Safe Transmute: Refactor error handling and Answer type
- Create `Answer` type that is not just a type alias of `Result` - Remove a usage of `map_layouts` to make the code easier to read - Don't hide errors related to Unknown Layout when computing transmutability
This commit is contained in:
Bryan Garza
parent
64a54df86f
commit
f4cf8f65a5
compiler
rustc_trait_selection/src
rustc_transmute/src
tests/ui/transmutability/malformed-program-gracefulness
@ -668,6 +668,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
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scope: Ty<'tcx>,
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assume: rustc_transmute::Assume,
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) -> Result<Certainty, NoSolution> {
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use rustc_transmute::Answer;
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// FIXME(transmutability): This really should be returning nested goals for `Answer::If*`
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match rustc_transmute::TransmuteTypeEnv::new(self.infcx).is_transmutable(
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ObligationCause::dummy(),
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@ -675,11 +676,8 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
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scope,
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assume,
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) {
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Ok(None) => Ok(Certainty::Yes),
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Err(_)
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| Ok(Some(rustc_transmute::Condition::IfTransmutable { .. }))
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| Ok(Some(rustc_transmute::Condition::IfAll(_)))
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| Ok(Some(rustc_transmute::Condition::IfAny(_))) => Err(NoSolution),
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Answer::Yes => Ok(Certainty::Yes),
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Answer::No(_) | Answer::If(_) => Err(NoSolution),
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}
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}
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}
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@ -65,6 +65,11 @@ pub struct ImplCandidate<'tcx> {
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pub similarity: CandidateSimilarity,
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}
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enum GetSafeTransmuteErrorAndReason {
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Silent,
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Error { err_msg: String, safe_transmute_explanation: String },
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}
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pub trait InferCtxtExt<'tcx> {
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/// Given some node representing a fn-like thing in the HIR map,
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/// returns a span and `ArgKind` information that describes the
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@ -724,11 +729,17 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
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== self.tcx.lang_items().transmute_trait()
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{
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// Recompute the safe transmute reason and use that for the error reporting
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self.get_safe_transmute_error_and_reason(
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match self.get_safe_transmute_error_and_reason(
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obligation.clone(),
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trait_ref,
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span,
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)
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) {
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GetSafeTransmuteErrorAndReason::Silent => return,
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GetSafeTransmuteErrorAndReason::Error {
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err_msg,
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safe_transmute_explanation,
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} => (err_msg, Some(safe_transmute_explanation)),
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}
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} else {
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(err_msg, None)
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};
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@ -1292,7 +1303,7 @@ trait InferCtxtPrivExt<'tcx> {
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obligation: PredicateObligation<'tcx>,
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trait_ref: ty::PolyTraitRef<'tcx>,
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span: Span,
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) -> (String, Option<String>);
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) -> GetSafeTransmuteErrorAndReason;
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fn add_tuple_trait_message(
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&self,
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@ -2738,7 +2749,9 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
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obligation: PredicateObligation<'tcx>,
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trait_ref: ty::PolyTraitRef<'tcx>,
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span: Span,
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) -> (String, Option<String>) {
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) -> GetSafeTransmuteErrorAndReason {
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use rustc_transmute::Answer;
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// Erase regions because layout code doesn't particularly care about regions.
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let trait_ref = self.tcx.erase_regions(self.tcx.erase_late_bound_regions(trait_ref));
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@ -2758,13 +2771,13 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
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scope,
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assume,
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) {
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Err(reason) => {
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Answer::No(reason) => {
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let dst = trait_ref.substs.type_at(0);
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let src = trait_ref.substs.type_at(1);
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let custom_err_msg = format!(
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let err_msg = format!(
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"`{src}` cannot be safely transmuted into `{dst}` in the defining scope of `{scope}`"
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);
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let reason_msg = match reason {
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let safe_transmute_explanation = match reason {
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rustc_transmute::Reason::SrcIsUnspecified => {
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format!("`{src}` does not have a well-specified layout")
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}
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@ -2794,11 +2807,21 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
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rustc_transmute::Reason::DstIsMoreUnique => {
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format!("`{src}` is a shared reference, but `{dst}` is a unique reference")
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}
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// Already reported by rustc
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rustc_transmute::Reason::TypeError => {
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return GetSafeTransmuteErrorAndReason::Silent;
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}
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rustc_transmute::Reason::SrcLayoutUnknown => {
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format!("`{src}` has an unknown layout")
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}
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rustc_transmute::Reason::DstLayoutUnknown => {
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format!("`{dst}` has an unknown layout")
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}
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};
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(custom_err_msg, Some(reason_msg))
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GetSafeTransmuteErrorAndReason::Error { err_msg, safe_transmute_explanation }
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}
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// Should never get a Yes at this point! We already ran it before, and did not get a Yes.
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Ok(None) => span_bug!(
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Answer::Yes => span_bug!(
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span,
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"Inconsistent rustc_transmute::is_transmutable(...) result, got Yes",
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),
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@ -285,28 +285,22 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
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&mut self,
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obligation: &TraitObligation<'tcx>,
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) -> Result<ImplSourceBuiltinData<PredicateObligation<'tcx>>, SelectionError<'tcx>> {
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use rustc_transmute::{Answer, Condition};
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#[instrument(level = "debug", skip(tcx, obligation, predicate))]
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fn flatten_answer_tree<'tcx>(
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tcx: TyCtxt<'tcx>,
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obligation: &TraitObligation<'tcx>,
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predicate: TraitPredicate<'tcx>,
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answer: rustc_transmute::Condition<rustc_transmute::layout::rustc::Ref<'tcx>>,
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cond: Condition<rustc_transmute::layout::rustc::Ref<'tcx>>,
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) -> Vec<PredicateObligation<'tcx>> {
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match answer {
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match cond {
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// FIXME(bryangarza): Add separate `IfAny` case, instead of treating as `IfAll`
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// Not possible until the trait solver supports disjunctions of obligations
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rustc_transmute::Condition::IfAll(answers)
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| rustc_transmute::Condition::IfAny(answers) => {
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let mut nested = vec![];
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for flattened in answers
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.into_iter()
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.map(|answer| flatten_answer_tree(tcx, obligation, predicate, answer))
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{
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nested.extend(flattened);
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}
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nested
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}
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rustc_transmute::Condition::IfTransmutable { src, dst } => {
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Condition::IfAll(conds) | Condition::IfAny(conds) => conds
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.into_iter()
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.flat_map(|cond| flatten_answer_tree(tcx, obligation, predicate, cond))
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.collect(),
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Condition::IfTransmutable { src, dst } => {
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let trait_def_id = obligation.predicate.def_id();
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let scope = predicate.trait_ref.substs.type_at(2);
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let assume_const = predicate.trait_ref.substs.const_at(3);
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@ -333,11 +327,10 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
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// If Dst is mutable, check bidirectionally.
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// For example, transmuting bool -> u8 is OK as long as you can't update that u8
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// to be > 1, because you could later transmute the u8 back to a bool and get UB.
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let mut obligations = vec![make_obl(src.ty, dst.ty)];
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if dst.mutability == Mutability::Mut {
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obligations.push(make_obl(dst.ty, src.ty));
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match dst.mutability {
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Mutability::Not => vec![make_obl(src.ty, dst.ty)],
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Mutability::Mut => vec![make_obl(src.ty, dst.ty), make_obl(dst.ty, src.ty)],
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}
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obligations
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}
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}
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}
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@ -370,9 +363,9 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
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);
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let fully_flattened = match maybe_transmutable {
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Err(_) => Err(Unimplemented)?,
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Ok(Some(mt)) => flatten_answer_tree(self.tcx(), obligation, predicate, mt),
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Ok(None) => vec![],
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Answer::No(_) => Err(Unimplemented)?,
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Answer::If(cond) => flatten_answer_tree(self.tcx(), obligation, predicate, cond),
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Answer::Yes => vec![],
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};
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debug!(?fully_flattened);
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@ -188,14 +188,14 @@ pub(crate) mod rustc {
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/// The layout of the type is unspecified.
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Unspecified,
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/// This error will be surfaced elsewhere by rustc, so don't surface it.
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Unknown,
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UnknownLayout,
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TypeError(ErrorGuaranteed),
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}
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impl<'tcx> From<LayoutError<'tcx>> for Err {
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fn from(err: LayoutError<'tcx>) -> Self {
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match err {
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LayoutError::Unknown(..) => Self::Unknown,
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LayoutError::Unknown(..) => Self::UnknownLayout,
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err => unimplemented!("{:?}", err),
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}
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}
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@ -19,10 +19,16 @@ pub struct Assume {
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pub validity: bool,
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}
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/// Either we have an error, or we have an optional Condition that must hold.
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pub type Answer<R> = Result<Option<Condition<R>>, Reason>;
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/// Either we have an error, transmutation is allowed, or we have an optional
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/// Condition that must hold.
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#[derive(Debug, Hash, Eq, PartialEq, Clone)]
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pub enum Answer<R> {
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Yes,
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No(Reason),
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If(Condition<R>),
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}
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/// A condition which must hold for safe transmutation to be possible
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/// A condition which must hold for safe transmutation to be possible.
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#[derive(Debug, Hash, Eq, PartialEq, Clone)]
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pub enum Condition<R> {
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/// `Src` is transmutable into `Dst`, if `src` is transmutable into `dst`.
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@ -35,7 +41,7 @@ pub enum Condition<R> {
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IfAny(Vec<Condition<R>>),
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}
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/// Answers: Why wasn't the source type transmutable into the destination type?
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/// Answers "why wasn't the source type transmutable into the destination type?"
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#[derive(Debug, Hash, Eq, PartialEq, PartialOrd, Ord, Clone)]
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pub enum Reason {
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/// The layout of the source type is unspecified.
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@ -52,6 +58,12 @@ pub enum Reason {
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DstHasStricterAlignment { src_min_align: usize, dst_min_align: usize },
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/// Can't go from shared pointer to unique pointer
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DstIsMoreUnique,
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/// Encountered a type error
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TypeError,
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/// The layout of src is unknown
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SrcLayoutUnknown,
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/// The layout of dst is unknown
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DstLayoutUnknown,
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}
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#[cfg(feature = "rustc")]
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@ -33,6 +33,7 @@ where
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Self { src, dst, scope, assume, context }
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}
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// FIXME(bryangarza): Delete this when all usages are removed
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pub(crate) fn map_layouts<F, M>(
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self,
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f: F,
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@ -67,30 +68,26 @@ mod rustc {
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/// then computes an answer using those trees.
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#[instrument(level = "debug", skip(self), fields(src = ?self.src, dst = ?self.dst))]
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pub fn answer(self) -> Answer<<TyCtxt<'tcx> as QueryContext>::Ref> {
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let query_or_answer = self.map_layouts(|src, dst, scope, &context| {
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// Convert `src` and `dst` from their rustc representations, to `Tree`-based
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// representations. If these conversions fail, conclude that the transmutation is
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// unacceptable; the layouts of both the source and destination types must be
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// well-defined.
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let src = Tree::from_ty(src, context);
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let dst = Tree::from_ty(dst, context);
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let Self { src, dst, scope, assume, context } = self;
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match (src, dst) {
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// Answer `Ok(None)` here, because 'unknown layout' and type errors will already
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// be reported by rustc. No need to spam the user with more errors.
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(Err(Err::TypeError(_)), _)
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| (_, Err(Err::TypeError(_)))
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| (Err(Err::Unknown), _)
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| (_, Err(Err::Unknown)) => Err(Ok(None)),
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(Err(Err::Unspecified), _) => Err(Err(Reason::SrcIsUnspecified)),
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(_, Err(Err::Unspecified)) => Err(Err(Reason::DstIsUnspecified)),
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(Ok(src), Ok(dst)) => Ok((src, dst)),
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// Convert `src` and `dst` from their rustc representations, to `Tree`-based
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// representations. If these conversions fail, conclude that the transmutation is
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// unacceptable; the layouts of both the source and destination types must be
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// well-defined.
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let src = Tree::from_ty(src, context);
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let dst = Tree::from_ty(dst, context);
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match (src, dst) {
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(Err(Err::TypeError(_)), _) | (_, Err(Err::TypeError(_))) => {
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Answer::No(Reason::TypeError)
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}
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(Err(Err::UnknownLayout), _) => Answer::No(Reason::SrcLayoutUnknown),
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(_, Err(Err::UnknownLayout)) => Answer::No(Reason::DstLayoutUnknown),
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(Err(Err::Unspecified), _) => Answer::No(Reason::SrcIsUnspecified),
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(_, Err(Err::Unspecified)) => Answer::No(Reason::DstIsUnspecified),
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(Ok(src), Ok(dst)) => {
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MaybeTransmutableQuery { src, dst, scope, assume, context }.answer()
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}
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});
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match query_or_answer {
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Ok(query) => query.answer(),
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Err(answer) => answer,
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}
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}
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}
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@ -108,6 +105,7 @@ where
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#[instrument(level = "debug", skip(self), fields(src = ?self.src, dst = ?self.dst))]
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pub(crate) fn answer(self) -> Answer<<C as QueryContext>::Ref> {
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let assume_visibility = self.assume.safety;
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// FIXME(bryangarza): Refactor this code to get rid of `map_layouts`
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let query_or_answer = self.map_layouts(|src, dst, scope, context| {
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// Remove all `Def` nodes from `src`, without checking their visibility.
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let src = src.prune(&|def| true);
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@ -128,12 +126,13 @@ where
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// Convert `src` from a tree-based representation to an NFA-based representation.
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// If the conversion fails because `src` is uninhabited, conclude that the transmutation
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// is acceptable, because instances of the `src` type do not exist.
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let src = Nfa::from_tree(src).map_err(|Uninhabited| Ok(None))?;
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let src = Nfa::from_tree(src).map_err(|Uninhabited| Answer::Yes)?;
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// Convert `dst` from a tree-based representation to an NFA-based representation.
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// If the conversion fails because `src` is uninhabited, conclude that the transmutation
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// is unacceptable, because instances of the `dst` type do not exist.
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let dst = Nfa::from_tree(dst).map_err(|Uninhabited| Err(Reason::DstIsPrivate))?;
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let dst =
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Nfa::from_tree(dst).map_err(|Uninhabited| Answer::No(Reason::DstIsPrivate))?;
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Ok((src, dst))
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});
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@ -155,6 +154,7 @@ where
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#[inline(always)]
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#[instrument(level = "debug", skip(self), fields(src = ?self.src, dst = ?self.dst))]
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pub(crate) fn answer(self) -> Answer<<C as QueryContext>::Ref> {
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// FIXME(bryangarza): Refactor this code to get rid of `map_layouts`
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let query_or_answer = self
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.map_layouts(|src, dst, scope, context| Ok((Dfa::from_nfa(src), Dfa::from_nfa(dst))));
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@ -226,13 +226,13 @@ where
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// So, if it's possible to transmute to a smaller Dst by truncating, and we can guarantee
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// that none of the actually-used data can introduce an invalid state for Dst's type, we
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// are able to safely transmute, even with truncation.
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Ok(None)
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Answer::Yes
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} else if src_state == self.src.accepting {
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// extension: `size_of(Src) >= size_of(Dst)`
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if let Some(dst_state_prime) = self.dst.byte_from(dst_state, Byte::Uninit) {
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self.answer_memo(cache, src_state, dst_state_prime)
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} else {
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Err(Reason::DstIsTooBig)
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Answer::No(Reason::DstIsTooBig)
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}
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} else {
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let src_quantifier = if self.assume.validity {
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@ -265,7 +265,7 @@ where
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} else {
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// otherwise, we've exhausted our options.
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// the DFAs, from this point onwards, are bit-incompatible.
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Err(Reason::DstIsBitIncompatible)
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Answer::No(Reason::DstIsBitIncompatible)
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}
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},
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),
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@ -282,8 +282,8 @@ where
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// the algoritm; only its performance.
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debug!(?bytes_answer);
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match bytes_answer {
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Err(_) if !self.assume.validity => return bytes_answer,
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Ok(None) if self.assume.validity => return bytes_answer,
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Answer::No(_) if !self.assume.validity => return bytes_answer,
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Answer::Yes if self.assume.validity => return bytes_answer,
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_ => {}
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};
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@ -299,11 +299,11 @@ where
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.into_iter()
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.map(|(&dst_ref, &dst_state_prime)| {
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if !src_ref.is_mutable() && dst_ref.is_mutable() {
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Err(Reason::DstIsMoreUnique)
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Answer::No(Reason::DstIsMoreUnique)
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} else if !self.assume.alignment
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&& src_ref.min_align() < dst_ref.min_align()
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{
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Err(Reason::DstHasStricterAlignment {
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Answer::No(Reason::DstHasStricterAlignment {
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src_min_align: src_ref.min_align(),
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dst_min_align: dst_ref.min_align(),
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})
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@ -311,10 +311,10 @@ where
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// ...such that `src` is transmutable into `dst`, if
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// `src_ref` is transmutability into `dst_ref`.
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and(
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Ok(Some(Condition::IfTransmutable {
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Answer::If(Condition::IfTransmutable {
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src: src_ref,
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dst: dst_ref,
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})),
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}),
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self.answer_memo(
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cache,
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src_state_prime,
|
||||
@ -346,65 +346,56 @@ fn and<R>(lhs: Answer<R>, rhs: Answer<R>) -> Answer<R>
|
||||
where
|
||||
R: PartialEq,
|
||||
{
|
||||
// If both are errors, then we should return the more specific one
|
||||
if lhs.is_err() && rhs.is_err() {
|
||||
if lhs == Err(Reason::DstIsBitIncompatible) {
|
||||
return rhs;
|
||||
} else {
|
||||
return lhs;
|
||||
}
|
||||
}
|
||||
Ok(match (lhs?, rhs?) {
|
||||
match (lhs, rhs) {
|
||||
// If both are errors, then we should return the more specific one
|
||||
(Answer::No(Reason::DstIsBitIncompatible), Answer::No(reason))
|
||||
| (Answer::No(reason), Answer::No(_))
|
||||
// If either is an error, return it
|
||||
| (Answer::No(reason), _) | (_, Answer::No(reason)) => Answer::No(reason),
|
||||
// If only one side has a condition, pass it along
|
||||
(None, other) | (other, None) => other,
|
||||
| (Answer::Yes, other) | (other, Answer::Yes) => other,
|
||||
// If both sides have IfAll conditions, merge them
|
||||
(Some(Condition::IfAll(mut lhs)), Some(Condition::IfAll(ref mut rhs))) => {
|
||||
(Answer::If(Condition::IfAll(mut lhs)), Answer::If(Condition::IfAll(ref mut rhs))) => {
|
||||
lhs.append(rhs);
|
||||
Some(Condition::IfAll(lhs))
|
||||
Answer::If(Condition::IfAll(lhs))
|
||||
}
|
||||
// If only one side is an IfAll, add the other Condition to it
|
||||
(Some(cond), Some(Condition::IfAll(mut conds)))
|
||||
| (Some(Condition::IfAll(mut conds)), Some(cond)) => {
|
||||
(Answer::If(cond), Answer::If(Condition::IfAll(mut conds)))
|
||||
| (Answer::If(Condition::IfAll(mut conds)), Answer::If(cond)) => {
|
||||
conds.push(cond);
|
||||
Some(Condition::IfAll(conds))
|
||||
Answer::If(Condition::IfAll(conds))
|
||||
}
|
||||
// Otherwise, both lhs and rhs conditions can be combined in a parent IfAll
|
||||
(Some(lhs), Some(rhs)) => Some(Condition::IfAll(vec![lhs, rhs])),
|
||||
})
|
||||
(Answer::If(lhs), Answer::If(rhs)) => Answer::If(Condition::IfAll(vec![lhs, rhs])),
|
||||
}
|
||||
}
|
||||
|
||||
fn or<R>(lhs: Answer<R>, rhs: Answer<R>) -> Answer<R>
|
||||
where
|
||||
R: PartialEq,
|
||||
{
|
||||
// If both are errors, then we should return the more specific one
|
||||
if lhs.is_err() && rhs.is_err() {
|
||||
if lhs == Err(Reason::DstIsBitIncompatible) {
|
||||
return rhs;
|
||||
} else {
|
||||
return lhs;
|
||||
}
|
||||
}
|
||||
// Otherwise, errors can be ignored for the rest of the pattern matching
|
||||
let lhs = lhs.unwrap_or(None);
|
||||
let rhs = rhs.unwrap_or(None);
|
||||
Ok(match (lhs, rhs) {
|
||||
match (lhs, rhs) {
|
||||
// If both are errors, then we should return the more specific one
|
||||
(Answer::No(Reason::DstIsBitIncompatible), Answer::No(reason))
|
||||
| (Answer::No(reason), Answer::No(_)) => Answer::No(reason),
|
||||
// Otherwise, errors can be ignored for the rest of the pattern matching
|
||||
(Answer::No(_), other) | (other, Answer::No(_)) => or(other, Answer::Yes),
|
||||
// If only one side has a condition, pass it along
|
||||
(None, other) | (other, None) => other,
|
||||
(Answer::Yes, other) | (other, Answer::Yes) => other,
|
||||
// If both sides have IfAny conditions, merge them
|
||||
(Some(Condition::IfAny(mut lhs)), Some(Condition::IfAny(ref mut rhs))) => {
|
||||
(Answer::If(Condition::IfAny(mut lhs)), Answer::If(Condition::IfAny(ref mut rhs))) => {
|
||||
lhs.append(rhs);
|
||||
Some(Condition::IfAny(lhs))
|
||||
Answer::If(Condition::IfAny(lhs))
|
||||
}
|
||||
// If only one side is an IfAny, add the other Condition to it
|
||||
(Some(cond), Some(Condition::IfAny(mut conds)))
|
||||
| (Some(Condition::IfAny(mut conds)), Some(cond)) => {
|
||||
(Answer::If(cond), Answer::If(Condition::IfAny(mut conds)))
|
||||
| (Answer::If(Condition::IfAny(mut conds)), Answer::If(cond)) => {
|
||||
conds.push(cond);
|
||||
Some(Condition::IfAny(conds))
|
||||
Answer::If(Condition::IfAny(conds))
|
||||
}
|
||||
// Otherwise, both lhs and rhs conditions can be combined in a parent IfAny
|
||||
(Some(lhs), Some(rhs)) => Some(Condition::IfAny(vec![lhs, rhs])),
|
||||
})
|
||||
(Answer::If(lhs), Answer::If(rhs)) => Answer::If(Condition::IfAny(vec![lhs, rhs])),
|
||||
}
|
||||
}
|
||||
|
||||
pub enum Quantifier {
|
||||
@ -421,16 +412,21 @@ impl Quantifier {
|
||||
use std::ops::ControlFlow::{Break, Continue};
|
||||
|
||||
let (init, try_fold_f): (_, fn(_, _) -> _) = match self {
|
||||
Self::ThereExists => (Err(Reason::DstIsBitIncompatible), |accum: Answer<R>, next| {
|
||||
match or(accum, next) {
|
||||
Ok(None) => Break(Ok(None)),
|
||||
Self::ThereExists => {
|
||||
(Answer::No(Reason::DstIsBitIncompatible), |accum: Answer<R>, next| {
|
||||
match or(accum, next) {
|
||||
Answer::Yes => Break(Answer::Yes),
|
||||
maybe => Continue(maybe),
|
||||
}
|
||||
})
|
||||
}
|
||||
Self::ForAll => (Answer::Yes, |accum: Answer<R>, next| {
|
||||
let answer = and(accum, next);
|
||||
match answer {
|
||||
Answer::No(_) => Break(answer),
|
||||
maybe => Continue(maybe),
|
||||
}
|
||||
}),
|
||||
Self::ForAll => (Ok(None), |accum: Answer<R>, next| match and(accum, next) {
|
||||
Err(reason) => Break(Err(reason)),
|
||||
maybe => Continue(maybe),
|
||||
}),
|
||||
};
|
||||
|
||||
let (Continue(result) | Break(result)) = iter.into_iter().try_fold(init, try_fold_f);
|
||||
|
||||
@ -4,6 +4,8 @@ use crate::{layout, Reason};
|
||||
use itertools::Itertools;
|
||||
|
||||
mod bool {
|
||||
use crate::Answer;
|
||||
|
||||
use super::*;
|
||||
|
||||
#[test]
|
||||
@ -17,7 +19,7 @@ mod bool {
|
||||
UltraMinimal,
|
||||
)
|
||||
.answer();
|
||||
assert_eq!(answer, Ok(None));
|
||||
assert_eq!(answer, Answer::Yes);
|
||||
}
|
||||
|
||||
#[test]
|
||||
@ -30,7 +32,7 @@ mod bool {
|
||||
UltraMinimal,
|
||||
)
|
||||
.answer();
|
||||
assert_eq!(answer, Ok(None));
|
||||
assert_eq!(answer, Answer::Yes);
|
||||
}
|
||||
|
||||
#[test]
|
||||
@ -65,7 +67,7 @@ mod bool {
|
||||
|
||||
if src_set.is_subset(&dst_set) {
|
||||
assert_eq!(
|
||||
Ok(None),
|
||||
Answer::Yes,
|
||||
MaybeTransmutableQuery::new(
|
||||
src_layout.clone(),
|
||||
dst_layout.clone(),
|
||||
@ -80,7 +82,7 @@ mod bool {
|
||||
);
|
||||
} else if !src_set.is_disjoint(&dst_set) {
|
||||
assert_eq!(
|
||||
Ok(None),
|
||||
Answer::Yes,
|
||||
MaybeTransmutableQuery::new(
|
||||
src_layout.clone(),
|
||||
dst_layout.clone(),
|
||||
@ -95,7 +97,7 @@ mod bool {
|
||||
);
|
||||
} else {
|
||||
assert_eq!(
|
||||
Err(Reason::DstIsBitIncompatible),
|
||||
Answer::No(Reason::DstIsBitIncompatible),
|
||||
MaybeTransmutableQuery::new(
|
||||
src_layout.clone(),
|
||||
dst_layout.clone(),
|
||||
|
||||
@ -18,5 +18,5 @@ fn should_gracefully_handle_unknown_dst_field() {
|
||||
struct Context;
|
||||
#[repr(C)] struct Src;
|
||||
#[repr(C)] struct Dst(Missing); //~ cannot find type
|
||||
assert::is_transmutable::<Src, Dst, Context>();
|
||||
assert::is_transmutable::<Src, Dst, Context>(); //~ ERROR cannot be safely transmuted
|
||||
}
|
||||
|
||||
@ -4,6 +4,22 @@ error[E0412]: cannot find type `Missing` in this scope
|
||||
LL | #[repr(C)] struct Dst(Missing);
|
||||
| ^^^^^^^ not found in this scope
|
||||
|
||||
error: aborting due to previous error
|
||||
error[E0277]: `Src` cannot be safely transmuted into `Dst` in the defining scope of `should_gracefully_handle_unknown_dst_field::Context`
|
||||
--> $DIR/unknown_src_field.rs:21:36
|
||||
|
|
||||
LL | assert::is_transmutable::<Src, Dst, Context>();
|
||||
| ^^^ `Dst` has an unknown layout
|
||||
|
|
||||
note: required by a bound in `is_transmutable`
|
||||
--> $DIR/unknown_src_field.rs:13:14
|
||||
|
|
||||
LL | pub fn is_transmutable<Src, Dst, Context>()
|
||||
| --------------- required by a bound in this function
|
||||
LL | where
|
||||
LL | Dst: BikeshedIntrinsicFrom<Src, Context>
|
||||
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
|
||||
|
||||
For more information about this error, try `rustc --explain E0412`.
|
||||
error: aborting due to 2 previous errors
|
||||
|
||||
Some errors have detailed explanations: E0277, E0412.
|
||||
For more information about an error, try `rustc --explain E0277`.
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user