Reorder
This commit is contained in:
Nadrieril
parent
75b064d269
commit
fedee8d524
@ -572,6 +572,111 @@ fn check_irrefutable(&mut self, pat: &Pat<'tcx>, origin: &str, sp: Option<Span>)
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}
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}
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/// Check if a by-value binding is by-value. That is, check if the binding's type is not `Copy`.
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/// Check that there are no borrow or move conflicts in `binding @ subpat` patterns.
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///
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/// For example, this would reject:
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/// - `ref x @ Some(ref mut y)`,
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/// - `ref mut x @ Some(ref y)`,
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/// - `ref mut x @ Some(ref mut y)`,
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/// - `ref mut? x @ Some(y)`, and
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/// - `x @ Some(ref mut? y)`.
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///
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/// This analysis is *not* subsumed by NLL.
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fn check_borrow_conflicts_in_at_patterns<'tcx>(cx: &MatchVisitor<'_, '_, 'tcx>, pat: &Pat<'tcx>) {
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// Extract `sub` in `binding @ sub`.
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let PatKind::Binding { name, mode, ty, subpattern: Some(box ref sub), .. } = pat.kind else {
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return;
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};
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let is_binding_by_move = |ty: Ty<'tcx>| !ty.is_copy_modulo_regions(cx.tcx, cx.param_env);
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let sess = cx.tcx.sess;
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// Get the binding move, extract the mutability if by-ref.
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let mut_outer = match mode {
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BindingMode::ByValue if is_binding_by_move(ty) => {
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// We have `x @ pat` where `x` is by-move. Reject all borrows in `pat`.
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let mut conflicts_ref = Vec::new();
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sub.each_binding(|_, mode, _, span| match mode {
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BindingMode::ByValue => {}
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BindingMode::ByRef(_) => conflicts_ref.push(span),
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});
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if !conflicts_ref.is_empty() {
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sess.emit_err(BorrowOfMovedValue {
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binding_span: pat.span,
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conflicts_ref,
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name,
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ty,
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suggest_borrowing: Some(pat.span.shrink_to_lo()),
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});
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}
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return;
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}
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BindingMode::ByValue => return,
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BindingMode::ByRef(m) => m.mutability(),
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};
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// We now have `ref $mut_outer binding @ sub` (semantically).
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// Recurse into each binding in `sub` and find mutability or move conflicts.
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let mut conflicts_move = Vec::new();
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let mut conflicts_mut_mut = Vec::new();
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let mut conflicts_mut_ref = Vec::new();
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sub.each_binding(|name, mode, ty, span| {
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match mode {
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BindingMode::ByRef(mut_inner) => match (mut_outer, mut_inner.mutability()) {
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// Both sides are `ref`.
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(Mutability::Not, Mutability::Not) => {}
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// 2x `ref mut`.
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(Mutability::Mut, Mutability::Mut) => {
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conflicts_mut_mut.push(Conflict::Mut { span, name })
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}
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(Mutability::Not, Mutability::Mut) => {
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conflicts_mut_ref.push(Conflict::Mut { span, name })
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}
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(Mutability::Mut, Mutability::Not) => {
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conflicts_mut_ref.push(Conflict::Ref { span, name })
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}
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},
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BindingMode::ByValue if is_binding_by_move(ty) => {
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conflicts_move.push(Conflict::Moved { span, name }) // `ref mut?` + by-move conflict.
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}
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BindingMode::ByValue => {} // `ref mut?` + by-copy is fine.
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}
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});
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let report_mut_mut = !conflicts_mut_mut.is_empty();
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let report_mut_ref = !conflicts_mut_ref.is_empty();
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let report_move_conflict = !conflicts_move.is_empty();
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let mut occurrences = match mut_outer {
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Mutability::Mut => vec![Conflict::Mut { span: pat.span, name }],
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Mutability::Not => vec![Conflict::Ref { span: pat.span, name }],
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};
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occurrences.extend(conflicts_mut_mut);
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occurrences.extend(conflicts_mut_ref);
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occurrences.extend(conflicts_move);
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// Report errors if any.
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if report_mut_mut {
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// Report mutability conflicts for e.g. `ref mut x @ Some(ref mut y)`.
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sess.emit_err(MultipleMutBorrows { span: pat.span, occurrences });
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} else if report_mut_ref {
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// Report mutability conflicts for e.g. `ref x @ Some(ref mut y)` or the converse.
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match mut_outer {
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Mutability::Mut => {
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sess.emit_err(AlreadyMutBorrowed { span: pat.span, occurrences });
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}
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Mutability::Not => {
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sess.emit_err(AlreadyBorrowed { span: pat.span, occurrences });
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}
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};
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} else if report_move_conflict {
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// Report by-ref and by-move conflicts, e.g. `ref x @ y`.
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sess.emit_err(MovedWhileBorrowed { span: pat.span, occurrences });
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}
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}
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fn check_for_bindings_named_same_as_variants(
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cx: &MatchVisitor<'_, '_, '_>,
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pat: &Pat<'_>,
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@ -616,25 +721,6 @@ fn check_for_bindings_named_same_as_variants(
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});
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}
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/// Checks for common cases of "catchall" patterns that may not be intended as such.
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fn pat_is_catchall(pat: &DeconstructedPat<'_, '_>) -> bool {
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use Constructor::*;
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match pat.ctor() {
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Wildcard => true,
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Single => pat.iter_fields().all(|pat| pat_is_catchall(pat)),
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_ => false,
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}
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}
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fn unreachable_pattern(tcx: TyCtxt<'_>, span: Span, id: HirId, catchall: Option<Span>) {
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tcx.emit_spanned_lint(
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UNREACHABLE_PATTERNS,
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id,
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span,
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UnreachablePattern { span: if catchall.is_some() { Some(span) } else { None }, catchall },
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);
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}
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fn irrefutable_let_patterns(
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tcx: TyCtxt<'_>,
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id: HirId,
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@ -680,11 +766,23 @@ fn report_arm_reachability<'p, 'tcx>(
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cx: &MatchCheckCtxt<'p, 'tcx>,
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report: &UsefulnessReport<'p, 'tcx>,
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) {
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let report_unreachable_pattern = |span, hir_id, catchall: Option<Span>| {
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cx.tcx.emit_spanned_lint(
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UNREACHABLE_PATTERNS,
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hir_id,
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span,
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UnreachablePattern {
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span: if catchall.is_some() { Some(span) } else { None },
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catchall,
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},
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);
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};
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use Reachability::*;
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let mut catchall = None;
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for (arm, is_useful) in report.arm_usefulness.iter() {
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match is_useful {
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Unreachable => unreachable_pattern(cx.tcx, arm.pat.span(), arm.hir_id, catchall),
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Unreachable => report_unreachable_pattern(arm.pat.span(), arm.hir_id, catchall),
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Reachable(unreachables) if unreachables.is_empty() => {}
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// The arm is reachable, but contains unreachable subpatterns (from or-patterns).
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Reachable(unreachables) => {
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@ -692,7 +790,7 @@ fn report_arm_reachability<'p, 'tcx>(
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// Emit lints in the order in which they occur in the file.
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unreachables.sort_unstable();
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for span in unreachables {
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unreachable_pattern(cx.tcx, span, arm.hir_id, None);
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report_unreachable_pattern(span, arm.hir_id, None);
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}
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}
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}
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@ -702,22 +800,14 @@ fn report_arm_reachability<'p, 'tcx>(
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}
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}
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fn collect_non_exhaustive_tys<'tcx>(
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tcx: TyCtxt<'tcx>,
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pat: &WitnessPat<'tcx>,
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non_exhaustive_tys: &mut FxHashSet<Ty<'tcx>>,
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) {
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if matches!(pat.ctor(), Constructor::NonExhaustive) {
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non_exhaustive_tys.insert(pat.ty());
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/// Checks for common cases of "catchall" patterns that may not be intended as such.
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fn pat_is_catchall(pat: &DeconstructedPat<'_, '_>) -> bool {
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use Constructor::*;
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match pat.ctor() {
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Wildcard => true,
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Single => pat.iter_fields().all(|pat| pat_is_catchall(pat)),
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_ => false,
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}
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if let Constructor::IntRange(range) = pat.ctor() {
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if range.is_beyond_boundaries(pat.ty(), tcx) {
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// The range denotes the values before `isize::MIN` or the values after `usize::MAX`/`isize::MAX`.
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non_exhaustive_tys.insert(pat.ty());
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}
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}
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pat.iter_fields()
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.for_each(|field_pat| collect_non_exhaustive_tys(tcx, field_pat, non_exhaustive_tys))
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}
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/// Report that a match is not exhaustive.
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@ -755,7 +845,14 @@ fn non_exhaustive_match<'p, 'tcx>(
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sp,
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format!("non-exhaustive patterns: {joined_patterns} not covered"),
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);
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err.span_label(sp, pattern_not_covered_label(&witnesses, &joined_patterns));
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err.span_label(
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sp,
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format!(
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"pattern{} {} not covered",
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rustc_errors::pluralize!(witnesses.len()),
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joined_patterns
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),
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);
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patterns_len = witnesses.len();
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pattern = if witnesses.len() < 4 {
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witnesses
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@ -910,7 +1007,7 @@ fn non_exhaustive_match<'p, 'tcx>(
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err.emit()
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}
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pub(crate) fn joined_uncovered_patterns<'p, 'tcx>(
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fn joined_uncovered_patterns<'p, 'tcx>(
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cx: &MatchCheckCtxt<'p, 'tcx>,
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witnesses: &[WitnessPat<'tcx>],
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) -> String {
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@ -931,11 +1028,22 @@ pub(crate) fn joined_uncovered_patterns<'p, 'tcx>(
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}
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}
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pub(crate) fn pattern_not_covered_label(
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witnesses: &[WitnessPat<'_>],
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joined_patterns: &str,
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) -> String {
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format!("pattern{} {} not covered", rustc_errors::pluralize!(witnesses.len()), joined_patterns)
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fn collect_non_exhaustive_tys<'tcx>(
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tcx: TyCtxt<'tcx>,
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pat: &WitnessPat<'tcx>,
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non_exhaustive_tys: &mut FxHashSet<Ty<'tcx>>,
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) {
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if matches!(pat.ctor(), Constructor::NonExhaustive) {
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non_exhaustive_tys.insert(pat.ty());
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}
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if let Constructor::IntRange(range) = pat.ctor() {
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if range.is_beyond_boundaries(pat.ty(), tcx) {
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// The range denotes the values before `isize::MIN` or the values after `usize::MAX`/`isize::MAX`.
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non_exhaustive_tys.insert(pat.ty());
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}
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}
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pat.iter_fields()
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.for_each(|field_pat| collect_non_exhaustive_tys(tcx, field_pat, non_exhaustive_tys))
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}
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/// Point at the definition of non-covered `enum` variants.
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@ -997,108 +1105,3 @@ fn maybe_point_at_variant<'a, 'p: 'a, 'tcx: 'a>(
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}
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covered
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}
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/// Check if a by-value binding is by-value. That is, check if the binding's type is not `Copy`.
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/// Check that there are no borrow or move conflicts in `binding @ subpat` patterns.
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///
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/// For example, this would reject:
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/// - `ref x @ Some(ref mut y)`,
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/// - `ref mut x @ Some(ref y)`,
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/// - `ref mut x @ Some(ref mut y)`,
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/// - `ref mut? x @ Some(y)`, and
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/// - `x @ Some(ref mut? y)`.
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///
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/// This analysis is *not* subsumed by NLL.
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fn check_borrow_conflicts_in_at_patterns<'tcx>(cx: &MatchVisitor<'_, '_, 'tcx>, pat: &Pat<'tcx>) {
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// Extract `sub` in `binding @ sub`.
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let PatKind::Binding { name, mode, ty, subpattern: Some(box ref sub), .. } = pat.kind else {
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return;
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};
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let is_binding_by_move = |ty: Ty<'tcx>| !ty.is_copy_modulo_regions(cx.tcx, cx.param_env);
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let sess = cx.tcx.sess;
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// Get the binding move, extract the mutability if by-ref.
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let mut_outer = match mode {
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BindingMode::ByValue if is_binding_by_move(ty) => {
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// We have `x @ pat` where `x` is by-move. Reject all borrows in `pat`.
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let mut conflicts_ref = Vec::new();
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sub.each_binding(|_, mode, _, span| match mode {
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BindingMode::ByValue => {}
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BindingMode::ByRef(_) => conflicts_ref.push(span),
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});
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if !conflicts_ref.is_empty() {
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sess.emit_err(BorrowOfMovedValue {
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binding_span: pat.span,
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conflicts_ref,
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name,
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ty,
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suggest_borrowing: Some(pat.span.shrink_to_lo()),
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});
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}
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return;
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}
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BindingMode::ByValue => return,
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BindingMode::ByRef(m) => m.mutability(),
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};
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// We now have `ref $mut_outer binding @ sub` (semantically).
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// Recurse into each binding in `sub` and find mutability or move conflicts.
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let mut conflicts_move = Vec::new();
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let mut conflicts_mut_mut = Vec::new();
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let mut conflicts_mut_ref = Vec::new();
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sub.each_binding(|name, mode, ty, span| {
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match mode {
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BindingMode::ByRef(mut_inner) => match (mut_outer, mut_inner.mutability()) {
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// Both sides are `ref`.
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(Mutability::Not, Mutability::Not) => {}
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// 2x `ref mut`.
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(Mutability::Mut, Mutability::Mut) => {
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conflicts_mut_mut.push(Conflict::Mut { span, name })
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}
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(Mutability::Not, Mutability::Mut) => {
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conflicts_mut_ref.push(Conflict::Mut { span, name })
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}
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(Mutability::Mut, Mutability::Not) => {
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conflicts_mut_ref.push(Conflict::Ref { span, name })
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}
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},
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BindingMode::ByValue if is_binding_by_move(ty) => {
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conflicts_move.push(Conflict::Moved { span, name }) // `ref mut?` + by-move conflict.
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}
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BindingMode::ByValue => {} // `ref mut?` + by-copy is fine.
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}
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});
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let report_mut_mut = !conflicts_mut_mut.is_empty();
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let report_mut_ref = !conflicts_mut_ref.is_empty();
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let report_move_conflict = !conflicts_move.is_empty();
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let mut occurrences = match mut_outer {
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Mutability::Mut => vec![Conflict::Mut { span: pat.span, name }],
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Mutability::Not => vec![Conflict::Ref { span: pat.span, name }],
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};
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occurrences.extend(conflicts_mut_mut);
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occurrences.extend(conflicts_mut_ref);
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occurrences.extend(conflicts_move);
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// Report errors if any.
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if report_mut_mut {
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// Report mutability conflicts for e.g. `ref mut x @ Some(ref mut y)`.
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sess.emit_err(MultipleMutBorrows { span: pat.span, occurrences });
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} else if report_mut_ref {
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// Report mutability conflicts for e.g. `ref x @ Some(ref mut y)` or the converse.
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match mut_outer {
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Mutability::Mut => {
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sess.emit_err(AlreadyMutBorrowed { span: pat.span, occurrences });
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}
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Mutability::Not => {
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sess.emit_err(AlreadyBorrowed { span: pat.span, occurrences });
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}
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};
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} else if report_move_conflict {
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// Report by-ref and by-move conflicts, e.g. `ref x @ y`.
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sess.emit_err(MovedWhileBorrowed { span: pat.span, occurrences });
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}
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}
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