bjoernager/rust
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Remove InferCtxt::in_snapshot().

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It's the same as `InferCtxt::commit_unconditionally()` except that it
is passed a snapshot and has a worse name.

The commit also changes `commit_unconditionally()` to receive a
snapshot, for consistency with `commit_if_ok()` and `probe()`.
This commit is contained in:
Nicholas Nethercote 2019-09-30 14:42:11 +10:00
parent 3f9aea199c
commit 1b41f958c5
2 changed files with 23 additions and 34 deletions
Download patch file Download diff file Expand all files Collapse all files

22
src/librustc/infer/mod.rs
View file

@ -814,16 +814,16 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
/// Executes `f` and commit the bindings. /// Executes `f` and commit the bindings.
pub fn commit_unconditionally<R, F>(&self, f: F) -> R pub fn commit_unconditionally<R, F>(&self, f: F) -> R
where where
F: FnOnce() -> R, F: FnOnce(&CombinedSnapshot<'a, 'tcx>) -> R,
{ {
debug!("commit()"); debug!("commit_unconditionally()");
let snapshot = self.start_snapshot(); let snapshot = self.start_snapshot();
let r = f(); let r = f(&snapshot);
self.commit_from(snapshot); self.commit_from(snapshot);
r r
} }
/// Executes `f` and commit the bindings if closure `f` returns `Ok(_)`. /// Execute `f` and commit the bindings if closure `f` returns `Ok(_)`.
pub fn commit_if_ok<T, E, F>(&self, f: F) -> Result<T, E> pub fn commit_if_ok<T, E, F>(&self, f: F) -> Result<T, E>
where where
F: FnOnce(&CombinedSnapshot<'a, 'tcx>) -> Result<T, E>, F: FnOnce(&CombinedSnapshot<'a, 'tcx>) -> Result<T, E>,
@ -843,19 +843,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
r r
} }
/// Execute `f` in a snapshot, and commit the bindings it creates. /// Execute `f` then unroll any bindings it creates.
pub fn in_snapshot<T, F>(&self, f: F) -> T
where
F: FnOnce(&CombinedSnapshot<'a, 'tcx>) -> T,
{
debug!("in_snapshot()");
let snapshot = self.start_snapshot();
let r = f(&snapshot);
self.commit_from(snapshot);
r
}
/// Executes `f` then unroll any bindings it creates.
pub fn probe<R, F>(&self, f: F) -> R pub fn probe<R, F>(&self, f: F) -> R
where where
F: FnOnce(&CombinedSnapshot<'a, 'tcx>) -> R, F: FnOnce(&CombinedSnapshot<'a, 'tcx>) -> R,

35
src/librustc/traits/select.rs
View file

@ -2819,7 +2819,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
// binder moved -\ // binder moved -\
let ty: ty::Binder<Ty<'tcx>> = ty::Binder::bind(ty); // <----/ let ty: ty::Binder<Ty<'tcx>> = ty::Binder::bind(ty); // <----/
self.infcx.in_snapshot(|_| { self.infcx.commit_unconditionally(|_| {
let (skol_ty, _) = self.infcx let (skol_ty, _) = self.infcx
.replace_bound_vars_with_placeholders(&ty); .replace_bound_vars_with_placeholders(&ty);
let Normalized { let Normalized {
@ -2932,7 +2932,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
} }
fn confirm_projection_candidate(&mut self, obligation: &TraitObligation<'tcx>) { fn confirm_projection_candidate(&mut self, obligation: &TraitObligation<'tcx>) {
self.infcx.in_snapshot(|snapshot| { self.infcx.commit_unconditionally(|snapshot| {
let result = let result =
self.match_projection_obligation_against_definition_bounds( self.match_projection_obligation_against_definition_bounds(
obligation, obligation,
@ -3054,19 +3054,20 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
nested, nested,
); );
let trait_obligations: Vec<PredicateObligation<'_>> = self.infcx.in_snapshot(|_| { let trait_obligations: Vec<PredicateObligation<'_>> =
let poly_trait_ref = obligation.predicate.to_poly_trait_ref(); self.infcx.commit_unconditionally(|_| {
let (trait_ref, _) = self.infcx let poly_trait_ref = obligation.predicate.to_poly_trait_ref();
.replace_bound_vars_with_placeholders(&poly_trait_ref); let (trait_ref, _) = self.infcx
let cause = obligation.derived_cause(ImplDerivedObligation); .replace_bound_vars_with_placeholders(&poly_trait_ref);
self.impl_or_trait_obligations( let cause = obligation.derived_cause(ImplDerivedObligation);
cause, self.impl_or_trait_obligations(
obligation.recursion_depth + 1, cause,
obligation.param_env, obligation.recursion_depth + 1,
trait_def_id, obligation.param_env,
&trait_ref.substs, trait_def_id,
) &trait_ref.substs,
}); )
});
// Adds the predicates from the trait. Note that this contains a `Self: Trait` // Adds the predicates from the trait. Note that this contains a `Self: Trait`
// predicate as usual. It won't have any effect since auto traits are coinductive. // predicate as usual. It won't have any effect since auto traits are coinductive.
@ -3089,7 +3090,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
// First, create the substitutions by matching the impl again, // First, create the substitutions by matching the impl again,
// this time not in a probe. // this time not in a probe.
self.infcx.in_snapshot(|snapshot| { self.infcx.commit_unconditionally(|snapshot| {
let substs = self.rematch_impl(impl_def_id, obligation, snapshot); let substs = self.rematch_impl(impl_def_id, obligation, snapshot);
debug!("confirm_impl_candidate: substs={:?}", substs); debug!("confirm_impl_candidate: substs={:?}", substs);
let cause = obligation.derived_cause(ImplDerivedObligation); let cause = obligation.derived_cause(ImplDerivedObligation);
@ -3253,7 +3254,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
obligation, alias_def_id obligation, alias_def_id
); );
self.infcx.in_snapshot(|_| { self.infcx.commit_unconditionally(|_| {
let (predicate, _) = self.infcx() let (predicate, _) = self.infcx()
.replace_bound_vars_with_placeholders(&obligation.predicate); .replace_bound_vars_with_placeholders(&obligation.predicate);
let trait_ref = predicate.trait_ref; let trait_ref = predicate.trait_ref;