src/librustdoc/clean/inline.rs - third_party/rust - Git at Google

 // Copyright 2012-2013 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.

 //! Support for inlining external documentation into the current AST.

 use std::iter::once;

 use syntax::ast;
 use rustc::hir;

 use rustc::hir::def::{Def, CtorKind};
 use rustc::hir::def_id::DefId;
 use rustc::ty;
 use rustc::util::nodemap::FxHashSet;

 use core::{DocContext, DocAccessLevels};
 use doctree;
 use clean::{self, GetDefId, get_auto_traits_with_def_id};

 use super::Clean;

 /// Attempt to inline a definition into this AST.
 ///
 /// This function will fetch the definition specified, and if it is
 /// from another crate it will attempt to inline the documentation
 /// from the other crate into this crate.
 ///
 /// This is primarily used for `pub use` statements which are, in general,
 /// implementation details. Inlining the documentation should help provide a
 /// better experience when reading the documentation in this use case.
 ///
 /// The returned value is `None` if the definition could not be inlined,
 /// and `Some` of a vector of items if it was successfully expanded.
 pub fn try_inline(cx: &DocContext, def: Def, name: ast::Name)
                   -> Option<Vec<clean::Item>> {
     if def == Def::Err { return None }
     let did = def.def_id();
     if did.is_local() { return None }
     let mut ret = Vec::new();
     let inner = match def {
         Def::Trait(did) => {
             record_extern_fqn(cx, did, clean::TypeKind::Trait);
             ret.extend(build_impls(cx, did, false));
             clean::TraitItem(build_external_trait(cx, did))
         }
         Def::Fn(did) => {
             record_extern_fqn(cx, did, clean::TypeKind::Function);
             clean::FunctionItem(build_external_function(cx, did))
         }
         Def::Struct(did) => {
             record_extern_fqn(cx, did, clean::TypeKind::Struct);
             ret.extend(build_impls(cx, did, true));
             clean::StructItem(build_struct(cx, did))
         }
         Def::Union(did) => {
             record_extern_fqn(cx, did, clean::TypeKind::Union);
             ret.extend(build_impls(cx, did, true));
             clean::UnionItem(build_union(cx, did))
         }
         Def::TyAlias(did) => {
             record_extern_fqn(cx, did, clean::TypeKind::Typedef);
             ret.extend(build_impls(cx, did, false));
             clean::TypedefItem(build_type_alias(cx, did), false)
         }
         Def::Enum(did) => {
             record_extern_fqn(cx, did, clean::TypeKind::Enum);
             ret.extend(build_impls(cx, did, true));
             clean::EnumItem(build_enum(cx, did))
         }
         Def::TyForeign(did) => {
             record_extern_fqn(cx, did, clean::TypeKind::Foreign);
             ret.extend(build_impls(cx, did, false));
             clean::ForeignTypeItem
         }
         // Never inline enum variants but leave them shown as re-exports.
         Def::Variant(..) => return None,
         // Assume that enum variants and struct types are re-exported next to
         // their constructors.
         Def::VariantCtor(..) |
         Def::StructCtor(..) => return Some(Vec::new()),
         Def::Mod(did) => {
             record_extern_fqn(cx, did, clean::TypeKind::Module);
             clean::ModuleItem(build_module(cx, did))
         }
         Def::Static(did, mtbl) => {
             record_extern_fqn(cx, did, clean::TypeKind::Static);
             clean::StaticItem(build_static(cx, did, mtbl))
         }
         Def::Const(did) => {
             record_extern_fqn(cx, did, clean::TypeKind::Const);
             clean::ConstantItem(build_const(cx, did))
         }
         _ => return None,
     };
     cx.renderinfo.borrow_mut().inlined.insert(did);
     ret.push(clean::Item {
         source: cx.tcx.def_span(did).clean(cx),
         name: Some(name.clean(cx)),
         attrs: load_attrs(cx, did),
         inner,
         visibility: Some(clean::Public),
         stability: cx.tcx.lookup_stability(did).clean(cx),
         deprecation: cx.tcx.lookup_deprecation(did).clean(cx),
         def_id: did,
     });
     Some(ret)
 }

 pub fn load_attrs(cx: &DocContext, did: DefId) -> clean::Attributes {
     cx.tcx.get_attrs(did).clean(cx)
 }

 /// Record an external fully qualified name in the external_paths cache.
 ///
 /// These names are used later on by HTML rendering to generate things like
 /// source links back to the original item.
 pub fn record_extern_fqn(cx: &DocContext, did: DefId, kind: clean::TypeKind) {
     if did.is_local() {
         debug!("record_extern_fqn(did={:?}, kind+{:?}): def_id is local, aborting", did, kind);
         return;
     }

     let crate_name = cx.tcx.crate_name(did.krate).to_string();
     let relative = cx.tcx.def_path(did).data.into_iter().filter_map(|elem| {
         // extern blocks have an empty name
         let s = elem.data.to_string();
         if !s.is_empty() {
             Some(s)
         } else {
             None
         }
     });
     let fqn = if let clean::TypeKind::Macro = kind {
         vec![crate_name, relative.last().unwrap()]
     } else {
         once(crate_name).chain(relative).collect()
     };
     cx.renderinfo.borrow_mut().external_paths.insert(did, (fqn, kind));
 }

 pub fn build_external_trait(cx: &DocContext, did: DefId) -> clean::Trait {
     let auto_trait = cx.tcx.trait_def(did).has_auto_impl;
     let trait_items = cx.tcx.associated_items(did).map(|item| item.clean(cx)).collect();
     let predicates = cx.tcx.predicates_of(did);
     let generics = (cx.tcx.generics_of(did), &predicates).clean(cx);
     let generics = filter_non_trait_generics(did, generics);
     let (generics, supertrait_bounds) = separate_supertrait_bounds(generics);
     let is_spotlight = load_attrs(cx, did).has_doc_flag("spotlight");
     let is_auto = cx.tcx.trait_is_auto(did);
     clean::Trait {
         auto: auto_trait,
         unsafety: cx.tcx.trait_def(did).unsafety,
         generics,
         items: trait_items,
         bounds: supertrait_bounds,
         is_spotlight,
         is_auto,
     }
 }

 fn build_external_function(cx: &DocContext, did: DefId) -> clean::Function {
     let sig = cx.tcx.fn_sig(did);

     let constness = if cx.tcx.is_const_fn(did) {
         hir::Constness::Const
     } else {
         hir::Constness::NotConst
     };

     let predicates = cx.tcx.predicates_of(did);
     clean::Function {
         decl: (did, sig).clean(cx),
         generics: (cx.tcx.generics_of(did), &predicates).clean(cx),
         unsafety: sig.unsafety(),
         constness,
         abi: sig.abi(),
     }
 }

 fn build_enum(cx: &DocContext, did: DefId) -> clean::Enum {
     let predicates = cx.tcx.predicates_of(did);

     clean::Enum {
         generics: (cx.tcx.generics_of(did), &predicates).clean(cx),
         variants_stripped: false,
         variants: cx.tcx.adt_def(did).variants.clean(cx),
     }
 }

 fn build_struct(cx: &DocContext, did: DefId) -> clean::Struct {
     let predicates = cx.tcx.predicates_of(did);
     let variant = cx.tcx.adt_def(did).non_enum_variant();

     clean::Struct {
         struct_type: match variant.ctor_kind {
             CtorKind::Fictive => doctree::Plain,
             CtorKind::Fn => doctree::Tuple,
             CtorKind::Const => doctree::Unit,
         },
         generics: (cx.tcx.generics_of(did), &predicates).clean(cx),
         fields: variant.fields.clean(cx),
         fields_stripped: false,
     }
 }

 fn build_union(cx: &DocContext, did: DefId) -> clean::Union {
     let predicates = cx.tcx.predicates_of(did);
     let variant = cx.tcx.adt_def(did).non_enum_variant();

     clean::Union {
         struct_type: doctree::Plain,
         generics: (cx.tcx.generics_of(did), &predicates).clean(cx),
         fields: variant.fields.clean(cx),
         fields_stripped: false,
     }
 }

 fn build_type_alias(cx: &DocContext, did: DefId) -> clean::Typedef {
     let predicates = cx.tcx.predicates_of(did);

     clean::Typedef {
         type_: cx.tcx.type_of(did).clean(cx),
         generics: (cx.tcx.generics_of(did), &predicates).clean(cx),
     }
 }

 pub fn build_impls(cx: &DocContext, did: DefId, auto_traits: bool) -> Vec<clean::Item> {
     let tcx = cx.tcx;
     let mut impls = Vec::new();

     for &did in tcx.inherent_impls(did).iter() {
         build_impl(cx, did, &mut impls);
     }

     if auto_traits {
         let auto_impls = get_auto_traits_with_def_id(cx, did);
         let mut renderinfo = cx.renderinfo.borrow_mut();

         let new_impls: Vec<clean::Item> = auto_impls.into_iter()
             .filter(|i| renderinfo.inlined.insert(i.def_id)).collect();

         impls.extend(new_impls);
     }

     // If this is the first time we've inlined something from another crate, then
     // we inline *all* impls from all the crates into this crate. Note that there's
     // currently no way for us to filter this based on type, and we likely need
     // many impls for a variety of reasons.
     //
     // Primarily, the impls will be used to populate the documentation for this
     // type being inlined, but impls can also be used when generating
     // documentation for primitives (no way to find those specifically).
     if cx.populated_all_crate_impls.get() {
         return impls;
     }

     cx.populated_all_crate_impls.set(true);

     for &cnum in tcx.crates().iter() {
         for did in tcx.all_trait_implementations(cnum).iter() {
             build_impl(cx, *did, &mut impls);
         }
     }

     // Also try to inline primitive impls from other crates.
     let lang_items = tcx.lang_items();
     let primitive_impls = [
         lang_items.isize_impl(),
         lang_items.i8_impl(),
         lang_items.i16_impl(),
         lang_items.i32_impl(),
         lang_items.i64_impl(),
         lang_items.i128_impl(),
         lang_items.usize_impl(),
         lang_items.u8_impl(),
         lang_items.u16_impl(),
         lang_items.u32_impl(),
         lang_items.u64_impl(),
         lang_items.u128_impl(),
         lang_items.f32_impl(),
         lang_items.f64_impl(),
         lang_items.char_impl(),
         lang_items.str_impl(),
         lang_items.slice_impl(),
         lang_items.slice_u8_impl(),
         lang_items.const_ptr_impl(),
         lang_items.mut_ptr_impl(),
     ];

     for def_id in primitive_impls.iter().filter_map(|&def_id| def_id) {
         if !def_id.is_local() {
             build_impl(cx, def_id, &mut impls);
         }
     }

     impls
 }

 pub fn build_impl(cx: &DocContext, did: DefId, ret: &mut Vec<clean::Item>) {
     if !cx.renderinfo.borrow_mut().inlined.insert(did) {
         return
     }

     let attrs = load_attrs(cx, did);
     let tcx = cx.tcx;
     let associated_trait = tcx.impl_trait_ref(did);

     // Only inline impl if the implemented trait is
     // reachable in rustdoc generated documentation
     if let Some(traitref) = associated_trait {
         if !cx.access_levels.borrow().is_doc_reachable(traitref.def_id) {
             return
         }
     }

     let for_ = tcx.type_of(did).clean(cx);

     // Only inline impl if the implementing type is
     // reachable in rustdoc generated documentation
     if let Some(did) = for_.def_id() {
         if !cx.access_levels.borrow().is_doc_reachable(did) {
             return
         }
     }

     let predicates = tcx.predicates_of(did);
     let trait_items = tcx.associated_items(did).filter_map(|item| {
         if associated_trait.is_some() || item.vis == ty::Visibility::Public {
             Some(item.clean(cx))
         } else {
             None
         }
     }).collect::<Vec<_>>();
     let polarity = tcx.impl_polarity(did);
     let trait_ = associated_trait.clean(cx).map(|bound| {
         match bound {
             clean::TraitBound(polyt, _) => polyt.trait_,
             clean::RegionBound(..) => unreachable!(),
         }
     });
     if trait_.def_id() == tcx.lang_items().deref_trait() {
         super::build_deref_target_impls(cx, &trait_items, ret);
     }
     if let Some(trait_did) = trait_.def_id() {
         record_extern_trait(cx, trait_did);
     }

     let provided = trait_.def_id().map(|did| {
         tcx.provided_trait_methods(did)
             .into_iter()
             .map(|meth| meth.name.to_string())
             .collect()
     }).unwrap_or(FxHashSet());

     ret.push(clean::Item {
         inner: clean::ImplItem(clean::Impl {
             unsafety: hir::Unsafety::Normal,
             generics: (tcx.generics_of(did), &predicates).clean(cx),
             provided_trait_methods: provided,
             trait_,
             for_,
             items: trait_items,
             polarity: Some(polarity.clean(cx)),
             synthetic: false,
         }),
         source: tcx.def_span(did).clean(cx),
         name: None,
         attrs,
         visibility: Some(clean::Inherited),
         stability: tcx.lookup_stability(did).clean(cx),
         deprecation: tcx.lookup_deprecation(did).clean(cx),
         def_id: did,
     });
 }

 fn build_module(cx: &DocContext, did: DefId) -> clean::Module {
     let mut items = Vec::new();
     fill_in(cx, did, &mut items);
     return clean::Module {
         items,
         is_crate: false,
     };

     fn fill_in(cx: &DocContext, did: DefId, items: &mut Vec<clean::Item>) {
         // If we're re-exporting a re-export it may actually re-export something in
         // two namespaces, so the target may be listed twice. Make sure we only
         // visit each node at most once.
         let mut visited = FxHashSet();
         for &item in cx.tcx.item_children(did).iter() {
             let def_id = item.def.def_id();
             if item.vis == ty::Visibility::Public {
                 if !visited.insert(def_id) { continue }
                 if let Some(i) = try_inline(cx, item.def, item.ident.name) {
                     items.extend(i)
                 }
             }
         }
     }
 }

 pub fn print_inlined_const(cx: &DocContext, did: DefId) -> String {
     cx.tcx.rendered_const(did)
 }

 fn build_const(cx: &DocContext, did: DefId) -> clean::Constant {
     clean::Constant {
         type_: cx.tcx.type_of(did).clean(cx),
         expr: print_inlined_const(cx, did)
     }
 }

 fn build_static(cx: &DocContext, did: DefId, mutable: bool) -> clean::Static {
     clean::Static {
         type_: cx.tcx.type_of(did).clean(cx),
         mutability: if mutable {clean::Mutable} else {clean::Immutable},
         expr: "\n\n\n".to_string(), // trigger the "[definition]" links
     }
 }

 /// A trait's generics clause actually contains all of the predicates for all of
 /// its associated types as well. We specifically move these clauses to the
 /// associated types instead when displaying, so when we're generating the
 /// generics for the trait itself we need to be sure to remove them.
 /// We also need to remove the implied "recursive" Self: Trait bound.
 ///
 /// The inverse of this filtering logic can be found in the `Clean`
 /// implementation for `AssociatedType`
 fn filter_non_trait_generics(trait_did: DefId, mut g: clean::Generics) -> clean::Generics {
     for pred in &mut g.where_predicates {
         match *pred {
             clean::WherePredicate::BoundPredicate {
                 ty: clean::Generic(ref s),
                 ref mut bounds
             } if *s == "Self" => {
                 bounds.retain(|bound| {
                     match *bound {
                         clean::TyParamBound::TraitBound(clean::PolyTrait {
                             trait_: clean::ResolvedPath { did, .. },
                             ..
                         }, _) => did != trait_did,
                         _ => true
                     }
                 });
             }
             _ => {}
         }
     }

     g.where_predicates.retain(|pred| {
         match *pred {
             clean::WherePredicate::BoundPredicate {
                 ty: clean::QPath {
                     self_type: box clean::Generic(ref s),
                     trait_: box clean::ResolvedPath { did, .. },
                     name: ref _name,
                 }, ref bounds
             } => !(*s == "Self" && did == trait_did) && !bounds.is_empty(),
             _ => true,
         }
     });
     g
 }

 /// Supertrait bounds for a trait are also listed in the generics coming from
 /// the metadata for a crate, so we want to separate those out and create a new
 /// list of explicit supertrait bounds to render nicely.
 fn separate_supertrait_bounds(mut g: clean::Generics)
                               -> (clean::Generics, Vec<clean::TyParamBound>) {
     let mut ty_bounds = Vec::new();
     g.where_predicates.retain(|pred| {
         match *pred {
             clean::WherePredicate::BoundPredicate {
                 ty: clean::Generic(ref s),
                 ref bounds
             } if *s == "Self" => {
                 ty_bounds.extend(bounds.iter().cloned());
                 false
             }
             _ => true,
         }
     });
     (g, ty_bounds)
 }

 pub fn record_extern_trait(cx: &DocContext, did: DefId) {
     if cx.external_traits.borrow().contains_key(&did) ||
         cx.active_extern_traits.borrow().contains(&did)
     {
         return;
     }

     cx.active_extern_traits.borrow_mut().push(did);

     let trait_ = build_external_trait(cx, did);

     cx.external_traits.borrow_mut().insert(did, trait_);
     cx.active_extern_traits.borrow_mut().remove_item(&did);
 }
	// Copyright 2012-2013 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.

	//! Support for inlining external documentation into the current AST.

	use std::iter::once;

	use syntax::ast;
	use rustc::hir;

	use rustc::hir::def::{Def, CtorKind};
	use rustc::hir::def_id::DefId;
	use rustc::ty;
	use rustc::util::nodemap::FxHashSet;

	use core::{DocContext, DocAccessLevels};
	use doctree;
	use clean::{self, GetDefId, get_auto_traits_with_def_id};

	use super::Clean;

	/// Attempt to inline a definition into this AST.
	///
	/// This function will fetch the definition specified, and if it is
	/// from another crate it will attempt to inline the documentation
	/// from the other crate into this crate.
	///
	/// This is primarily used for `pub use` statements which are, in general,
	/// implementation details. Inlining the documentation should help provide a
	/// better experience when reading the documentation in this use case.
	///
	/// The returned value is `None` if the definition could not be inlined,
	/// and `Some` of a vector of items if it was successfully expanded.
	pub fn try_inline(cx: &DocContext, def: Def, name: ast::Name)
	-> Option<Vec<clean::Item>> {
	if def == Def::Err { return None }
	let did = def.def_id();
	if did.is_local() { return None }
	let mut ret = Vec::new();
	let inner = match def {
	Def::Trait(did) => {
	record_extern_fqn(cx, did, clean::TypeKind::Trait);
	ret.extend(build_impls(cx, did, false));
	clean::TraitItem(build_external_trait(cx, did))
	}
	Def::Fn(did) => {
	record_extern_fqn(cx, did, clean::TypeKind::Function);
	clean::FunctionItem(build_external_function(cx, did))
	}
	Def::Struct(did) => {
	record_extern_fqn(cx, did, clean::TypeKind::Struct);
	ret.extend(build_impls(cx, did, true));
	clean::StructItem(build_struct(cx, did))
	}
	Def::Union(did) => {
	record_extern_fqn(cx, did, clean::TypeKind::Union);
	ret.extend(build_impls(cx, did, true));
	clean::UnionItem(build_union(cx, did))
	}
	Def::TyAlias(did) => {
	record_extern_fqn(cx, did, clean::TypeKind::Typedef);
	ret.extend(build_impls(cx, did, false));
	clean::TypedefItem(build_type_alias(cx, did), false)
	}
	Def::Enum(did) => {
	record_extern_fqn(cx, did, clean::TypeKind::Enum);
	ret.extend(build_impls(cx, did, true));
	clean::EnumItem(build_enum(cx, did))
	}
	Def::TyForeign(did) => {
	record_extern_fqn(cx, did, clean::TypeKind::Foreign);
	ret.extend(build_impls(cx, did, false));
	clean::ForeignTypeItem
	}
	// Never inline enum variants but leave them shown as re-exports.
	Def::Variant(..) => return None,
	// Assume that enum variants and struct types are re-exported next to
	// their constructors.
	Def::VariantCtor(..) \|
	Def::StructCtor(..) => return Some(Vec::new()),
	Def::Mod(did) => {
	record_extern_fqn(cx, did, clean::TypeKind::Module);
	clean::ModuleItem(build_module(cx, did))
	}
	Def::Static(did, mtbl) => {
	record_extern_fqn(cx, did, clean::TypeKind::Static);
	clean::StaticItem(build_static(cx, did, mtbl))
	}
	Def::Const(did) => {
	record_extern_fqn(cx, did, clean::TypeKind::Const);
	clean::ConstantItem(build_const(cx, did))
	}
	_ => return None,
	};
	cx.renderinfo.borrow_mut().inlined.insert(did);
	ret.push(clean::Item {
	source: cx.tcx.def_span(did).clean(cx),
	name: Some(name.clean(cx)),
	attrs: load_attrs(cx, did),
	inner,
	visibility: Some(clean::Public),
	stability: cx.tcx.lookup_stability(did).clean(cx),
	deprecation: cx.tcx.lookup_deprecation(did).clean(cx),
	def_id: did,
	});
	Some(ret)
	}

	pub fn load_attrs(cx: &DocContext, did: DefId) -> clean::Attributes {
	cx.tcx.get_attrs(did).clean(cx)
	}

	/// Record an external fully qualified name in the external_paths cache.
	///
	/// These names are used later on by HTML rendering to generate things like
	/// source links back to the original item.
	pub fn record_extern_fqn(cx: &DocContext, did: DefId, kind: clean::TypeKind) {
	if did.is_local() {
	debug!("record_extern_fqn(did={:?}, kind+{:?}): def_id is local, aborting", did, kind);
	return;
	}

	let crate_name = cx.tcx.crate_name(did.krate).to_string();
	let relative = cx.tcx.def_path(did).data.into_iter().filter_map(\|elem\| {
	// extern blocks have an empty name
	let s = elem.data.to_string();
	if !s.is_empty() {
	Some(s)
	} else {
	None
	}
	});
	let fqn = if let clean::TypeKind::Macro = kind {
	vec![crate_name, relative.last().unwrap()]
	} else {
	once(crate_name).chain(relative).collect()
	};
	cx.renderinfo.borrow_mut().external_paths.insert(did, (fqn, kind));
	}

	pub fn build_external_trait(cx: &DocContext, did: DefId) -> clean::Trait {
	let auto_trait = cx.tcx.trait_def(did).has_auto_impl;
	let trait_items = cx.tcx.associated_items(did).map(\|item\| item.clean(cx)).collect();
	let predicates = cx.tcx.predicates_of(did);
	let generics = (cx.tcx.generics_of(did), &predicates).clean(cx);
	let generics = filter_non_trait_generics(did, generics);
	let (generics, supertrait_bounds) = separate_supertrait_bounds(generics);
	let is_spotlight = load_attrs(cx, did).has_doc_flag("spotlight");
	let is_auto = cx.tcx.trait_is_auto(did);
	clean::Trait {
	auto: auto_trait,
	unsafety: cx.tcx.trait_def(did).unsafety,
	generics,
	items: trait_items,
	bounds: supertrait_bounds,
	is_spotlight,
	is_auto,
	}
	}

	fn build_external_function(cx: &DocContext, did: DefId) -> clean::Function {
	let sig = cx.tcx.fn_sig(did);

	let constness = if cx.tcx.is_const_fn(did) {
	hir::Constness::Const
	} else {
	hir::Constness::NotConst
	};

	let predicates = cx.tcx.predicates_of(did);
	clean::Function {
	decl: (did, sig).clean(cx),
	generics: (cx.tcx.generics_of(did), &predicates).clean(cx),
	unsafety: sig.unsafety(),
	constness,
	abi: sig.abi(),
	}
	}

	fn build_enum(cx: &DocContext, did: DefId) -> clean::Enum {
	let predicates = cx.tcx.predicates_of(did);

	clean::Enum {
	generics: (cx.tcx.generics_of(did), &predicates).clean(cx),
	variants_stripped: false,
	variants: cx.tcx.adt_def(did).variants.clean(cx),
	}
	}

	fn build_struct(cx: &DocContext, did: DefId) -> clean::Struct {
	let predicates = cx.tcx.predicates_of(did);
	let variant = cx.tcx.adt_def(did).non_enum_variant();

	clean::Struct {
	struct_type: match variant.ctor_kind {
	CtorKind::Fictive => doctree::Plain,
	CtorKind::Fn => doctree::Tuple,
	CtorKind::Const => doctree::Unit,
	},
	generics: (cx.tcx.generics_of(did), &predicates).clean(cx),
	fields: variant.fields.clean(cx),
	fields_stripped: false,
	}
	}

	fn build_union(cx: &DocContext, did: DefId) -> clean::Union {
	let predicates = cx.tcx.predicates_of(did);
	let variant = cx.tcx.adt_def(did).non_enum_variant();

	clean::Union {
	struct_type: doctree::Plain,
	generics: (cx.tcx.generics_of(did), &predicates).clean(cx),
	fields: variant.fields.clean(cx),
	fields_stripped: false,
	}
	}

	fn build_type_alias(cx: &DocContext, did: DefId) -> clean::Typedef {
	let predicates = cx.tcx.predicates_of(did);

	clean::Typedef {
	type_: cx.tcx.type_of(did).clean(cx),
	generics: (cx.tcx.generics_of(did), &predicates).clean(cx),
	}
	}

	pub fn build_impls(cx: &DocContext, did: DefId, auto_traits: bool) -> Vec<clean::Item> {
	let tcx = cx.tcx;
	let mut impls = Vec::new();

	for &did in tcx.inherent_impls(did).iter() {
	build_impl(cx, did, &mut impls);
	}

	if auto_traits {
	let auto_impls = get_auto_traits_with_def_id(cx, did);
	let mut renderinfo = cx.renderinfo.borrow_mut();

	let new_impls: Vec<clean::Item> = auto_impls.into_iter()
	.filter(\|i\| renderinfo.inlined.insert(i.def_id)).collect();

	impls.extend(new_impls);
	}

	// If this is the first time we've inlined something from another crate, then
	// we inline all impls from all the crates into this crate. Note that there's
	// currently no way for us to filter this based on type, and we likely need
	// many impls for a variety of reasons.
	//
	// Primarily, the impls will be used to populate the documentation for this
	// type being inlined, but impls can also be used when generating
	// documentation for primitives (no way to find those specifically).
	if cx.populated_all_crate_impls.get() {
	return impls;
	}

	cx.populated_all_crate_impls.set(true);

	for &cnum in tcx.crates().iter() {
	for did in tcx.all_trait_implementations(cnum).iter() {
	build_impl(cx, *did, &mut impls);
	}
	}

	// Also try to inline primitive impls from other crates.
	let lang_items = tcx.lang_items();
	let primitive_impls = [
	lang_items.isize_impl(),
	lang_items.i8_impl(),
	lang_items.i16_impl(),
	lang_items.i32_impl(),
	lang_items.i64_impl(),
	lang_items.i128_impl(),
	lang_items.usize_impl(),
	lang_items.u8_impl(),
	lang_items.u16_impl(),
	lang_items.u32_impl(),
	lang_items.u64_impl(),
	lang_items.u128_impl(),
	lang_items.f32_impl(),
	lang_items.f64_impl(),
	lang_items.char_impl(),
	lang_items.str_impl(),
	lang_items.slice_impl(),
	lang_items.slice_u8_impl(),
	lang_items.const_ptr_impl(),
	lang_items.mut_ptr_impl(),
	];

	for def_id in primitive_impls.iter().filter_map(\|&def_id\| def_id) {
	if !def_id.is_local() {
	build_impl(cx, def_id, &mut impls);
	}
	}

	impls
	}

	pub fn build_impl(cx: &DocContext, did: DefId, ret: &mut Vec<clean::Item>) {
	if !cx.renderinfo.borrow_mut().inlined.insert(did) {
	return
	}

	let attrs = load_attrs(cx, did);
	let tcx = cx.tcx;
	let associated_trait = tcx.impl_trait_ref(did);

	// Only inline impl if the implemented trait is
	// reachable in rustdoc generated documentation
	if let Some(traitref) = associated_trait {
	if !cx.access_levels.borrow().is_doc_reachable(traitref.def_id) {
	return
	}
	}

	let for_ = tcx.type_of(did).clean(cx);

	// Only inline impl if the implementing type is
	// reachable in rustdoc generated documentation
	if let Some(did) = for_.def_id() {
	if !cx.access_levels.borrow().is_doc_reachable(did) {
	return
	}
	}

	let predicates = tcx.predicates_of(did);
	let trait_items = tcx.associated_items(did).filter_map(\|item\| {
	if associated_trait.is_some() \|\| item.vis == ty::Visibility::Public {
	Some(item.clean(cx))
	} else {
	None
	}
	}).collect::<Vec<_>>();
	let polarity = tcx.impl_polarity(did);
	let trait_ = associated_trait.clean(cx).map(\|bound\| {
	match bound {
	clean::TraitBound(polyt, _) => polyt.trait_,
	clean::RegionBound(..) => unreachable!(),
	}
	});
	if trait_.def_id() == tcx.lang_items().deref_trait() {
	super::build_deref_target_impls(cx, &trait_items, ret);
	}
	if let Some(trait_did) = trait_.def_id() {
	record_extern_trait(cx, trait_did);
	}

	let provided = trait_.def_id().map(\|did\| {
	tcx.provided_trait_methods(did)
	.into_iter()
	.map(\|meth\| meth.name.to_string())
	.collect()
	}).unwrap_or(FxHashSet());

	ret.push(clean::Item {
	inner: clean::ImplItem(clean::Impl {
	unsafety: hir::Unsafety::Normal,
	generics: (tcx.generics_of(did), &predicates).clean(cx),
	provided_trait_methods: provided,
	trait_,
	for_,
	items: trait_items,
	polarity: Some(polarity.clean(cx)),
	synthetic: false,
	}),
	source: tcx.def_span(did).clean(cx),
	name: None,
	attrs,
	visibility: Some(clean::Inherited),
	stability: tcx.lookup_stability(did).clean(cx),
	deprecation: tcx.lookup_deprecation(did).clean(cx),
	def_id: did,
	});
	}

	fn build_module(cx: &DocContext, did: DefId) -> clean::Module {
	let mut items = Vec::new();
	fill_in(cx, did, &mut items);
	return clean::Module {
	items,
	is_crate: false,
	};

	fn fill_in(cx: &DocContext, did: DefId, items: &mut Vec<clean::Item>) {
	// If we're re-exporting a re-export it may actually re-export something in
	// two namespaces, so the target may be listed twice. Make sure we only
	// visit each node at most once.
	let mut visited = FxHashSet();
	for &item in cx.tcx.item_children(did).iter() {
	let def_id = item.def.def_id();
	if item.vis == ty::Visibility::Public {
	if !visited.insert(def_id) { continue }
	if let Some(i) = try_inline(cx, item.def, item.ident.name) {
	items.extend(i)
	}
	}
	}
	}
	}

	pub fn print_inlined_const(cx: &DocContext, did: DefId) -> String {
	cx.tcx.rendered_const(did)
	}

	fn build_const(cx: &DocContext, did: DefId) -> clean::Constant {
	clean::Constant {
	type_: cx.tcx.type_of(did).clean(cx),
	expr: print_inlined_const(cx, did)
	}
	}

	fn build_static(cx: &DocContext, did: DefId, mutable: bool) -> clean::Static {
	clean::Static {
	type_: cx.tcx.type_of(did).clean(cx),
	mutability: if mutable {clean::Mutable} else {clean::Immutable},
	expr: "\n\n\n".to_string(), // trigger the "[definition]" links
	}
	}

	/// A trait's generics clause actually contains all of the predicates for all of
	/// its associated types as well. We specifically move these clauses to the
	/// associated types instead when displaying, so when we're generating the
	/// generics for the trait itself we need to be sure to remove them.
	/// We also need to remove the implied "recursive" Self: Trait bound.
	///
	/// The inverse of this filtering logic can be found in the `Clean`
	/// implementation for `AssociatedType`
	fn filter_non_trait_generics(trait_did: DefId, mut g: clean::Generics) -> clean::Generics {
	for pred in &mut g.where_predicates {
	match *pred {
	clean::WherePredicate::BoundPredicate {
	ty: clean::Generic(ref s),
	ref mut bounds
	} if *s == "Self" => {
	bounds.retain(\|bound\| {
	match *bound {
	clean::TyParamBound::TraitBound(clean::PolyTrait {
	trait_: clean::ResolvedPath { did, .. },
	..
	}, _) => did != trait_did,
	_ => true
	}
	});
	}
	_ => {}
	}
	}

	g.where_predicates.retain(\|pred\| {
	match *pred {
	clean::WherePredicate::BoundPredicate {
	ty: clean::QPath {
	self_type: box clean::Generic(ref s),
	trait_: box clean::ResolvedPath { did, .. },
	name: ref _name,
	}, ref bounds
	} => !(*s == "Self" && did == trait_did) && !bounds.is_empty(),
	_ => true,
	}
	});
	g
	}

	/// Supertrait bounds for a trait are also listed in the generics coming from
	/// the metadata for a crate, so we want to separate those out and create a new
	/// list of explicit supertrait bounds to render nicely.
	fn separate_supertrait_bounds(mut g: clean::Generics)
	-> (clean::Generics, Vec<clean::TyParamBound>) {
	let mut ty_bounds = Vec::new();
	g.where_predicates.retain(\|pred\| {
	match *pred {
	clean::WherePredicate::BoundPredicate {
	ty: clean::Generic(ref s),
	ref bounds
	} if *s == "Self" => {
	ty_bounds.extend(bounds.iter().cloned());
	false
	}
	_ => true,
	}
	});
	(g, ty_bounds)
	}

	pub fn record_extern_trait(cx: &DocContext, did: DefId) {
	if cx.external_traits.borrow().contains_key(&did) \|\|
	cx.active_extern_traits.borrow().contains(&did)
	{
	return;
	}

	cx.active_extern_traits.borrow_mut().push(did);

	let trait_ = build_external_trait(cx, did);

	cx.external_traits.borrow_mut().insert(did, trait_);
	cx.active_extern_traits.borrow_mut().remove_item(&did);
	}