Auto merge of rust-lang#33002 - mitaa:rdoc-cross-impls, r=alexcrichton

rustdoc: refine cross-crate impl inlining

This changes the current rule that impls within `doc(hidden)` modules aren't inlined, to only inlining impls where the implemented trait and type are reachable in documentation.

fixes rust-lang#14586
fixes rust-lang#31948

.. and also applies the reachability checking to cross-crate links.

fixes rust-lang#28480

r? @alexcrichton

Author: bors

src/librustc/middle/cstore.rs

@@ -113,6 +113,7 @@ pub enum InlinedItemRef<'a> {
 /// LOCAL_CRATE in their DefId.
 pub const LOCAL_CRATE: ast::CrateNum = 0;
 
+#[derive(Copy, Clone)]
 pub struct ChildItem {
     pub def: DefLike,
     pub name: ast::Name,

src/librustc/middle/privacy.rs

@@ -15,10 +15,11 @@
 use util::nodemap::{DefIdSet, FnvHashMap};
 
 use std::hash::Hash;
+use std::fmt;
 use syntax::ast::NodeId;
 
 // Accessibility levels, sorted in ascending order
-#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord)]
 pub enum AccessLevel {
     // Exported items + items participating in various kinds of public interfaces,
     // but not directly nameable. For example, if function `fn f() -> T {...}` is
@@ -56,6 +57,12 @@ impl<Id: Hash + Eq> Default for AccessLevels<Id> {
     }
 }
 
+impl<Id: Hash + Eq + fmt::Debug> fmt::Debug for AccessLevels<Id> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        fmt::Debug::fmt(&self.map, f)
+    }
+}
+
 /// A set containing all exported definitions from external crates.
 /// The set does not contain any entries from local crates.
 pub type ExternalExports = DefIdSet;

src/librustdoc/clean/inline.rs

@@ -26,9 +26,9 @@ use rustc::middle::stability;
 
 use rustc_const_eval::lookup_const_by_id;
 
-use core::DocContext;
+use core::{DocContext, DocAccessLevels};
 use doctree;
-use clean::{self, Attributes, GetDefId};
+use clean::{self, GetDefId};
 
 use super::{Clean, ToSource};
 
@@ -116,7 +116,7 @@ fn try_inline_def(cx: &DocContext, tcx: &TyCtxt,
         }
         _ => return None,
     };
-    cx.inlined.borrow_mut().as_mut().unwrap().insert(did);
+    cx.renderinfo.borrow_mut().inlined.insert(did);
     ret.push(clean::Item {
         source: clean::Span::empty(),
         name: Some(tcx.item_name(did).to_string()),
@@ -146,7 +146,7 @@ pub fn record_extern_fqn(cx: &DocContext, did: DefId, kind: clean::TypeKind) {
             elem.data.to_string()
         });
         let fqn = once(crate_name).chain(relative).collect();
-        cx.external_paths.borrow_mut().as_mut().unwrap().insert(did, (fqn, kind));
+        cx.renderinfo.borrow_mut().external_paths.insert(did, (fqn, kind));
     }
 }
 
@@ -260,11 +260,6 @@ pub fn build_impls(cx: &DocContext,
             match def {
                 cstore::DlImpl(did) => build_impl(cx, tcx, did, impls),
                 cstore::DlDef(Def::Mod(did)) => {
-                    // Don't recurse if this is a #[doc(hidden)] module
-                    if load_attrs(cx, tcx, did).list("doc").has_word("hidden") {
-                        return;
-                    }
-
                     for item in tcx.sess.cstore.item_children(did) {
                         populate_impls(cx, tcx, item.def, impls)
                     }
@@ -295,16 +290,17 @@ pub fn build_impl(cx: &DocContext,
                   tcx: &TyCtxt,
                   did: DefId,
                   ret: &mut Vec<clean::Item>) {
-    if !cx.inlined.borrow_mut().as_mut().unwrap().insert(did) {
+    if !cx.renderinfo.borrow_mut().inlined.insert(did) {
         return
     }
 
     let attrs = load_attrs(cx, tcx, did);
     let associated_trait = tcx.impl_trait_ref(did);
-    if let Some(ref t) = associated_trait {
-        // If this is an impl for a #[doc(hidden)] trait, be sure to not inline
-        let trait_attrs = load_attrs(cx, tcx, t.def_id);
-        if trait_attrs.list("doc").has_word("hidden") {
+
+    // 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
         }
     }
@@ -330,6 +326,17 @@ pub fn build_impl(cx: &DocContext,
         });
     }
 
+    let ty = tcx.lookup_item_type(did);
+    let for_ = ty.ty.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.lookup_predicates(did);
     let trait_items = tcx.sess.cstore.impl_items(did)
             .iter()
@@ -412,7 +419,6 @@ pub fn build_impl(cx: &DocContext,
         }
     }).collect::<Vec<_>>();
     let polarity = tcx.trait_impl_polarity(did);
-    let ty = tcx.lookup_item_type(did);
     let trait_ = associated_trait.clean(cx).map(|bound| {
         match bound {
             clean::TraitBound(polyt, _) => polyt.trait_,
@@ -436,7 +442,7 @@ pub fn build_impl(cx: &DocContext,
             derived: clean::detect_derived(&attrs),
             provided_trait_methods: provided,
             trait_: trait_,
-            for_: ty.ty.clean(cx),
+            for_: for_,
             generics: (&ty.generics, &predicates, subst::TypeSpace).clean(cx),
             items: trait_items,
             polarity: polarity.map(|p| { p.clean(cx) }),

src/librustdoc/clean/mod.rs

@@ -36,6 +36,7 @@ use syntax::ptr::P;
 
 use rustc_trans::back::link;
 use rustc::middle::cstore::{self, CrateStore};
+use rustc::middle::privacy::AccessLevels;
 use rustc::hir::def::Def;
 use rustc::hir::def_id::{DefId, DefIndex};
 use rustc::ty::subst::{self, ParamSpace, VecPerParamSpace};
@@ -47,15 +48,17 @@ use rustc::hir;
 use std::collections::{HashMap, HashSet};
 use std::path::PathBuf;
 use std::rc::Rc;
+use std::sync::Arc;
 use std::u32;
 use std::env::current_dir;
+use std::mem;
 
 use core::DocContext;
 use doctree;
 use visit_ast;
 use html::item_type::ItemType;
 
-mod inline;
+pub mod inline;
 mod simplify;
 
 // extract the stability index for a node from tcx, if possible
@@ -113,13 +116,16 @@ impl<T: Clean<U>, U> Clean<Vec<U>> for P<[T]> {
     }
 }
 
-#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
+#[derive(Clone, Debug)]
 pub struct Crate {
     pub name: String,
     pub src: PathBuf,
     pub module: Option<Item>,
     pub externs: Vec<(ast::CrateNum, ExternalCrate)>,
     pub primitives: Vec<PrimitiveType>,
+    pub access_levels: Arc<AccessLevels<DefId>>,
+    // These are later on moved into `CACHEKEY`, leaving the map empty.
+    // Only here so that they can be filtered through the rustdoc passes.
     pub external_traits: HashMap<DefId, Trait>,
 }
 
@@ -128,14 +134,20 @@ struct CrateNum(ast::CrateNum);
 impl<'a, 'tcx> Clean<Crate> for visit_ast::RustdocVisitor<'a, 'tcx> {
     fn clean(&self, cx: &DocContext) -> Crate {
         use rustc::session::config::Input;
+        use ::visit_lib::LibEmbargoVisitor;
 
         if let Some(t) = cx.tcx_opt() {
             cx.deref_trait_did.set(t.lang_items.deref_trait());
+            cx.renderinfo.borrow_mut().deref_trait_did = cx.deref_trait_did.get();
         }
 
         let mut externs = Vec::new();
         for cnum in cx.sess().cstore.crates() {
             externs.push((cnum, CrateNum(cnum).clean(cx)));
+            if cx.tcx_opt().is_some() {
+                // Analyze doc-reachability for extern items
+                LibEmbargoVisitor::new(cx).visit_lib(cnum);
+            }
         }
         externs.sort_by(|&(a, _), &(b, _)| a.cmp(&b));
 
@@ -205,14 +217,17 @@ impl<'a, 'tcx> Clean<Crate> for visit_ast::RustdocVisitor<'a, 'tcx> {
             Input::Str { ref name, .. } => PathBuf::from(name.clone()),
         };
 
+        let mut access_levels = cx.access_levels.borrow_mut();
+        let mut external_traits = cx.external_traits.borrow_mut();
+
         Crate {
             name: name.to_string(),
             src: src,
             module: Some(module),
             externs: externs,
             primitives: primitives,
-            external_traits: cx.external_traits.borrow_mut().take()
-                               .unwrap_or(HashMap::new()),
+            access_levels: Arc::new(mem::replace(&mut access_levels, Default::default())),
+            external_traits: mem::replace(&mut external_traits, Default::default()),
         }
     }
 }
@@ -541,8 +556,7 @@ impl Clean<TyParam> for hir::TyParam {
 
 impl<'tcx> Clean<TyParam> for ty::TypeParameterDef<'tcx> {
     fn clean(&self, cx: &DocContext) -> TyParam {
-        cx.external_typarams.borrow_mut().as_mut().unwrap()
-          .insert(self.def_id, self.name.clean(cx));
+        cx.renderinfo.borrow_mut().external_typarams.insert(self.def_id, self.name.clean(cx));
         TyParam {
             name: self.name.clean(cx),
             did: self.def_id,
@@ -2685,7 +2699,7 @@ fn register_def(cx: &DocContext, def: Def) -> DefId {
     inline::record_extern_fqn(cx, did, kind);
     if let TypeTrait = kind {
         let t = inline::build_external_trait(cx, tcx, did);
-        cx.external_traits.borrow_mut().as_mut().unwrap().insert(did, t);
+        cx.external_traits.borrow_mut().insert(did, t);
     }
     did
 }

src/librustdoc/core.rs

@@ -29,12 +29,13 @@ use syntax::feature_gate::UnstableFeatures;
 use syntax::parse::token;
 
 use std::cell::{RefCell, Cell};
-use std::collections::{HashMap, HashSet};
+use std::collections::HashMap;
 use std::rc::Rc;
 
 use visit_ast::RustdocVisitor;
 use clean;
 use clean::Clean;
+use html::render::RenderInfo;
 
 pub use rustc::session::config::Input;
 pub use rustc::session::search_paths::SearchPaths;
@@ -45,19 +46,24 @@ pub enum MaybeTyped<'a, 'tcx: 'a> {
     NotTyped(&'a session::Session)
 }
 
-pub type ExternalPaths = RefCell<Option<HashMap<DefId,
-                                                (Vec<String>, clean::TypeKind)>>>;
+pub type Externs = HashMap<String, Vec<String>>;
+pub type ExternalPaths = HashMap<DefId, (Vec<String>, clean::TypeKind)>;
 
 pub struct DocContext<'a, 'tcx: 'a> {
     pub map: &'a hir_map::Map<'tcx>,
     pub maybe_typed: MaybeTyped<'a, 'tcx>,
     pub input: Input,
-    pub external_paths: ExternalPaths,
-    pub external_traits: RefCell<Option<HashMap<DefId, clean::Trait>>>,
-    pub external_typarams: RefCell<Option<HashMap<DefId, String>>>,
-    pub inlined: RefCell<Option<HashSet<DefId>>>,
     pub all_crate_impls: RefCell<HashMap<ast::CrateNum, Vec<clean::Item>>>,
     pub deref_trait_did: Cell<Option<DefId>>,
+    // Note that external items for which `doc(hidden)` applies to are shown as
+    // non-reachable while local items aren't. This is because we're reusing
+    // the access levels from crateanalysis.
+    /// Later on moved into `clean::Crate`
+    pub access_levels: RefCell<AccessLevels<DefId>>,
+    /// Later on moved into `html::render::CACHE_KEY`
+    pub renderinfo: RefCell<RenderInfo>,
+    /// Later on moved through `clean::Crate` into `html::render::CACHE_KEY`
+    pub external_traits: RefCell<HashMap<DefId, clean::Trait>>,
 }
 
 impl<'b, 'tcx> DocContext<'b, 'tcx> {
@@ -81,20 +87,23 @@ impl<'b, 'tcx> DocContext<'b, 'tcx> {
     }
 }
 
-pub struct CrateAnalysis {
-    pub access_levels: AccessLevels<DefId>,
-    pub external_paths: ExternalPaths,
-    pub external_typarams: RefCell<Option<HashMap<DefId, String>>>,
-    pub inlined: RefCell<Option<HashSet<DefId>>>,
-    pub deref_trait_did: Option<DefId>,
+pub trait DocAccessLevels {
+    fn is_doc_reachable(&self, DefId) -> bool;
 }
 
-pub type Externs = HashMap<String, Vec<String>>;
+impl DocAccessLevels for AccessLevels<DefId> {
+    fn is_doc_reachable(&self, did: DefId) -> bool {
+        self.is_public(did)
+    }
+}
 
-pub fn run_core(search_paths: SearchPaths, cfgs: Vec<String>, externs: Externs,
-                input: Input, triple: Option<String>)
-                -> (clean::Crate, CrateAnalysis) {
 
+pub fn run_core(search_paths: SearchPaths,
+                cfgs: Vec<String>,
+                externs: Externs,
+                input: Input,
+                triple: Option<String>) -> (clean::Crate, RenderInfo)
+{
     // Parse, resolve, and typecheck the given crate.
 
     let cpath = match input {
@@ -148,7 +157,7 @@ pub fn run_core(search_paths: SearchPaths, cfgs: Vec<String>, externs: Externs,
     let arenas = ty::CtxtArenas::new();
     let hir_map = driver::make_map(&sess, &mut hir_forest);
 
-    let krate_and_analysis = abort_on_err(driver::phase_3_run_analysis_passes(&sess,
+    abort_on_err(driver::phase_3_run_analysis_passes(&sess,
                                                      &cstore,
                                                      hir_map,
                                                      &arenas,
@@ -175,42 +184,20 @@ pub fn run_core(search_paths: SearchPaths, cfgs: Vec<String>, externs: Externs,
             map: &tcx.map,
             maybe_typed: Typed(tcx),
             input: input,
-            external_traits: RefCell::new(Some(HashMap::new())),
-            external_typarams: RefCell::new(Some(HashMap::new())),
-            external_paths: RefCell::new(Some(HashMap::new())),
-            inlined: RefCell::new(Some(HashSet::new())),
             all_crate_impls: RefCell::new(HashMap::new()),
             deref_trait_did: Cell::new(None),
+            access_levels: RefCell::new(access_levels),
+            external_traits: RefCell::new(HashMap::new()),
+            renderinfo: RefCell::new(Default::default()),
         };
         debug!("crate: {:?}", ctxt.map.krate());
 
-        let mut analysis = CrateAnalysis {
-            access_levels: access_levels,
-            external_paths: RefCell::new(None),
-            external_typarams: RefCell::new(None),
-            inlined: RefCell::new(None),
-            deref_trait_did: None,
-        };
-
         let krate = {
-            let mut v = RustdocVisitor::new(&ctxt, Some(&analysis));
+            let mut v = RustdocVisitor::new(&ctxt);
             v.visit(ctxt.map.krate());
             v.clean(&ctxt)
         };
 
-        let external_paths = ctxt.external_paths.borrow_mut().take();
-        *analysis.external_paths.borrow_mut() = external_paths;
-
-        let map = ctxt.external_typarams.borrow_mut().take();
-        *analysis.external_typarams.borrow_mut() = map;
-
-        let map = ctxt.inlined.borrow_mut().take();
-        *analysis.inlined.borrow_mut() = map;
-
-        analysis.deref_trait_did = ctxt.deref_trait_did.get();
-
-        Some((krate, analysis))
-    }), &sess);
-
-    krate_and_analysis.unwrap()
+        Some((krate, ctxt.renderinfo.into_inner()))
+    }), &sess).unwrap()
 }

src/librustdoc/html/format.rs

@@ -24,6 +24,7 @@ use syntax::abi::Abi;
 use rustc::hir;
 
 use clean;
+use core::DocAccessLevels;
 use html::item_type::ItemType;
 use html::render;
 use html::render::{cache, CURRENT_LOCATION_KEY};
@@ -298,6 +299,9 @@ pub fn href(did: DefId) -> Option<(String, ItemType, Vec<String>)> {
     let mut url = if did.is_local() || cache.inlined.contains(&did) {
         repeat("../").take(loc.len()).collect::<String>()
     } else {
+        if !cache.access_levels.is_doc_reachable(did) {
+            return None
+        }
         match cache.extern_locations[&did.krate] {
             (_, render::Remote(ref s)) => s.to_string(),
             (_, render::Local) => repeat("../").take(loc.len()).collect(),