bjoernager/rust
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wf: {Int,Float}Var can only infer to always-WF ints/floats.

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This commit is contained in:
Eduard-Mihai Burtescu 2020-04-03 01:01:30 +03:00
parent d1dc2afd05
commit 05a872df2b
1 changed files with 8 additions and 2 deletions
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10
src/librustc_trait_selection/traits/wf.rs
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@ -24,7 +24,7 @@ pub fn obligations<'a, 'tcx>(
) -> Option<Vec<traits::PredicateObligation<'tcx>>> { ) -> Option<Vec<traits::PredicateObligation<'tcx>>> {
// Handle the "livelock" case (see comment above) by bailing out if necessary. // Handle the "livelock" case (see comment above) by bailing out if necessary.
let ty = match ty.kind { let ty = match ty.kind {
ty::Infer(_) => { ty::Infer(ty::TyVar(_)) => {
let resolved_ty = infcx.shallow_resolve(ty); let resolved_ty = infcx.shallow_resolve(ty);
if resolved_ty == ty { if resolved_ty == ty {
// No progress, bail out to prevent "livelock". // No progress, bail out to prevent "livelock".
@ -356,6 +356,12 @@ impl<'a, 'tcx> WfPredicates<'a, 'tcx> {
// WfScalar, WfParameter, etc // WfScalar, WfParameter, etc
} }
// Can only infer to `ty::Int(_) | ty::Uint(_)`.
ty::Infer(ty::IntVar(_)) => {}
// Can only infer to `ty::Float(_)`.
ty::Infer(ty::FloatVar(_)) => {}
ty::Slice(subty) => { ty::Slice(subty) => {
self.require_sized(subty, traits::SliceOrArrayElem); self.require_sized(subty, traits::SliceOrArrayElem);
} }
@ -514,7 +520,7 @@ impl<'a, 'tcx> WfPredicates<'a, 'tcx> {
// prevention, which happens before this can be reached. // prevention, which happens before this can be reached.
ty::Infer(_) => { ty::Infer(_) => {
let ty = self.infcx.shallow_resolve(ty); let ty = self.infcx.shallow_resolve(ty);
if let ty::Infer(_) = ty.kind { if let ty::Infer(ty::TyVar(_)) = ty.kind {
// Not yet resolved, but we've made progress. // Not yet resolved, but we've made progress.
let cause = self.cause(traits::MiscObligation); let cause = self.cause(traits::MiscObligation);
self.out.push(traits::Obligation::new( self.out.push(traits::Obligation::new(