src/librustc_trans/meth.rs - third_party/rust - Git at Google

 // Copyright 2012 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.

 use std::rc::Rc;

 use attributes;
 use arena::TypedArena;
 use back::symbol_names;
 use llvm::{ValueRef, get_params};
 use rustc::hir::def_id::DefId;
 use rustc::ty::subst::{FnSpace, Subst, Substs};
 use rustc::ty::subst;
 use rustc::traits::{self, ProjectionMode};
 use abi::FnType;
 use base::*;
 use build::*;
 use callee::{Callee, Virtual, ArgVals, trans_fn_pointer_shim};
 use closure;
 use common::*;
 use consts;
 use debuginfo::DebugLoc;
 use declare;
 use expr;
 use glue;
 use machine;
 use type_::Type;
 use type_of::*;
 use value::Value;
 use rustc::ty::{self, Ty, TyCtxt, TypeFoldable};

 use syntax::ast::Name;
 use syntax_pos::DUMMY_SP;

 // drop_glue pointer, size, align.
 const VTABLE_OFFSET: usize = 3;

 /// Extracts a method from a trait object's vtable, at the specified index.
 pub fn get_virtual_method<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
                                       llvtable: ValueRef,
                                       vtable_index: usize)
                                       -> ValueRef {
     // Load the data pointer from the object.
     debug!("get_virtual_method(vtable_index={}, llvtable={:?})",
            vtable_index, Value(llvtable));

     Load(bcx, GEPi(bcx, llvtable, &[vtable_index + VTABLE_OFFSET]))
 }

 /// Generate a shim function that allows an object type like `SomeTrait` to
 /// implement the type `SomeTrait`. Imagine a trait definition:
 ///
 ///    trait SomeTrait { fn get(&self) -> i32; ... }
 ///
 /// And a generic bit of code:
 ///
 ///    fn foo<T:SomeTrait>(t: &T) {
 ///        let x = SomeTrait::get;
 ///        x(t)
 ///    }
 ///
 /// What is the value of `x` when `foo` is invoked with `T=SomeTrait`?
 /// The answer is that it is a shim function generated by this routine:
 ///
 ///    fn shim(t: &SomeTrait) -> i32 {
 ///        // ... call t.get() virtually ...
 ///    }
 ///
 /// In fact, all virtual calls can be thought of as normal trait calls
 /// that go through this shim function.
 pub fn trans_object_shim<'a, 'tcx>(ccx: &'a CrateContext<'a, 'tcx>,
                                    method_ty: Ty<'tcx>,
                                    vtable_index: usize)
                                    -> ValueRef {
     let _icx = push_ctxt("trans_object_shim");
     let tcx = ccx.tcx();

     debug!("trans_object_shim(vtable_index={}, method_ty={:?})",
            vtable_index,
            method_ty);

     let sig = tcx.erase_late_bound_regions(&method_ty.fn_sig());
     let sig = tcx.normalize_associated_type(&sig);
     let fn_ty = FnType::new(ccx, method_ty.fn_abi(), &sig, &[]);

     let function_name =
         symbol_names::internal_name_from_type_and_suffix(ccx, method_ty, "object_shim");
     let llfn = declare::define_internal_fn(ccx, &function_name, method_ty);
     attributes::set_frame_pointer_elimination(ccx, llfn);

     let (block_arena, fcx): (TypedArena<_>, FunctionContext);
     block_arena = TypedArena::new();
     fcx = FunctionContext::new(ccx, llfn, fn_ty, None, &block_arena);
     let mut bcx = fcx.init(false, None);
     assert!(!fcx.needs_ret_allocas);


     let dest =
         fcx.llretslotptr.get().map(
             |_| expr::SaveIn(fcx.get_ret_slot(bcx, "ret_slot")));

     debug!("trans_object_shim: method_offset_in_vtable={}",
            vtable_index);

     let llargs = get_params(fcx.llfn);
     let args = ArgVals(&llargs[fcx.fn_ty.ret.is_indirect() as usize..]);

     let callee = Callee {
         data: Virtual(vtable_index),
         ty: method_ty
     };
     bcx = callee.call(bcx, DebugLoc::None, args, dest).bcx;

     fcx.finish(bcx, DebugLoc::None);

     llfn
 }

 /// Creates a returns a dynamic vtable for the given type and vtable origin.
 /// This is used only for objects.
 ///
 /// The `trait_ref` encodes the erased self type. Hence if we are
 /// making an object `Foo<Trait>` from a value of type `Foo<T>`, then
 /// `trait_ref` would map `T:Trait`.
 pub fn get_vtable<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
                             trait_ref: ty::PolyTraitRef<'tcx>)
                             -> ValueRef
 {
     let tcx = ccx.tcx();
     let _icx = push_ctxt("meth::get_vtable");

     debug!("get_vtable(trait_ref={:?})", trait_ref);

     // Check the cache.
     match ccx.vtables().borrow().get(&trait_ref) {
         Some(&val) => { return val }
         None => { }
     }

     // Not in the cache. Build it.
     let methods = traits::supertraits(tcx, trait_ref.clone()).flat_map(|trait_ref| {
         let vtable = fulfill_obligation(ccx.shared(), DUMMY_SP, trait_ref.clone());
         match vtable {
             // Should default trait error here?
             traits::VtableDefaultImpl(_) |
             traits::VtableBuiltin(_) => {
                 Vec::new().into_iter()
             }
             traits::VtableImpl(
                 traits::VtableImplData {
                     impl_def_id: id,
                     substs,
                     nested: _ }) => {
                 let nullptr = C_null(Type::nil(ccx).ptr_to());
                 get_vtable_methods(tcx, id, substs)
                     .into_iter()
                     .map(|opt_mth| opt_mth.map_or(nullptr, |mth| {
                         Callee::def(ccx, mth.method.def_id, &mth.substs).reify(ccx).val
                     }))
                     .collect::<Vec<_>>()
                     .into_iter()
             }
             traits::VtableClosure(
                 traits::VtableClosureData {
                     closure_def_id,
                     substs,
                     nested: _ }) => {
                 let trait_closure_kind = tcx.lang_items.fn_trait_kind(trait_ref.def_id()).unwrap();
                 let llfn = closure::trans_closure_method(ccx,
                                                          closure_def_id,
                                                          substs,
                                                          trait_closure_kind);
                 vec![llfn].into_iter()
             }
             traits::VtableFnPointer(
                 traits::VtableFnPointerData {
                     fn_ty: bare_fn_ty,
                     nested: _ }) => {
                 let trait_closure_kind = tcx.lang_items.fn_trait_kind(trait_ref.def_id()).unwrap();
                 vec![trans_fn_pointer_shim(ccx, trait_closure_kind, bare_fn_ty)].into_iter()
             }
             traits::VtableObject(ref data) => {
                 // this would imply that the Self type being erased is
                 // an object type; this cannot happen because we
                 // cannot cast an unsized type into a trait object
                 bug!("cannot get vtable for an object type: {:?}",
                      data);
             }
             traits::VtableParam(..) => {
                 bug!("resolved vtable for {:?} to bad vtable {:?} in trans",
                      trait_ref,
                      vtable);
             }
         }
     });

     let size_ty = sizing_type_of(ccx, trait_ref.self_ty());
     let size = machine::llsize_of_alloc(ccx, size_ty);
     let align = align_of(ccx, trait_ref.self_ty());

     let components: Vec<_> = vec![
         // Generate a destructor for the vtable.
         glue::get_drop_glue(ccx, trait_ref.self_ty()),
         C_uint(ccx, size),
         C_uint(ccx, align)
     ].into_iter().chain(methods).collect();

     let vtable_const = C_struct(ccx, &components, false);
     let align = machine::llalign_of_pref(ccx, val_ty(vtable_const));
     let vtable = consts::addr_of(ccx, vtable_const, align, "vtable");

     ccx.vtables().borrow_mut().insert(trait_ref, vtable);
     vtable
 }

 pub fn get_vtable_methods<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                                     impl_id: DefId,
                                     substs: &'tcx subst::Substs<'tcx>)
                                     -> Vec<Option<ImplMethod<'tcx>>>
 {
     debug!("get_vtable_methods(impl_id={:?}, substs={:?}", impl_id, substs);

     let trt_id = match tcx.impl_trait_ref(impl_id) {
         Some(t_id) => t_id.def_id,
         None       => bug!("make_impl_vtable: don't know how to \
                             make a vtable for a type impl!")
     };

     tcx.populate_implementations_for_trait_if_necessary(trt_id);

     let trait_item_def_ids = tcx.trait_item_def_ids(trt_id);
     trait_item_def_ids
         .iter()

         // Filter out non-method items.
         .filter_map(|item_def_id| {
             match *item_def_id {
                 ty::MethodTraitItemId(def_id) => Some(def_id),
                 _ => None,
             }
         })

         // Now produce pointers for each remaining method. If the
         // method could never be called from this object, just supply
         // null.
         .map(|trait_method_def_id| {
             debug!("get_vtable_methods: trait_method_def_id={:?}",
                    trait_method_def_id);

             let trait_method_type = match tcx.impl_or_trait_item(trait_method_def_id) {
                 ty::MethodTraitItem(m) => m,
                 _ => bug!("should be a method, not other assoc item"),
             };
             let name = trait_method_type.name;

             // Some methods cannot be called on an object; skip those.
             if !tcx.is_vtable_safe_method(trt_id, &trait_method_type) {
                 debug!("get_vtable_methods: not vtable safe");
                 return None;
             }

             debug!("get_vtable_methods: trait_method_type={:?}",
                    trait_method_type);

             // the method may have some early-bound lifetimes, add
             // regions for those
             let num_dummy_regions = trait_method_type.generics.regions.len(FnSpace);
             let dummy_regions = vec![ty::ReErased; num_dummy_regions];
             let method_substs = substs.clone()
                                       .with_method(vec![], dummy_regions);
             let method_substs = tcx.mk_substs(method_substs);

             // The substitutions we have are on the impl, so we grab
             // the method type from the impl to substitute into.
             let mth = get_impl_method(tcx, impl_id, method_substs, name);

             debug!("get_vtable_methods: mth={:?}", mth);

             // If this is a default method, it's possible that it
             // relies on where clauses that do not hold for this
             // particular set of type parameters. Note that this
             // method could then never be called, so we do not want to
             // try and trans it, in that case. Issue #23435.
             if mth.is_provided {
                 let predicates = mth.method.predicates.predicates.subst(tcx, &mth.substs);
                 if !normalize_and_test_predicates(tcx, predicates.into_vec()) {
                     debug!("get_vtable_methods: predicates do not hold");
                     return None;
                 }
             }

             Some(mth)
         })
         .collect()
 }

 #[derive(Debug)]
 pub struct ImplMethod<'tcx> {
     pub method: Rc<ty::Method<'tcx>>,
     pub substs: &'tcx Substs<'tcx>,
     pub is_provided: bool
 }

 /// Locates the applicable definition of a method, given its name.
 pub fn get_impl_method<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                                  impl_def_id: DefId,
                                  substs: &'tcx Substs<'tcx>,
                                  name: Name)
                                  -> ImplMethod<'tcx>
 {
     assert!(!substs.types.needs_infer());

     let trait_def_id = tcx.trait_id_of_impl(impl_def_id).unwrap();
     let trait_def = tcx.lookup_trait_def(trait_def_id);

     match trait_def.ancestors(impl_def_id).fn_defs(tcx, name).next() {
         Some(node_item) => {
             let substs = tcx.normalizing_infer_ctxt(ProjectionMode::Any).enter(|infcx| {
                 let substs = traits::translate_substs(&infcx, impl_def_id,
                                                       substs, node_item.node);
                 tcx.lift(&substs).unwrap_or_else(|| {
                     bug!("trans::meth::get_impl_method: translate_substs \
                           returned {:?} which contains inference types/regions",
                          substs);
                 })
             });
             ImplMethod {
                 method: node_item.item,
                 substs: substs,
                 is_provided: node_item.node.is_from_trait(),
             }
         }
         None => {
             bug!("method {:?} not found in {:?}", name, impl_def_id)
         }
     }
 }
	// Copyright 2012 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.

	use std::rc::Rc;

	use attributes;
	use arena::TypedArena;
	use back::symbol_names;
	use llvm::{ValueRef, get_params};
	use rustc::hir::def_id::DefId;
	use rustc::ty::subst::{FnSpace, Subst, Substs};
	use rustc::ty::subst;
	use rustc::traits::{self, ProjectionMode};
	use abi::FnType;
	use base::*;
	use build::*;
	use callee::{Callee, Virtual, ArgVals, trans_fn_pointer_shim};
	use closure;
	use common::*;
	use consts;
	use debuginfo::DebugLoc;
	use declare;
	use expr;
	use glue;
	use machine;
	use type_::Type;
	use type_of::*;
	use value::Value;
	use rustc::ty::{self, Ty, TyCtxt, TypeFoldable};

	use syntax::ast::Name;
	use syntax_pos::DUMMY_SP;

	// drop_glue pointer, size, align.
	const VTABLE_OFFSET: usize = 3;

	/// Extracts a method from a trait object's vtable, at the specified index.
	pub fn get_virtual_method<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
	llvtable: ValueRef,
	vtable_index: usize)
	-> ValueRef {
	// Load the data pointer from the object.
	debug!("get_virtual_method(vtable_index={}, llvtable={:?})",
	vtable_index, Value(llvtable));

	Load(bcx, GEPi(bcx, llvtable, &[vtable_index + VTABLE_OFFSET]))
	}

	/// Generate a shim function that allows an object type like `SomeTrait` to
	/// implement the type `SomeTrait`. Imagine a trait definition:
	///
	/// trait SomeTrait { fn get(&self) -> i32; ... }
	///
	/// And a generic bit of code:
	///
	/// fn foo<T:SomeTrait>(t: &T) {
	/// let x = SomeTrait::get;
	/// x(t)
	/// }
	///
	/// What is the value of `x` when `foo` is invoked with `T=SomeTrait`?
	/// The answer is that it is a shim function generated by this routine:
	///
	/// fn shim(t: &SomeTrait) -> i32 {
	/// // ... call t.get() virtually ...
	/// }
	///
	/// In fact, all virtual calls can be thought of as normal trait calls
	/// that go through this shim function.
	pub fn trans_object_shim<'a, 'tcx>(ccx: &'a CrateContext<'a, 'tcx>,
	method_ty: Ty<'tcx>,
	vtable_index: usize)
	-> ValueRef {
	let _icx = push_ctxt("trans_object_shim");
	let tcx = ccx.tcx();

	debug!("trans_object_shim(vtable_index={}, method_ty={:?})",
	vtable_index,
	method_ty);

	let sig = tcx.erase_late_bound_regions(&method_ty.fn_sig());
	let sig = tcx.normalize_associated_type(&sig);
	let fn_ty = FnType::new(ccx, method_ty.fn_abi(), &sig, &[]);

	let function_name =
	symbol_names::internal_name_from_type_and_suffix(ccx, method_ty, "object_shim");
	let llfn = declare::define_internal_fn(ccx, &function_name, method_ty);
	attributes::set_frame_pointer_elimination(ccx, llfn);

	let (block_arena, fcx): (TypedArena<_>, FunctionContext);
	block_arena = TypedArena::new();
	fcx = FunctionContext::new(ccx, llfn, fn_ty, None, &block_arena);
	let mut bcx = fcx.init(false, None);
	assert!(!fcx.needs_ret_allocas);


	let dest =
	fcx.llretslotptr.get().map(
	\|_\| expr::SaveIn(fcx.get_ret_slot(bcx, "ret_slot")));

	debug!("trans_object_shim: method_offset_in_vtable={}",
	vtable_index);

	let llargs = get_params(fcx.llfn);
	let args = ArgVals(&llargs[fcx.fn_ty.ret.is_indirect() as usize..]);

	let callee = Callee {
	data: Virtual(vtable_index),
	ty: method_ty
	};
	bcx = callee.call(bcx, DebugLoc::None, args, dest).bcx;

	fcx.finish(bcx, DebugLoc::None);

	llfn
	}

	/// Creates a returns a dynamic vtable for the given type and vtable origin.
	/// This is used only for objects.
	///
	/// The `trait_ref` encodes the erased self type. Hence if we are
	/// making an object `Foo<Trait>` from a value of type `Foo<T>`, then
	/// `trait_ref` would map `T:Trait`.
	pub fn get_vtable<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
	trait_ref: ty::PolyTraitRef<'tcx>)
	-> ValueRef
	{
	let tcx = ccx.tcx();
	let _icx = push_ctxt("meth::get_vtable");

	debug!("get_vtable(trait_ref={:?})", trait_ref);

	// Check the cache.
	match ccx.vtables().borrow().get(&trait_ref) {
	Some(&val) => { return val }
	None => { }
	}

	// Not in the cache. Build it.
	let methods = traits::supertraits(tcx, trait_ref.clone()).flat_map(\|trait_ref\| {
	let vtable = fulfill_obligation(ccx.shared(), DUMMY_SP, trait_ref.clone());
	match vtable {
	// Should default trait error here?
	traits::VtableDefaultImpl(_) \|
	traits::VtableBuiltin(_) => {
	Vec::new().into_iter()
	}
	traits::VtableImpl(
	traits::VtableImplData {
	impl_def_id: id,
	substs,
	nested: _ }) => {
	let nullptr = C_null(Type::nil(ccx).ptr_to());
	get_vtable_methods(tcx, id, substs)
	.into_iter()
	.map(\|opt_mth\| opt_mth.map_or(nullptr, \|mth\| {
	Callee::def(ccx, mth.method.def_id, &mth.substs).reify(ccx).val
	}))
	.collect::<Vec<_>>()
	.into_iter()
	}
	traits::VtableClosure(
	traits::VtableClosureData {
	closure_def_id,
	substs,
	nested: _ }) => {
	let trait_closure_kind = tcx.lang_items.fn_trait_kind(trait_ref.def_id()).unwrap();
	let llfn = closure::trans_closure_method(ccx,
	closure_def_id,
	substs,
	trait_closure_kind);
	vec![llfn].into_iter()
	}
	traits::VtableFnPointer(
	traits::VtableFnPointerData {
	fn_ty: bare_fn_ty,
	nested: _ }) => {
	let trait_closure_kind = tcx.lang_items.fn_trait_kind(trait_ref.def_id()).unwrap();
	vec![trans_fn_pointer_shim(ccx, trait_closure_kind, bare_fn_ty)].into_iter()
	}
	traits::VtableObject(ref data) => {
	// this would imply that the Self type being erased is
	// an object type; this cannot happen because we
	// cannot cast an unsized type into a trait object
	bug!("cannot get vtable for an object type: {:?}",
	data);
	}
	traits::VtableParam(..) => {
	bug!("resolved vtable for {:?} to bad vtable {:?} in trans",
	trait_ref,
	vtable);
	}
	}
	});

	let size_ty = sizing_type_of(ccx, trait_ref.self_ty());
	let size = machine::llsize_of_alloc(ccx, size_ty);
	let align = align_of(ccx, trait_ref.self_ty());

	let components: Vec<_> = vec![
	// Generate a destructor for the vtable.
	glue::get_drop_glue(ccx, trait_ref.self_ty()),
	C_uint(ccx, size),
	C_uint(ccx, align)
	].into_iter().chain(methods).collect();

	let vtable_const = C_struct(ccx, &components, false);
	let align = machine::llalign_of_pref(ccx, val_ty(vtable_const));
	let vtable = consts::addr_of(ccx, vtable_const, align, "vtable");

	ccx.vtables().borrow_mut().insert(trait_ref, vtable);
	vtable
	}

	pub fn get_vtable_methods<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
	impl_id: DefId,
	substs: &'tcx subst::Substs<'tcx>)
	-> Vec<Option<ImplMethod<'tcx>>>
	{
	debug!("get_vtable_methods(impl_id={:?}, substs={:?}", impl_id, substs);

	let trt_id = match tcx.impl_trait_ref(impl_id) {
	Some(t_id) => t_id.def_id,
	None => bug!("make_impl_vtable: don't know how to \
	make a vtable for a type impl!")
	};

	tcx.populate_implementations_for_trait_if_necessary(trt_id);

	let trait_item_def_ids = tcx.trait_item_def_ids(trt_id);
	trait_item_def_ids
	.iter()

	// Filter out non-method items.
	.filter_map(\|item_def_id\| {
	match *item_def_id {
	ty::MethodTraitItemId(def_id) => Some(def_id),
	_ => None,
	}
	})

	// Now produce pointers for each remaining method. If the
	// method could never be called from this object, just supply
	// null.
	.map(\|trait_method_def_id\| {
	debug!("get_vtable_methods: trait_method_def_id={:?}",
	trait_method_def_id);

	let trait_method_type = match tcx.impl_or_trait_item(trait_method_def_id) {
	ty::MethodTraitItem(m) => m,
	_ => bug!("should be a method, not other assoc item"),
	};
	let name = trait_method_type.name;

	// Some methods cannot be called on an object; skip those.
	if !tcx.is_vtable_safe_method(trt_id, &trait_method_type) {
	debug!("get_vtable_methods: not vtable safe");
	return None;
	}

	debug!("get_vtable_methods: trait_method_type={:?}",
	trait_method_type);

	// the method may have some early-bound lifetimes, add
	// regions for those
	let num_dummy_regions = trait_method_type.generics.regions.len(FnSpace);
	let dummy_regions = vec![ty::ReErased; num_dummy_regions];
	let method_substs = substs.clone()
	.with_method(vec![], dummy_regions);
	let method_substs = tcx.mk_substs(method_substs);

	// The substitutions we have are on the impl, so we grab
	// the method type from the impl to substitute into.
	let mth = get_impl_method(tcx, impl_id, method_substs, name);

	debug!("get_vtable_methods: mth={:?}", mth);

	// If this is a default method, it's possible that it
	// relies on where clauses that do not hold for this
	// particular set of type parameters. Note that this
	// method could then never be called, so we do not want to
	// try and trans it, in that case. Issue #23435.
	if mth.is_provided {
	let predicates = mth.method.predicates.predicates.subst(tcx, &mth.substs);
	if !normalize_and_test_predicates(tcx, predicates.into_vec()) {
	debug!("get_vtable_methods: predicates do not hold");
	return None;
	}
	}

	Some(mth)
	})
	.collect()
	}

	#[derive(Debug)]
	pub struct ImplMethod<'tcx> {
	pub method: Rc<ty::Method<'tcx>>,
	pub substs: &'tcx Substs<'tcx>,
	pub is_provided: bool
	}

	/// Locates the applicable definition of a method, given its name.
	pub fn get_impl_method<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
	impl_def_id: DefId,
	substs: &'tcx Substs<'tcx>,
	name: Name)
	-> ImplMethod<'tcx>
	{
	assert!(!substs.types.needs_infer());

	let trait_def_id = tcx.trait_id_of_impl(impl_def_id).unwrap();
	let trait_def = tcx.lookup_trait_def(trait_def_id);

	match trait_def.ancestors(impl_def_id).fn_defs(tcx, name).next() {
	Some(node_item) => {
	let substs = tcx.normalizing_infer_ctxt(ProjectionMode::Any).enter(\|infcx\| {
	let substs = traits::translate_substs(&infcx, impl_def_id,
	substs, node_item.node);
	tcx.lift(&substs).unwrap_or_else(\|\| {
	bug!("trans::meth::get_impl_method: translate_substs \
	returned {:?} which contains inference types/regions",
	substs);
	})
	});
	ImplMethod {
	method: node_item.item,
	substs: substs,
	is_provided: node_item.node.is_from_trait(),
	}
	}
	None => {
	bug!("method {:?} not found in {:?}", name, impl_def_id)
	}
	}
	}