Rollup merge of #131822 - lcnr:typeck-error-reporting, r=jieyouxu
extract `expr_assign_expected_bool_error` moving diagnostics code out of the happy path makes it a lot easier to read imo
This commit is contained in:
Matthias Krüger
GitHub
commit
c7356559e5
@ -1320,84 +1320,8 @@ fn check_expr_assign(
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) -> Ty<'tcx> {
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) -> Ty<'tcx> {
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let expected_ty = expected.coercion_target_type(self, expr.span);
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let expected_ty = expected.coercion_target_type(self, expr.span);
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if expected_ty == self.tcx.types.bool {
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if expected_ty == self.tcx.types.bool {
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// The expected type is `bool` but this will result in `()` so we can reasonably
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let guar = self.expr_assign_expected_bool_error(expr, lhs, rhs, span);
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// say that the user intended to write `lhs == rhs` instead of `lhs = rhs`.
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return Ty::new_error(self.tcx, guar);
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// The likely cause of this is `if foo = bar { .. }`.
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let actual_ty = self.tcx.types.unit;
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let mut err = self.demand_suptype_diag(expr.span, expected_ty, actual_ty).unwrap_err();
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let lhs_ty = self.check_expr(lhs);
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let rhs_ty = self.check_expr(rhs);
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let refs_can_coerce = |lhs: Ty<'tcx>, rhs: Ty<'tcx>| {
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let lhs = Ty::new_imm_ref(self.tcx, self.tcx.lifetimes.re_erased, lhs.peel_refs());
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let rhs = Ty::new_imm_ref(self.tcx, self.tcx.lifetimes.re_erased, rhs.peel_refs());
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self.may_coerce(rhs, lhs)
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};
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let (applicability, eq) = if self.may_coerce(rhs_ty, lhs_ty) {
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(Applicability::MachineApplicable, true)
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} else if refs_can_coerce(rhs_ty, lhs_ty) {
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// The lhs and rhs are likely missing some references in either side. Subsequent
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// suggestions will show up.
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(Applicability::MaybeIncorrect, true)
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} else if let ExprKind::Binary(
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Spanned { node: hir::BinOpKind::And | hir::BinOpKind::Or, .. },
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_,
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rhs_expr,
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) = lhs.kind
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{
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// if x == 1 && y == 2 { .. }
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// +
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let actual_lhs_ty = self.check_expr(rhs_expr);
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(
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Applicability::MaybeIncorrect,
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self.may_coerce(rhs_ty, actual_lhs_ty)
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|| refs_can_coerce(rhs_ty, actual_lhs_ty),
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)
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} else if let ExprKind::Binary(
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Spanned { node: hir::BinOpKind::And | hir::BinOpKind::Or, .. },
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lhs_expr,
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_,
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) = rhs.kind
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{
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// if x == 1 && y == 2 { .. }
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// +
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let actual_rhs_ty = self.check_expr(lhs_expr);
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(
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Applicability::MaybeIncorrect,
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self.may_coerce(actual_rhs_ty, lhs_ty)
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|| refs_can_coerce(actual_rhs_ty, lhs_ty),
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)
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} else {
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(Applicability::MaybeIncorrect, false)
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};
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if !lhs.is_syntactic_place_expr()
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&& lhs.is_approximately_pattern()
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&& !matches!(lhs.kind, hir::ExprKind::Lit(_))
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{
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// Do not suggest `if let x = y` as `==` is way more likely to be the intention.
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if let hir::Node::Expr(hir::Expr { kind: ExprKind::If { .. }, .. }) =
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self.tcx.parent_hir_node(expr.hir_id)
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{
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err.span_suggestion_verbose(
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expr.span.shrink_to_lo(),
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"you might have meant to use pattern matching",
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"let ",
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applicability,
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);
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};
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}
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if eq {
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err.span_suggestion_verbose(
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span.shrink_to_hi(),
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"you might have meant to compare for equality",
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'=',
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applicability,
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);
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}
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// If the assignment expression itself is ill-formed, don't
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// bother emitting another error
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let reported = err.emit_unless(lhs_ty.references_error() || rhs_ty.references_error());
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return Ty::new_error(self.tcx, reported);
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}
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}
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let lhs_ty = self.check_expr_with_needs(lhs, Needs::MutPlace);
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let lhs_ty = self.check_expr_with_needs(lhs, Needs::MutPlace);
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@ -1450,6 +1374,88 @@ fn check_expr_assign(
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}
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}
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}
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}
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/// The expected type is `bool` but this will result in `()` so we can reasonably
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/// say that the user intended to write `lhs == rhs` instead of `lhs = rhs`.
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/// The likely cause of this is `if foo = bar { .. }`.
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fn expr_assign_expected_bool_error(
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&self,
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expr: &'tcx hir::Expr<'tcx>,
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lhs: &'tcx hir::Expr<'tcx>,
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rhs: &'tcx hir::Expr<'tcx>,
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span: Span,
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) -> ErrorGuaranteed {
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let actual_ty = self.tcx.types.unit;
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let expected_ty = self.tcx.types.bool;
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let mut err = self.demand_suptype_diag(expr.span, expected_ty, actual_ty).unwrap_err();
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let lhs_ty = self.check_expr(lhs);
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let rhs_ty = self.check_expr(rhs);
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let refs_can_coerce = |lhs: Ty<'tcx>, rhs: Ty<'tcx>| {
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let lhs = Ty::new_imm_ref(self.tcx, self.tcx.lifetimes.re_erased, lhs.peel_refs());
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let rhs = Ty::new_imm_ref(self.tcx, self.tcx.lifetimes.re_erased, rhs.peel_refs());
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self.may_coerce(rhs, lhs)
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};
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let (applicability, eq) = if self.may_coerce(rhs_ty, lhs_ty) {
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(Applicability::MachineApplicable, true)
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} else if refs_can_coerce(rhs_ty, lhs_ty) {
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// The lhs and rhs are likely missing some references in either side. Subsequent
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// suggestions will show up.
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(Applicability::MaybeIncorrect, true)
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} else if let ExprKind::Binary(
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Spanned { node: hir::BinOpKind::And | hir::BinOpKind::Or, .. },
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_,
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rhs_expr,
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) = lhs.kind
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{
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// if x == 1 && y == 2 { .. }
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// +
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let actual_lhs = self.check_expr(rhs_expr);
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let may_eq = self.may_coerce(rhs_ty, actual_lhs) || refs_can_coerce(rhs_ty, actual_lhs);
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(Applicability::MaybeIncorrect, may_eq)
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} else if let ExprKind::Binary(
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Spanned { node: hir::BinOpKind::And | hir::BinOpKind::Or, .. },
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lhs_expr,
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_,
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) = rhs.kind
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{
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// if x == 1 && y == 2 { .. }
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// +
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let actual_rhs = self.check_expr(lhs_expr);
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let may_eq = self.may_coerce(actual_rhs, lhs_ty) || refs_can_coerce(actual_rhs, lhs_ty);
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(Applicability::MaybeIncorrect, may_eq)
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} else {
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(Applicability::MaybeIncorrect, false)
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};
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if !lhs.is_syntactic_place_expr()
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&& lhs.is_approximately_pattern()
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&& !matches!(lhs.kind, hir::ExprKind::Lit(_))
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{
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// Do not suggest `if let x = y` as `==` is way more likely to be the intention.
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if let hir::Node::Expr(hir::Expr { kind: ExprKind::If { .. }, .. }) =
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self.tcx.parent_hir_node(expr.hir_id)
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{
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err.span_suggestion_verbose(
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expr.span.shrink_to_lo(),
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"you might have meant to use pattern matching",
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"let ",
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applicability,
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);
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};
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}
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if eq {
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err.span_suggestion_verbose(
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span.shrink_to_hi(),
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"you might have meant to compare for equality",
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'=',
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applicability,
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);
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}
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// If the assignment expression itself is ill-formed, don't
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// bother emitting another error
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err.emit_unless(lhs_ty.references_error() || rhs_ty.references_error())
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}
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pub(super) fn check_expr_let(
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pub(super) fn check_expr_let(
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&self,
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&self,
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let_expr: &'tcx hir::LetExpr<'tcx>,
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let_expr: &'tcx hir::LetExpr<'tcx>,
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