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Auto merge of #61857 - Centril:typeck-extract-expr, r=oli-obk
typeck: extract expr type-checking to expr.rs + refactor check_expr_kind In this PR we: - Extract out the bulk of the expression type checking logic from `check/mod.rs` into a new file `check/expr.rs`. - Refactor `fn check_expr_kind` into several smaller functions. More functions should probably be moved but I think this is a reasonable start. r? @oli-obk cc @eddyb
This commit is contained in:
bors
@@ -0,0 +1,1537 @@
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//! 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::check::BreakableCtxt;
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use crate::check::cast;
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use crate::check::coercion::CoerceMany;
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use crate::check::Diverges;
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use crate::check::FnCtxt;
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use crate::check::Expectation::{self, NoExpectation, ExpectHasType, ExpectCastableToType};
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use crate::check::fatally_break_rust;
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use crate::check::report_unexpected_variant_res;
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use crate::check::Needs;
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use crate::check::TupleArgumentsFlag::DontTupleArguments;
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use crate::check::method::SelfSource;
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use crate::middle::lang_items;
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use crate::util::common::ErrorReported;
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use crate::util::nodemap::FxHashMap;
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use crate::astconv::AstConv as _;
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use errors::{Applicability, DiagnosticBuilder};
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use syntax::ast;
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use syntax::ptr::P;
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use syntax::symbol::{Symbol, LocalInternedString, kw, sym};
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use syntax::source_map::Span;
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use syntax::util::lev_distance::find_best_match_for_name;
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use rustc::hir;
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use rustc::hir::{ExprKind, QPath};
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use rustc::hir::def::{CtorKind, Res, DefKind};
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use rustc::infer;
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use rustc::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
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use rustc::mir::interpret::GlobalId;
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use rustc::ty;
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use rustc::ty::adjustment::{
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Adjust, Adjustment, AllowTwoPhase, AutoBorrow, AutoBorrowMutability,
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};
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use rustc::ty::{AdtKind, Visibility};
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use rustc::ty::Ty;
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use rustc::ty::TypeFoldable;
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use rustc::ty::subst::InternalSubsts;
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use rustc::traits::{self, ObligationCauseCode};
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use std::fmt::Display;
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impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
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fn check_expr_eq_type(&self, expr: &'tcx hir::Expr, 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,
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expected: Ty<'tcx>,
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) -> Ty<'tcx> {
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self.check_expr_meets_expectation_or_error(expr, ExpectHasType(expected))
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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,
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expected: Expectation<'tcx>,
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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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assert!(!self.tables.borrow().adjustments().contains_key(expr.hir_id),
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"expression with never type wound up being adjusted");
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let adj_ty = self.next_diverging_ty_var(
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TypeVariableOrigin {
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kind: TypeVariableOriginKind::AdjustmentType,
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span: expr.span,
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},
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);
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self.apply_adjustments(expr, vec![Adjustment {
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kind: Adjust::NeverToAny,
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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 = match &expr.node {
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ExprKind::DropTemps(expr) => expr,
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_ => expr,
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};
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// Error possibly reported in `check_assign` so avoid emitting error again.
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err.emit_unless(self.is_assign_to_bool(expr, expected_ty));
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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,
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expected: Ty<'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, 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,
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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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pub(super) fn check_expr_with_expectation(
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&self,
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expr: &'tcx hir::Expr,
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expected: Expectation<'tcx>,
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) -> Ty<'tcx> {
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self.check_expr_with_expectation_and_needs(expr, expected, Needs::None)
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}
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pub(super) fn check_expr(&self, expr: &'tcx hir::Expr) -> 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(&self, expr: &'tcx hir::Expr, needs: Needs) -> 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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fn check_expr_with_expectation_and_needs(
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&self,
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expr: &'tcx hir::Expr,
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expected: Expectation<'tcx>,
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needs: Needs,
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) -> Ty<'tcx> {
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debug!(">> type-checking: expr={:?} expected={:?}",
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expr, expected);
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// Warn for expressions after diverging siblings.
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self.warn_if_unreachable(expr.hir_id, expr.span, "expression");
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// Hide the outer diverging and has_errors flags.
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let old_diverges = self.diverges.get();
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let old_has_errors = self.has_errors.get();
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self.diverges.set(Diverges::Maybe);
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self.has_errors.set(false);
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let ty = self.check_expr_kind(expr, expected, needs);
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// Warn for non-block expressions with diverging children.
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match expr.node {
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ExprKind::Block(..) |
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ExprKind::Loop(..) | ExprKind::While(..) |
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ExprKind::Match(..) => {}
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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);
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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().hir_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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fn check_expr_kind(
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&self,
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expr: &'tcx hir::Expr,
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expected: Expectation<'tcx>,
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needs: Needs,
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) -> Ty<'tcx> {
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debug!(
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"check_expr_kind(expr={:?}, expected={:?}, needs={:?})",
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expr,
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expected,
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needs,
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);
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let tcx = self.tcx;
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match expr.node {
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ExprKind::Box(ref subexpr) => {
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self.check_expr_box(subexpr, expected)
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}
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ExprKind::Lit(ref lit) => {
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self.check_lit(&lit, expected)
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}
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ExprKind::Binary(op, ref lhs, ref rhs) => {
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self.check_binop(expr, op, lhs, rhs)
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}
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ExprKind::AssignOp(op, ref lhs, ref rhs) => {
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self.check_binop_assign(expr, op, lhs, rhs)
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}
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ExprKind::Unary(unop, ref oprnd) => {
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self.check_expr_unary(unop, oprnd, expected, needs, expr)
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}
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ExprKind::AddrOf(mutbl, ref oprnd) => {
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self.check_expr_addr_of(mutbl, oprnd, expected, expr)
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}
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ExprKind::Path(ref qpath) => {
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self.check_expr_path(qpath, expr)
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}
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ExprKind::InlineAsm(_, ref outputs, ref inputs) => {
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for expr in outputs.iter().chain(inputs.iter()) {
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self.check_expr(expr);
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}
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tcx.mk_unit()
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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.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.types.err
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}
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}
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ExprKind::Ret(ref expr_opt) => {
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self.check_expr_return(expr_opt.deref(), expr)
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}
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ExprKind::Assign(ref lhs, ref rhs) => {
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self.check_expr_assign(expr, expected, lhs, rhs)
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}
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ExprKind::While(ref cond, ref body, _) => {
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self.check_expr_while(cond, body, expr)
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}
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ExprKind::Loop(ref body, _, source) => {
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self.check_expr_loop(body, source, expected, expr)
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}
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ExprKind::Match(ref discrim, ref 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(capture, ref decl, body_id, _, gen) => {
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self.check_expr_closure(expr, capture, &decl, body_id, gen, expected)
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}
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ExprKind::Block(ref body, _) => {
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self.check_block_with_expected(&body, expected)
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}
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ExprKind::Call(ref callee, ref args) => {
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self.check_call(expr, &callee, args, expected)
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}
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ExprKind::MethodCall(ref segment, span, ref args) => {
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self.check_method_call(expr, segment, span, args, expected, needs)
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}
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ExprKind::Cast(ref e, ref t) => {
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self.check_expr_cast(e, t, expr)
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}
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ExprKind::Type(ref e, ref 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::DropTemps(ref e) => {
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self.check_expr_with_expectation(e, expected)
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}
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ExprKind::Array(ref args) => {
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self.check_expr_array(args, expected, expr)
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}
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ExprKind::Repeat(ref 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(ref elts) => {
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self.check_expr_tuple(elts, expected, expr)
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}
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ExprKind::Struct(ref qpath, ref 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(ref base, field) => {
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self.check_field(expr, needs, &base, field)
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}
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ExprKind::Index(ref base, ref idx) => {
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self.check_expr_index(base, idx, needs, expr)
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}
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ExprKind::Yield(ref value) => {
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self.check_expr_yield(value, expr)
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}
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hir::ExprKind::Err => {
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tcx.types.err
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}
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}
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}
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fn check_expr_box(&self, expr: &'tcx hir::Expr, expected: Expectation<'tcx>) -> Ty<'tcx> {
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let expected_inner = expected.to_option(self).map_or(NoExpectation, |ty| {
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match ty.sty {
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ty::Adt(def, _) if def.is_box()
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=> Expectation::rvalue_hint(self, ty.boxed_ty()),
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_ => NoExpectation
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}
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});
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let referent_ty = self.check_expr_with_expectation(expr, expected_inner);
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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,
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expected: Expectation<'tcx>,
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needs: Needs,
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expr: &'tcx hir::Expr,
|
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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::UnNot | hir::UnNeg => expected,
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hir::UnDeref => NoExpectation,
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};
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let needs = match unop {
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hir::UnDeref => needs,
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_ => Needs::None
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};
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let mut oprnd_t = self.check_expr_with_expectation_and_needs(&oprnd, expected_inner, needs);
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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::UnDeref => {
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if let Some(mt) = oprnd_t.builtin_deref(true) {
|
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oprnd_t = mt.ty;
|
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} else if let Some(ok) = self.try_overloaded_deref(
|
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expr.span, oprnd_t, needs) {
|
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let method = self.register_infer_ok_obligations(ok);
|
||||
if let ty::Ref(region, _, mutbl) = method.sig.inputs()[0].sty {
|
||||
let mutbl = match mutbl {
|
||||
hir::MutImmutable => AutoBorrowMutability::Immutable,
|
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hir::MutMutable => AutoBorrowMutability::Mutable {
|
||||
// (It shouldn't actually matter for unary ops whether
|
||||
// we enable two-phase borrows or not, since a unary
|
||||
// op has no additional operands.)
|
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allow_two_phase_borrow: AllowTwoPhase::No,
|
||||
}
|
||||
};
|
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self.apply_adjustments(oprnd, vec![Adjustment {
|
||||
kind: Adjust::Borrow(AutoBorrow::Ref(region, mutbl)),
|
||||
target: method.sig.inputs()[0]
|
||||
}]);
|
||||
}
|
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oprnd_t = self.make_overloaded_place_return_type(method).ty;
|
||||
self.write_method_call(expr.hir_id, method);
|
||||
} else {
|
||||
let mut err = type_error_struct!(
|
||||
tcx.sess,
|
||||
expr.span,
|
||||
oprnd_t,
|
||||
E0614,
|
||||
"type `{}` cannot be dereferenced",
|
||||
oprnd_t,
|
||||
);
|
||||
let sp = tcx.sess.source_map().start_point(expr.span);
|
||||
if let Some(sp) = tcx.sess.parse_sess.ambiguous_block_expr_parse
|
||||
.borrow().get(&sp)
|
||||
{
|
||||
tcx.sess.parse_sess.expr_parentheses_needed(
|
||||
&mut err,
|
||||
*sp,
|
||||
None,
|
||||
);
|
||||
}
|
||||
err.emit();
|
||||
oprnd_t = tcx.types.err;
|
||||
}
|
||||
}
|
||||
hir::UnNot => {
|
||||
let result = self.check_user_unop(expr, oprnd_t, unop);
|
||||
// If it's builtin, we can reuse the type, this helps inference.
|
||||
if !(oprnd_t.is_integral() || oprnd_t.sty == ty::Bool) {
|
||||
oprnd_t = result;
|
||||
}
|
||||
}
|
||||
hir::UnNeg => {
|
||||
let result = self.check_user_unop(expr, oprnd_t, unop);
|
||||
// If it's builtin, we can reuse the type, this helps inference.
|
||||
if !oprnd_t.is_numeric() {
|
||||
oprnd_t = result;
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
oprnd_t
|
||||
}
|
||||
|
||||
fn check_expr_addr_of(
|
||||
&self,
|
||||
mutbl: hir::Mutability,
|
||||
oprnd: &'tcx hir::Expr,
|
||||
expected: Expectation<'tcx>,
|
||||
expr: &'tcx hir::Expr,
|
||||
) -> Ty<'tcx> {
|
||||
let hint = expected.only_has_type(self).map_or(NoExpectation, |ty| {
|
||||
match ty.sty {
|
||||
ty::Ref(_, ty, _) | ty::RawPtr(ty::TypeAndMut { ty, .. }) => {
|
||||
if oprnd.is_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 needs = Needs::maybe_mut_place(mutbl);
|
||||
let ty = self.check_expr_with_expectation_and_needs(&oprnd, hint, needs);
|
||||
|
||||
let tm = ty::TypeAndMut { ty: ty, mutbl: mutbl };
|
||||
if tm.ty.references_error() {
|
||||
self.tcx.types.err
|
||||
} else {
|
||||
// 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 the ultimate value.
|
||||
// Finally, borrowck is charged with guaranteeing 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)
|
||||
}
|
||||
}
|
||||
|
||||
fn check_expr_path(&self, qpath: &hir::QPath, expr: &'tcx hir::Expr) -> Ty<'tcx> {
|
||||
let tcx = self.tcx;
|
||||
let (res, opt_ty, segs) = self.resolve_ty_and_res_ufcs(qpath, expr.hir_id, expr.span);
|
||||
let ty = match res {
|
||||
Res::Err => {
|
||||
self.set_tainted_by_errors();
|
||||
tcx.types.err
|
||||
}
|
||||
Res::Def(DefKind::Ctor(_, CtorKind::Fictive), _) => {
|
||||
report_unexpected_variant_res(tcx, res, expr.span, qpath);
|
||||
tcx.types.err
|
||||
}
|
||||
_ => self.instantiate_value_path(segs, opt_ty, res, expr.span, expr.hir_id).0,
|
||||
};
|
||||
|
||||
if let ty::FnDef(..) = ty.sty {
|
||||
let fn_sig = ty.fn_sig(tcx);
|
||||
if !tcx.features().unsized_locals {
|
||||
// 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 input = self.replace_bound_vars_with_fresh_vars(
|
||||
expr.span,
|
||||
infer::LateBoundRegionConversionTime::FnCall,
|
||||
&fn_sig.input(i)).0;
|
||||
self.require_type_is_sized_deferred(input, expr.span,
|
||||
traits::SizedArgumentType);
|
||||
}
|
||||
}
|
||||
// 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 presense 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()).0;
|
||||
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.tables.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>,
|
||||
expr: &'tcx hir::Expr,
|
||||
) -> Ty<'tcx> {
|
||||
let tcx = self.tcx;
|
||||
if let Ok(target_id) = destination.target_id {
|
||||
let (e_ty, cause);
|
||||
if let Some(ref 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 = {
|
||||
let mut enclosing_breakables = self.enclosing_breakables.borrow_mut();
|
||||
enclosing_breakables.find_breakable(target_id)
|
||||
.coerce
|
||||
.as_ref()
|
||||
.map(|coerce| coerce.expected_ty())
|
||||
};
|
||||
|
||||
// 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(tcx.types.err);
|
||||
|
||||
// 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 ctxt = enclosing_breakables.find_breakable(target_id);
|
||||
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());
|
||||
coerce.coerce_forced_unit(self, &cause, &mut |_| (), true);
|
||||
}
|
||||
} else {
|
||||
// If `ctxt.coerce` is `None`, we can just ignore
|
||||
// the type of the expresison. 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.err_count() > 0);
|
||||
}
|
||||
|
||||
ctxt.may_break = true;
|
||||
|
||||
// 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.
|
||||
if self.tcx.sess.err_count() == 0 {
|
||||
self.tcx.sess.delay_span_bug(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(ref e) = expr_opt {
|
||||
self.check_expr_with_hint(e, tcx.types.err);
|
||||
|
||||
// ... except when we try to 'break rust;'.
|
||||
// ICE this expression in particular (see #43162).
|
||||
if let ExprKind::Path(QPath::Resolved(_, ref path)) = e.node {
|
||||
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.
|
||||
tcx.types.err
|
||||
}
|
||||
}
|
||||
|
||||
fn check_expr_return(
|
||||
&self,
|
||||
expr_opt: Option<&'tcx hir::Expr>,
|
||||
expr: &'tcx hir::Expr
|
||||
) -> Ty<'tcx> {
|
||||
if self.ret_coercion.is_none() {
|
||||
struct_span_err!(self.tcx.sess, expr.span, E0572,
|
||||
"return statement outside of function body").emit();
|
||||
} else if let Some(ref e) = expr_opt {
|
||||
if self.ret_coercion_span.borrow().is_none() {
|
||||
*self.ret_coercion_span.borrow_mut() = Some(e.span);
|
||||
}
|
||||
self.check_return_expr(e);
|
||||
} else {
|
||||
let mut coercion = self.ret_coercion.as_ref().unwrap().borrow_mut();
|
||||
if self.ret_coercion_span.borrow().is_none() {
|
||||
*self.ret_coercion_span.borrow_mut() = 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| {
|
||||
db.span_label(
|
||||
fn_decl.output.span(),
|
||||
format!(
|
||||
"expected `{}` because of this return type",
|
||||
fn_decl.output,
|
||||
),
|
||||
);
|
||||
},
|
||||
true,
|
||||
);
|
||||
} else {
|
||||
coercion.coerce_forced_unit(self, &cause, &mut |_| (), true);
|
||||
}
|
||||
}
|
||||
self.tcx.types.never
|
||||
}
|
||||
|
||||
pub(super) fn check_return_expr(&self, return_expr: &'tcx hir::Expr) {
|
||||
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.clone());
|
||||
ret_coercion.borrow_mut()
|
||||
.coerce(self,
|
||||
&self.cause(return_expr.span,
|
||||
ObligationCauseCode::ReturnType(return_expr.hir_id)),
|
||||
return_expr,
|
||||
return_expr_ty);
|
||||
}
|
||||
|
||||
/// Type check assignment expression `expr` of form `lhs = rhs`.
|
||||
/// The expected type is `()` and is passsed to the function for the purposes of diagnostics.
|
||||
fn check_expr_assign(
|
||||
&self,
|
||||
expr: &'tcx hir::Expr,
|
||||
expected: Expectation<'tcx>,
|
||||
lhs: &'tcx hir::Expr,
|
||||
rhs: &'tcx hir::Expr,
|
||||
) -> Ty<'tcx> {
|
||||
let lhs_ty = self.check_expr_with_needs(&lhs, Needs::MutPlace);
|
||||
let rhs_ty = self.check_expr_coercable_to_type(&rhs, lhs_ty);
|
||||
|
||||
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 msg = "try comparing for equality";
|
||||
let left = self.tcx.sess.source_map().span_to_snippet(lhs.span);
|
||||
let right = self.tcx.sess.source_map().span_to_snippet(rhs.span);
|
||||
if let (Ok(left), Ok(right)) = (left, right) {
|
||||
let help = format!("{} == {}", left, right);
|
||||
err.span_suggestion(expr.span, msg, help, Applicability::MaybeIncorrect);
|
||||
} else {
|
||||
err.help(msg);
|
||||
}
|
||||
err.emit();
|
||||
} else if !lhs.is_place_expr() {
|
||||
struct_span_err!(self.tcx.sess, expr.span, E0070,
|
||||
"invalid left-hand side expression")
|
||||
.span_label(expr.span, "left-hand of expression not valid")
|
||||
.emit();
|
||||
}
|
||||
|
||||
self.require_type_is_sized(lhs_ty, lhs.span, traits::AssignmentLhsSized);
|
||||
|
||||
if lhs_ty.references_error() || rhs_ty.references_error() {
|
||||
self.tcx.types.err
|
||||
} else {
|
||||
self.tcx.mk_unit()
|
||||
}
|
||||
}
|
||||
|
||||
fn check_expr_while(
|
||||
&self,
|
||||
cond: &'tcx hir::Expr,
|
||||
body: &'tcx hir::Block,
|
||||
expr: &'tcx hir::Expr
|
||||
) -> Ty<'tcx> {
|
||||
let ctxt = BreakableCtxt {
|
||||
// Cannot use break with a value from a while loop.
|
||||
coerce: None,
|
||||
may_break: false, // Will get updated if/when we find a `break`.
|
||||
};
|
||||
|
||||
let (ctxt, ()) = self.with_breakable_ctxt(expr.hir_id, ctxt, || {
|
||||
self.check_expr_has_type_or_error(&cond, self.tcx.types.bool);
|
||||
let cond_diverging = self.diverges.get();
|
||||
self.check_block_no_value(&body);
|
||||
|
||||
// We may never reach the body so it diverging means nothing.
|
||||
self.diverges.set(cond_diverging);
|
||||
});
|
||||
|
||||
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);
|
||||
}
|
||||
|
||||
self.tcx.mk_unit()
|
||||
}
|
||||
|
||||
fn check_expr_loop(
|
||||
&self,
|
||||
body: &'tcx hir::Block,
|
||||
source: hir::LoopSource,
|
||||
expected: Expectation<'tcx>,
|
||||
expr: &'tcx hir::Expr,
|
||||
) -> 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::WhileLet |
|
||||
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,
|
||||
segment: &hir::PathSegment,
|
||||
span: Span,
|
||||
args: &'tcx [hir::Expr],
|
||||
expected: Expectation<'tcx>,
|
||||
needs: Needs,
|
||||
) -> Ty<'tcx> {
|
||||
let rcvr = &args[0];
|
||||
let rcvr_t = self.check_expr_with_needs(&rcvr, needs);
|
||||
// no need to check for bot/err -- callee does that
|
||||
let rcvr_t = self.structurally_resolved_type(args[0].span, rcvr_t);
|
||||
|
||||
let method = match self.lookup_method(rcvr_t,
|
||||
segment,
|
||||
span,
|
||||
expr,
|
||||
rcvr) {
|
||||
Ok(method) => {
|
||||
self.write_method_call(expr.hir_id, method);
|
||||
Ok(method)
|
||||
}
|
||||
Err(error) => {
|
||||
if segment.ident.name != kw::Invalid {
|
||||
self.report_method_error(span,
|
||||
rcvr_t,
|
||||
segment.ident,
|
||||
SelfSource::MethodCall(rcvr),
|
||||
error,
|
||||
Some(args));
|
||||
}
|
||||
Err(())
|
||||
}
|
||||
};
|
||||
|
||||
// Call the generic checker.
|
||||
self.check_method_argument_types(span,
|
||||
expr.span,
|
||||
method,
|
||||
&args[1..],
|
||||
DontTupleArguments,
|
||||
expected)
|
||||
}
|
||||
|
||||
fn check_expr_cast(
|
||||
&self,
|
||||
e: &'tcx hir::Expr,
|
||||
t: &'tcx hir::Ty,
|
||||
expr: &'tcx hir::Expr,
|
||||
) -> 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_cast = self.resolve_vars_if_possible(&t_cast);
|
||||
|
||||
// Eagerly check for some obvious errors.
|
||||
if t_expr.references_error() || t_cast.references_error() {
|
||||
self.tcx.types.err
|
||||
} 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) => {
|
||||
deferred_cast_checks.push(cast_check);
|
||||
t_cast
|
||||
}
|
||||
Err(ErrorReported) => {
|
||||
self.tcx.types.err
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
fn check_expr_array(
|
||||
&self,
|
||||
args: &'tcx [hir::Expr],
|
||||
expected: Expectation<'tcx>,
|
||||
expr: &'tcx hir::Expr
|
||||
) -> Ty<'tcx> {
|
||||
let uty = expected.to_option(self).and_then(|uty| {
|
||||
match uty.sty {
|
||||
ty::Array(ty, _) | ty::Slice(ty) => Some(ty),
|
||||
_ => None
|
||||
}
|
||||
});
|
||||
|
||||
let element_ty = if !args.is_empty() {
|
||||
let coerce_to = uty.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,
|
||||
})
|
||||
};
|
||||
self.tcx.mk_array(element_ty, args.len() as u64)
|
||||
}
|
||||
|
||||
fn check_expr_repeat(
|
||||
&self,
|
||||
element: &'tcx hir::Expr,
|
||||
count: &'tcx hir::AnonConst,
|
||||
expected: Expectation<'tcx>,
|
||||
expr: &'tcx hir::Expr,
|
||||
) -> Ty<'tcx> {
|
||||
let tcx = self.tcx;
|
||||
let count_def_id = tcx.hir().local_def_id_from_hir_id(count.hir_id);
|
||||
let count = if self.const_param_def_id(count).is_some() {
|
||||
Ok(self.to_const(count, tcx.type_of(count_def_id)))
|
||||
} else {
|
||||
let param_env = ty::ParamEnv::empty();
|
||||
let substs = InternalSubsts::identity_for_item(tcx.global_tcx(), count_def_id);
|
||||
let instance = ty::Instance::resolve(
|
||||
tcx.global_tcx(),
|
||||
param_env,
|
||||
count_def_id,
|
||||
substs,
|
||||
).unwrap();
|
||||
let global_id = GlobalId {
|
||||
instance,
|
||||
promoted: None
|
||||
};
|
||||
|
||||
tcx.const_eval(param_env.and(global_id))
|
||||
};
|
||||
|
||||
let uty = match expected {
|
||||
ExpectHasType(uty) => {
|
||||
match uty.sty {
|
||||
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);
|
||||
(uty, uty)
|
||||
}
|
||||
None => {
|
||||
let ty = self.next_ty_var(TypeVariableOrigin {
|
||||
kind: TypeVariableOriginKind::MiscVariable,
|
||||
span: element.span,
|
||||
});
|
||||
let element_ty = self.check_expr_has_type_or_error(&element, ty);
|
||||
(element_ty, ty)
|
||||
}
|
||||
};
|
||||
|
||||
if let Ok(count) = count {
|
||||
let zero_or_one = count.assert_usize(tcx).map_or(false, |count| count <= 1);
|
||||
if !zero_or_one {
|
||||
// For [foo, ..n] where n > 1, `foo` must have
|
||||
// Copy type:
|
||||
let lang_item = tcx.require_lang_item(lang_items::CopyTraitLangItem);
|
||||
self.require_type_meets(t, expr.span, traits::RepeatVec, lang_item);
|
||||
}
|
||||
}
|
||||
|
||||
if element_ty.references_error() {
|
||||
tcx.types.err
|
||||
} else if let Ok(count) = count {
|
||||
tcx.mk_ty(ty::Array(t, count))
|
||||
} else {
|
||||
tcx.types.err
|
||||
}
|
||||
}
|
||||
|
||||
fn check_expr_tuple(
|
||||
&self,
|
||||
elts: &'tcx [hir::Expr],
|
||||
expected: Expectation<'tcx>,
|
||||
expr: &'tcx hir::Expr,
|
||||
) -> Ty<'tcx> {
|
||||
let flds = expected.only_has_type(self).and_then(|ty| {
|
||||
let ty = self.resolve_type_vars_with_obligations(ty);
|
||||
match ty.sty {
|
||||
ty::Tuple(ref flds) => Some(&flds[..]),
|
||||
_ => None
|
||||
}
|
||||
});
|
||||
|
||||
let elt_ts_iter = elts.iter().enumerate().map(|(i, e)| {
|
||||
let t = match flds {
|
||||
Some(ref fs) if i < fs.len() => {
|
||||
let ety = fs[i].expect_ty();
|
||||
self.check_expr_coercable_to_type(&e, ety);
|
||||
ety
|
||||
}
|
||||
_ => {
|
||||
self.check_expr_with_expectation(&e, NoExpectation)
|
||||
}
|
||||
};
|
||||
t
|
||||
});
|
||||
let tuple = self.tcx.mk_tup(elt_ts_iter);
|
||||
if tuple.references_error() {
|
||||
self.tcx.types.err
|
||||
} 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::Field],
|
||||
base_expr: &'tcx Option<P<hir::Expr>>,
|
||||
) -> Ty<'tcx> {
|
||||
// Find the relevant variant
|
||||
let (variant, adt_ty) =
|
||||
if let Some(variant_ty) = self.check_struct_path(qpath, expr.hir_id) {
|
||||
variant_ty
|
||||
} else {
|
||||
self.check_struct_fields_on_error(fields, base_expr);
|
||||
return self.tcx.types.err;
|
||||
};
|
||||
|
||||
let path_span = match *qpath {
|
||||
QPath::Resolved(_, ref path) => path.span,
|
||||
QPath::TypeRelative(ref qself, _) => qself.span
|
||||
};
|
||||
|
||||
// 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() {
|
||||
span_err!(self.tcx.sess, expr.span, E0639,
|
||||
"cannot create non-exhaustive {} using struct expression",
|
||||
adt.variant_descr());
|
||||
}
|
||||
|
||||
let error_happened = self.check_expr_struct_fields(adt_ty, expected, expr.hir_id, path_span,
|
||||
variant, fields, base_expr.is_none());
|
||||
if let &Some(ref base_expr) = base_expr {
|
||||
// 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 {
|
||||
self.check_expr_has_type_or_error(base_expr, adt_ty);
|
||||
match adt_ty.sty {
|
||||
ty::Adt(adt, substs) if adt.is_struct() => {
|
||||
let fru_field_types = adt.non_enum_variant().fields.iter().map(|f| {
|
||||
self.normalize_associated_types_in(expr.span, &f.ty(self.tcx, substs))
|
||||
}).collect();
|
||||
|
||||
self.tables
|
||||
.borrow_mut()
|
||||
.fru_field_types_mut()
|
||||
.insert(expr.hir_id, fru_field_types);
|
||||
}
|
||||
_ => {
|
||||
span_err!(self.tcx.sess, base_expr.span, E0436,
|
||||
"functional record update syntax requires a struct");
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
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::Field],
|
||||
check_completeness: bool,
|
||||
) -> bool {
|
||||
let tcx = self.tcx;
|
||||
|
||||
let adt_ty_hint =
|
||||
self.expected_inputs_for_expected_output(span, expected, adt_ty, &[adt_ty])
|
||||
.get(0).cloned().unwrap_or(adt_ty);
|
||||
// re-link the regions that EIfEO can erase.
|
||||
self.demand_eqtype(span, adt_ty_hint, adt_ty);
|
||||
|
||||
let (substs, adt_kind, kind_name) = match &adt_ty.sty {
|
||||
&ty::Adt(adt, substs) => {
|
||||
(substs, adt.adt_kind(), adt.variant_descr())
|
||||
}
|
||||
_ => span_bug!(span, "non-ADT passed to check_expr_struct_fields")
|
||||
};
|
||||
|
||||
let mut remaining_fields = variant.fields.iter().enumerate().map(|(i, field)|
|
||||
(field.ident.modern(), (i, field))
|
||||
).collect::<FxHashMap<_, _>>();
|
||||
|
||||
let mut seen_fields = FxHashMap::default();
|
||||
|
||||
let mut error_happened = false;
|
||||
|
||||
// Type-check each field.
|
||||
for field in ast_fields {
|
||||
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);
|
||||
}
|
||||
|
||||
self.field_ty(field.span, v_field, substs)
|
||||
} else {
|
||||
error_happened = true;
|
||||
if let Some(prev_span) = seen_fields.get(&ident) {
|
||||
let mut err = struct_span_err!(self.tcx.sess,
|
||||
field.ident.span,
|
||||
E0062,
|
||||
"field `{}` specified more than once",
|
||||
ident);
|
||||
|
||||
err.span_label(field.ident.span, "used more than once");
|
||||
err.span_label(*prev_span, format!("first use of `{}`", ident));
|
||||
|
||||
err.emit();
|
||||
} else {
|
||||
self.report_unknown_field(adt_ty, variant, field, ast_fields, kind_name);
|
||||
}
|
||||
|
||||
tcx.types.err
|
||||
};
|
||||
|
||||
// Make sure to give a type to the field even if there's
|
||||
// an error, so we can continue type-checking.
|
||||
self.check_expr_coercable_to_type(&field.expr, field_type);
|
||||
}
|
||||
|
||||
// Make sure the programmer specified correct number of fields.
|
||||
if kind_name == "union" {
|
||||
if ast_fields.len() != 1 {
|
||||
tcx.sess.span_err(span, "union expressions should have exactly one field");
|
||||
}
|
||||
} else if check_completeness && !error_happened && !remaining_fields.is_empty() {
|
||||
let len = remaining_fields.len();
|
||||
|
||||
let mut displayable_field_names = remaining_fields
|
||||
.keys()
|
||||
.map(|ident| ident.as_str())
|
||||
.collect::<Vec<_>>();
|
||||
|
||||
displayable_field_names.sort();
|
||||
|
||||
let truncated_fields_error = if len <= 3 {
|
||||
String::new()
|
||||
} else {
|
||||
format!(" and {} other field{}", (len - 3), if len - 3 == 1 {""} else {"s"})
|
||||
};
|
||||
|
||||
let remaining_fields_names = displayable_field_names.iter().take(3)
|
||||
.map(|n| format!("`{}`", n))
|
||||
.collect::<Vec<_>>()
|
||||
.join(", ");
|
||||
|
||||
struct_span_err!(tcx.sess, span, E0063,
|
||||
"missing field{} {}{} in initializer of `{}`",
|
||||
if remaining_fields.len() == 1 { "" } else { "s" },
|
||||
remaining_fields_names,
|
||||
truncated_fields_error,
|
||||
adt_ty)
|
||||
.span_label(span, format!("missing {}{}",
|
||||
remaining_fields_names,
|
||||
truncated_fields_error))
|
||||
.emit();
|
||||
}
|
||||
error_happened
|
||||
}
|
||||
|
||||
fn check_struct_fields_on_error(
|
||||
&self,
|
||||
fields: &'tcx [hir::Field],
|
||||
base_expr: &'tcx Option<P<hir::Expr>>,
|
||||
) {
|
||||
for field in fields {
|
||||
self.check_expr(&field.expr);
|
||||
}
|
||||
if let Some(ref base) = *base_expr {
|
||||
self.check_expr(&base);
|
||||
}
|
||||
}
|
||||
|
||||
fn report_unknown_field(
|
||||
&self,
|
||||
ty: Ty<'tcx>,
|
||||
variant: &'tcx ty::VariantDef,
|
||||
field: &hir::Field,
|
||||
skip_fields: &[hir::Field],
|
||||
kind_name: &str,
|
||||
) {
|
||||
if variant.recovered {
|
||||
return;
|
||||
}
|
||||
let mut err = self.type_error_struct_with_diag(
|
||||
field.ident.span,
|
||||
|actual| match ty.sty {
|
||||
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.ident, field.ident)
|
||||
}
|
||||
_ => {
|
||||
struct_span_err!(self.tcx.sess, field.ident.span, E0560,
|
||||
"{} `{}` has no field named `{}`",
|
||||
kind_name, actual, field.ident)
|
||||
}
|
||||
},
|
||||
ty);
|
||||
// prevent all specified fields from being suggested
|
||||
let skip_fields = skip_fields.iter().map(|ref x| x.ident.as_str());
|
||||
if let Some(field_name) = Self::suggest_field_name(variant,
|
||||
&field.ident.as_str(),
|
||||
skip_fields.collect()) {
|
||||
err.span_suggestion(
|
||||
field.ident.span,
|
||||
"a field with a similar name exists",
|
||||
field_name.to_string(),
|
||||
Applicability::MaybeIncorrect,
|
||||
);
|
||||
} else {
|
||||
match ty.sty {
|
||||
ty::Adt(adt, ..) => {
|
||||
if adt.is_enum() {
|
||||
err.span_label(field.ident.span,
|
||||
format!("`{}::{}` does not have this field",
|
||||
ty, variant.ident));
|
||||
} else {
|
||||
err.span_label(field.ident.span,
|
||||
format!("`{}` does not have this field", ty));
|
||||
}
|
||||
let available_field_names = self.available_field_names(variant);
|
||||
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 an hint about the closest match in field names
|
||||
fn suggest_field_name(variant: &'tcx ty::VariantDef,
|
||||
field: &str,
|
||||
skip: Vec<LocalInternedString>)
|
||||
-> Option<Symbol> {
|
||||
let names = variant.fields.iter().filter_map(|field| {
|
||||
// ignore already set fields and private fields from non-local crates
|
||||
if skip.iter().any(|x| *x == field.ident.as_str()) ||
|
||||
(!variant.def_id.is_local() && field.vis != Visibility::Public)
|
||||
{
|
||||
None
|
||||
} else {
|
||||
Some(&field.ident.name)
|
||||
}
|
||||
});
|
||||
|
||||
find_best_match_for_name(names, field, None)
|
||||
}
|
||||
|
||||
fn available_field_names(&self, variant: &'tcx ty::VariantDef) -> Vec<ast::Name> {
|
||||
variant.fields.iter().filter(|field| {
|
||||
let def_scope =
|
||||
self.tcx.adjust_ident_and_get_scope(field.ident, variant.def_id, self.body_id).1;
|
||||
field.vis.is_accessible_from(def_scope, self.tcx)
|
||||
})
|
||||
.map(|field| field.ident.name)
|
||||
.collect()
|
||||
}
|
||||
|
||||
fn name_series_display(&self, names: Vec<ast::Name>) -> 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,
|
||||
needs: Needs,
|
||||
base: &'tcx hir::Expr,
|
||||
field: ast::Ident,
|
||||
) -> Ty<'tcx> {
|
||||
let expr_t = self.check_expr_with_needs(base, needs);
|
||||
let expr_t = self.structurally_resolved_type(base.span,
|
||||
expr_t);
|
||||
let mut private_candidate = None;
|
||||
let mut autoderef = self.autoderef(expr.span, expr_t);
|
||||
while let Some((base_t, _)) = autoderef.next() {
|
||||
match base_t.sty {
|
||||
ty::Adt(base_def, substs) if !base_def.is_enum() => {
|
||||
debug!("struct named {:?}", base_t);
|
||||
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.modern() == 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);
|
||||
if field.vis.is_accessible_from(def_scope, self.tcx) {
|
||||
let adjustments = autoderef.adjust_steps(self, needs);
|
||||
self.apply_adjustments(base, adjustments);
|
||||
autoderef.finalize(self);
|
||||
|
||||
self.tcx.check_stability(field.did, Some(expr.hir_id), expr.span);
|
||||
return field_ty;
|
||||
}
|
||||
private_candidate = Some((base_def.did, field_ty));
|
||||
}
|
||||
}
|
||||
ty::Tuple(ref 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 = autoderef.adjust_steps(self, needs);
|
||||
self.apply_adjustments(base, adjustments);
|
||||
autoderef.finalize(self);
|
||||
|
||||
self.write_field_index(expr.hir_id, index);
|
||||
return field_ty.expect_ty();
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
_ => {}
|
||||
}
|
||||
}
|
||||
autoderef.unambiguous_final_ty(self);
|
||||
|
||||
if let Some((did, field_ty)) = private_candidate {
|
||||
let struct_path = self.tcx().def_path_str(did);
|
||||
let mut err = struct_span_err!(self.tcx().sess, expr.span, E0616,
|
||||
"field `{}` of struct `{}` is private",
|
||||
field, struct_path);
|
||||
// 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 `{}` also exists, call it with parentheses", field),
|
||||
field,
|
||||
expr_t,
|
||||
expr.hir_id,
|
||||
);
|
||||
}
|
||||
err.emit();
|
||||
field_ty
|
||||
} else if field.name == kw::Invalid {
|
||||
self.tcx().types.err
|
||||
} else if self.method_exists(field, expr_t, expr.hir_id, true) {
|
||||
let mut err = type_error_struct!(self.tcx().sess, field.span, expr_t, E0615,
|
||||
"attempted to take value of method `{}` on type `{}`",
|
||||
field, expr_t);
|
||||
|
||||
if !self.expr_in_place(expr.hir_id) {
|
||||
self.suggest_method_call(
|
||||
&mut err,
|
||||
"use parentheses to call the method",
|
||||
field,
|
||||
expr_t,
|
||||
expr.hir_id
|
||||
);
|
||||
} else {
|
||||
err.help("methods are immutable and cannot be assigned to");
|
||||
}
|
||||
|
||||
err.emit();
|
||||
self.tcx().types.err
|
||||
} else {
|
||||
if !expr_t.is_primitive_ty() {
|
||||
let mut err = self.no_such_field_err(field.span, field, expr_t);
|
||||
|
||||
match expr_t.sty {
|
||||
ty::Adt(def, _) if !def.is_enum() => {
|
||||
if let Some(suggested_field_name) =
|
||||
Self::suggest_field_name(def.non_enum_variant(),
|
||||
&field.as_str(), vec![]) {
|
||||
err.span_suggestion(
|
||||
field.span,
|
||||
"a field with a similar name exists",
|
||||
suggested_field_name.to_string(),
|
||||
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);
|
||||
if !field_names.is_empty() {
|
||||
err.note(&format!("available fields are: {}",
|
||||
self.name_series_display(field_names)));
|
||||
}
|
||||
};
|
||||
}
|
||||
ty::Array(_, len) => {
|
||||
if let (Some(len), Ok(user_index)) = (
|
||||
len.assert_usize(self.tcx),
|
||||
field.as_str().parse::<u64>()
|
||||
) {
|
||||
let base = self.tcx.sess.source_map()
|
||||
.span_to_snippet(base.span)
|
||||
.unwrap_or_else(|_|
|
||||
self.tcx.hir().hir_to_pretty_string(base.hir_id));
|
||||
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
|
||||
);
|
||||
}
|
||||
}
|
||||
ty::RawPtr(..) => {
|
||||
let base = self.tcx.sess.source_map()
|
||||
.span_to_snippet(base.span)
|
||||
.unwrap_or_else(|_| self.tcx.hir().hir_to_pretty_string(base.hir_id));
|
||||
let msg = format!("`{}` is a raw pointer; try dereferencing it", base);
|
||||
let suggestion = format!("(*{}).{}", base, field);
|
||||
err.span_suggestion(
|
||||
expr.span,
|
||||
&msg,
|
||||
suggestion,
|
||||
Applicability::MaybeIncorrect,
|
||||
);
|
||||
}
|
||||
_ => {}
|
||||
}
|
||||
err
|
||||
} else {
|
||||
type_error_struct!(self.tcx().sess, field.span, expr_t, E0610,
|
||||
"`{}` is a primitive type and therefore doesn't have fields",
|
||||
expr_t)
|
||||
}.emit();
|
||||
self.tcx().types.err
|
||||
}
|
||||
}
|
||||
|
||||
fn no_such_field_err<T: Display>(&self, span: Span, field: T, expr_t: &ty::TyS<'_>)
|
||||
-> DiagnosticBuilder<'_> {
|
||||
type_error_struct!(self.tcx().sess, span, expr_t, E0609,
|
||||
"no field `{}` on type `{}`",
|
||||
field, expr_t)
|
||||
}
|
||||
|
||||
fn check_expr_index(
|
||||
&self,
|
||||
base: &'tcx hir::Expr,
|
||||
idx: &'tcx hir::Expr,
|
||||
needs: Needs,
|
||||
expr: &'tcx hir::Expr,
|
||||
) -> Ty<'tcx> {
|
||||
let base_t = self.check_expr_with_needs(&base, needs);
|
||||
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_t, needs) {
|
||||
Some((index_ty, element_ty)) => {
|
||||
// two-phase not needed because index_ty is never mutable
|
||||
self.demand_coerce(idx, idx_t, index_ty, AllowTwoPhase::No);
|
||||
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.sty {
|
||||
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.node {
|
||||
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.types.err
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
fn check_expr_yield(&self, value: &'tcx hir::Expr, expr: &'tcx hir::Expr) -> Ty<'tcx> {
|
||||
match self.yield_ty {
|
||||
Some(ty) => {
|
||||
self.check_expr_coercable_to_type(&value, ty);
|
||||
}
|
||||
None => {
|
||||
struct_span_err!(self.tcx.sess, expr.span, E0627,
|
||||
"yield statement outside of generator literal").emit();
|
||||
}
|
||||
}
|
||||
self.tcx.mk_unit()
|
||||
}
|
||||
}
|
||||
@@ -74,6 +74,7 @@
|
||||
mod regionck;
|
||||
pub mod coercion;
|
||||
pub mod demand;
|
||||
mod expr;
|
||||
pub mod method;
|
||||
mod upvar;
|
||||
mod wfcheck;
|
||||
@@ -88,7 +89,7 @@
|
||||
use crate::astconv::{AstConv, PathSeg};
|
||||
use errors::{Applicability, DiagnosticBuilder, DiagnosticId};
|
||||
use rustc::hir::{self, ExprKind, GenericArg, ItemKind, Node, PatKind, QPath};
|
||||
use rustc::hir::def::{CtorOf, CtorKind, Res, DefKind};
|
||||
use rustc::hir::def::{CtorOf, Res, DefKind};
|
||||
use rustc::hir::def_id::{CrateNum, DefId, LOCAL_CRATE};
|
||||
use rustc::hir::intravisit::{self, Visitor, NestedVisitorMap};
|
||||
use rustc::hir::itemlikevisit::ItemLikeVisitor;
|
||||
@@ -105,7 +106,7 @@
|
||||
use rustc::mir::interpret::{ConstValue, GlobalId};
|
||||
use rustc::traits::{self, ObligationCause, ObligationCauseCode, TraitEngine};
|
||||
use rustc::ty::{
|
||||
self, AdtKind, CanonicalUserType, Ty, TyCtxt, Const, GenericParamDefKind, Visibility,
|
||||
self, AdtKind, CanonicalUserType, Ty, TyCtxt, Const, GenericParamDefKind,
|
||||
ToPolyTraitRef, ToPredicate, RegionKind, UserType
|
||||
};
|
||||
use rustc::ty::adjustment::{
|
||||
@@ -123,13 +124,11 @@
|
||||
use syntax::feature_gate::{GateIssue, emit_feature_err};
|
||||
use syntax::ptr::P;
|
||||
use syntax::source_map::{DUMMY_SP, original_sp};
|
||||
use syntax::symbol::{Symbol, LocalInternedString, kw, sym};
|
||||
use syntax::util::lev_distance::find_best_match_for_name;
|
||||
use syntax::symbol::{kw, sym};
|
||||
|
||||
use std::cell::{Cell, RefCell, Ref, RefMut};
|
||||
use std::collections::hash_map::Entry;
|
||||
use std::cmp;
|
||||
use std::fmt::Display;
|
||||
use std::iter;
|
||||
use std::mem::replace;
|
||||
use std::ops::{self, Deref};
|
||||
@@ -142,7 +141,7 @@
|
||||
use crate::lint;
|
||||
use crate::util::captures::Captures;
|
||||
use crate::util::common::{ErrorReported, indenter};
|
||||
use crate::util::nodemap::{DefIdMap, DefIdSet, FxHashMap, FxHashSet, HirIdMap};
|
||||
use crate::util::nodemap::{DefIdMap, DefIdSet, FxHashSet, HirIdMap};
|
||||
|
||||
pub use self::Expectation::*;
|
||||
use self::autoderef::Autoderef;
|
||||
@@ -3196,82 +3195,6 @@ fn check_lit(&self,
|
||||
}
|
||||
}
|
||||
|
||||
fn check_expr_eq_type(&self, expr: &'tcx hir::Expr, expected: Ty<'tcx>) {
|
||||
let ty = self.check_expr_with_hint(expr, expected);
|
||||
self.demand_eqtype(expr.span, expected, ty);
|
||||
}
|
||||
|
||||
pub fn check_expr_has_type_or_error(
|
||||
&self,
|
||||
expr: &'tcx hir::Expr,
|
||||
expected: Ty<'tcx>,
|
||||
) -> Ty<'tcx> {
|
||||
self.check_expr_meets_expectation_or_error(expr, ExpectHasType(expected))
|
||||
}
|
||||
|
||||
fn check_expr_meets_expectation_or_error(
|
||||
&self,
|
||||
expr: &'tcx hir::Expr,
|
||||
expected: Expectation<'tcx>,
|
||||
) -> Ty<'tcx> {
|
||||
let expected_ty = expected.to_option(&self).unwrap_or(self.tcx.types.bool);
|
||||
let mut ty = self.check_expr_with_expectation(expr, expected);
|
||||
|
||||
// While we don't allow *arbitrary* coercions here, we *do* allow
|
||||
// coercions from ! to `expected`.
|
||||
if ty.is_never() {
|
||||
assert!(!self.tables.borrow().adjustments().contains_key(expr.hir_id),
|
||||
"expression with never type wound up being adjusted");
|
||||
let adj_ty = self.next_diverging_ty_var(
|
||||
TypeVariableOrigin {
|
||||
kind: TypeVariableOriginKind::AdjustmentType,
|
||||
span: expr.span,
|
||||
},
|
||||
);
|
||||
self.apply_adjustments(expr, vec![Adjustment {
|
||||
kind: Adjust::NeverToAny,
|
||||
target: adj_ty
|
||||
}]);
|
||||
ty = adj_ty;
|
||||
}
|
||||
|
||||
if let Some(mut err) = self.demand_suptype_diag(expr.span, expected_ty, ty) {
|
||||
let expr = match &expr.node {
|
||||
ExprKind::DropTemps(expr) => expr,
|
||||
_ => expr,
|
||||
};
|
||||
// Error possibly reported in `check_assign` so avoid emitting error again.
|
||||
err.emit_unless(self.is_assign_to_bool(expr, expected_ty));
|
||||
}
|
||||
ty
|
||||
}
|
||||
|
||||
fn check_expr_coercable_to_type(&self, expr: &'tcx hir::Expr, expected: Ty<'tcx>) -> Ty<'tcx> {
|
||||
let ty = self.check_expr_with_hint(expr, expected);
|
||||
// checks don't need two phase
|
||||
self.demand_coerce(expr, ty, expected, AllowTwoPhase::No)
|
||||
}
|
||||
|
||||
fn check_expr_with_hint(&self, expr: &'tcx hir::Expr, expected: Ty<'tcx>) -> Ty<'tcx> {
|
||||
self.check_expr_with_expectation(expr, ExpectHasType(expected))
|
||||
}
|
||||
|
||||
fn check_expr_with_expectation(
|
||||
&self,
|
||||
expr: &'tcx hir::Expr,
|
||||
expected: Expectation<'tcx>,
|
||||
) -> Ty<'tcx> {
|
||||
self.check_expr_with_expectation_and_needs(expr, expected, Needs::None)
|
||||
}
|
||||
|
||||
fn check_expr(&self, expr: &'tcx hir::Expr) -> Ty<'tcx> {
|
||||
self.check_expr_with_expectation(expr, NoExpectation)
|
||||
}
|
||||
|
||||
fn check_expr_with_needs(&self, expr: &'tcx hir::Expr, needs: Needs) -> Ty<'tcx> {
|
||||
self.check_expr_with_expectation_and_needs(expr, NoExpectation, needs)
|
||||
}
|
||||
|
||||
// Determine the `Self` type, using fresh variables for all variables
|
||||
// declared on the impl declaration e.g., `impl<A,B> for Vec<(A,B)>`
|
||||
// would return `($0, $1)` where `$0` and `$1` are freshly instantiated type
|
||||
@@ -3341,470 +3264,6 @@ fn expected_inputs_for_expected_output(&self,
|
||||
expect_args
|
||||
}
|
||||
|
||||
// Checks a method call.
|
||||
fn check_method_call(
|
||||
&self,
|
||||
expr: &'tcx hir::Expr,
|
||||
segment: &hir::PathSegment,
|
||||
span: Span,
|
||||
args: &'tcx [hir::Expr],
|
||||
expected: Expectation<'tcx>,
|
||||
needs: Needs,
|
||||
) -> Ty<'tcx> {
|
||||
let rcvr = &args[0];
|
||||
let rcvr_t = self.check_expr_with_needs(&rcvr, needs);
|
||||
// no need to check for bot/err -- callee does that
|
||||
let rcvr_t = self.structurally_resolved_type(args[0].span, rcvr_t);
|
||||
|
||||
let method = match self.lookup_method(rcvr_t,
|
||||
segment,
|
||||
span,
|
||||
expr,
|
||||
rcvr) {
|
||||
Ok(method) => {
|
||||
self.write_method_call(expr.hir_id, method);
|
||||
Ok(method)
|
||||
}
|
||||
Err(error) => {
|
||||
if segment.ident.name != kw::Invalid {
|
||||
self.report_method_error(span,
|
||||
rcvr_t,
|
||||
segment.ident,
|
||||
SelfSource::MethodCall(rcvr),
|
||||
error,
|
||||
Some(args));
|
||||
}
|
||||
Err(())
|
||||
}
|
||||
};
|
||||
|
||||
// Call the generic checker.
|
||||
self.check_method_argument_types(span,
|
||||
expr.span,
|
||||
method,
|
||||
&args[1..],
|
||||
DontTupleArguments,
|
||||
expected)
|
||||
}
|
||||
|
||||
fn check_return_expr(&self, return_expr: &'tcx hir::Expr) {
|
||||
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.clone());
|
||||
ret_coercion.borrow_mut()
|
||||
.coerce(self,
|
||||
&self.cause(return_expr.span,
|
||||
ObligationCauseCode::ReturnType(return_expr.hir_id)),
|
||||
return_expr,
|
||||
return_expr_ty);
|
||||
}
|
||||
|
||||
// Check field access expressions
|
||||
fn check_field(
|
||||
&self,
|
||||
expr: &'tcx hir::Expr,
|
||||
needs: Needs,
|
||||
base: &'tcx hir::Expr,
|
||||
field: ast::Ident,
|
||||
) -> Ty<'tcx> {
|
||||
let expr_t = self.check_expr_with_needs(base, needs);
|
||||
let expr_t = self.structurally_resolved_type(base.span,
|
||||
expr_t);
|
||||
let mut private_candidate = None;
|
||||
let mut autoderef = self.autoderef(expr.span, expr_t);
|
||||
while let Some((base_t, _)) = autoderef.next() {
|
||||
match base_t.sty {
|
||||
ty::Adt(base_def, substs) if !base_def.is_enum() => {
|
||||
debug!("struct named {:?}", base_t);
|
||||
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.modern() == 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);
|
||||
if field.vis.is_accessible_from(def_scope, self.tcx) {
|
||||
let adjustments = autoderef.adjust_steps(self, needs);
|
||||
self.apply_adjustments(base, adjustments);
|
||||
autoderef.finalize(self);
|
||||
|
||||
self.tcx.check_stability(field.did, Some(expr.hir_id), expr.span);
|
||||
return field_ty;
|
||||
}
|
||||
private_candidate = Some((base_def.did, field_ty));
|
||||
}
|
||||
}
|
||||
ty::Tuple(ref 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 = autoderef.adjust_steps(self, needs);
|
||||
self.apply_adjustments(base, adjustments);
|
||||
autoderef.finalize(self);
|
||||
|
||||
self.write_field_index(expr.hir_id, index);
|
||||
return field_ty.expect_ty();
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
_ => {}
|
||||
}
|
||||
}
|
||||
autoderef.unambiguous_final_ty(self);
|
||||
|
||||
if let Some((did, field_ty)) = private_candidate {
|
||||
let struct_path = self.tcx().def_path_str(did);
|
||||
let mut err = struct_span_err!(self.tcx().sess, expr.span, E0616,
|
||||
"field `{}` of struct `{}` is private",
|
||||
field, struct_path);
|
||||
// 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 `{}` also exists, call it with parentheses", field),
|
||||
field,
|
||||
expr_t,
|
||||
expr.hir_id,
|
||||
);
|
||||
}
|
||||
err.emit();
|
||||
field_ty
|
||||
} else if field.name == kw::Invalid {
|
||||
self.tcx().types.err
|
||||
} else if self.method_exists(field, expr_t, expr.hir_id, true) {
|
||||
let mut err = type_error_struct!(self.tcx().sess, field.span, expr_t, E0615,
|
||||
"attempted to take value of method `{}` on type `{}`",
|
||||
field, expr_t);
|
||||
|
||||
if !self.expr_in_place(expr.hir_id) {
|
||||
self.suggest_method_call(
|
||||
&mut err,
|
||||
"use parentheses to call the method",
|
||||
field,
|
||||
expr_t,
|
||||
expr.hir_id
|
||||
);
|
||||
} else {
|
||||
err.help("methods are immutable and cannot be assigned to");
|
||||
}
|
||||
|
||||
err.emit();
|
||||
self.tcx().types.err
|
||||
} else {
|
||||
if !expr_t.is_primitive_ty() {
|
||||
let mut err = self.no_such_field_err(field.span, field, expr_t);
|
||||
|
||||
match expr_t.sty {
|
||||
ty::Adt(def, _) if !def.is_enum() => {
|
||||
if let Some(suggested_field_name) =
|
||||
Self::suggest_field_name(def.non_enum_variant(),
|
||||
&field.as_str(), vec![]) {
|
||||
err.span_suggestion(
|
||||
field.span,
|
||||
"a field with a similar name exists",
|
||||
suggested_field_name.to_string(),
|
||||
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);
|
||||
if !field_names.is_empty() {
|
||||
err.note(&format!("available fields are: {}",
|
||||
self.name_series_display(field_names)));
|
||||
}
|
||||
};
|
||||
}
|
||||
ty::Array(_, len) => {
|
||||
if let (Some(len), Ok(user_index)) = (
|
||||
len.assert_usize(self.tcx),
|
||||
field.as_str().parse::<u64>()
|
||||
) {
|
||||
let base = self.tcx.sess.source_map()
|
||||
.span_to_snippet(base.span)
|
||||
.unwrap_or_else(|_|
|
||||
self.tcx.hir().hir_to_pretty_string(base.hir_id));
|
||||
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
|
||||
);
|
||||
}
|
||||
}
|
||||
ty::RawPtr(..) => {
|
||||
let base = self.tcx.sess.source_map()
|
||||
.span_to_snippet(base.span)
|
||||
.unwrap_or_else(|_| self.tcx.hir().hir_to_pretty_string(base.hir_id));
|
||||
let msg = format!("`{}` is a raw pointer; try dereferencing it", base);
|
||||
let suggestion = format!("(*{}).{}", base, field);
|
||||
err.span_suggestion(
|
||||
expr.span,
|
||||
&msg,
|
||||
suggestion,
|
||||
Applicability::MaybeIncorrect,
|
||||
);
|
||||
}
|
||||
_ => {}
|
||||
}
|
||||
err
|
||||
} else {
|
||||
type_error_struct!(self.tcx().sess, field.span, expr_t, E0610,
|
||||
"`{}` is a primitive type and therefore doesn't have fields",
|
||||
expr_t)
|
||||
}.emit();
|
||||
self.tcx().types.err
|
||||
}
|
||||
}
|
||||
|
||||
// Return an hint about the closest match in field names
|
||||
fn suggest_field_name(variant: &'tcx ty::VariantDef,
|
||||
field: &str,
|
||||
skip: Vec<LocalInternedString>)
|
||||
-> Option<Symbol> {
|
||||
let names = variant.fields.iter().filter_map(|field| {
|
||||
// ignore already set fields and private fields from non-local crates
|
||||
if skip.iter().any(|x| *x == field.ident.as_str()) ||
|
||||
(!variant.def_id.is_local() && field.vis != Visibility::Public)
|
||||
{
|
||||
None
|
||||
} else {
|
||||
Some(&field.ident.name)
|
||||
}
|
||||
});
|
||||
|
||||
find_best_match_for_name(names, field, None)
|
||||
}
|
||||
|
||||
fn available_field_names(&self, variant: &'tcx ty::VariantDef) -> Vec<ast::Name> {
|
||||
variant.fields.iter().filter(|field| {
|
||||
let def_scope =
|
||||
self.tcx.adjust_ident_and_get_scope(field.ident, variant.def_id, self.body_id).1;
|
||||
field.vis.is_accessible_from(def_scope, self.tcx)
|
||||
})
|
||||
.map(|field| field.ident.name)
|
||||
.collect()
|
||||
}
|
||||
|
||||
fn name_series_display(&self, names: Vec<ast::Name>) -> 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
|
||||
}
|
||||
|
||||
fn no_such_field_err<T: Display>(&self, span: Span, field: T, expr_t: &ty::TyS<'_>)
|
||||
-> DiagnosticBuilder<'_> {
|
||||
type_error_struct!(self.tcx().sess, span, expr_t, E0609,
|
||||
"no field `{}` on type `{}`",
|
||||
field, expr_t)
|
||||
}
|
||||
|
||||
fn report_unknown_field(
|
||||
&self,
|
||||
ty: Ty<'tcx>,
|
||||
variant: &'tcx ty::VariantDef,
|
||||
field: &hir::Field,
|
||||
skip_fields: &[hir::Field],
|
||||
kind_name: &str,
|
||||
) {
|
||||
if variant.recovered {
|
||||
return;
|
||||
}
|
||||
let mut err = self.type_error_struct_with_diag(
|
||||
field.ident.span,
|
||||
|actual| match ty.sty {
|
||||
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.ident, field.ident)
|
||||
}
|
||||
_ => {
|
||||
struct_span_err!(self.tcx.sess, field.ident.span, E0560,
|
||||
"{} `{}` has no field named `{}`",
|
||||
kind_name, actual, field.ident)
|
||||
}
|
||||
},
|
||||
ty);
|
||||
// prevent all specified fields from being suggested
|
||||
let skip_fields = skip_fields.iter().map(|ref x| x.ident.as_str());
|
||||
if let Some(field_name) = Self::suggest_field_name(variant,
|
||||
&field.ident.as_str(),
|
||||
skip_fields.collect()) {
|
||||
err.span_suggestion(
|
||||
field.ident.span,
|
||||
"a field with a similar name exists",
|
||||
field_name.to_string(),
|
||||
Applicability::MaybeIncorrect,
|
||||
);
|
||||
} else {
|
||||
match ty.sty {
|
||||
ty::Adt(adt, ..) => {
|
||||
if adt.is_enum() {
|
||||
err.span_label(field.ident.span,
|
||||
format!("`{}::{}` does not have this field",
|
||||
ty, variant.ident));
|
||||
} else {
|
||||
err.span_label(field.ident.span,
|
||||
format!("`{}` does not have this field", ty));
|
||||
}
|
||||
let available_field_names = self.available_field_names(variant);
|
||||
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();
|
||||
}
|
||||
|
||||
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::Field],
|
||||
check_completeness: bool,
|
||||
) -> bool {
|
||||
let tcx = self.tcx;
|
||||
|
||||
let adt_ty_hint =
|
||||
self.expected_inputs_for_expected_output(span, expected, adt_ty, &[adt_ty])
|
||||
.get(0).cloned().unwrap_or(adt_ty);
|
||||
// re-link the regions that EIfEO can erase.
|
||||
self.demand_eqtype(span, adt_ty_hint, adt_ty);
|
||||
|
||||
let (substs, adt_kind, kind_name) = match &adt_ty.sty {
|
||||
&ty::Adt(adt, substs) => {
|
||||
(substs, adt.adt_kind(), adt.variant_descr())
|
||||
}
|
||||
_ => span_bug!(span, "non-ADT passed to check_expr_struct_fields")
|
||||
};
|
||||
|
||||
let mut remaining_fields = variant.fields.iter().enumerate().map(|(i, field)|
|
||||
(field.ident.modern(), (i, field))
|
||||
).collect::<FxHashMap<_, _>>();
|
||||
|
||||
let mut seen_fields = FxHashMap::default();
|
||||
|
||||
let mut error_happened = false;
|
||||
|
||||
// Type-check each field.
|
||||
for field in ast_fields {
|
||||
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);
|
||||
}
|
||||
|
||||
self.field_ty(field.span, v_field, substs)
|
||||
} else {
|
||||
error_happened = true;
|
||||
if let Some(prev_span) = seen_fields.get(&ident) {
|
||||
let mut err = struct_span_err!(self.tcx.sess,
|
||||
field.ident.span,
|
||||
E0062,
|
||||
"field `{}` specified more than once",
|
||||
ident);
|
||||
|
||||
err.span_label(field.ident.span, "used more than once");
|
||||
err.span_label(*prev_span, format!("first use of `{}`", ident));
|
||||
|
||||
err.emit();
|
||||
} else {
|
||||
self.report_unknown_field(adt_ty, variant, field, ast_fields, kind_name);
|
||||
}
|
||||
|
||||
tcx.types.err
|
||||
};
|
||||
|
||||
// Make sure to give a type to the field even if there's
|
||||
// an error, so we can continue type-checking.
|
||||
self.check_expr_coercable_to_type(&field.expr, field_type);
|
||||
}
|
||||
|
||||
// Make sure the programmer specified correct number of fields.
|
||||
if kind_name == "union" {
|
||||
if ast_fields.len() != 1 {
|
||||
tcx.sess.span_err(span, "union expressions should have exactly one field");
|
||||
}
|
||||
} else if check_completeness && !error_happened && !remaining_fields.is_empty() {
|
||||
let len = remaining_fields.len();
|
||||
|
||||
let mut displayable_field_names = remaining_fields
|
||||
.keys()
|
||||
.map(|ident| ident.as_str())
|
||||
.collect::<Vec<_>>();
|
||||
|
||||
displayable_field_names.sort();
|
||||
|
||||
let truncated_fields_error = if len <= 3 {
|
||||
String::new()
|
||||
} else {
|
||||
format!(" and {} other field{}", (len - 3), if len - 3 == 1 {""} else {"s"})
|
||||
};
|
||||
|
||||
let remaining_fields_names = displayable_field_names.iter().take(3)
|
||||
.map(|n| format!("`{}`", n))
|
||||
.collect::<Vec<_>>()
|
||||
.join(", ");
|
||||
|
||||
struct_span_err!(tcx.sess, span, E0063,
|
||||
"missing field{} {}{} in initializer of `{}`",
|
||||
if remaining_fields.len() == 1 { "" } else { "s" },
|
||||
remaining_fields_names,
|
||||
truncated_fields_error,
|
||||
adt_ty)
|
||||
.span_label(span, format!("missing {}{}",
|
||||
remaining_fields_names,
|
||||
truncated_fields_error))
|
||||
.emit();
|
||||
}
|
||||
error_happened
|
||||
}
|
||||
|
||||
fn check_struct_fields_on_error(
|
||||
&self,
|
||||
fields: &'tcx [hir::Field],
|
||||
base_expr: &'tcx Option<P<hir::Expr>>,
|
||||
) {
|
||||
for field in fields {
|
||||
self.check_expr(&field.expr);
|
||||
}
|
||||
if let Some(ref base) = *base_expr {
|
||||
self.check_expr(&base);
|
||||
}
|
||||
}
|
||||
|
||||
pub fn check_struct_path(&self,
|
||||
qpath: &QPath,
|
||||
hir_id: hir::HirId)
|
||||
@@ -3863,842 +3322,6 @@ pub fn check_struct_path(&self,
|
||||
}
|
||||
}
|
||||
|
||||
fn check_expr_struct(
|
||||
&self,
|
||||
expr: &hir::Expr,
|
||||
expected: Expectation<'tcx>,
|
||||
qpath: &QPath,
|
||||
fields: &'tcx [hir::Field],
|
||||
base_expr: &'tcx Option<P<hir::Expr>>,
|
||||
) -> Ty<'tcx> {
|
||||
// Find the relevant variant
|
||||
let (variant, adt_ty) =
|
||||
if let Some(variant_ty) = self.check_struct_path(qpath, expr.hir_id) {
|
||||
variant_ty
|
||||
} else {
|
||||
self.check_struct_fields_on_error(fields, base_expr);
|
||||
return self.tcx.types.err;
|
||||
};
|
||||
|
||||
let path_span = match *qpath {
|
||||
QPath::Resolved(_, ref path) => path.span,
|
||||
QPath::TypeRelative(ref qself, _) => qself.span
|
||||
};
|
||||
|
||||
// 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() {
|
||||
span_err!(self.tcx.sess, expr.span, E0639,
|
||||
"cannot create non-exhaustive {} using struct expression",
|
||||
adt.variant_descr());
|
||||
}
|
||||
|
||||
let error_happened = self.check_expr_struct_fields(adt_ty, expected, expr.hir_id, path_span,
|
||||
variant, fields, base_expr.is_none());
|
||||
if let &Some(ref base_expr) = base_expr {
|
||||
// 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 {
|
||||
self.check_expr_has_type_or_error(base_expr, adt_ty);
|
||||
match adt_ty.sty {
|
||||
ty::Adt(adt, substs) if adt.is_struct() => {
|
||||
let fru_field_types = adt.non_enum_variant().fields.iter().map(|f| {
|
||||
self.normalize_associated_types_in(expr.span, &f.ty(self.tcx, substs))
|
||||
}).collect();
|
||||
|
||||
self.tables
|
||||
.borrow_mut()
|
||||
.fru_field_types_mut()
|
||||
.insert(expr.hir_id, fru_field_types);
|
||||
}
|
||||
_ => {
|
||||
span_err!(self.tcx.sess, base_expr.span, E0436,
|
||||
"functional record update syntax requires a struct");
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
self.require_type_is_sized(adt_ty, expr.span, traits::StructInitializerSized);
|
||||
adt_ty
|
||||
}
|
||||
|
||||
|
||||
/// Invariant:
|
||||
/// If an expression has any sub-expressions that result in a type error,
|
||||
/// inspecting that expression's type with `ty.references_error()` will return
|
||||
/// true. Likewise, if an expression is known to diverge, inspecting its
|
||||
/// type with `ty::type_is_bot` will return true (n.b.: since Rust is
|
||||
/// strict, _|_ can appear in the type of an expression that does not,
|
||||
/// itself, diverge: for example, fn() -> _|_.)
|
||||
/// Note that inspecting a type's structure *directly* may expose the fact
|
||||
/// that there are actually multiple representations for `Error`, so avoid
|
||||
/// that when err needs to be handled differently.
|
||||
fn check_expr_with_expectation_and_needs(
|
||||
&self,
|
||||
expr: &'tcx hir::Expr,
|
||||
expected: Expectation<'tcx>,
|
||||
needs: Needs,
|
||||
) -> Ty<'tcx> {
|
||||
debug!(">> type-checking: expr={:?} expected={:?}",
|
||||
expr, expected);
|
||||
|
||||
// Warn for expressions after diverging siblings.
|
||||
self.warn_if_unreachable(expr.hir_id, expr.span, "expression");
|
||||
|
||||
// Hide the outer diverging and has_errors flags.
|
||||
let old_diverges = self.diverges.get();
|
||||
let old_has_errors = self.has_errors.get();
|
||||
self.diverges.set(Diverges::Maybe);
|
||||
self.has_errors.set(false);
|
||||
|
||||
let ty = self.check_expr_kind(expr, expected, needs);
|
||||
|
||||
// Warn for non-block expressions with diverging children.
|
||||
match expr.node {
|
||||
ExprKind::Block(..) |
|
||||
ExprKind::Loop(..) | ExprKind::While(..) |
|
||||
ExprKind::Match(..) => {}
|
||||
|
||||
_ => self.warn_if_unreachable(expr.hir_id, expr.span, "expression")
|
||||
}
|
||||
|
||||
// Any expression that produces a value of type `!` must have diverged
|
||||
if ty.is_never() {
|
||||
self.diverges.set(self.diverges.get() | Diverges::Always);
|
||||
}
|
||||
|
||||
// Record the type, which applies it effects.
|
||||
// We need to do this after the warning above, so that
|
||||
// we don't warn for the diverging expression itself.
|
||||
self.write_ty(expr.hir_id, ty);
|
||||
|
||||
// Combine the diverging and has_error flags.
|
||||
self.diverges.set(self.diverges.get() | old_diverges);
|
||||
self.has_errors.set(self.has_errors.get() | old_has_errors);
|
||||
|
||||
debug!("type of {} is...", self.tcx.hir().hir_to_string(expr.hir_id));
|
||||
debug!("... {:?}, expected is {:?}", ty, expected);
|
||||
|
||||
ty
|
||||
}
|
||||
|
||||
fn check_expr_kind(
|
||||
&self,
|
||||
expr: &'tcx hir::Expr,
|
||||
expected: Expectation<'tcx>,
|
||||
needs: Needs,
|
||||
) -> Ty<'tcx> {
|
||||
debug!(
|
||||
"check_expr_kind(expr={:?}, expected={:?}, needs={:?})",
|
||||
expr,
|
||||
expected,
|
||||
needs,
|
||||
);
|
||||
|
||||
let tcx = self.tcx;
|
||||
let id = expr.hir_id;
|
||||
match expr.node {
|
||||
ExprKind::Box(ref subexpr) => {
|
||||
let expected_inner = expected.to_option(self).map_or(NoExpectation, |ty| {
|
||||
match ty.sty {
|
||||
ty::Adt(def, _) if def.is_box()
|
||||
=> Expectation::rvalue_hint(self, ty.boxed_ty()),
|
||||
_ => NoExpectation
|
||||
}
|
||||
});
|
||||
let referent_ty = self.check_expr_with_expectation(subexpr, expected_inner);
|
||||
tcx.mk_box(referent_ty)
|
||||
}
|
||||
|
||||
ExprKind::Lit(ref lit) => {
|
||||
self.check_lit(&lit, expected)
|
||||
}
|
||||
ExprKind::Binary(op, ref lhs, ref rhs) => {
|
||||
self.check_binop(expr, op, lhs, rhs)
|
||||
}
|
||||
ExprKind::AssignOp(op, ref lhs, ref rhs) => {
|
||||
self.check_binop_assign(expr, op, lhs, rhs)
|
||||
}
|
||||
ExprKind::Unary(unop, ref oprnd) => {
|
||||
let expected_inner = match unop {
|
||||
hir::UnNot | hir::UnNeg => {
|
||||
expected
|
||||
}
|
||||
hir::UnDeref => {
|
||||
NoExpectation
|
||||
}
|
||||
};
|
||||
let needs = match unop {
|
||||
hir::UnDeref => needs,
|
||||
_ => Needs::None
|
||||
};
|
||||
let mut oprnd_t = self.check_expr_with_expectation_and_needs(&oprnd,
|
||||
expected_inner,
|
||||
needs);
|
||||
|
||||
if !oprnd_t.references_error() {
|
||||
oprnd_t = self.structurally_resolved_type(expr.span, oprnd_t);
|
||||
match unop {
|
||||
hir::UnDeref => {
|
||||
if let Some(mt) = oprnd_t.builtin_deref(true) {
|
||||
oprnd_t = mt.ty;
|
||||
} else if let Some(ok) = self.try_overloaded_deref(
|
||||
expr.span, oprnd_t, needs) {
|
||||
let method = self.register_infer_ok_obligations(ok);
|
||||
if let ty::Ref(region, _, mutbl) = method.sig.inputs()[0].sty {
|
||||
let mutbl = match mutbl {
|
||||
hir::MutImmutable => AutoBorrowMutability::Immutable,
|
||||
hir::MutMutable => AutoBorrowMutability::Mutable {
|
||||
// (It shouldn't actually matter for unary ops whether
|
||||
// we enable two-phase borrows or not, since a unary
|
||||
// op has no additional operands.)
|
||||
allow_two_phase_borrow: AllowTwoPhase::No,
|
||||
}
|
||||
};
|
||||
self.apply_adjustments(oprnd, vec![Adjustment {
|
||||
kind: Adjust::Borrow(AutoBorrow::Ref(region, mutbl)),
|
||||
target: method.sig.inputs()[0]
|
||||
}]);
|
||||
}
|
||||
oprnd_t = self.make_overloaded_place_return_type(method).ty;
|
||||
self.write_method_call(expr.hir_id, method);
|
||||
} else {
|
||||
let mut err = type_error_struct!(
|
||||
tcx.sess,
|
||||
expr.span,
|
||||
oprnd_t,
|
||||
E0614,
|
||||
"type `{}` cannot be dereferenced",
|
||||
oprnd_t,
|
||||
);
|
||||
let sp = tcx.sess.source_map().start_point(expr.span);
|
||||
if let Some(sp) = tcx.sess.parse_sess.ambiguous_block_expr_parse
|
||||
.borrow().get(&sp)
|
||||
{
|
||||
tcx.sess.parse_sess.expr_parentheses_needed(
|
||||
&mut err,
|
||||
*sp,
|
||||
None,
|
||||
);
|
||||
}
|
||||
err.emit();
|
||||
oprnd_t = tcx.types.err;
|
||||
}
|
||||
}
|
||||
hir::UnNot => {
|
||||
let result = self.check_user_unop(expr, oprnd_t, unop);
|
||||
// If it's builtin, we can reuse the type, this helps inference.
|
||||
if !(oprnd_t.is_integral() || oprnd_t.sty == ty::Bool) {
|
||||
oprnd_t = result;
|
||||
}
|
||||
}
|
||||
hir::UnNeg => {
|
||||
let result = self.check_user_unop(expr, oprnd_t, unop);
|
||||
// If it's builtin, we can reuse the type, this helps inference.
|
||||
if !oprnd_t.is_numeric() {
|
||||
oprnd_t = result;
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
oprnd_t
|
||||
}
|
||||
ExprKind::AddrOf(mutbl, ref oprnd) => {
|
||||
let hint = expected.only_has_type(self).map_or(NoExpectation, |ty| {
|
||||
match ty.sty {
|
||||
ty::Ref(_, ty, _) | ty::RawPtr(ty::TypeAndMut { ty, .. }) => {
|
||||
if oprnd.is_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 needs = Needs::maybe_mut_place(mutbl);
|
||||
let ty = self.check_expr_with_expectation_and_needs(&oprnd, hint, needs);
|
||||
|
||||
let tm = ty::TypeAndMut { ty: ty, mutbl: mutbl };
|
||||
if tm.ty.references_error() {
|
||||
tcx.types.err
|
||||
} else {
|
||||
// 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 the ultimate value.
|
||||
// Finally, borrowck is charged with guaranteeing 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));
|
||||
tcx.mk_ref(region, tm)
|
||||
}
|
||||
}
|
||||
ExprKind::Path(ref qpath) => {
|
||||
let (res, opt_ty, segs) = self.resolve_ty_and_res_ufcs(qpath, expr.hir_id,
|
||||
expr.span);
|
||||
let ty = match res {
|
||||
Res::Err => {
|
||||
self.set_tainted_by_errors();
|
||||
tcx.types.err
|
||||
}
|
||||
Res::Def(DefKind::Ctor(_, CtorKind::Fictive), _) => {
|
||||
report_unexpected_variant_res(tcx, res, expr.span, qpath);
|
||||
tcx.types.err
|
||||
}
|
||||
_ => self.instantiate_value_path(segs, opt_ty, res, expr.span, id).0,
|
||||
};
|
||||
|
||||
if let ty::FnDef(..) = ty.sty {
|
||||
let fn_sig = ty.fn_sig(tcx);
|
||||
if !tcx.features().unsized_locals {
|
||||
// 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 input = self.replace_bound_vars_with_fresh_vars(
|
||||
expr.span,
|
||||
infer::LateBoundRegionConversionTime::FnCall,
|
||||
&fn_sig.input(i)).0;
|
||||
self.require_type_is_sized_deferred(input, expr.span,
|
||||
traits::SizedArgumentType);
|
||||
}
|
||||
}
|
||||
// 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 presense 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()).0;
|
||||
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.tables.borrow().node_substs(expr.hir_id);
|
||||
self.add_wf_bounds(substs, expr);
|
||||
|
||||
ty
|
||||
}
|
||||
ExprKind::InlineAsm(_, ref outputs, ref inputs) => {
|
||||
for expr in outputs.iter().chain(inputs.iter()) {
|
||||
self.check_expr(expr);
|
||||
}
|
||||
tcx.mk_unit()
|
||||
}
|
||||
ExprKind::Break(destination, ref expr_opt) => {
|
||||
if let Ok(target_id) = destination.target_id {
|
||||
let (e_ty, cause);
|
||||
if let Some(ref 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 = {
|
||||
let mut enclosing_breakables = self.enclosing_breakables.borrow_mut();
|
||||
enclosing_breakables.find_breakable(target_id)
|
||||
.coerce
|
||||
.as_ref()
|
||||
.map(|coerce| coerce.expected_ty())
|
||||
};
|
||||
|
||||
// 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(tcx.types.err);
|
||||
|
||||
// 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 ctxt = enclosing_breakables.find_breakable(target_id);
|
||||
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());
|
||||
coerce.coerce_forced_unit(self, &cause, &mut |_| (), true);
|
||||
}
|
||||
} else {
|
||||
// If `ctxt.coerce` is `None`, we can just ignore
|
||||
// the type of the expresison. 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.err_count() > 0);
|
||||
}
|
||||
|
||||
ctxt.may_break = true;
|
||||
|
||||
// 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.
|
||||
if self.tcx.sess.err_count() == 0 {
|
||||
self.tcx.sess.delay_span_bug(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(ref e) = *expr_opt {
|
||||
self.check_expr_with_hint(e, tcx.types.err);
|
||||
|
||||
// ... except when we try to 'break rust;'.
|
||||
// ICE this expression in particular (see #43162).
|
||||
if let ExprKind::Path(QPath::Resolved(_, ref path)) = e.node {
|
||||
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.
|
||||
tcx.types.err
|
||||
}
|
||||
|
||||
}
|
||||
ExprKind::Continue(destination) => {
|
||||
if destination.target_id.is_ok() {
|
||||
tcx.types.never
|
||||
} else {
|
||||
// There was an error; make type-check fail.
|
||||
tcx.types.err
|
||||
}
|
||||
}
|
||||
ExprKind::Ret(ref expr_opt) => {
|
||||
if self.ret_coercion.is_none() {
|
||||
struct_span_err!(self.tcx.sess, expr.span, E0572,
|
||||
"return statement outside of function body").emit();
|
||||
} else if let Some(ref e) = *expr_opt {
|
||||
if self.ret_coercion_span.borrow().is_none() {
|
||||
*self.ret_coercion_span.borrow_mut() = Some(e.span);
|
||||
}
|
||||
self.check_return_expr(e);
|
||||
} else {
|
||||
let mut coercion = self.ret_coercion.as_ref().unwrap().borrow_mut();
|
||||
if self.ret_coercion_span.borrow().is_none() {
|
||||
*self.ret_coercion_span.borrow_mut() = 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| {
|
||||
db.span_label(
|
||||
fn_decl.output.span(),
|
||||
format!(
|
||||
"expected `{}` because of this return type",
|
||||
fn_decl.output,
|
||||
),
|
||||
);
|
||||
},
|
||||
true,
|
||||
);
|
||||
} else {
|
||||
coercion.coerce_forced_unit(self, &cause, &mut |_| (), true);
|
||||
}
|
||||
}
|
||||
tcx.types.never
|
||||
}
|
||||
ExprKind::Assign(ref lhs, ref rhs) => {
|
||||
self.check_assign(expr, expected, lhs, rhs)
|
||||
}
|
||||
ExprKind::While(ref cond, ref body, _) => {
|
||||
let ctxt = BreakableCtxt {
|
||||
// cannot use break with a value from a while loop
|
||||
coerce: None,
|
||||
may_break: false, // Will get updated if/when we find a `break`.
|
||||
};
|
||||
|
||||
let (ctxt, ()) = self.with_breakable_ctxt(expr.hir_id, ctxt, || {
|
||||
self.check_expr_has_type_or_error(&cond, tcx.types.bool);
|
||||
let cond_diverging = self.diverges.get();
|
||||
self.check_block_no_value(&body);
|
||||
|
||||
// We may never reach the body so it diverging means nothing.
|
||||
self.diverges.set(cond_diverging);
|
||||
});
|
||||
|
||||
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);
|
||||
}
|
||||
|
||||
self.tcx.mk_unit()
|
||||
}
|
||||
ExprKind::Loop(ref body, _, source) => {
|
||||
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::WhileLet |
|
||||
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())
|
||||
}
|
||||
ExprKind::Match(ref discrim, ref arms, match_src) => {
|
||||
self.check_match(expr, &discrim, arms, expected, match_src)
|
||||
}
|
||||
ExprKind::Closure(capture, ref decl, body_id, _, gen) => {
|
||||
self.check_expr_closure(expr, capture, &decl, body_id, gen, expected)
|
||||
}
|
||||
ExprKind::Block(ref body, _) => {
|
||||
self.check_block_with_expected(&body, expected)
|
||||
}
|
||||
ExprKind::Call(ref callee, ref args) => {
|
||||
self.check_call(expr, &callee, args, expected)
|
||||
}
|
||||
ExprKind::MethodCall(ref segment, span, ref args) => {
|
||||
self.check_method_call(expr, segment, span, args, expected, needs)
|
||||
}
|
||||
ExprKind::Cast(ref e, ref t) => {
|
||||
// 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_cast = self.resolve_vars_if_possible(&t_cast);
|
||||
|
||||
// Eagerly check for some obvious errors.
|
||||
if t_expr.references_error() || t_cast.references_error() {
|
||||
tcx.types.err
|
||||
} 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) => {
|
||||
deferred_cast_checks.push(cast_check);
|
||||
t_cast
|
||||
}
|
||||
Err(ErrorReported) => {
|
||||
tcx.types.err
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
ExprKind::Type(ref e, ref t) => {
|
||||
let ty = self.to_ty_saving_user_provided_ty(&t);
|
||||
self.check_expr_eq_type(&e, ty);
|
||||
ty
|
||||
}
|
||||
ExprKind::DropTemps(ref e) => {
|
||||
self.check_expr_with_expectation(e, expected)
|
||||
}
|
||||
ExprKind::Array(ref args) => {
|
||||
let uty = expected.to_option(self).and_then(|uty| {
|
||||
match uty.sty {
|
||||
ty::Array(ty, _) | ty::Slice(ty) => Some(ty),
|
||||
_ => None
|
||||
}
|
||||
});
|
||||
|
||||
let element_ty = if !args.is_empty() {
|
||||
let coerce_to = uty.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,
|
||||
})
|
||||
};
|
||||
tcx.mk_array(element_ty, args.len() as u64)
|
||||
}
|
||||
ExprKind::Repeat(ref element, ref count) => {
|
||||
let count_def_id = tcx.hir().local_def_id_from_hir_id(count.hir_id);
|
||||
let count = if self.const_param_def_id(count).is_some() {
|
||||
Ok(self.to_const(count, self.tcx.type_of(count_def_id)))
|
||||
} else {
|
||||
let param_env = ty::ParamEnv::empty();
|
||||
let substs = InternalSubsts::identity_for_item(tcx.global_tcx(), count_def_id);
|
||||
let instance = ty::Instance::resolve(
|
||||
tcx.global_tcx(),
|
||||
param_env,
|
||||
count_def_id,
|
||||
substs,
|
||||
).unwrap();
|
||||
let global_id = GlobalId {
|
||||
instance,
|
||||
promoted: None
|
||||
};
|
||||
|
||||
tcx.const_eval(param_env.and(global_id))
|
||||
};
|
||||
|
||||
let uty = match expected {
|
||||
ExpectHasType(uty) => {
|
||||
match uty.sty {
|
||||
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);
|
||||
(uty, uty)
|
||||
}
|
||||
None => {
|
||||
let ty = self.next_ty_var(TypeVariableOrigin {
|
||||
kind: TypeVariableOriginKind::MiscVariable,
|
||||
span: element.span,
|
||||
});
|
||||
let element_ty = self.check_expr_has_type_or_error(&element, ty);
|
||||
(element_ty, ty)
|
||||
}
|
||||
};
|
||||
|
||||
if let Ok(count) = count {
|
||||
let zero_or_one = count.assert_usize(tcx).map_or(false, |count| count <= 1);
|
||||
if !zero_or_one {
|
||||
// For [foo, ..n] where n > 1, `foo` must have
|
||||
// Copy type:
|
||||
let lang_item = self.tcx.require_lang_item(lang_items::CopyTraitLangItem);
|
||||
self.require_type_meets(t, expr.span, traits::RepeatVec, lang_item);
|
||||
}
|
||||
}
|
||||
|
||||
if element_ty.references_error() {
|
||||
tcx.types.err
|
||||
} else if let Ok(count) = count {
|
||||
tcx.mk_ty(ty::Array(t, count))
|
||||
} else {
|
||||
tcx.types.err
|
||||
}
|
||||
}
|
||||
ExprKind::Tup(ref elts) => {
|
||||
let flds = expected.only_has_type(self).and_then(|ty| {
|
||||
let ty = self.resolve_type_vars_with_obligations(ty);
|
||||
match ty.sty {
|
||||
ty::Tuple(ref flds) => Some(&flds[..]),
|
||||
_ => None
|
||||
}
|
||||
});
|
||||
|
||||
let elt_ts_iter = elts.iter().enumerate().map(|(i, e)| {
|
||||
let t = match flds {
|
||||
Some(ref fs) if i < fs.len() => {
|
||||
let ety = fs[i].expect_ty();
|
||||
self.check_expr_coercable_to_type(&e, ety);
|
||||
ety
|
||||
}
|
||||
_ => {
|
||||
self.check_expr_with_expectation(&e, NoExpectation)
|
||||
}
|
||||
};
|
||||
t
|
||||
});
|
||||
let tuple = tcx.mk_tup(elt_ts_iter);
|
||||
if tuple.references_error() {
|
||||
tcx.types.err
|
||||
} else {
|
||||
self.require_type_is_sized(tuple, expr.span, traits::TupleInitializerSized);
|
||||
tuple
|
||||
}
|
||||
}
|
||||
ExprKind::Struct(ref qpath, ref fields, ref base_expr) => {
|
||||
self.check_expr_struct(expr, expected, qpath, fields, base_expr)
|
||||
}
|
||||
ExprKind::Field(ref base, field) => {
|
||||
self.check_field(expr, needs, &base, field)
|
||||
}
|
||||
ExprKind::Index(ref base, ref idx) => {
|
||||
let base_t = self.check_expr_with_needs(&base, needs);
|
||||
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_t, needs) {
|
||||
Some((index_ty, element_ty)) => {
|
||||
// two-phase not needed because index_ty is never mutable
|
||||
self.demand_coerce(idx, idx_t, index_ty, AllowTwoPhase::No);
|
||||
element_ty
|
||||
}
|
||||
None => {
|
||||
let mut err =
|
||||
type_error_struct!(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.sty {
|
||||
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.node {
|
||||
if let ast::LitKind::Int(i,
|
||||
ast::LitIntType::Unsuffixed) = lit.node {
|
||||
let snip = 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.types.err
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
ExprKind::Yield(ref value) => {
|
||||
match self.yield_ty {
|
||||
Some(ty) => {
|
||||
self.check_expr_coercable_to_type(&value, ty);
|
||||
}
|
||||
None => {
|
||||
struct_span_err!(self.tcx.sess, expr.span, E0627,
|
||||
"yield statement outside of generator literal").emit();
|
||||
}
|
||||
}
|
||||
tcx.mk_unit()
|
||||
}
|
||||
hir::ExprKind::Err => {
|
||||
tcx.types.err
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
/// Type check assignment expression `expr` of form `lhs = rhs`.
|
||||
/// The expected type is `()` and is passsed to the function for the purposes of diagnostics.
|
||||
fn check_assign(
|
||||
&self,
|
||||
expr: &'tcx hir::Expr,
|
||||
expected: Expectation<'tcx>,
|
||||
lhs: &'tcx hir::Expr,
|
||||
rhs: &'tcx hir::Expr,
|
||||
) -> Ty<'tcx> {
|
||||
let lhs_ty = self.check_expr_with_needs(&lhs, Needs::MutPlace);
|
||||
let rhs_ty = self.check_expr_coercable_to_type(&rhs, lhs_ty);
|
||||
|
||||
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 msg = "try comparing for equality";
|
||||
let left = self.tcx.sess.source_map().span_to_snippet(lhs.span);
|
||||
let right = self.tcx.sess.source_map().span_to_snippet(rhs.span);
|
||||
if let (Ok(left), Ok(right)) = (left, right) {
|
||||
let help = format!("{} == {}", left, right);
|
||||
err.span_suggestion(expr.span, msg, help, Applicability::MaybeIncorrect);
|
||||
} else {
|
||||
err.help(msg);
|
||||
}
|
||||
err.emit();
|
||||
} else if !lhs.is_place_expr() {
|
||||
struct_span_err!(self.tcx.sess, expr.span, E0070,
|
||||
"invalid left-hand side expression")
|
||||
.span_label(expr.span, "left-hand of expression not valid")
|
||||
.emit();
|
||||
}
|
||||
|
||||
self.require_type_is_sized(lhs_ty, lhs.span, traits::AssignmentLhsSized);
|
||||
|
||||
if lhs_ty.references_error() || rhs_ty.references_error() {
|
||||
self.tcx.types.err
|
||||
} else {
|
||||
self.tcx.mk_unit()
|
||||
}
|
||||
}
|
||||
|
||||
// Finish resolving a path in a struct expression or pattern `S::A { .. }` if necessary.
|
||||
// The newly resolved definition is written into `type_dependent_defs`.
|
||||
fn finish_resolving_struct_path(&self,
|
||||
|
||||
@@ -68,6 +68,7 @@
|
||||
#![feature(rustc_diagnostic_macros)]
|
||||
#![feature(slice_patterns)]
|
||||
#![feature(never_type)]
|
||||
#![feature(inner_deref)]
|
||||
|
||||
#![recursion_limit="256"]
|
||||
|
||||
|
||||
Reference in New Issue
Block a user