stop using commit_if_ok where no errors can happen
This commit is contained in:
Ariel Ben-Yehuda
Ariel Ben-Yehuda
parent
6057a7f188
commit
62db786fc8
@ -814,6 +814,17 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
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r
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}
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// Execute `f` in a snapshot, and commit the bindings it creates
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pub fn in_snapshot<T, F>(&self, f: F) -> T where
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F: FnOnce(&CombinedSnapshot) -> T
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{
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debug!("in_snapshot()");
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let snapshot = self.start_snapshot();
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let r = f(&snapshot);
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self.commit_from(snapshot);
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r
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}
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/// Execute `f` and commit only the region bindings if successful.
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/// The function f must be very careful not to leak any non-region
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/// variables that get created.
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@ -49,7 +49,6 @@ use std::fmt;
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use std::rc::Rc;
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use syntax::abi::Abi;
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use hir;
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use util::common::ErrorReported;
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use util::nodemap::FnvHashMap;
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pub struct SelectionContext<'cx, 'tcx:'cx> {
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@ -1402,7 +1401,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
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return;
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}
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self.infcx.commit_if_ok(|snapshot| {
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self.infcx.in_snapshot(|snapshot| {
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let (self_ty, _) =
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self.infcx().skolemize_late_bound_regions(&obligation.self_ty(), snapshot);
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let poly_trait_ref = match self_ty.sty {
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@ -1413,7 +1412,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
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debug!("assemble_candidates_from_object_ty: matched builtin bound, \
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pushing candidate");
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candidates.vec.push(BuiltinObjectCandidate);
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return Ok(());
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return;
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}
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}
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_ => {}
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@ -1424,10 +1423,10 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
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ty::TyInfer(ty::TyVar(_)) => {
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debug!("assemble_candidates_from_object_ty: ambiguous");
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candidates.ambiguous = true; // could wind up being an object type
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return Ok(());
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return;
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}
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_ => {
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return Ok(());
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return;
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}
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};
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@ -1455,9 +1454,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
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} else if upcast_trait_refs == 1 {
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candidates.vec.push(ObjectCandidate);
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}
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Ok::<(),()>(())
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}).unwrap();
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})
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}
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/// Search for unsizing that might apply to `obligation`.
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@ -1854,21 +1851,15 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
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// 2. Produce something like `&'0 int : Copy`
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// 3. Re-bind the regions back to `for<'a> &'a int : Copy`
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// Move the binder into the individual types
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let bound_types: Vec<ty::Binder<Ty<'tcx>>> =
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types.skip_binder()
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.iter()
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.map(|&nested_ty| ty::Binder(nested_ty))
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.collect();
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types.skip_binder().into_iter().flat_map(|ty| { // binder moved -\
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let ty: ty::Binder<Ty<'tcx>> = ty::Binder(ty); // <----------/
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// For each type, produce a vector of resulting obligations
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let obligations: Result<Vec<Vec<_>>, _> = bound_types.iter().map(|nested_ty| {
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self.infcx.commit_if_ok(|snapshot| {
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self.infcx.in_snapshot(|snapshot| {
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let (skol_ty, skol_map) =
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self.infcx().skolemize_late_bound_regions(nested_ty, snapshot);
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self.infcx().skolemize_late_bound_regions(&ty, snapshot);
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let Normalized { value: normalized_ty, mut obligations } =
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project::normalize_with_depth(self,
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obligation.cause.clone(),
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derived_cause.clone(),
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obligation.recursion_depth + 1,
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&skol_ty);
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let skol_obligation =
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@ -1879,15 +1870,9 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
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normalized_ty,
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vec![]);
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obligations.push(skol_obligation);
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Ok(self.infcx().plug_leaks(skol_map, snapshot, &obligations))
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self.infcx().plug_leaks(skol_map, snapshot, &obligations)
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})
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}).collect();
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// Flatten those vectors (couldn't do it above due `collect`)
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match obligations {
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Ok(obligations) => obligations.into_iter().flat_map(|o| o).collect(),
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Err(ErrorReported) => Vec::new(),
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}
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}).collect()
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}
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///////////////////////////////////////////////////////////////////////////
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@ -1928,9 +1913,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
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}
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ImplCandidate(impl_def_id) => {
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let vtable_impl =
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self.confirm_impl_candidate(obligation, impl_def_id)?;
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Ok(VtableImpl(vtable_impl))
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Ok(VtableImpl(self.confirm_impl_candidate(obligation, impl_def_id)))
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}
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ClosureCandidate(closure_def_id, substs, kind) => {
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@ -1974,14 +1957,12 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
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fn confirm_projection_candidate(&mut self,
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obligation: &TraitObligation<'tcx>)
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{
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let _: Result<(),()> =
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self.infcx.commit_if_ok(|snapshot| {
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let result =
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self.match_projection_obligation_against_bounds_from_trait(obligation,
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snapshot);
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assert!(result);
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Ok(())
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});
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self.infcx.in_snapshot(|snapshot| {
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let result =
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self.match_projection_obligation_against_bounds_from_trait(obligation,
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snapshot);
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assert!(result);
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})
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}
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fn confirm_param_candidate(&mut self,
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@ -2112,20 +2093,19 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
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trait_def_id,
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nested);
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let trait_obligations: Result<Vec<_>,()> = self.infcx.commit_if_ok(|snapshot| {
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let trait_obligations = self.infcx.in_snapshot(|snapshot| {
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let poly_trait_ref = obligation.predicate.to_poly_trait_ref();
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let (trait_ref, skol_map) =
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self.infcx().skolemize_late_bound_regions(&poly_trait_ref, snapshot);
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Ok(self.impl_or_trait_obligations(obligation.cause.clone(),
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obligation.recursion_depth + 1,
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trait_def_id,
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&trait_ref.substs,
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skol_map,
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snapshot))
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self.impl_or_trait_obligations(obligation.cause.clone(),
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obligation.recursion_depth + 1,
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trait_def_id,
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&trait_ref.substs,
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skol_map,
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snapshot)
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});
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// no Errors in that code above
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obligations.append(&mut trait_obligations.unwrap());
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obligations.extend(trait_obligations);
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debug!("vtable_default_impl_data: obligations={:?}", obligations);
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@ -2138,8 +2118,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
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fn confirm_impl_candidate(&mut self,
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obligation: &TraitObligation<'tcx>,
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impl_def_id: DefId)
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-> Result<VtableImplData<'tcx, PredicateObligation<'tcx>>,
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SelectionError<'tcx>>
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-> VtableImplData<'tcx, PredicateObligation<'tcx>>
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{
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debug!("confirm_impl_candidate({:?},{:?})",
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obligation,
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@ -2147,13 +2126,13 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
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// First, create the substitutions by matching the impl again,
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// this time not in a probe.
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self.infcx.commit_if_ok(|snapshot| {
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self.infcx.in_snapshot(|snapshot| {
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let (substs, skol_map) =
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self.rematch_impl(impl_def_id, obligation,
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snapshot);
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debug!("confirm_impl_candidate substs={:?}", substs);
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Ok(self.vtable_impl(impl_def_id, substs, obligation.cause.clone(),
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obligation.recursion_depth + 1, skol_map, snapshot))
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self.vtable_impl(impl_def_id, substs, obligation.cause.clone(),
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obligation.recursion_depth + 1, skol_map, snapshot)
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})
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}
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