src/librustc/traits/coherence.rs - third_party/rust - Git at Google

 // Copyright 2014 The Rust Project Developers. See the COPYRIGHT
 // file at the top-level directory of this distribution and at
 // http://rust-lang.org/COPYRIGHT.
 //
 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.

 //! See `README.md` for high-level documentation

 use hir::def_id::{DefId, LOCAL_CRATE};
 use syntax_pos::DUMMY_SP;
 use traits::{self, Normalized, SelectionContext, Obligation, ObligationCause, Reveal};
 use traits::select::IntercrateAmbiguityCause;
 use ty::{self, Ty, TyCtxt};
 use ty::subst::Subst;

 use infer::{InferCtxt, InferOk};

 #[derive(Copy, Clone)]
 struct InferIsLocal(bool);

 pub struct OverlapResult<'tcx> {
     pub impl_header: ty::ImplHeader<'tcx>,
     pub intercrate_ambiguity_causes: Vec<IntercrateAmbiguityCause>,
 }

 /// If there are types that satisfy both impls, returns a suitably-freshened
 /// `ImplHeader` with those types substituted
 pub fn overlapping_impls<'cx, 'gcx, 'tcx>(infcx: &InferCtxt<'cx, 'gcx, 'tcx>,
                                           impl1_def_id: DefId,
                                           impl2_def_id: DefId)
                                           -> Option<OverlapResult<'tcx>>
 {
     debug!("impl_can_satisfy(\
            impl1_def_id={:?}, \
            impl2_def_id={:?})",
            impl1_def_id,
            impl2_def_id);

     let selcx = &mut SelectionContext::intercrate(infcx);
     overlap(selcx, impl1_def_id, impl2_def_id)
 }

 fn with_fresh_ty_vars<'cx, 'gcx, 'tcx>(selcx: &mut SelectionContext<'cx, 'gcx, 'tcx>,
                                        param_env: ty::ParamEnv<'tcx>,
                                        impl_def_id: DefId)
                                        -> ty::ImplHeader<'tcx>
 {
     let tcx = selcx.tcx();
     let impl_substs = selcx.infcx().fresh_substs_for_item(DUMMY_SP, impl_def_id);

     let header = ty::ImplHeader {
         impl_def_id,
         self_ty: tcx.type_of(impl_def_id),
         trait_ref: tcx.impl_trait_ref(impl_def_id),
         predicates: tcx.predicates_of(impl_def_id).predicates
     }.subst(tcx, impl_substs);

     let Normalized { value: mut header, obligations } =
         traits::normalize(selcx, param_env, ObligationCause::dummy(), &header);

     header.predicates.extend(obligations.into_iter().map(|o| o.predicate));
     header
 }

 /// Can both impl `a` and impl `b` be satisfied by a common type (including
 /// `where` clauses)? If so, returns an `ImplHeader` that unifies the two impls.
 fn overlap<'cx, 'gcx, 'tcx>(selcx: &mut SelectionContext<'cx, 'gcx, 'tcx>,
                             a_def_id: DefId,
                             b_def_id: DefId)
                             -> Option<OverlapResult<'tcx>>
 {
     debug!("overlap(a_def_id={:?}, b_def_id={:?})",
            a_def_id,
            b_def_id);

     // For the purposes of this check, we don't bring any skolemized
     // types into scope; instead, we replace the generic types with
     // fresh type variables, and hence we do our evaluations in an
     // empty environment.
     let param_env = ty::ParamEnv::empty(Reveal::UserFacing);

     let a_impl_header = with_fresh_ty_vars(selcx, param_env, a_def_id);
     let b_impl_header = with_fresh_ty_vars(selcx, param_env, b_def_id);

     debug!("overlap: a_impl_header={:?}", a_impl_header);
     debug!("overlap: b_impl_header={:?}", b_impl_header);

     // Do `a` and `b` unify? If not, no overlap.
     let obligations = match selcx.infcx().at(&ObligationCause::dummy(), param_env)
                                          .eq_impl_headers(&a_impl_header, &b_impl_header) {
         Ok(InferOk { obligations, value: () }) => {
             obligations
         }
         Err(_) => return None
     };

     debug!("overlap: unification check succeeded");

     // Are any of the obligations unsatisfiable? If so, no overlap.
     let infcx = selcx.infcx();
     let opt_failing_obligation =
         a_impl_header.predicates
                      .iter()
                      .chain(&b_impl_header.predicates)
                      .map(|p| infcx.resolve_type_vars_if_possible(p))
                      .map(|p| Obligation { cause: ObligationCause::dummy(),
                                            param_env,
                                            recursion_depth: 0,
                                            predicate: p })
                      .chain(obligations)
                      .find(|o| !selcx.evaluate_obligation(o));

     if let Some(failing_obligation) = opt_failing_obligation {
         debug!("overlap: obligation unsatisfiable {:?}", failing_obligation);
         return None
     }

     Some(OverlapResult {
         impl_header: selcx.infcx().resolve_type_vars_if_possible(&a_impl_header),
         intercrate_ambiguity_causes: selcx.intercrate_ambiguity_causes().to_vec(),
     })
 }

 pub fn trait_ref_is_knowable<'a, 'gcx, 'tcx>(tcx: TyCtxt<'a, 'gcx, 'tcx>,
                                              trait_ref: ty::TraitRef<'tcx>) -> bool
 {
     debug!("trait_ref_is_knowable(trait_ref={:?})", trait_ref);

     // if the orphan rules pass, that means that no ancestor crate can
     // impl this, so it's up to us.
     if orphan_check_trait_ref(tcx, trait_ref, InferIsLocal(false)).is_ok() {
         debug!("trait_ref_is_knowable: orphan check passed");
         return true;
     }

     // if the trait is not marked fundamental, then it's always possible that
     // an ancestor crate will impl this in the future, if they haven't
     // already
     if !trait_ref_is_local_or_fundamental(tcx, trait_ref) {
         debug!("trait_ref_is_knowable: trait is neither local nor fundamental");
         return false;
     }

     // find out when some downstream (or cousin) crate could impl this
     // trait-ref, presuming that all the parameters were instantiated
     // with downstream types. If not, then it could only be
     // implemented by an upstream crate, which means that the impl
     // must be visible to us, and -- since the trait is fundamental
     // -- we can test.
     orphan_check_trait_ref(tcx, trait_ref, InferIsLocal(true)).is_err()
 }

 pub fn trait_ref_is_local_or_fundamental<'a, 'gcx, 'tcx>(tcx: TyCtxt<'a, 'gcx, 'tcx>,
                                                          trait_ref: ty::TraitRef<'tcx>)
                                                          -> bool {
     trait_ref.def_id.krate == LOCAL_CRATE || tcx.has_attr(trait_ref.def_id, "fundamental")
 }

 pub enum OrphanCheckErr<'tcx> {
     NoLocalInputType,
     UncoveredTy(Ty<'tcx>),
 }

 /// Checks the coherence orphan rules. `impl_def_id` should be the
 /// def-id of a trait impl. To pass, either the trait must be local, or else
 /// two conditions must be satisfied:
 ///
 /// 1. All type parameters in `Self` must be "covered" by some local type constructor.
 /// 2. Some local type must appear in `Self`.
 pub fn orphan_check<'a, 'gcx, 'tcx>(tcx: TyCtxt<'a, 'gcx, 'tcx>,
                                     impl_def_id: DefId)
                                     -> Result<(), OrphanCheckErr<'tcx>>
 {
     debug!("orphan_check({:?})", impl_def_id);

     // We only except this routine to be invoked on implementations
     // of a trait, not inherent implementations.
     let trait_ref = tcx.impl_trait_ref(impl_def_id).unwrap();
     debug!("orphan_check: trait_ref={:?}", trait_ref);

     // If the *trait* is local to the crate, ok.
     if trait_ref.def_id.is_local() {
         debug!("trait {:?} is local to current crate",
                trait_ref.def_id);
         return Ok(());
     }

     orphan_check_trait_ref(tcx, trait_ref, InferIsLocal(false))
 }

 fn orphan_check_trait_ref<'tcx>(tcx: TyCtxt,
                                 trait_ref: ty::TraitRef<'tcx>,
                                 infer_is_local: InferIsLocal)
                                 -> Result<(), OrphanCheckErr<'tcx>>
 {
     debug!("orphan_check_trait_ref(trait_ref={:?}, infer_is_local={})",
            trait_ref, infer_is_local.0);

     // First, create an ordered iterator over all the type parameters to the trait, with the self
     // type appearing first.
     // Find the first input type that either references a type parameter OR
     // some local type.
     for input_ty in trait_ref.input_types() {
         if ty_is_local(tcx, input_ty, infer_is_local) {
             debug!("orphan_check_trait_ref: ty_is_local `{:?}`", input_ty);

             // First local input type. Check that there are no
             // uncovered type parameters.
             let uncovered_tys = uncovered_tys(tcx, input_ty, infer_is_local);
             for uncovered_ty in uncovered_tys {
                 if let Some(param) = uncovered_ty.walk().find(|t| is_type_parameter(t)) {
                     debug!("orphan_check_trait_ref: uncovered type `{:?}`", param);
                     return Err(OrphanCheckErr::UncoveredTy(param));
                 }
             }

             // OK, found local type, all prior types upheld invariant.
             return Ok(());
         }

         // Otherwise, enforce invariant that there are no type
         // parameters reachable.
         if !infer_is_local.0 {
             if let Some(param) = input_ty.walk().find(|t| is_type_parameter(t)) {
                 debug!("orphan_check_trait_ref: uncovered type `{:?}`", param);
                 return Err(OrphanCheckErr::UncoveredTy(param));
             }
         }
     }

     // If we exit above loop, never found a local type.
     debug!("orphan_check_trait_ref: no local type");
     return Err(OrphanCheckErr::NoLocalInputType);
 }

 fn uncovered_tys<'tcx>(tcx: TyCtxt, ty: Ty<'tcx>, infer_is_local: InferIsLocal)
                        -> Vec<Ty<'tcx>> {
     if ty_is_local_constructor(ty, infer_is_local) {
         vec![]
     } else if fundamental_ty(tcx, ty) {
         ty.walk_shallow()
           .flat_map(|t| uncovered_tys(tcx, t, infer_is_local))
           .collect()
     } else {
         vec![ty]
     }
 }

 fn is_type_parameter(ty: Ty) -> bool {
     match ty.sty {
         // FIXME(#20590) straighten story about projection types
         ty::TyProjection(..) | ty::TyParam(..) => true,
         _ => false,
     }
 }

 fn ty_is_local(tcx: TyCtxt, ty: Ty, infer_is_local: InferIsLocal) -> bool {
     ty_is_local_constructor(ty, infer_is_local) ||
         fundamental_ty(tcx, ty) && ty.walk_shallow().any(|t| ty_is_local(tcx, t, infer_is_local))
 }

 fn fundamental_ty(tcx: TyCtxt, ty: Ty) -> bool {
     match ty.sty {
         ty::TyRef(..) => true,
         ty::TyAdt(def, _) => def.is_fundamental(),
         ty::TyDynamic(ref data, ..) => {
             data.principal().map_or(false, |p| tcx.has_attr(p.def_id(), "fundamental"))
         }
         _ => false
     }
 }

 fn ty_is_local_constructor(ty: Ty, infer_is_local: InferIsLocal)-> bool {
     debug!("ty_is_local_constructor({:?})", ty);

     match ty.sty {
         ty::TyBool |
         ty::TyChar |
         ty::TyInt(..) |
         ty::TyUint(..) |
         ty::TyFloat(..) |
         ty::TyStr |
         ty::TyFnDef(..) |
         ty::TyFnPtr(_) |
         ty::TyArray(..) |
         ty::TySlice(..) |
         ty::TyRawPtr(..) |
         ty::TyRef(..) |
         ty::TyNever |
         ty::TyTuple(..) |
         ty::TyParam(..) |
         ty::TyProjection(..) => {
             false
         }

         ty::TyInfer(..) => {
             infer_is_local.0
         }

         ty::TyAdt(def, _) => {
             def.did.is_local()
         }

         ty::TyDynamic(ref tt, ..) => {
             tt.principal().map_or(false, |p| p.def_id().is_local())
         }

         ty::TyError => {
             true
         }

         ty::TyClosure(..) | ty::TyGenerator(..) | ty::TyAnon(..) => {
             bug!("ty_is_local invoked on unexpected type: {:?}", ty)
         }
     }
 }
	// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
	// file at the top-level directory of this distribution and at
	// http://rust-lang.org/COPYRIGHT.
	//
	// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
	// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
	// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
	// option. This file may not be copied, modified, or distributed
	// except according to those terms.

	//! See `README.md` for high-level documentation

	use hir::def_id::{DefId, LOCAL_CRATE};
	use syntax_pos::DUMMY_SP;
	use traits::{self, Normalized, SelectionContext, Obligation, ObligationCause, Reveal};
	use traits::select::IntercrateAmbiguityCause;
	use ty::{self, Ty, TyCtxt};
	use ty::subst::Subst;

	use infer::{InferCtxt, InferOk};

	#[derive(Copy, Clone)]
	struct InferIsLocal(bool);

	pub struct OverlapResult<'tcx> {
	pub impl_header: ty::ImplHeader<'tcx>,
	pub intercrate_ambiguity_causes: Vec<IntercrateAmbiguityCause>,
	}

	/// If there are types that satisfy both impls, returns a suitably-freshened
	/// `ImplHeader` with those types substituted
	pub fn overlapping_impls<'cx, 'gcx, 'tcx>(infcx: &InferCtxt<'cx, 'gcx, 'tcx>,
	impl1_def_id: DefId,
	impl2_def_id: DefId)
	-> Option<OverlapResult<'tcx>>
	{
	debug!("impl_can_satisfy(\
	impl1_def_id={:?}, \
	impl2_def_id={:?})",
	impl1_def_id,
	impl2_def_id);

	let selcx = &mut SelectionContext::intercrate(infcx);
	overlap(selcx, impl1_def_id, impl2_def_id)
	}

	fn with_fresh_ty_vars<'cx, 'gcx, 'tcx>(selcx: &mut SelectionContext<'cx, 'gcx, 'tcx>,
	param_env: ty::ParamEnv<'tcx>,
	impl_def_id: DefId)
	-> ty::ImplHeader<'tcx>
	{
	let tcx = selcx.tcx();
	let impl_substs = selcx.infcx().fresh_substs_for_item(DUMMY_SP, impl_def_id);

	let header = ty::ImplHeader {
	impl_def_id,
	self_ty: tcx.type_of(impl_def_id),
	trait_ref: tcx.impl_trait_ref(impl_def_id),
	predicates: tcx.predicates_of(impl_def_id).predicates
	}.subst(tcx, impl_substs);

	let Normalized { value: mut header, obligations } =
	traits::normalize(selcx, param_env, ObligationCause::dummy(), &header);

	header.predicates.extend(obligations.into_iter().map(\|o\| o.predicate));
	header
	}

	/// Can both impl `a` and impl `b` be satisfied by a common type (including
	/// `where` clauses)? If so, returns an `ImplHeader` that unifies the two impls.
	fn overlap<'cx, 'gcx, 'tcx>(selcx: &mut SelectionContext<'cx, 'gcx, 'tcx>,
	a_def_id: DefId,
	b_def_id: DefId)
	-> Option<OverlapResult<'tcx>>
	{
	debug!("overlap(a_def_id={:?}, b_def_id={:?})",
	a_def_id,
	b_def_id);

	// For the purposes of this check, we don't bring any skolemized
	// types into scope; instead, we replace the generic types with
	// fresh type variables, and hence we do our evaluations in an
	// empty environment.
	let param_env = ty::ParamEnv::empty(Reveal::UserFacing);

	let a_impl_header = with_fresh_ty_vars(selcx, param_env, a_def_id);
	let b_impl_header = with_fresh_ty_vars(selcx, param_env, b_def_id);

	debug!("overlap: a_impl_header={:?}", a_impl_header);
	debug!("overlap: b_impl_header={:?}", b_impl_header);

	// Do `a` and `b` unify? If not, no overlap.
	let obligations = match selcx.infcx().at(&ObligationCause::dummy(), param_env)
	.eq_impl_headers(&a_impl_header, &b_impl_header) {
	Ok(InferOk { obligations, value: () }) => {
	obligations
	}
	Err(_) => return None
	};

	debug!("overlap: unification check succeeded");

	// Are any of the obligations unsatisfiable? If so, no overlap.
	let infcx = selcx.infcx();
	let opt_failing_obligation =
	a_impl_header.predicates
	.iter()
	.chain(&b_impl_header.predicates)
	.map(\|p\| infcx.resolve_type_vars_if_possible(p))
	.map(\|p\| Obligation { cause: ObligationCause::dummy(),
	param_env,
	recursion_depth: 0,
	predicate: p })
	.chain(obligations)
	.find(\|o\| !selcx.evaluate_obligation(o));

	if let Some(failing_obligation) = opt_failing_obligation {
	debug!("overlap: obligation unsatisfiable {:?}", failing_obligation);
	return None
	}

	Some(OverlapResult {
	impl_header: selcx.infcx().resolve_type_vars_if_possible(&a_impl_header),
	intercrate_ambiguity_causes: selcx.intercrate_ambiguity_causes().to_vec(),
	})
	}

	pub fn trait_ref_is_knowable<'a, 'gcx, 'tcx>(tcx: TyCtxt<'a, 'gcx, 'tcx>,
	trait_ref: ty::TraitRef<'tcx>) -> bool
	{
	debug!("trait_ref_is_knowable(trait_ref={:?})", trait_ref);

	// if the orphan rules pass, that means that no ancestor crate can
	// impl this, so it's up to us.
	if orphan_check_trait_ref(tcx, trait_ref, InferIsLocal(false)).is_ok() {
	debug!("trait_ref_is_knowable: orphan check passed");
	return true;
	}

	// if the trait is not marked fundamental, then it's always possible that
	// an ancestor crate will impl this in the future, if they haven't
	// already
	if !trait_ref_is_local_or_fundamental(tcx, trait_ref) {
	debug!("trait_ref_is_knowable: trait is neither local nor fundamental");
	return false;
	}

	// find out when some downstream (or cousin) crate could impl this
	// trait-ref, presuming that all the parameters were instantiated
	// with downstream types. If not, then it could only be
	// implemented by an upstream crate, which means that the impl
	// must be visible to us, and -- since the trait is fundamental
	// -- we can test.
	orphan_check_trait_ref(tcx, trait_ref, InferIsLocal(true)).is_err()
	}

	pub fn trait_ref_is_local_or_fundamental<'a, 'gcx, 'tcx>(tcx: TyCtxt<'a, 'gcx, 'tcx>,
	trait_ref: ty::TraitRef<'tcx>)
	-> bool {
	trait_ref.def_id.krate == LOCAL_CRATE \|\| tcx.has_attr(trait_ref.def_id, "fundamental")
	}

	pub enum OrphanCheckErr<'tcx> {
	NoLocalInputType,
	UncoveredTy(Ty<'tcx>),
	}

	/// Checks the coherence orphan rules. `impl_def_id` should be the
	/// def-id of a trait impl. To pass, either the trait must be local, or else
	/// two conditions must be satisfied:
	///
	/// 1. All type parameters in `Self` must be "covered" by some local type constructor.
	/// 2. Some local type must appear in `Self`.
	pub fn orphan_check<'a, 'gcx, 'tcx>(tcx: TyCtxt<'a, 'gcx, 'tcx>,
	impl_def_id: DefId)
	-> Result<(), OrphanCheckErr<'tcx>>
	{
	debug!("orphan_check({:?})", impl_def_id);

	// We only except this routine to be invoked on implementations
	// of a trait, not inherent implementations.
	let trait_ref = tcx.impl_trait_ref(impl_def_id).unwrap();
	debug!("orphan_check: trait_ref={:?}", trait_ref);

	// If the trait is local to the crate, ok.
	if trait_ref.def_id.is_local() {
	debug!("trait {:?} is local to current crate",
	trait_ref.def_id);
	return Ok(());
	}

	orphan_check_trait_ref(tcx, trait_ref, InferIsLocal(false))
	}

	fn orphan_check_trait_ref<'tcx>(tcx: TyCtxt,
	trait_ref: ty::TraitRef<'tcx>,
	infer_is_local: InferIsLocal)
	-> Result<(), OrphanCheckErr<'tcx>>
	{
	debug!("orphan_check_trait_ref(trait_ref={:?}, infer_is_local={})",
	trait_ref, infer_is_local.0);

	// First, create an ordered iterator over all the type parameters to the trait, with the self
	// type appearing first.
	// Find the first input type that either references a type parameter OR
	// some local type.
	for input_ty in trait_ref.input_types() {
	if ty_is_local(tcx, input_ty, infer_is_local) {
	debug!("orphan_check_trait_ref: ty_is_local `{:?}`", input_ty);

	// First local input type. Check that there are no
	// uncovered type parameters.
	let uncovered_tys = uncovered_tys(tcx, input_ty, infer_is_local);
	for uncovered_ty in uncovered_tys {
	if let Some(param) = uncovered_ty.walk().find(\|t\| is_type_parameter(t)) {
	debug!("orphan_check_trait_ref: uncovered type `{:?}`", param);
	return Err(OrphanCheckErr::UncoveredTy(param));
	}
	}

	// OK, found local type, all prior types upheld invariant.
	return Ok(());
	}

	// Otherwise, enforce invariant that there are no type
	// parameters reachable.
	if !infer_is_local.0 {
	if let Some(param) = input_ty.walk().find(\|t\| is_type_parameter(t)) {
	debug!("orphan_check_trait_ref: uncovered type `{:?}`", param);
	return Err(OrphanCheckErr::UncoveredTy(param));
	}
	}
	}

	// If we exit above loop, never found a local type.
	debug!("orphan_check_trait_ref: no local type");
	return Err(OrphanCheckErr::NoLocalInputType);
	}

	fn uncovered_tys<'tcx>(tcx: TyCtxt, ty: Ty<'tcx>, infer_is_local: InferIsLocal)
	-> Vec<Ty<'tcx>> {
	if ty_is_local_constructor(ty, infer_is_local) {
	vec![]
	} else if fundamental_ty(tcx, ty) {
	ty.walk_shallow()
	.flat_map(\|t\| uncovered_tys(tcx, t, infer_is_local))
	.collect()
	} else {
	vec![ty]
	}
	}

	fn is_type_parameter(ty: Ty) -> bool {
	match ty.sty {
	// FIXME(#20590) straighten story about projection types
	ty::TyProjection(..) \| ty::TyParam(..) => true,
	_ => false,
	}
	}

	fn ty_is_local(tcx: TyCtxt, ty: Ty, infer_is_local: InferIsLocal) -> bool {
	ty_is_local_constructor(ty, infer_is_local) \|\|
	fundamental_ty(tcx, ty) && ty.walk_shallow().any(\|t\| ty_is_local(tcx, t, infer_is_local))
	}

	fn fundamental_ty(tcx: TyCtxt, ty: Ty) -> bool {
	match ty.sty {
	ty::TyRef(..) => true,
	ty::TyAdt(def, _) => def.is_fundamental(),
	ty::TyDynamic(ref data, ..) => {
	data.principal().map_or(false, \|p\| tcx.has_attr(p.def_id(), "fundamental"))
	}
	_ => false
	}
	}

	fn ty_is_local_constructor(ty: Ty, infer_is_local: InferIsLocal)-> bool {
	debug!("ty_is_local_constructor({:?})", ty);

	match ty.sty {
	ty::TyBool \|
	ty::TyChar \|
	ty::TyInt(..) \|
	ty::TyUint(..) \|
	ty::TyFloat(..) \|
	ty::TyStr \|
	ty::TyFnDef(..) \|
	ty::TyFnPtr(_) \|
	ty::TyArray(..) \|
	ty::TySlice(..) \|
	ty::TyRawPtr(..) \|
	ty::TyRef(..) \|
	ty::TyNever \|
	ty::TyTuple(..) \|
	ty::TyParam(..) \|
	ty::TyProjection(..) => {
	false
	}

	ty::TyInfer(..) => {
	infer_is_local.0
	}

	ty::TyAdt(def, _) => {
	def.did.is_local()
	}

	ty::TyDynamic(ref tt, ..) => {
	tt.principal().map_or(false, \|p\| p.def_id().is_local())
	}

	ty::TyError => {
	true
	}

	ty::TyClosure(..) \| ty::TyGenerator(..) \| ty::TyAnon(..) => {
	bug!("ty_is_local invoked on unexpected type: {:?}", ty)
	}
	}
	}