make TypeOutlives parameterized over a delegate
It was only using the `infcx` to "accumulate" constraints anyhow.
This commit is contained in:
Niko Matsakis
parent
b858ed5919
commit
65ceec71ec
@ -159,8 +159,13 @@ impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
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}
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}
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let outlives =
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TypeOutlives::new(self, region_bound_pairs, implicit_region_bound, param_env);
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let outlives = &mut TypeOutlives::new(
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self,
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self.tcx,
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region_bound_pairs,
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implicit_region_bound,
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param_env,
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);
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for RegionObligation {
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sup_type,
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@ -193,32 +198,68 @@ impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
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ty: Ty<'tcx>,
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region: ty::Region<'tcx>,
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) {
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let outlives =
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TypeOutlives::new(self, region_bound_pairs, implicit_region_bound, param_env);
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let outlives = &mut TypeOutlives::new(
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self,
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self.tcx,
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region_bound_pairs,
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implicit_region_bound,
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param_env,
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);
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let ty = self.resolve_type_vars_if_possible(&ty);
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outlives.type_must_outlive(origin, ty, region);
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}
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}
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#[must_use] // you ought to invoke `into_accrued_obligations` when you are done =)
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struct TypeOutlives<'cx, 'gcx: 'tcx, 'tcx: 'cx> {
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/// The `TypeOutlives` struct has the job of "lowering" a `T: 'a`
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/// obligation into a series of `'a: 'b` constraints and "verifys", as
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/// described on the module comment. The final constraints are emitted
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/// via a "delegate" of type `D` -- this is usually the `infcx`, which
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/// accrues them into the `region_obligations` code, but for NLL we
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/// use something else.
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pub struct TypeOutlives<'cx, 'gcx: 'tcx, 'tcx: 'cx, D>
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where
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D: TypeOutlivesDelegate<'tcx>,
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{
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// See the comments on `process_registered_region_obligations` for the meaning
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// of these fields.
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infcx: &'cx InferCtxt<'cx, 'gcx, 'tcx>,
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delegate: D,
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tcx: TyCtxt<'cx, 'gcx, 'tcx>,
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region_bound_pairs: &'cx [(ty::Region<'tcx>, GenericKind<'tcx>)],
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implicit_region_bound: Option<ty::Region<'tcx>>,
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param_env: ty::ParamEnv<'tcx>,
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}
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impl<'cx, 'gcx, 'tcx> TypeOutlives<'cx, 'gcx, 'tcx> {
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pub trait TypeOutlivesDelegate<'tcx> {
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fn push_sub_region_constraint(
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&mut self,
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origin: SubregionOrigin<'tcx>,
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a: ty::Region<'tcx>,
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b: ty::Region<'tcx>,
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);
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fn push_verify(
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&mut self,
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origin: SubregionOrigin<'tcx>,
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kind: GenericKind<'tcx>,
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a: ty::Region<'tcx>,
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bound: VerifyBound<'tcx>,
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);
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}
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impl<'cx, 'gcx, 'tcx, D> TypeOutlives<'cx, 'gcx, 'tcx, D>
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where
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D: TypeOutlivesDelegate<'tcx>,
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{
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fn new(
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infcx: &'cx InferCtxt<'cx, 'gcx, 'tcx>,
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delegate: D,
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tcx: TyCtxt<'cx, 'gcx, 'tcx>,
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region_bound_pairs: &'cx [(ty::Region<'tcx>, GenericKind<'tcx>)],
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implicit_region_bound: Option<ty::Region<'tcx>>,
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param_env: ty::ParamEnv<'tcx>,
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) -> Self {
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Self {
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infcx,
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delegate,
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tcx,
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region_bound_pairs,
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implicit_region_bound,
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param_env,
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@ -234,7 +275,7 @@ impl<'cx, 'gcx, 'tcx> TypeOutlives<'cx, 'gcx, 'tcx> {
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/// - `ty`, the type `T`
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/// - `region`, the region `'a`
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fn type_must_outlive(
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&self,
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&mut self,
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origin: infer::SubregionOrigin<'tcx>,
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ty: Ty<'tcx>,
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region: ty::Region<'tcx>,
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@ -246,16 +287,12 @@ impl<'cx, 'gcx, 'tcx> TypeOutlives<'cx, 'gcx, 'tcx> {
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assert!(!ty.has_escaping_regions());
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let components = self.tcx().outlives_components(ty);
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let components = self.tcx.outlives_components(ty);
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self.components_must_outlive(origin, components, region);
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}
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fn tcx(&self) -> TyCtxt<'cx, 'gcx, 'tcx> {
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self.infcx.tcx
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}
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fn components_must_outlive(
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&self,
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&mut self,
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origin: infer::SubregionOrigin<'tcx>,
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components: Vec<Component<'tcx>>,
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region: ty::Region<'tcx>,
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@ -264,7 +301,7 @@ impl<'cx, 'gcx, 'tcx> TypeOutlives<'cx, 'gcx, 'tcx> {
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let origin = origin.clone();
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match component {
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Component::Region(region1) => {
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self.infcx.sub_regions(origin, region, region1);
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self.delegate.push_sub_region_constraint(origin, region, region1);
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}
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Component::Param(param_ty) => {
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self.param_ty_must_outlive(origin, region, param_ty);
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@ -279,7 +316,7 @@ impl<'cx, 'gcx, 'tcx> TypeOutlives<'cx, 'gcx, 'tcx> {
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// ignore this, we presume it will yield an error
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// later, since if a type variable is not resolved by
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// this point it never will be
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self.infcx.tcx.sess.delay_span_bug(
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self.tcx.sess.delay_span_bug(
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origin.span(),
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&format!("unresolved inference variable in outlives: {:?}", v),
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);
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@ -289,7 +326,7 @@ impl<'cx, 'gcx, 'tcx> TypeOutlives<'cx, 'gcx, 'tcx> {
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}
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fn param_ty_must_outlive(
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&self,
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&mut self,
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origin: infer::SubregionOrigin<'tcx>,
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region: ty::Region<'tcx>,
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param_ty: ty::ParamTy,
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@ -301,12 +338,12 @@ impl<'cx, 'gcx, 'tcx> TypeOutlives<'cx, 'gcx, 'tcx> {
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let verify_bound = self.param_bound(param_ty);
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let generic = GenericKind::Param(param_ty);
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self.infcx
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.verify_generic_bound(origin, generic, region, verify_bound);
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self.delegate
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.push_verify(origin, generic, region, verify_bound);
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}
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fn projection_must_outlive(
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&self,
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&mut self,
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origin: infer::SubregionOrigin<'tcx>,
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region: ty::Region<'tcx>,
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projection_ty: ty::ProjectionTy<'tcx>,
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@ -367,7 +404,7 @@ impl<'cx, 'gcx, 'tcx> TypeOutlives<'cx, 'gcx, 'tcx> {
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}
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for r in projection_ty.substs.regions() {
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self.infcx.sub_regions(origin.clone(), region, r);
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self.delegate.push_sub_region_constraint(origin.clone(), region, r);
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}
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return;
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@ -393,7 +430,8 @@ impl<'cx, 'gcx, 'tcx> TypeOutlives<'cx, 'gcx, 'tcx> {
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.any(|r| env_bounds.contains(&r))
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{
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debug!("projection_must_outlive: unique declared bound appears in trait ref");
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self.infcx.sub_regions(origin.clone(), region, unique_bound);
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self.delegate
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.push_sub_region_constraint(origin.clone(), region, unique_bound);
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return;
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}
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}
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@ -405,8 +443,8 @@ impl<'cx, 'gcx, 'tcx> TypeOutlives<'cx, 'gcx, 'tcx> {
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// even though a satisfactory solution exists.
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let verify_bound = self.projection_bound(env_bounds, projection_ty);
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let generic = GenericKind::Projection(projection_ty);
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self.infcx
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.verify_generic_bound(origin, generic.clone(), region, verify_bound);
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self.delegate
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.push_verify(origin, generic.clone(), region, verify_bound);
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}
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fn type_bound(&self, ty: Ty<'tcx>) -> VerifyBound<'tcx> {
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@ -459,7 +497,6 @@ impl<'cx, 'gcx, 'tcx> TypeOutlives<'cx, 'gcx, 'tcx> {
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// see the extensive comment in projection_must_outlive
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let ty = self
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.infcx
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.tcx
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.mk_projection(projection_ty.item_def_id, projection_ty.substs);
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let recursive_bound = self.recursive_type_bound(ty);
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@ -492,7 +529,7 @@ impl<'cx, 'gcx, 'tcx> TypeOutlives<'cx, 'gcx, 'tcx> {
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&self,
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generic: GenericKind<'tcx>,
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) -> Vec<ty::Region<'tcx>> {
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let tcx = self.tcx();
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let tcx = self.tcx;
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// To start, collect bounds from user environment. Note that
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// parameter environments are already elaborated, so we don't
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@ -544,7 +581,7 @@ impl<'cx, 'gcx, 'tcx> TypeOutlives<'cx, 'gcx, 'tcx> {
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debug!("projection_bounds(projection_ty={:?})", projection_ty);
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let mut bounds = self.region_bounds_declared_on_associated_item(projection_ty.item_def_id);
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for r in &mut bounds {
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*r = r.subst(self.tcx(), projection_ty.substs);
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*r = r.subst(self.tcx, projection_ty.substs);
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}
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bounds
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}
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@ -583,7 +620,7 @@ impl<'cx, 'gcx, 'tcx> TypeOutlives<'cx, 'gcx, 'tcx> {
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&self,
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assoc_item_def_id: DefId,
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) -> Vec<ty::Region<'tcx>> {
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let tcx = self.tcx();
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let tcx = self.tcx;
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let assoc_item = tcx.associated_item(assoc_item_def_id);
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let trait_def_id = assoc_item.container.assert_trait();
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let trait_predicates = tcx.predicates_of(trait_def_id);
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@ -619,3 +656,25 @@ impl<'cx, 'gcx, 'tcx> TypeOutlives<'cx, 'gcx, 'tcx> {
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.collect()
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}
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}
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impl<'cx, 'gcx, 'tcx> TypeOutlivesDelegate<'tcx> for &'cx InferCtxt<'cx, 'gcx, 'tcx> {
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fn push_sub_region_constraint(
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&mut self,
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origin: SubregionOrigin<'tcx>,
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a: ty::Region<'tcx>,
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b: ty::Region<'tcx>,
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) {
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self.sub_regions(origin, a, b)
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}
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fn push_verify(
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&mut self,
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origin: SubregionOrigin<'tcx>,
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kind: GenericKind<'tcx>,
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a: ty::Region<'tcx>,
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bound: VerifyBound<'tcx>,
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) {
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self.verify_generic_bound(origin, kind, a, bound)
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}
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}
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