683 lines
23 KiB
Rust
683 lines
23 KiB
Rust
// Copyright 2012-2013 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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/*!
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* Generalized type folding mechanism. The setup is a bit convoluted
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* but allows for convenient usage. Let T be an instance of some
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* "foldable type" (one which implements `TypeFoldable`) and F be an
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* instance of a "folder" (a type which implements `TypeFolder`). Then
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* the setup is intended to be:
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*
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* T.fold_with(F) --calls--> F.fold_T(T) --calls--> super_fold_T(F, T)
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*
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* This way, when you define a new folder F, you can override
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* `fold_T()` to customize the behavior, and invoke `super_fold_T()`
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* to get the original behavior. Meanwhile, to actually fold
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* something, you can just write `T.fold_with(F)`, which is
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* convenient. (Note that `fold_with` will also transparently handle
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* things like a `Vec<T>` where T is foldable and so on.)
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*
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* In this ideal setup, the only function that actually *does*
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* anything is `super_fold_T`, which traverses the type `T`. Moreover,
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* `super_fold_T` should only ever call `T.fold_with()`.
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*
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* In some cases, we follow a degenerate pattern where we do not have
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* a `fold_T` nor `super_fold_T` method. Instead, `T.fold_with`
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* traverses the structure directly. This is suboptimal because the
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* behavior cannot be overriden, but it's much less work to implement.
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* If you ever *do* need an override that doesn't exist, it's not hard
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* to convert the degenerate pattern into the proper thing.
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*/
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use middle::subst;
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use middle::subst::VecPerParamSpace;
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use middle::ty;
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use middle::traits;
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use middle::typeck;
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use std::rc::Rc;
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use syntax::ast;
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use syntax::owned_slice::OwnedSlice;
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use util::ppaux::Repr;
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///////////////////////////////////////////////////////////////////////////
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// Two generic traits
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/// The TypeFoldable trait is implemented for every type that can be folded.
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/// Basically, every type that has a corresponding method in TypeFolder.
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pub trait TypeFoldable {
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fn fold_with<'tcx, F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self;
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}
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/// The TypeFolder trait defines the actual *folding*. There is a
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/// method defined for every foldable type. Each of these has a
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/// default implementation that does an "identity" fold. Within each
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/// identity fold, it should invoke `foo.fold_with(self)` to fold each
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/// sub-item.
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pub trait TypeFolder<'tcx> {
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fn tcx<'a>(&'a self) -> &'a ty::ctxt<'tcx>;
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fn fold_ty(&mut self, t: ty::t) -> ty::t {
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super_fold_ty(self, t)
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}
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fn fold_mt(&mut self, t: &ty::mt) -> ty::mt {
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super_fold_mt(self, t)
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}
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fn fold_trait_ref(&mut self, t: &ty::TraitRef) -> ty::TraitRef {
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super_fold_trait_ref(self, t)
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}
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fn fold_sty(&mut self, sty: &ty::sty) -> ty::sty {
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super_fold_sty(self, sty)
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}
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fn fold_substs(&mut self,
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substs: &subst::Substs)
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-> subst::Substs {
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super_fold_substs(self, substs)
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}
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fn fold_sig(&mut self,
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sig: &ty::FnSig)
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-> ty::FnSig {
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super_fold_sig(self, sig)
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}
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fn fold_bare_fn_ty(&mut self,
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fty: &ty::BareFnTy)
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-> ty::BareFnTy
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{
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super_fold_bare_fn_ty(self, fty)
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}
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fn fold_closure_ty(&mut self,
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fty: &ty::ClosureTy)
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-> ty::ClosureTy {
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super_fold_closure_ty(self, fty)
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}
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fn fold_region(&mut self, r: ty::Region) -> ty::Region {
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r
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}
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fn fold_trait_store(&mut self, s: ty::TraitStore) -> ty::TraitStore {
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super_fold_trait_store(self, s)
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}
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fn fold_existential_bounds(&mut self, s: ty::ExistentialBounds)
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-> ty::ExistentialBounds {
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super_fold_existential_bounds(self, s)
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}
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fn fold_autoref(&mut self, ar: &ty::AutoRef) -> ty::AutoRef {
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super_fold_autoref(self, ar)
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}
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fn fold_item_substs(&mut self, i: ty::ItemSubsts) -> ty::ItemSubsts {
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super_fold_item_substs(self, i)
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}
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fn fold_obligation(&mut self, o: &traits::Obligation) -> traits::Obligation {
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super_fold_obligation(self, o)
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}
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}
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///////////////////////////////////////////////////////////////////////////
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// TypeFoldable implementations.
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//
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// Ideally, each type should invoke `folder.fold_foo(self)` and
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// nothing else. In some cases, though, we haven't gotten around to
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// adding methods on the `folder` yet, and thus the folding is
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// hard-coded here. This is less-flexible, because folders cannot
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// override the behavior, but there are a lot of random types and one
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// can easily refactor the folding into the TypeFolder trait as
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// needed.
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impl TypeFoldable for () {
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fn fold_with<'tcx, F:TypeFolder<'tcx>>(&self, _: &mut F) -> () {
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()
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}
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}
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impl<T:TypeFoldable> TypeFoldable for Option<T> {
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fn fold_with<'tcx, F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Option<T> {
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self.as_ref().map(|t| t.fold_with(folder))
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}
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}
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impl<T:TypeFoldable> TypeFoldable for Rc<T> {
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fn fold_with<'tcx, F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Rc<T> {
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Rc::new((**self).fold_with(folder))
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}
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}
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impl<T:TypeFoldable> TypeFoldable for Vec<T> {
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fn fold_with<'tcx, F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Vec<T> {
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self.iter().map(|t| t.fold_with(folder)).collect()
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}
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}
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impl<T:TypeFoldable> TypeFoldable for OwnedSlice<T> {
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fn fold_with<'tcx, F: TypeFolder<'tcx>>(&self, folder: &mut F) -> OwnedSlice<T> {
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self.iter().map(|t| t.fold_with(folder)).collect()
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}
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}
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impl<T:TypeFoldable> TypeFoldable for VecPerParamSpace<T> {
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fn fold_with<'tcx, F: TypeFolder<'tcx>>(&self, folder: &mut F) -> VecPerParamSpace<T> {
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self.map(|t| t.fold_with(folder))
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}
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}
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impl TypeFoldable for ty::TraitStore {
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fn fold_with<'tcx, F: TypeFolder<'tcx>>(&self, folder: &mut F) -> ty::TraitStore {
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folder.fold_trait_store(*self)
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}
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}
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impl TypeFoldable for ty::t {
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fn fold_with<'tcx, F: TypeFolder<'tcx>>(&self, folder: &mut F) -> ty::t {
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folder.fold_ty(*self)
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}
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}
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impl TypeFoldable for ty::BareFnTy {
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fn fold_with<'tcx, F: TypeFolder<'tcx>>(&self, folder: &mut F) -> ty::BareFnTy {
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folder.fold_bare_fn_ty(self)
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}
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}
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impl TypeFoldable for ty::ClosureTy {
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fn fold_with<'tcx, F: TypeFolder<'tcx>>(&self, folder: &mut F) -> ty::ClosureTy {
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folder.fold_closure_ty(self)
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}
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}
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impl TypeFoldable for ty::mt {
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fn fold_with<'tcx, F: TypeFolder<'tcx>>(&self, folder: &mut F) -> ty::mt {
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folder.fold_mt(self)
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}
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}
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impl TypeFoldable for ty::FnSig {
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fn fold_with<'tcx, F: TypeFolder<'tcx>>(&self, folder: &mut F) -> ty::FnSig {
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folder.fold_sig(self)
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}
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}
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impl TypeFoldable for ty::sty {
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fn fold_with<'tcx, F: TypeFolder<'tcx>>(&self, folder: &mut F) -> ty::sty {
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folder.fold_sty(self)
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}
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}
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impl TypeFoldable for ty::TraitRef {
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fn fold_with<'tcx, F: TypeFolder<'tcx>>(&self, folder: &mut F) -> ty::TraitRef {
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folder.fold_trait_ref(self)
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}
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}
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impl TypeFoldable for ty::Region {
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fn fold_with<'tcx, F: TypeFolder<'tcx>>(&self, folder: &mut F) -> ty::Region {
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folder.fold_region(*self)
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}
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}
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impl TypeFoldable for subst::Substs {
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fn fold_with<'tcx, F: TypeFolder<'tcx>>(&self, folder: &mut F) -> subst::Substs {
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folder.fold_substs(self)
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}
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}
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impl TypeFoldable for ty::ItemSubsts {
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fn fold_with<'tcx, F: TypeFolder<'tcx>>(&self, folder: &mut F) -> ty::ItemSubsts {
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ty::ItemSubsts {
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substs: self.substs.fold_with(folder),
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}
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}
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}
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impl TypeFoldable for ty::AutoRef {
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fn fold_with<'tcx, F: TypeFolder<'tcx>>(&self, folder: &mut F) -> ty::AutoRef {
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folder.fold_autoref(self)
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}
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}
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impl TypeFoldable for typeck::vtable_origin {
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fn fold_with<'tcx, F: TypeFolder<'tcx>>(&self, folder: &mut F) -> typeck::vtable_origin {
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match *self {
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typeck::vtable_static(def_id, ref substs, ref origins) => {
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let r_substs = substs.fold_with(folder);
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let r_origins = origins.fold_with(folder);
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typeck::vtable_static(def_id, r_substs, r_origins)
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}
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typeck::vtable_param(n, b) => {
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typeck::vtable_param(n, b)
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}
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typeck::vtable_unboxed_closure(def_id) => {
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typeck::vtable_unboxed_closure(def_id)
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}
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typeck::vtable_error => {
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typeck::vtable_error
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}
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}
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}
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}
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impl TypeFoldable for ty::BuiltinBounds {
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fn fold_with<'tcx, F: TypeFolder<'tcx>>(&self, _folder: &mut F) -> ty::BuiltinBounds {
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*self
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}
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}
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impl TypeFoldable for ty::ExistentialBounds {
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fn fold_with<'tcx, F: TypeFolder<'tcx>>(&self, folder: &mut F) -> ty::ExistentialBounds {
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folder.fold_existential_bounds(*self)
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}
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}
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impl TypeFoldable for ty::ParamBounds {
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fn fold_with<'tcx, F: TypeFolder<'tcx>>(&self, folder: &mut F) -> ty::ParamBounds {
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ty::ParamBounds {
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opt_region_bound: self.opt_region_bound.fold_with(folder),
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builtin_bounds: self.builtin_bounds.fold_with(folder),
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trait_bounds: self.trait_bounds.fold_with(folder),
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}
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}
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}
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impl TypeFoldable for ty::TypeParameterDef {
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fn fold_with<'tcx, F: TypeFolder<'tcx>>(&self, folder: &mut F) -> ty::TypeParameterDef {
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ty::TypeParameterDef {
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ident: self.ident,
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def_id: self.def_id,
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space: self.space,
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index: self.index,
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bounds: self.bounds.fold_with(folder),
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default: self.default.fold_with(folder),
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}
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}
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}
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impl TypeFoldable for ty::RegionParameterDef {
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fn fold_with<'tcx, F: TypeFolder<'tcx>>(&self, folder: &mut F) -> ty::RegionParameterDef {
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ty::RegionParameterDef {
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name: self.name,
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def_id: self.def_id,
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space: self.space,
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index: self.index,
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bounds: self.bounds.fold_with(folder)
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}
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}
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}
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impl TypeFoldable for ty::Generics {
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fn fold_with<'tcx, F: TypeFolder<'tcx>>(&self, folder: &mut F) -> ty::Generics {
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ty::Generics {
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types: self.types.fold_with(folder),
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regions: self.regions.fold_with(folder),
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}
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}
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}
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impl TypeFoldable for ty::UnsizeKind {
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fn fold_with<'tcx, F: TypeFolder<'tcx>>(&self, folder: &mut F) -> ty::UnsizeKind {
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match *self {
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ty::UnsizeLength(len) => ty::UnsizeLength(len),
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ty::UnsizeStruct(box ref k, n) => ty::UnsizeStruct(box k.fold_with(folder), n),
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ty::UnsizeVtable(ty::TyTrait{bounds, def_id, substs: ref substs}, self_ty) => {
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ty::UnsizeVtable(
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ty::TyTrait {
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bounds: bounds.fold_with(folder),
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def_id: def_id,
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substs: substs.fold_with(folder)
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},
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self_ty.fold_with(folder))
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}
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}
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}
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}
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impl TypeFoldable for traits::Obligation {
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fn fold_with<'tcx, F:TypeFolder<'tcx>>(&self, folder: &mut F) -> traits::Obligation {
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folder.fold_obligation(self)
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}
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}
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impl<N:TypeFoldable> TypeFoldable for traits::VtableImpl<N> {
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fn fold_with<'tcx, F:TypeFolder<'tcx>>(&self, folder: &mut F) -> traits::VtableImpl<N> {
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traits::VtableImpl {
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impl_def_id: self.impl_def_id,
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substs: self.substs.fold_with(folder),
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nested: self.nested.fold_with(folder),
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}
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}
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}
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impl<N:TypeFoldable> TypeFoldable for traits::Vtable<N> {
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fn fold_with<'tcx, F:TypeFolder<'tcx>>(&self, folder: &mut F) -> traits::Vtable<N> {
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match *self {
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traits::VtableImpl(ref v) => traits::VtableImpl(v.fold_with(folder)),
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traits::VtableUnboxedClosure(d) => traits::VtableUnboxedClosure(d),
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traits::VtableParam(ref p) => traits::VtableParam(p.fold_with(folder)),
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traits::VtableBuiltin => traits::VtableBuiltin,
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}
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}
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}
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impl TypeFoldable for traits::VtableParam {
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fn fold_with<'tcx, F:TypeFolder<'tcx>>(&self, folder: &mut F) -> traits::VtableParam {
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traits::VtableParam {
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bound: self.bound.fold_with(folder),
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}
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}
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}
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///////////////////////////////////////////////////////////////////////////
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// "super" routines: these are the default implementations for TypeFolder.
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//
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// They should invoke `foo.fold_with()` to do recursive folding.
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pub fn super_fold_ty<'tcx, T: TypeFolder<'tcx>>(this: &mut T,
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t: ty::t)
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-> ty::t {
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let sty = ty::get(t).sty.fold_with(this);
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ty::mk_t(this.tcx(), sty)
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}
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pub fn super_fold_substs<'tcx, T: TypeFolder<'tcx>>(this: &mut T,
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substs: &subst::Substs)
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-> subst::Substs {
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let regions = match substs.regions {
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subst::ErasedRegions => {
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subst::ErasedRegions
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}
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subst::NonerasedRegions(ref regions) => {
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subst::NonerasedRegions(regions.fold_with(this))
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}
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};
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subst::Substs { regions: regions,
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types: substs.types.fold_with(this) }
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}
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pub fn super_fold_sig<'tcx, T: TypeFolder<'tcx>>(this: &mut T,
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sig: &ty::FnSig)
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-> ty::FnSig {
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ty::FnSig { binder_id: sig.binder_id,
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inputs: sig.inputs.fold_with(this),
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output: sig.output.fold_with(this),
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variadic: sig.variadic }
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}
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pub fn super_fold_bare_fn_ty<'tcx, T: TypeFolder<'tcx>>(this: &mut T,
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fty: &ty::BareFnTy)
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-> ty::BareFnTy
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{
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ty::BareFnTy { sig: fty.sig.fold_with(this),
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abi: fty.abi,
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fn_style: fty.fn_style }
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}
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pub fn super_fold_closure_ty<'tcx, T: TypeFolder<'tcx>>(this: &mut T,
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fty: &ty::ClosureTy)
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-> ty::ClosureTy
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{
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ty::ClosureTy {
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store: fty.store.fold_with(this),
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sig: fty.sig.fold_with(this),
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fn_style: fty.fn_style,
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onceness: fty.onceness,
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bounds: fty.bounds.fold_with(this),
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abi: fty.abi,
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}
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}
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pub fn super_fold_trait_ref<'tcx, T: TypeFolder<'tcx>>(this: &mut T,
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t: &ty::TraitRef)
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-> ty::TraitRef {
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ty::TraitRef {
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def_id: t.def_id,
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substs: t.substs.fold_with(this),
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}
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}
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pub fn super_fold_mt<'tcx, T: TypeFolder<'tcx>>(this: &mut T,
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mt: &ty::mt) -> ty::mt {
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ty::mt {ty: mt.ty.fold_with(this),
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mutbl: mt.mutbl}
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}
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pub fn super_fold_sty<'tcx, T: TypeFolder<'tcx>>(this: &mut T,
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sty: &ty::sty) -> ty::sty {
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match *sty {
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ty::ty_box(typ) => {
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ty::ty_box(typ.fold_with(this))
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}
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ty::ty_uniq(typ) => {
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ty::ty_uniq(typ.fold_with(this))
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}
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ty::ty_ptr(ref tm) => {
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ty::ty_ptr(tm.fold_with(this))
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}
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ty::ty_vec(typ, sz) => {
|
|
ty::ty_vec(typ.fold_with(this), sz)
|
|
}
|
|
ty::ty_open(typ) => {
|
|
ty::ty_open(typ.fold_with(this))
|
|
}
|
|
ty::ty_enum(tid, ref substs) => {
|
|
ty::ty_enum(tid, substs.fold_with(this))
|
|
}
|
|
ty::ty_trait(box ty::TyTrait {
|
|
def_id,
|
|
ref substs,
|
|
bounds
|
|
}) => {
|
|
ty::ty_trait(box ty::TyTrait {
|
|
def_id: def_id,
|
|
substs: substs.fold_with(this),
|
|
bounds: this.fold_existential_bounds(bounds),
|
|
})
|
|
}
|
|
ty::ty_tup(ref ts) => {
|
|
ty::ty_tup(ts.fold_with(this))
|
|
}
|
|
ty::ty_bare_fn(ref f) => {
|
|
ty::ty_bare_fn(f.fold_with(this))
|
|
}
|
|
ty::ty_closure(ref f) => {
|
|
ty::ty_closure(box f.fold_with(this))
|
|
}
|
|
ty::ty_rptr(r, ref tm) => {
|
|
ty::ty_rptr(r.fold_with(this), tm.fold_with(this))
|
|
}
|
|
ty::ty_struct(did, ref substs) => {
|
|
ty::ty_struct(did, substs.fold_with(this))
|
|
}
|
|
ty::ty_unboxed_closure(did, ref region) => {
|
|
ty::ty_unboxed_closure(did, region.fold_with(this))
|
|
}
|
|
ty::ty_nil | ty::ty_bot | ty::ty_bool | ty::ty_char | ty::ty_str |
|
|
ty::ty_int(_) | ty::ty_uint(_) | ty::ty_float(_) |
|
|
ty::ty_err | ty::ty_infer(_) |
|
|
ty::ty_param(..) => {
|
|
(*sty).clone()
|
|
}
|
|
}
|
|
}
|
|
|
|
pub fn super_fold_trait_store<'tcx, T: TypeFolder<'tcx>>(this: &mut T,
|
|
trait_store: ty::TraitStore)
|
|
-> ty::TraitStore {
|
|
match trait_store {
|
|
ty::UniqTraitStore => ty::UniqTraitStore,
|
|
ty::RegionTraitStore(r, m) => {
|
|
ty::RegionTraitStore(r.fold_with(this), m)
|
|
}
|
|
}
|
|
}
|
|
|
|
pub fn super_fold_existential_bounds<'tcx, T: TypeFolder<'tcx>>(this: &mut T,
|
|
bounds: ty::ExistentialBounds)
|
|
-> ty::ExistentialBounds {
|
|
ty::ExistentialBounds {
|
|
region_bound: bounds.region_bound.fold_with(this),
|
|
builtin_bounds: bounds.builtin_bounds,
|
|
}
|
|
}
|
|
|
|
pub fn super_fold_autoref<'tcx, T: TypeFolder<'tcx>>(this: &mut T,
|
|
autoref: &ty::AutoRef)
|
|
-> ty::AutoRef
|
|
{
|
|
match *autoref {
|
|
ty::AutoPtr(r, m, None) => ty::AutoPtr(this.fold_region(r), m, None),
|
|
ty::AutoPtr(r, m, Some(ref a)) => {
|
|
ty::AutoPtr(this.fold_region(r), m, Some(box super_fold_autoref(this, &**a)))
|
|
}
|
|
ty::AutoUnsafe(m, None) => ty::AutoUnsafe(m, None),
|
|
ty::AutoUnsafe(m, Some(ref a)) => {
|
|
ty::AutoUnsafe(m, Some(box super_fold_autoref(this, &**a)))
|
|
}
|
|
ty::AutoUnsize(ref k) => ty::AutoUnsize(k.fold_with(this)),
|
|
ty::AutoUnsizeUniq(ref k) => ty::AutoUnsizeUniq(k.fold_with(this)),
|
|
}
|
|
}
|
|
|
|
pub fn super_fold_item_substs<'tcx, T: TypeFolder<'tcx>>(this: &mut T,
|
|
substs: ty::ItemSubsts)
|
|
-> ty::ItemSubsts
|
|
{
|
|
ty::ItemSubsts {
|
|
substs: substs.substs.fold_with(this),
|
|
}
|
|
}
|
|
|
|
pub fn super_fold_obligation<'tcx, T:TypeFolder<'tcx>>(this: &mut T,
|
|
obligation: &traits::Obligation)
|
|
-> traits::Obligation
|
|
{
|
|
traits::Obligation {
|
|
cause: obligation.cause,
|
|
recursion_depth: obligation.recursion_depth,
|
|
trait_ref: obligation.trait_ref.fold_with(this),
|
|
}
|
|
}
|
|
|
|
///////////////////////////////////////////////////////////////////////////
|
|
// Some sample folders
|
|
|
|
pub struct BottomUpFolder<'a, 'tcx: 'a> {
|
|
pub tcx: &'a ty::ctxt<'tcx>,
|
|
pub fldop: |ty::t|: 'a -> ty::t,
|
|
}
|
|
|
|
impl<'a, 'tcx> TypeFolder<'tcx> for BottomUpFolder<'a, 'tcx> {
|
|
fn tcx<'a>(&'a self) -> &'a ty::ctxt<'tcx> { self.tcx }
|
|
|
|
fn fold_ty(&mut self, ty: ty::t) -> ty::t {
|
|
let t1 = super_fold_ty(self, ty);
|
|
(self.fldop)(t1)
|
|
}
|
|
}
|
|
|
|
///////////////////////////////////////////////////////////////////////////
|
|
// Region folder
|
|
|
|
/// Folds over the substructure of a type, visiting its component
|
|
/// types and all regions that occur *free* within it.
|
|
///
|
|
/// That is, `ty::t` can contain function or method types that bind
|
|
/// regions at the call site (`ReLateBound`), and occurrences of
|
|
/// regions (aka "lifetimes") that are bound within a type are not
|
|
/// visited by this folder; only regions that occur free will be
|
|
/// visited by `fld_r`.
|
|
///
|
|
/// (The distinction between "free" and "bound" is represented by
|
|
/// keeping track of each `FnSig` in the lexical context of the
|
|
/// current position of the fold.)
|
|
pub struct RegionFolder<'a, 'tcx: 'a> {
|
|
tcx: &'a ty::ctxt<'tcx>,
|
|
fld_t: |ty::t|: 'a -> ty::t,
|
|
fld_r: |ty::Region|: 'a -> ty::Region,
|
|
within_binder_ids: Vec<ast::NodeId>,
|
|
}
|
|
|
|
impl<'a, 'tcx> RegionFolder<'a, 'tcx> {
|
|
pub fn general(tcx: &'a ty::ctxt<'tcx>,
|
|
fld_r: |ty::Region|: 'a -> ty::Region,
|
|
fld_t: |ty::t|: 'a -> ty::t)
|
|
-> RegionFolder<'a, 'tcx> {
|
|
RegionFolder {
|
|
tcx: tcx,
|
|
fld_t: fld_t,
|
|
fld_r: fld_r,
|
|
within_binder_ids: vec![],
|
|
}
|
|
}
|
|
|
|
pub fn regions(tcx: &'a ty::ctxt<'tcx>, fld_r: |ty::Region|: 'a -> ty::Region)
|
|
-> RegionFolder<'a, 'tcx> {
|
|
fn noop(t: ty::t) -> ty::t { t }
|
|
|
|
RegionFolder {
|
|
tcx: tcx,
|
|
fld_t: noop,
|
|
fld_r: fld_r,
|
|
within_binder_ids: vec![],
|
|
}
|
|
}
|
|
}
|
|
|
|
/// If `ty` has `FnSig` (i.e. closure or fn), return its binder_id;
|
|
/// else None.
|
|
fn opt_binder_id_of_function(t: ty::t) -> Option<ast::NodeId> {
|
|
match ty::get(t).sty {
|
|
ty::ty_closure(ref f) => Some(f.sig.binder_id),
|
|
ty::ty_bare_fn(ref f) => Some(f.sig.binder_id),
|
|
_ => None,
|
|
}
|
|
}
|
|
|
|
impl<'a, 'tcx> TypeFolder<'tcx> for RegionFolder<'a, 'tcx> {
|
|
fn tcx<'a>(&'a self) -> &'a ty::ctxt<'tcx> { self.tcx }
|
|
|
|
fn fold_ty(&mut self, ty: ty::t) -> ty::t {
|
|
debug!("RegionFolder.fold_ty({})", ty.repr(self.tcx()));
|
|
let opt_binder_id = opt_binder_id_of_function(ty);
|
|
match opt_binder_id {
|
|
Some(binder_id) => self.within_binder_ids.push(binder_id),
|
|
None => {}
|
|
}
|
|
|
|
let t1 = super_fold_ty(self, ty);
|
|
let ret = (self.fld_t)(t1);
|
|
|
|
if opt_binder_id.is_some() {
|
|
self.within_binder_ids.pop();
|
|
}
|
|
|
|
ret
|
|
}
|
|
|
|
fn fold_region(&mut self, r: ty::Region) -> ty::Region {
|
|
match r {
|
|
ty::ReLateBound(binder_id, _) if self.within_binder_ids.contains(&binder_id) => {
|
|
debug!("RegionFolder.fold_region({}) skipped bound region", r.repr(self.tcx()));
|
|
r
|
|
}
|
|
_ => {
|
|
debug!("RegionFolder.fold_region({}) folding free region", r.repr(self.tcx()));
|
|
(self.fld_r)(r)
|
|
}
|
|
}
|
|
}
|
|
}
|