) =
|
|
self.tcx.adjust_ident_and_get_scope(field, base_def.did(), self.body_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(), field_ty));
|
|
}
|
|
}
|
|
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, field_ty)) = private_candidate {
|
|
// (#90483) apply adjustments to avoid ExprUseVisitor from
|
|
// creating erroneous projection.
|
|
self.apply_adjustments(base, adjustments);
|
|
self.ban_private_field_access(expr, base_ty, field, did);
|
|
return field_ty;
|
|
}
|
|
|
|
if field.name == kw::Empty {
|
|
} else if self.method_exists(field, base_ty, expr.hir_id, true) {
|
|
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()
|
|
}
|
|
|
|
fn suggest_await_on_field_access(
|
|
&self,
|
|
err: &mut Diagnostic,
|
|
field_ident: Ident,
|
|
base: &'tcx hir::Expr<'tcx>,
|
|
ty: Ty<'tcx>,
|
|
) {
|
|
let output_ty = match self.get_impl_future_output_ty(ty) {
|
|
Some(output_ty) => self.resolve_vars_if_possible(output_ty),
|
|
_ => return,
|
|
};
|
|
let mut add_label = true;
|
|
if let ty::Adt(def, _) = output_ty.skip_binder().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>,
|
|
) {
|
|
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::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");
|
|
err.help_use_latest_edition();
|
|
}
|
|
|
|
err.emit();
|
|
}
|
|
|
|
fn ban_private_field_access(
|
|
&self,
|
|
expr: &hir::Expr<'_>,
|
|
expr_t: Ty<'tcx>,
|
|
field: Ident,
|
|
base_did: DefId,
|
|
) {
|
|
let struct_path = self.tcx().def_path_str(base_did);
|
|
let kind_name = self.tcx().def_kind(base_did).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) && !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<'_>, expr_t: Ty<'tcx>, field: Ident) {
|
|
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(self.tcx.hir().get_parent_node(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.owner.to_def_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_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(false, |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`)",
|
|
);
|
|
}
|
|
}
|
|
err.emit();
|
|
self.tcx.ty_error()
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
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::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()
|
|
}
|
|
}
|
|
}
|
|
|
|
pub(super) fn ty_kind_suggestion(ty: Ty<'_>) -> Option<&'static str> {
|
|
Some(match ty.kind() {
|
|
ty::Bool => "true",
|
|
ty::Char => "'a'",
|
|
ty::Int(_) | ty::Uint(_) => "42",
|
|
ty::Float(_) => "3.14159",
|
|
ty::Error(_) | ty::Never => return None,
|
|
_ => "value",
|
|
})
|
|
}
|