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Fix transmute goal
This commit is contained in:
parent
38bbcc001e
commit
9453d2cfeb
@ -295,6 +295,37 @@ where
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Ok(ty)
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Ok(ty)
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}
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}
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}
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}
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/// Normalize a const for when it is structurally matched on, or more likely
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/// when it needs `.try_to_*` called on it (e.g. to turn it into a usize).
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///
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/// This function is necessary in nearly all cases before matching on a const.
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/// Not doing so is likely to be incomplete and therefore unsound during
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/// coherence.
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#[instrument(level = "trace", skip(self, param_env), ret)]
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fn structurally_normalize_const(
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&mut self,
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param_env: I::ParamEnv,
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ct: I::Const,
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) -> Result<I::Const, NoSolution> {
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if let ty::ConstKind::Unevaluated(..) = ct.kind() {
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let normalized_ct = self.next_const_infer();
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let alias_relate_goal = Goal::new(
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self.cx(),
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param_env,
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ty::PredicateKind::AliasRelate(
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ct.into(),
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normalized_ct.into(),
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ty::AliasRelationDirection::Equate,
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),
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);
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self.add_goal(GoalSource::Misc, alias_relate_goal);
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self.try_evaluate_added_goals()?;
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Ok(self.resolve_vars_if_possible(normalized_ct))
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} else {
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Ok(ct)
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}
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}
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}
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}
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fn response_no_constraints_raw<I: Interner>(
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fn response_no_constraints_raw<I: Interner>(
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@ -627,11 +627,16 @@ where
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}
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}
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ecx.probe_builtin_trait_candidate(BuiltinImplSource::Misc).enter(|ecx| {
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ecx.probe_builtin_trait_candidate(BuiltinImplSource::Misc).enter(|ecx| {
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let assume = ecx.structurally_normalize_const(
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goal.param_env,
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goal.predicate.trait_ref.args.const_at(2),
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)?;
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let certainty = ecx.is_transmutable(
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let certainty = ecx.is_transmutable(
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goal.param_env,
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goal.param_env,
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goal.predicate.trait_ref.args.type_at(0),
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goal.predicate.trait_ref.args.type_at(0),
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goal.predicate.trait_ref.args.type_at(1),
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goal.predicate.trait_ref.args.type_at(1),
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goal.predicate.trait_ref.args.const_at(2),
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assume,
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)?;
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)?;
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ecx.evaluate_added_goals_and_make_canonical_response(certainty)
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ecx.evaluate_added_goals_and_make_canonical_response(certainty)
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})
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})
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@ -2247,124 +2247,143 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
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span: Span,
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span: Span,
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) -> GetSafeTransmuteErrorAndReason {
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) -> GetSafeTransmuteErrorAndReason {
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use rustc_transmute::Answer;
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use rustc_transmute::Answer;
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self.probe(|_| {
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// We don't assemble a transmutability candidate for types that are generic
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// and we should have ambiguity for types that still have non-region infer.
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if obligation.predicate.has_non_region_param() || obligation.has_non_region_infer() {
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return GetSafeTransmuteErrorAndReason::Default;
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}
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// We don't assemble a transmutability candidate for types that are generic
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// Erase regions because layout code doesn't particularly care about regions.
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// and we should have ambiguity for types that still have non-region infer.
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let trait_ref =
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if obligation.predicate.has_non_region_param() || obligation.has_non_region_infer() {
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self.tcx.erase_regions(self.tcx.instantiate_bound_regions_with_erased(trait_ref));
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return GetSafeTransmuteErrorAndReason::Default;
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}
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// Erase regions because layout code doesn't particularly care about regions.
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let src_and_dst = rustc_transmute::Types {
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let trait_ref =
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dst: trait_ref.args.type_at(0),
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self.tcx.erase_regions(self.tcx.instantiate_bound_regions_with_erased(trait_ref));
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src: trait_ref.args.type_at(1),
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};
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let src_and_dst = rustc_transmute::Types {
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let ocx = ObligationCtxt::new(self);
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dst: trait_ref.args.type_at(0),
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let Ok(assume) = ocx.structurally_normalize_const(
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src: trait_ref.args.type_at(1),
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&obligation.cause,
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};
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obligation.param_env,
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let Some(assume) = rustc_transmute::Assume::from_const(
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trait_ref.args.const_at(2),
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self.infcx.tcx,
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) else {
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obligation.param_env,
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self.dcx().span_delayed_bug(
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trait_ref.args.const_at(2),
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span,
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) else {
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"Unable to construct rustc_transmute::Assume where it was previously possible",
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self.dcx().span_delayed_bug(
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);
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span,
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return GetSafeTransmuteErrorAndReason::Silent;
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"Unable to construct rustc_transmute::Assume where it was previously possible",
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};
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);
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return GetSafeTransmuteErrorAndReason::Silent;
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};
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let dst = trait_ref.args.type_at(0);
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let Some(assume) =
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let src = trait_ref.args.type_at(1);
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rustc_transmute::Assume::from_const(self.infcx.tcx, obligation.param_env, assume)
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else {
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self.dcx().span_delayed_bug(
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span,
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"Unable to construct rustc_transmute::Assume where it was previously possible",
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);
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return GetSafeTransmuteErrorAndReason::Silent;
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};
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let err_msg = format!("`{src}` cannot be safely transmuted into `{dst}`");
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let dst = trait_ref.args.type_at(0);
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let src = trait_ref.args.type_at(1);
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let err_msg = format!("`{src}` cannot be safely transmuted into `{dst}`");
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match rustc_transmute::TransmuteTypeEnv::new(self.infcx).is_transmutable(
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match rustc_transmute::TransmuteTypeEnv::new(self.infcx).is_transmutable(
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obligation.cause,
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obligation.cause,
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src_and_dst,
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src_and_dst,
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assume,
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assume,
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) {
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) {
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Answer::No(reason) => {
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Answer::No(reason) => {
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let safe_transmute_explanation = match reason {
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let safe_transmute_explanation = match reason {
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rustc_transmute::Reason::SrcIsNotYetSupported => {
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rustc_transmute::Reason::SrcIsNotYetSupported => {
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format!("analyzing the transmutability of `{src}` is not yet supported")
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format!("analyzing the transmutability of `{src}` is not yet supported")
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}
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}
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rustc_transmute::Reason::DstIsNotYetSupported => {
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rustc_transmute::Reason::DstIsNotYetSupported => {
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format!("analyzing the transmutability of `{dst}` is not yet supported")
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format!("analyzing the transmutability of `{dst}` is not yet supported")
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}
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}
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rustc_transmute::Reason::DstIsBitIncompatible => {
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rustc_transmute::Reason::DstIsBitIncompatible => {
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format!("at least one value of `{src}` isn't a bit-valid value of `{dst}`")
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format!(
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}
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"at least one value of `{src}` isn't a bit-valid value of `{dst}`"
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)
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}
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rustc_transmute::Reason::DstUninhabited => {
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rustc_transmute::Reason::DstUninhabited => {
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format!("`{dst}` is uninhabited")
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format!("`{dst}` is uninhabited")
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}
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}
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rustc_transmute::Reason::DstMayHaveSafetyInvariants => {
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rustc_transmute::Reason::DstMayHaveSafetyInvariants => {
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format!("`{dst}` may carry safety invariants")
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format!("`{dst}` may carry safety invariants")
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}
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rustc_transmute::Reason::DstIsTooBig => {
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format!("the size of `{src}` is smaller than the size of `{dst}`")
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}
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rustc_transmute::Reason::DstRefIsTooBig { src, dst } => {
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let src_size = src.size;
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let dst_size = dst.size;
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format!(
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"the referent size of `{src}` ({src_size} bytes) \
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is smaller than that of `{dst}` ({dst_size} bytes)"
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)
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}
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rustc_transmute::Reason::SrcSizeOverflow => {
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format!(
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"values of the type `{src}` are too big for the target architecture"
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)
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}
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rustc_transmute::Reason::DstSizeOverflow => {
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format!(
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"values of the type `{dst}` are too big for the target architecture"
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)
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}
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rustc_transmute::Reason::DstHasStricterAlignment {
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src_min_align,
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dst_min_align,
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} => {
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format!(
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"the minimum alignment of `{src}` ({src_min_align}) should \
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be greater than that of `{dst}` ({dst_min_align})"
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)
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}
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rustc_transmute::Reason::DstIsMoreUnique => {
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format!(
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"`{src}` is a shared reference, but `{dst}` is a unique reference"
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)
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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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GetSafeTransmuteErrorAndReason::Error {
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err_msg,
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safe_transmute_explanation: Some(safe_transmute_explanation),
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}
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}
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rustc_transmute::Reason::DstIsTooBig => {
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format!("the size of `{src}` is smaller than the size of `{dst}`")
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}
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rustc_transmute::Reason::DstRefIsTooBig { src, dst } => {
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let src_size = src.size;
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let dst_size = dst.size;
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format!(
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"the referent size of `{src}` ({src_size} bytes) is smaller than that of `{dst}` ({dst_size} bytes)"
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)
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}
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rustc_transmute::Reason::SrcSizeOverflow => {
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format!(
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"values of the type `{src}` are too big for the target architecture"
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)
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}
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rustc_transmute::Reason::DstSizeOverflow => {
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format!(
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"values of the type `{dst}` are too big for the target architecture"
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)
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}
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rustc_transmute::Reason::DstHasStricterAlignment {
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src_min_align,
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dst_min_align,
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} => {
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format!(
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"the minimum alignment of `{src}` ({src_min_align}) should be greater than that of `{dst}` ({dst_min_align})"
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)
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}
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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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GetSafeTransmuteErrorAndReason::Error {
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err_msg,
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safe_transmute_explanation: Some(safe_transmute_explanation),
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}
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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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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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// Reached when a different obligation (namely `Freeze`) causes the
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// transmutability analysis to fail. In this case, silence the
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// transmutability error message in favor of that more specific
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// error.
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Answer::If(_) => GetSafeTransmuteErrorAndReason::Error {
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err_msg,
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safe_transmute_explanation: None,
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},
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}
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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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})
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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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// Reached when a different obligation (namely `Freeze`) causes the
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// transmutability analysis to fail. In this case, silence the
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// transmutability error message in favor of that more specific
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// error.
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Answer::If(_) => {
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GetSafeTransmuteErrorAndReason::Error { err_msg, safe_transmute_explanation: None }
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}
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}
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}
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}
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/// For effects predicates such as `<u32 as Add>::Effects: Compat<host>`, pretend that the
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/// For effects predicates such as `<u32 as Add>::Effects: Compat<host>`, pretend that the
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@ -329,4 +329,15 @@ where
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.at(cause, param_env)
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.at(cause, param_env)
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.structurally_normalize(value, &mut **self.engine.borrow_mut())
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.structurally_normalize(value, &mut **self.engine.borrow_mut())
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}
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}
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pub fn structurally_normalize_const(
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&self,
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cause: &ObligationCause<'tcx>,
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param_env: ty::ParamEnv<'tcx>,
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value: ty::Const<'tcx>,
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) -> Result<ty::Const<'tcx>, Vec<E>> {
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self.infcx
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.at(cause, param_env)
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.structurally_normalize_const(value, &mut **self.engine.borrow_mut())
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}
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}
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}
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@ -405,11 +405,14 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
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|
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let predicate = obligation.predicate.skip_binder();
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let predicate = obligation.predicate.skip_binder();
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|
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let Some(assume) = rustc_transmute::Assume::from_const(
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let mut assume = predicate.trait_ref.args.const_at(2);
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self.infcx.tcx,
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// FIXME(min_generic_const_exprs): We should shallowly normalize this.
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obligation.param_env,
|
if self.tcx().features().generic_const_exprs {
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predicate.trait_ref.args.const_at(2),
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assume = assume.normalize_internal(self.tcx(), obligation.param_env);
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) else {
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}
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let Some(assume) =
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rustc_transmute::Assume::from_const(self.infcx.tcx, obligation.param_env, assume)
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else {
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return Err(Unimplemented);
|
return Err(Unimplemented);
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};
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};
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|
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|
@ -82,6 +82,8 @@ impl<'tcx> At<'_, 'tcx> {
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}
|
}
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|
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Ok(self.infcx.resolve_vars_if_possible(new_infer_ct))
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Ok(self.infcx.resolve_vars_if_possible(new_infer_ct))
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} else if self.infcx.tcx.features().generic_const_exprs {
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Ok(ct.normalize_internal(self.infcx.tcx, self.param_env))
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} else {
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} else {
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Ok(self.normalize(ct).into_value_registering_obligations(self.infcx, fulfill_cx))
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Ok(self.normalize(ct).into_value_registering_obligations(self.infcx, fulfill_cx))
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}
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}
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|
@ -134,12 +134,7 @@ mod rustc {
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use rustc_span::symbol::sym;
|
use rustc_span::symbol::sym;
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|
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let Some((cv, ty)) = c.try_to_valtree() else {
|
let Some((cv, ty)) = c.try_to_valtree() else {
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return Some(Self {
|
return None;
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alignment: true,
|
|
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lifetimes: true,
|
|
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safety: true,
|
|
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validity: true,
|
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});
|
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};
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};
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|
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let adt_def = ty.ty_adt_def()?;
|
let adt_def = ty.ty_adt_def()?;
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|
@ -0,0 +1,19 @@
|
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|
#![feature(transmutability)]
|
||||||
|
#![feature(generic_const_exprs)]
|
||||||
|
//~^ WARN the feature `generic_const_exprs` is incomplete
|
||||||
|
|
||||||
|
use std::mem::{Assume, TransmuteFrom};
|
||||||
|
|
||||||
|
pub fn is_transmutable<const ASSUME_ALIGNMENT: bool>()
|
||||||
|
where
|
||||||
|
(): TransmuteFrom<(), { Assume::SAFETY }>,
|
||||||
|
{
|
||||||
|
}
|
||||||
|
|
||||||
|
fn foo<const N: usize>() {
|
||||||
|
is_transmutable::<{}>();
|
||||||
|
//~^ ERROR the trait bound `(): TransmuteFrom<(), { Assume::SAFETY }>` is not satisfied
|
||||||
|
//~| ERROR mismatched types
|
||||||
|
}
|
||||||
|
|
||||||
|
fn main() {}
|
@ -0,0 +1,34 @@
|
|||||||
|
warning: the feature `generic_const_exprs` is incomplete and may not be safe to use and/or cause compiler crashes
|
||||||
|
--> $DIR/dont-assume-err-is-yes-issue-126377.rs:2:12
|
||||||
|
|
|
||||||
|
LL | #![feature(generic_const_exprs)]
|
||||||
|
| ^^^^^^^^^^^^^^^^^^^
|
||||||
|
|
|
||||||
|
= note: see issue #76560 <https://github.com/rust-lang/rust/issues/76560> for more information
|
||||||
|
= note: `#[warn(incomplete_features)]` on by default
|
||||||
|
|
||||||
|
error[E0308]: mismatched types
|
||||||
|
--> $DIR/dont-assume-err-is-yes-issue-126377.rs:14:23
|
||||||
|
|
|
||||||
|
LL | is_transmutable::<{}>();
|
||||||
|
| ^^ expected `bool`, found `()`
|
||||||
|
|
||||||
|
error[E0277]: the trait bound `(): TransmuteFrom<(), { Assume::SAFETY }>` is not satisfied
|
||||||
|
--> $DIR/dont-assume-err-is-yes-issue-126377.rs:14:23
|
||||||
|
|
|
||||||
|
LL | is_transmutable::<{}>();
|
||||||
|
| ^^ the trait `TransmuteFrom<(), { Assume::SAFETY }>` is not implemented for `()`
|
||||||
|
|
|
||||||
|
note: required by a bound in `is_transmutable`
|
||||||
|
--> $DIR/dont-assume-err-is-yes-issue-126377.rs:9:9
|
||||||
|
|
|
||||||
|
LL | pub fn is_transmutable<const ASSUME_ALIGNMENT: bool>()
|
||||||
|
| --------------- required by a bound in this function
|
||||||
|
LL | where
|
||||||
|
LL | (): TransmuteFrom<(), { Assume::SAFETY }>,
|
||||||
|
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
|
||||||
|
|
||||||
|
error: aborting due to 2 previous errors; 1 warning emitted
|
||||||
|
|
||||||
|
Some errors have detailed explanations: E0277, E0308.
|
||||||
|
For more information about an error, try `rustc --explain E0277`.
|
Loading…
Reference in New Issue
Block a user