Auto merge of #67202 - JohnTitor:rollup-0xjm5pz, r=JohnTitor

Rollup of 9 pull requests

Successful merges:

 - #66377 (Update RELEASES.md for 1.40.0)
 - #67134 (Ensure that we get a hard error on generic ZST constants if their bod…)
 - #67152 (Sort auto trait and blanket implementations display)
 - #67154 (Fix typos in src/libcore/alloc.rs docs)
 - #67168 (corrected comment in E0478)
 - #67178 (Move non clean impls items)
 - #67180 (doc: Use .copied() instead of .cloned() in Vec example)
 - #67181 (Update hashmap doc)
 - #67193 (In which we start tracking polonius in `-Z self-profile`)

Failed merges:

r? @ghost

RELEASES.md

@@ -1,3 +1,140 @@
+Version 1.40.0 (2019-12-19)
+===========================
+
+Language
+--------
+- [You can now use tuple `struct`s and tuple `enum` variant's constructors in
+  `const` contexts.][65188] e.g.
+
+  ```rust
+  pub struct Point(i32, i32);
+
+  const ORIGIN: Point = {
+      let constructor = Point;
+
+      constructor(0, 0)
+  };
+  ```
+
+- [You can now mark `struct`s, `enum`s, and `enum` variants with the `#[non_exhaustive]` attribute to
+  indicate that there may be variants or fields added in the future.][64639]
+  For example this requires adding a wild-card branch (`_ => {}`) to any match
+  statements on a non-exhaustive `enum`. [(RFC 2008)]
+- [You can now use function-like procedural macros in `extern` blocks and in
+  type positions.][63931] e.g. `type Generated = macro!();`
+- [Function-like and attribute procedural macros can now emit
+  `macro_rules!` items, so you can now have your macros generate macros.][64035]
+- [The `meta` pattern matcher in `macro_rules!` now correctly matches the modern
+  attribute syntax.][63674] For example `(#[$m:meta])` now matches `#[attr]`,
+  `#[attr{tokens}]`, `#[attr[tokens]]`, and `#[attr(tokens)]`.
+
+Compiler
+--------
+- [Added tier 3 support\* for the
+  `thumbv7neon-unknown-linux-musleabihf` target.][66103]
+- [Added tier 3 support for the
+  `aarch64-unknown-none-softfloat` target.][64589]
+- [Added tier 3 support for the `mips64-unknown-linux-muslabi64`, and
+  `mips64el-unknown-linux-muslabi64` targets.][65843]
+
+\* Refer to Rust's [platform support page][forge-platform-support] for more
+  information on Rust's tiered platform support.
+
+Libraries
+---------
+- [The `is_power_of_two` method on unsigned numeric types is now a `const` function.][65092]
+
+Stabilized APIs
+---------------
+- [`BTreeMap::get_key_value`]
+- [`HashMap::get_key_value`]
+- [`Option::as_deref_mut`]
+- [`Option::as_deref`]
+- [`Option::flatten`]
+- [`UdpSocket::peer_addr`]
+- [`f32::to_be_bytes`]
+- [`f32::to_le_bytes`]
+- [`f32::to_ne_bytes`]
+- [`f64::to_be_bytes`]
+- [`f64::to_le_bytes`]
+- [`f64::to_ne_bytes`]
+- [`f32::from_be_bytes`]
+- [`f32::from_le_bytes`]
+- [`f32::from_ne_bytes`]
+- [`f64::from_be_bytes`]
+- [`f64::from_le_bytes`]
+- [`f64::from_ne_bytes`]
+- [`mem::take`]
+- [`slice::repeat`]
+- [`todo!`]
+
+Cargo
+-----
+- [Cargo will now always display warnings, rather than only on
+  fresh builds.][cargo/7450]
+- [Feature flags (except `--all-features`) passed to a virtual workspace will
+  now produce an error.][cargo/7507] Previously these flags were ignored.
+- [You can now publish `dev-dependencies` without including
+  a `version`.][cargo/7333]
+
+Misc
+----
+- [You can now specify the `#[cfg(doctest)]` attribute to include an item only
+  when running documentation tests with `rustdoc`.][63803]
+
+Compatibility Notes
+-------------------
+- [As previously announced, any previous NLL warnings in the 2015 edition are
+  now hard errors.][64221]
+- [The `include!` macro will now warn if it failed to include the
+  entire file.][64284] The `include!` macro unintentionally only includes the
+  first _expression_ in a file, and this can be unintuitive. This will become
+  either a hard error in a future release, or the behavior may be fixed to include all expressions as expected.
+- [Using `#[inline]` on function prototypes and consts now emits a warning under
+  `unused_attribute` lint.][65294] Using `#[inline]` anywhere else inside traits
+  or `extern` blocks now correctly emits a hard error.
+  
+[65294]: https://github.com/rust-lang/rust/pull/65294/
+[66103]: https://github.com/rust-lang/rust/pull/66103/
+[65843]: https://github.com/rust-lang/rust/pull/65843/
+[65188]: https://github.com/rust-lang/rust/pull/65188/
+[65092]: https://github.com/rust-lang/rust/pull/65092/
+[64589]: https://github.com/rust-lang/rust/pull/64589/
+[64639]: https://github.com/rust-lang/rust/pull/64639/
+[64221]: https://github.com/rust-lang/rust/pull/64221/
+[64284]: https://github.com/rust-lang/rust/pull/64284/
+[63931]: https://github.com/rust-lang/rust/pull/63931/
+[64035]: https://github.com/rust-lang/rust/pull/64035/
+[63674]: https://github.com/rust-lang/rust/pull/63674/
+[63803]: https://github.com/rust-lang/rust/pull/63803/
+[cargo/7450]: https://github.com/rust-lang/cargo/pull/7450/
+[cargo/7507]: https://github.com/rust-lang/cargo/pull/7507/
+[cargo/7525]: https://github.com/rust-lang/cargo/pull/7525/
+[cargo/7333]: https://github.com/rust-lang/cargo/pull/7333/
+[(rfc 2008)]: https://rust-lang.github.io/rfcs/2008-non-exhaustive.html
+[`f32::to_be_bytes`]: https://doc.rust-lang.org/std/primitive.f32.html#method.to_be_bytes
+[`f32::to_le_bytes`]: https://doc.rust-lang.org/std/primitive.f32.html#method.to_le_bytes
+[`f32::to_ne_bytes`]: https://doc.rust-lang.org/std/primitive.f32.html#method.to_ne_bytes
+[`f64::to_be_bytes`]: https://doc.rust-lang.org/std/primitive.f64.html#method.to_be_bytes
+[`f64::to_le_bytes`]: https://doc.rust-lang.org/std/primitive.f64.html#method.to_le_bytes
+[`f64::to_ne_bytes`]: https://doc.rust-lang.org/std/primitive.f64.html#method.to_ne_bytes
+[`f32::from_be_bytes`]: https://doc.rust-lang.org/std/primitive.f32.html#method.from_be_bytes
+[`f32::from_le_bytes`]: https://doc.rust-lang.org/std/primitive.f32.html#method.from_le_bytes
+[`f32::from_ne_bytes`]: https://doc.rust-lang.org/std/primitive.f32.html#method.from_ne_bytes
+[`f64::from_be_bytes`]: https://doc.rust-lang.org/std/primitive.f64.html#method.from_be_bytes
+[`f64::from_le_bytes`]: https://doc.rust-lang.org/std/primitive.f64.html#method.from_le_bytes
+[`f64::from_ne_bytes`]: https://doc.rust-lang.org/std/primitive.f64.html#method.from_ne_bytes
+[`option::flatten`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.flatten
+[`option::as_deref`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.as_deref
+[`option::as_deref_mut`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.as_deref_mut
+[`hashmap::get_key_value`]: https://doc.rust-lang.org/std/collections/struct.HashMap.html#method.get_key_value
+[`btreemap::get_key_value`]: https://doc.rust-lang.org/std/collections/struct.BTreeMap.html#method.get_key_value
+[`slice::repeat`]: https://doc.rust-lang.org/std/primitive.slice.html#method.repeat
+[`mem::take`]: https://doc.rust-lang.org/std/mem/fn.take.html
+[`udpsocket::peer_addr`]: https://doc.rust-lang.org/std/net/struct.UdpSocket.html#method.peer_addr
+[`todo!`]: https://doc.rust-lang.org/std/macro.todo.html
+
+
 Version 1.39.0 (2019-11-07)
 ===========================
 

src/liballoc/vec.rs

@@ -92,7 +92,7 @@ use crate::raw_vec::RawVec;
 /// vec[0] = 7;
 /// assert_eq!(vec[0], 7);
 ///
-/// vec.extend([1, 2, 3].iter().cloned());
+/// vec.extend([1, 2, 3].iter().copied());
 ///
 /// for x in &vec {
 ///     println!("{}", x);

src/libcore/alloc.rs

@@ -253,7 +253,7 @@ impl Layout {
 
     /// Creates a layout describing the record for `self` followed by
     /// `next`, including any necessary padding to ensure that `next`
-    /// will be properly aligned. Note that the result layout will
+    /// will be properly aligned. Note that the resulting layout will
     /// satisfy the alignment properties of both `self` and `next`.
     ///
     /// The resulting layout will be the same as that of a C struct containing
@@ -387,7 +387,7 @@ impl fmt::Display for CannotReallocInPlace {
 }
 
 /// A memory allocator that can be registered as the standard library’s default
-/// though the `#[global_allocator]` attributes.
+/// through the `#[global_allocator]` attribute.
 ///
 /// Some of the methods require that a memory block be *currently
 /// allocated* via an allocator. This means that:
@@ -458,7 +458,7 @@ pub unsafe trait GlobalAlloc {
     /// # Errors
     ///
     /// Returning a null pointer indicates that either memory is exhausted
-    /// or `layout` does not meet allocator's size or alignment constraints.
+    /// or `layout` does not meet this allocator's size or alignment constraints.
     ///
     /// Implementations are encouraged to return null on memory
     /// exhaustion rather than aborting, but this is not
@@ -1045,7 +1045,7 @@ pub unsafe trait Alloc {
     /// Captures a common usage pattern for allocators.
     ///
     /// The returned block is suitable for passing to the
-    /// `alloc`/`realloc` methods of this allocator.
+    /// `realloc`/`dealloc` methods of this allocator.
     ///
     /// Note to implementors: If this returns `Ok(ptr)`, then `ptr`
     /// must be considered "currently allocated" and must be
@@ -1111,7 +1111,7 @@ pub unsafe trait Alloc {
     /// Captures a common usage pattern for allocators.
     ///
     /// The returned block is suitable for passing to the
-    /// `alloc`/`realloc` methods of this allocator.
+    /// `realloc`/`dealloc` methods of this allocator.
     ///
     /// Note to implementors: If this returns `Ok(ptr)`, then `ptr`
     /// must be considered "currently allocated" and must be
@@ -1158,7 +1158,7 @@ pub unsafe trait Alloc {
     /// Captures a common usage pattern for allocators.
     ///
     /// The returned block is suitable for passing to the
-    /// `alloc`/`realloc` methods of this allocator.
+    /// `realloc`/`dealloc` methods of this allocator.
     ///
     /// # Safety
     ///

src/librustc_codegen_ssa/mir/constant.rs

@@ -16,6 +16,10 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         constant: &mir::Constant<'tcx>,
     ) -> Result<OperandRef<'tcx, Bx::Value>, ErrorHandled> {
         match constant.literal.val {
+            // Special case unevaluated statics, because statics have an identity and thus should
+            // use `get_static` to get at their id.
+            // FIXME(oli-obk): can we unify this somehow, maybe by making const eval of statics
+            // always produce `&STATIC`. This may also simplify how const eval works with statics.
             ty::ConstKind::Unevaluated(def_id, substs)
                 if self.cx.tcx().is_static(def_id) => {
                     assert!(substs.is_empty(), "we don't support generic statics yet");
@@ -46,7 +50,10 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                     instance,
                     promoted: None,
                 };
-                self.cx.tcx().const_eval(ty::ParamEnv::reveal_all().and(cid))
+                self.cx.tcx().const_eval(ty::ParamEnv::reveal_all().and(cid)).map_err(|err| {
+                    self.cx.tcx().sess.span_err(constant.span, "erroneous constant encountered");
+                    err
+                })
             },
             _ => Ok(self.monomorphize(&constant.literal)),
         }

src/librustc_error_codes/error_codes/E0478.md

@@ -21,8 +21,8 @@ this issue, you need to specify it:
 ```
 trait Wedding<'t>: 't { }
 
-struct Prince<'kiss, 'SnowWhite: 'kiss> { // You say here that 'kiss must live
+struct Prince<'kiss, 'SnowWhite: 'kiss> { // You say here that 'SnowWhite
-                                          // longer than 'SnowWhite.
+                                          // must live longer than 'kiss.
     child: Box<Wedding<'kiss> + 'SnowWhite>, // And now it's all good!
 }
 ```

src/librustc_mir/borrow_check/nll/constraint_generation.rs

@@ -97,6 +97,7 @@ impl<'cg, 'cx, 'tcx> Visitor<'tcx> for ConstraintGeneration<'cg, 'cx, 'tcx> {
         location: Location,
     ) {
         if let Some(all_facts) = self.all_facts {
+            let _prof_timer = self.infcx.tcx.prof.generic_activity("polonius_fact_generation");
             all_facts.cfg_edge.push((
                 self.location_table.start_index(location),
                 self.location_table.mid_index(location),
@@ -142,6 +143,7 @@ impl<'cg, 'cx, 'tcx> Visitor<'tcx> for ConstraintGeneration<'cg, 'cx, 'tcx> {
         location: Location,
     ) {
         if let Some(all_facts) = self.all_facts {
+            let _prof_timer = self.infcx.tcx.prof.generic_activity("polonius_fact_generation");
             all_facts.cfg_edge.push((
                 self.location_table.start_index(location),
                 self.location_table.mid_index(location),
@@ -205,6 +207,8 @@ impl<'cx, 'cg, 'tcx> ConstraintGeneration<'cx, 'cg, 'tcx> {
     /// as `killed`. For example, when assigning to a local, or on a call's return destination.
     fn record_killed_borrows_for_place(&mut self, place: &Place<'tcx>, location: Location) {
         if let Some(all_facts) = self.all_facts {
+            let _prof_timer = self.infcx.tcx.prof.generic_activity("polonius_fact_generation");
+
             // Depending on the `Place` we're killing:
             // - if it's a local, or a single deref of a local,
             //   we kill all the borrows on the local.

src/librustc_mir/borrow_check/nll/invalidation.rs

@@ -31,6 +31,7 @@ pub(super) fn generate_invalidates<'tcx>(
     }
 
     if let Some(all_facts) = all_facts {
+        let _prof_timer = tcx.prof.generic_activity("polonius_fact_generation");
         let dominators = body.dominators();
         let mut ig = InvalidationGenerator {
             all_facts,

src/librustc_mir/borrow_check/nll/mod.rs

@@ -201,6 +201,7 @@ pub(in crate::borrow_check) fn compute_regions<'cx, 'tcx>(
     );
 
     if let Some(all_facts) = &mut all_facts {
+        let _prof_timer = infcx.tcx.prof.generic_activity("polonius_fact_generation");
         all_facts
             .universal_region
             .extend(universal_regions.universal_regions());
@@ -302,6 +303,7 @@ pub(in crate::borrow_check) fn compute_regions<'cx, 'tcx>(
                 .unwrap_or_else(|_| String::from("Naive"));
             let algorithm = Algorithm::from_str(&algorithm).unwrap();
             debug!("compute_regions: using polonius algorithm {:?}", algorithm);
+            let _prof_timer = infcx.tcx.prof.generic_activity("polonius_analysis");
             Some(Rc::new(Output::compute(
                 &all_facts,
                 algorithm,

src/librustc_mir/borrow_check/nll/type_check/liveness/polonius.rs

@@ -5,20 +5,19 @@ use crate::util::liveness::{categorize, DefUse};
 use rustc::mir::visit::{MutatingUseContext, PlaceContext, Visitor};
 use rustc::mir::{Local, Location, Place, ReadOnlyBodyAndCache};
 use rustc::ty::subst::GenericArg;
-use rustc::ty::Ty;
 
 use super::TypeChecker;
 
-type VarPointRelations = Vec<(Local, LocationIndex)>;
+type VarPointRelation = Vec<(Local, LocationIndex)>;
-type MovePathPointRelations = Vec<(MovePathIndex, LocationIndex)>;
+type PathPointRelation = Vec<(MovePathIndex, LocationIndex)>;
 
 struct UseFactsExtractor<'me> {
-    var_defined: &'me mut VarPointRelations,
+    var_defined: &'me mut VarPointRelation,
-    var_used: &'me mut VarPointRelations,
+    var_used: &'me mut VarPointRelation,
     location_table: &'me LocationTable,
     var_drop_used: &'me mut Vec<(Local, Location)>,
     move_data: &'me MoveData<'me>,
-    path_accessed_at: &'me mut MovePathPointRelations,
+    path_accessed_at: &'me mut PathPointRelation,
 }
 
 // A Visitor to walk through the MIR and extract point-wise facts
@@ -28,22 +27,22 @@ impl UseFactsExtractor<'_> {
     }
 
     fn insert_def(&mut self, local: Local, location: Location) {
-        debug!("LivenessFactsExtractor::insert_def()");
+        debug!("UseFactsExtractor::insert_def()");
         self.var_defined.push((local, self.location_to_index(location)));
     }
 
     fn insert_use(&mut self, local: Local, location: Location) {
-        debug!("LivenessFactsExtractor::insert_use()");
+        debug!("UseFactsExtractor::insert_use()");
         self.var_used.push((local, self.location_to_index(location)));
     }
 
     fn insert_drop_use(&mut self, local: Local, location: Location) {
-        debug!("LivenessFactsExtractor::insert_drop_use()");
+        debug!("UseFactsExtractor::insert_drop_use()");
         self.var_drop_used.push((local, location));
     }
 
     fn insert_path_access(&mut self, path: MovePathIndex, location: Location) {
-        debug!("LivenessFactsExtractor::insert_path_access({:?}, {:?})", path, location);
+        debug!("UseFactsExtractor::insert_path_access({:?}, {:?})", path, location);
         self.path_accessed_at.push((path, self.location_to_index(location)));
     }
 
@@ -84,17 +83,6 @@ impl Visitor<'tcx> for UseFactsExtractor<'_> {
     }
 }
 
-fn add_var_uses_regions(typeck: &mut TypeChecker<'_, 'tcx>, local: Local, ty: Ty<'tcx>) {
-    debug!("add_regions(local={:?}, type={:?})", local, ty);
-    typeck.tcx().for_each_free_region(&ty, |region| {
-        let region_vid = typeck.borrowck_context.universal_regions.to_region_vid(region);
-        debug!("add_regions for region {:?}", region_vid);
-        if let Some(facts) = typeck.borrowck_context.all_facts {
-            facts.var_uses_region.push((local, region_vid));
-        }
-    });
-}
-
 pub(super) fn populate_access_facts(
     typeck: &mut TypeChecker<'_, 'tcx>,
     body: ReadOnlyBodyAndCache<'_, 'tcx>,
@@ -102,26 +90,32 @@ pub(super) fn populate_access_facts(
     move_data: &MoveData<'_>,
     drop_used: &mut Vec<(Local, Location)>,
 ) {
-    debug!("populate_var_liveness_facts()");
+    debug!("populate_access_facts()");
 
     if let Some(facts) = typeck.borrowck_context.all_facts.as_mut() {
-        UseFactsExtractor {
+        let mut extractor = UseFactsExtractor {
             var_defined: &mut facts.var_defined,
             var_used: &mut facts.var_used,
             var_drop_used: drop_used,
             path_accessed_at: &mut facts.path_accessed_at,
             location_table,
             move_data,
-        }
+        };
-        .visit_body(body);
+        extractor.visit_body(body);
 
         facts.var_drop_used.extend(drop_used.iter().map(|&(local, location)| {
             (local, location_table.mid_index(location))
         }));
-    }
 
         for (local, local_decl) in body.local_decls.iter_enumerated() {
-        add_var_uses_regions(typeck, local, local_decl.ty);
+            debug!("add var_uses_regions facts - local={:?}, type={:?}", local, local_decl.ty);
+            let _prof_timer = typeck.infcx.tcx.prof.generic_activity("polonius_fact_generation");
+            let universal_regions = &typeck.borrowck_context.universal_regions;
+            typeck.infcx.tcx.for_each_free_region(&local_decl.ty, |region| {
+                let region_vid = universal_regions.to_region_vid(region);
+                facts.var_uses_region.push((local, region_vid));
+            });
+        }
     }
 }
 
@@ -133,12 +127,12 @@ pub(super) fn add_var_drops_regions(
     kind: &GenericArg<'tcx>,
 ) {
     debug!("add_var_drops_region(local={:?}, kind={:?}", local, kind);
-    let tcx = typeck.tcx();
-
-    tcx.for_each_free_region(kind, |drop_live_region| {
-        let region_vid = typeck.borrowck_context.universal_regions.to_region_vid(drop_live_region);
     if let Some(facts) = typeck.borrowck_context.all_facts.as_mut() {
+        let _prof_timer = typeck.infcx.tcx.prof.generic_activity("polonius_fact_generation");
+        let universal_regions = &typeck.borrowck_context.universal_regions;
+        typeck.infcx.tcx.for_each_free_region(kind, |drop_live_region| {
+            let region_vid = universal_regions.to_region_vid(drop_live_region);
             facts.var_drops_region.push((local, region_vid));
-        };
         });
+    }
 }

src/librustc_mir/borrow_check/nll/type_check/mod.rs

@@ -182,7 +182,7 @@ pub(crate) fn type_check<'tcx>(
                 move_data,
                 location_table);
 
-            translate_outlives_facts(cx.borrowck_context);
+            translate_outlives_facts(&mut cx);
         },
     );
 
@@ -228,8 +228,10 @@ fn type_check_internal<'a, 'tcx, R>(
     extra(&mut checker)
 }
 
-fn translate_outlives_facts(cx: &mut BorrowCheckContext<'_, '_>) {
+fn translate_outlives_facts(typeck: &mut TypeChecker<'_, '_>) {
+    let cx = &mut typeck.borrowck_context;
     if let Some(facts) = cx.all_facts {
+        let _prof_timer = typeck.infcx.tcx.prof.generic_activity("polonius_fact_generation");
         let location_table = cx.location_table;
         facts
             .outlives
@@ -2489,6 +2491,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
         // that occurs when we are borrowing an unsafe place, for
         // example).
         if let Some(all_facts) = all_facts {
+            let _prof_timer = self.infcx.tcx.prof.generic_activity("polonius_fact_generation");
             if let Some(borrow_index) = borrow_set.location_map.get(&location) {
                 let region_vid = borrow_region.to_region_vid();
                 all_facts.borrow_region.push((

src/librustc_mir/transform/simplify.rs

@@ -29,7 +29,7 @@
 
 use rustc_index::bit_set::BitSet;
 use rustc_index::vec::{Idx, IndexVec};
-use rustc::ty::TyCtxt;
+use rustc::ty::{self, TyCtxt};
 use rustc::mir::*;
 use rustc::mir::visit::{MutVisitor, Visitor, PlaceContext, MutatingUseContext};
 use std::borrow::Cow;
@@ -367,9 +367,14 @@ impl<'a, 'tcx> Visitor<'tcx> for DeclMarker<'a, 'tcx> {
                 if let StatementKind::Assign(
                     box (p, Rvalue::Use(Operand::Constant(c)))
                 ) = &stmt.kind {
-                    if !p.is_indirect() {
+                    match c.literal.val {
+                        // Keep assignments from unevaluated constants around, since the evaluation
+                        // may report errors, even if the use of the constant is dead code.
+                        ty::ConstKind::Unevaluated(..) => {}
+                        _ => if !p.is_indirect() {
                             trace!("skipping store of const value {:?} to {:?}", c, p);
                             return;
+                        },
                     }
                 }
             }

src/librustdoc/clean/auto_trait.rs

@@ -1,10 +1,24 @@
 use rustc::hir;
 use rustc::traits::auto_trait::{self, AutoTraitResult};
-use rustc::ty::{self, TypeFoldable};
+use rustc::ty::{self, Region, RegionVid, TypeFoldable};
+use rustc::util::nodemap::FxHashSet;
+
 use std::fmt::Debug;
 
 use super::*;
 
+#[derive(Eq, PartialEq, Hash, Copy, Clone, Debug)]
+enum RegionTarget<'tcx> {
+    Region(Region<'tcx>),
+    RegionVid(RegionVid)
+}
+
+#[derive(Default, Debug, Clone)]
+struct RegionDeps<'tcx> {
+    larger: FxHashSet<RegionTarget<'tcx>>,
+    smaller: FxHashSet<RegionTarget<'tcx>>
+}
+
 pub struct AutoTraitFinder<'a, 'tcx> {
     pub cx: &'a core::DocContext<'tcx>,
     pub f: auto_trait::AutoTraitFinder<'tcx>,

src/librustdoc/clean/mod.rs

@@ -1,10 +1,9 @@
-// ignore-tidy-filelength
-
 //! This module contains the "cleaned" pieces of the AST, and the functions
 //! that clean them.
 
 pub mod inline;
 pub mod cfg;
+pub mod utils;
 mod auto_trait;
 mod blanket_impl;
 mod simplify;
@@ -19,15 +18,15 @@ use rustc::middle::stability;
 use rustc::mir::interpret::GlobalId;
 use rustc::hir;
 use rustc::hir::def::{CtorKind, DefKind, Res};
-use rustc::hir::def_id::{CrateNum, DefId, CRATE_DEF_INDEX, LOCAL_CRATE};
+use rustc::hir::def_id::{CrateNum, DefId, CRATE_DEF_INDEX};
 use rustc::hir::ptr::P;
-use rustc::ty::subst::{InternalSubsts, SubstsRef, GenericArgKind};
+use rustc::ty::subst::InternalSubsts;
-use rustc::ty::{self, DefIdTree, TyCtxt, Region, RegionVid, Ty, AdtKind};
+use rustc::ty::{self, TyCtxt, Ty, AdtKind};
 use rustc::ty::fold::TypeFolder;
 use rustc::util::nodemap::{FxHashMap, FxHashSet};
 use syntax::ast::{self, Ident};
 use syntax::attr;
-use syntax_pos::symbol::{Symbol, kw, sym};
+use syntax_pos::symbol::{kw, sym};
 use syntax_pos::hygiene::MacroKind;
 use syntax_pos::{self, Pos};
 
@@ -41,8 +40,9 @@ use std::u32;
 use crate::core::{self, DocContext, ImplTraitParam};
 use crate::doctree;
 
-use self::auto_trait::AutoTraitFinder;
+use utils::*;
-use self::blanket_impl::BlanketImplFinder;
+
+pub use utils::{get_auto_trait_and_blanket_impls, krate, register_res};
 
 pub use self::types::*;
 pub use self::types::Type::*;
@@ -54,15 +54,6 @@ pub use self::types::Visibility::{Public, Inherited};
 
 const FN_OUTPUT_NAME: &'static str = "Output";
 
-// extract the stability index for a node from tcx, if possible
-fn get_stability(cx: &DocContext<'_>, def_id: DefId) -> Option<Stability> {
-    cx.tcx.lookup_stability(def_id).clean(cx)
-}
-
-fn get_deprecation(cx: &DocContext<'_>, def_id: DefId) -> Option<Deprecation> {
-    cx.tcx.lookup_deprecation(def_id).clean(cx)
-}
-
 pub trait Clean<T> {
     fn clean(&self, cx: &DocContext<'_>) -> T;
 }
@@ -109,91 +100,6 @@ impl<T: Clean<U>, U> Clean<Vec<U>> for P<[T]> {
     }
 }
 
-pub fn krate(mut cx: &mut DocContext<'_>) -> Crate {
-    use crate::visit_lib::LibEmbargoVisitor;
-
-    let krate = cx.tcx.hir().krate();
-    let module = crate::visit_ast::RustdocVisitor::new(&mut cx).visit(krate);
-
-    let mut r = cx.renderinfo.get_mut();
-    r.deref_trait_did = cx.tcx.lang_items().deref_trait();
-    r.deref_mut_trait_did = cx.tcx.lang_items().deref_mut_trait();
-    r.owned_box_did = cx.tcx.lang_items().owned_box();
-
-    let mut externs = Vec::new();
-    for &cnum in cx.tcx.crates().iter() {
-        externs.push((cnum, cnum.clean(cx)));
-        // Analyze doc-reachability for extern items
-        LibEmbargoVisitor::new(&mut cx).visit_lib(cnum);
-    }
-    externs.sort_by(|&(a, _), &(b, _)| a.cmp(&b));
-
-    // Clean the crate, translating the entire libsyntax AST to one that is
-    // understood by rustdoc.
-    let mut module = module.clean(cx);
-    let mut masked_crates = FxHashSet::default();
-
-    match module.inner {
-        ModuleItem(ref module) => {
-            for it in &module.items {
-                // `compiler_builtins` should be masked too, but we can't apply
-                // `#[doc(masked)]` to the injected `extern crate` because it's unstable.
-                if it.is_extern_crate()
-                    && (it.attrs.has_doc_flag(sym::masked)
-                        || cx.tcx.is_compiler_builtins(it.def_id.krate))
-                {
-                    masked_crates.insert(it.def_id.krate);
-                }
-            }
-        }
-        _ => unreachable!(),
-    }
-
-    let ExternalCrate { name, src, primitives, keywords, .. } = LOCAL_CRATE.clean(cx);
-    {
-        let m = match module.inner {
-            ModuleItem(ref mut m) => m,
-            _ => unreachable!(),
-        };
-        m.items.extend(primitives.iter().map(|&(def_id, prim, ref attrs)| {
-            Item {
-                source: Span::empty(),
-                name: Some(prim.to_url_str().to_string()),
-                attrs: attrs.clone(),
-                visibility: Public,
-                stability: get_stability(cx, def_id),
-                deprecation: get_deprecation(cx, def_id),
-                def_id,
-                inner: PrimitiveItem(prim),
-            }
-        }));
-        m.items.extend(keywords.into_iter().map(|(def_id, kw, attrs)| {
-            Item {
-                source: Span::empty(),
-                name: Some(kw.clone()),
-                attrs,
-                visibility: Public,
-                stability: get_stability(cx, def_id),
-                deprecation: get_deprecation(cx, def_id),
-                def_id,
-                inner: KeywordItem(kw),
-            }
-        }));
-    }
-
-    Crate {
-        name,
-        version: None,
-        src,
-        module: Some(module),
-        externs,
-        primitives,
-        external_traits: cx.external_traits.clone(),
-        masked_crates,
-        collapsed: false,
-    }
-}
-
 impl Clean<ExternalCrate> for CrateNum {
     fn clean(&self, cx: &DocContext<'_>) -> ExternalCrate {
         let root = DefId { krate: *self, index: CRATE_DEF_INDEX };
@@ -394,66 +300,6 @@ impl Clean<GenericBound> for hir::GenericBound {
     }
 }
 
-fn external_generic_args(
-    cx: &DocContext<'_>,
-    trait_did: Option<DefId>,
-    has_self: bool,
-    bindings: Vec<TypeBinding>,
-    substs: SubstsRef<'_>,
-) -> GenericArgs {
-    let mut skip_self = has_self;
-    let mut ty_kind = None;
-    let args: Vec<_> = substs.iter().filter_map(|kind| match kind.unpack() {
-        GenericArgKind::Lifetime(lt) => {
-            lt.clean(cx).and_then(|lt| Some(GenericArg::Lifetime(lt)))
-        }
-        GenericArgKind::Type(_) if skip_self => {
-            skip_self = false;
-            None
-        }
-        GenericArgKind::Type(ty) => {
-            ty_kind = Some(&ty.kind);
-            Some(GenericArg::Type(ty.clean(cx)))
-        }
-        GenericArgKind::Const(ct) => Some(GenericArg::Const(ct.clean(cx))),
-    }).collect();
-
-    match trait_did {
-        // Attempt to sugar an external path like Fn<(A, B,), C> to Fn(A, B) -> C
-        Some(did) if cx.tcx.lang_items().fn_trait_kind(did).is_some() => {
-            assert!(ty_kind.is_some());
-            let inputs = match ty_kind {
-                Some(ty::Tuple(ref tys)) => tys.iter().map(|t| t.expect_ty().clean(cx)).collect(),
-                _ => return GenericArgs::AngleBracketed { args, bindings },
-            };
-            let output = None;
-            // FIXME(#20299) return type comes from a projection now
-            // match types[1].kind {
-            //     ty::Tuple(ref v) if v.is_empty() => None, // -> ()
-            //     _ => Some(types[1].clean(cx))
-            // };
-            GenericArgs::Parenthesized { inputs, output }
-        },
-        _ => {
-            GenericArgs::AngleBracketed { args, bindings }
-        }
-    }
-}
-
-// trait_did should be set to a trait's DefId if called on a TraitRef, in order to sugar
-// from Fn<(A, B,), C> to Fn(A, B) -> C
-fn external_path(cx: &DocContext<'_>, name: Symbol, trait_did: Option<DefId>, has_self: bool,
-                 bindings: Vec<TypeBinding>, substs: SubstsRef<'_>) -> Path {
-    Path {
-        global: false,
-        res: Res::Err,
-        segments: vec![PathSegment {
-            name: name.to_string(),
-            args: external_generic_args(cx, trait_did, has_self, bindings, substs)
-        }],
-    }
-}
-
 impl<'a, 'tcx> Clean<GenericBound> for (&'a ty::TraitRef<'tcx>, Vec<TypeBinding>) {
     fn clean(&self, cx: &DocContext<'_>) -> GenericBound {
         let (trait_ref, ref bounds) = *self;
@@ -1036,118 +882,6 @@ impl<'a, 'tcx> Clean<Generics> for (&'a ty::Generics, ty::GenericPredicates<'tcx
     }
 }
 
-/// The point of this function is to replace bounds with types.
-///
-/// i.e. `[T, U]` when you have the following bounds: `T: Display, U: Option<T>` will return
-/// `[Display, Option]` (we just returns the list of the types, we don't care about the
-/// wrapped types in here).
-fn get_real_types(
-    generics: &Generics,
-    arg: &Type,
-    cx: &DocContext<'_>,
-    recurse: i32,
-) -> FxHashSet<Type> {
-    let arg_s = arg.print().to_string();
-    let mut res = FxHashSet::default();
-    if recurse >= 10 { // FIXME: remove this whole recurse thing when the recursion bug is fixed
-        return res;
-    }
-    if arg.is_full_generic() {
-        if let Some(where_pred) = generics.where_predicates.iter().find(|g| {
-            match g {
-                &WherePredicate::BoundPredicate { ref ty, .. } => ty.def_id() == arg.def_id(),
-                _ => false,
-            }
-        }) {
-            let bounds = where_pred.get_bounds().unwrap_or_else(|| &[]);
-            for bound in bounds.iter() {
-                match *bound {
-                    GenericBound::TraitBound(ref poly_trait, _) => {
-                        for x in poly_trait.generic_params.iter() {
-                            if !x.is_type() {
-                                continue
-                            }
-                            if let Some(ty) = x.get_type() {
-                                let adds = get_real_types(generics, &ty, cx, recurse + 1);
-                                if !adds.is_empty() {
-                                    res.extend(adds);
-                                } else if !ty.is_full_generic() {
-                                    res.insert(ty);
-                                }
-                            }
-                        }
-                    }
-                    _ => {}
-                }
-            }
-        }
-        if let Some(bound) = generics.params.iter().find(|g| {
-            g.is_type() && g.name == arg_s
-        }) {
-            for bound in bound.get_bounds().unwrap_or_else(|| &[]) {
-                if let Some(ty) = bound.get_trait_type() {
-                    let adds = get_real_types(generics, &ty, cx, recurse + 1);
-                    if !adds.is_empty() {
-                        res.extend(adds);
-                    } else if !ty.is_full_generic() {
-                        res.insert(ty.clone());
-                    }
-                }
-            }
-        }
-    } else {
-        res.insert(arg.clone());
-        if let Some(gens) = arg.generics() {
-            for gen in gens.iter() {
-                if gen.is_full_generic() {
-                    let adds = get_real_types(generics, gen, cx, recurse + 1);
-                    if !adds.is_empty() {
-                        res.extend(adds);
-                    }
-                } else {
-                    res.insert(gen.clone());
-                }
-            }
-        }
-    }
-    res
-}
-
-/// Return the full list of types when bounds have been resolved.
-///
-/// i.e. `fn foo<A: Display, B: Option<A>>(x: u32, y: B)` will return
-/// `[u32, Display, Option]`.
-pub fn get_all_types(
-    generics: &Generics,
-    decl: &FnDecl,
-    cx: &DocContext<'_>,
-) -> (Vec<Type>, Vec<Type>) {
-    let mut all_types = FxHashSet::default();
-    for arg in decl.inputs.values.iter() {
-        if arg.type_.is_self_type() {
-            continue;
-        }
-        let args = get_real_types(generics, &arg.type_, cx, 0);
-        if !args.is_empty() {
-            all_types.extend(args);
-        } else {
-            all_types.insert(arg.type_.clone());
-        }
-    }
-
-    let ret_types = match decl.output {
-        FunctionRetTy::Return(ref return_type) => {
-            let mut ret = get_real_types(generics, &return_type, cx, 0);
-            if ret.is_empty() {
-                ret.insert(return_type.clone());
-            }
-            ret.into_iter().collect()
-        }
-        _ => Vec::new(),
-    };
-    (all_types.into_iter().collect(), ret_types)
-}
-
 impl<'a> Clean<Method> for (&'a hir::FnSig, &'a hir::Generics, hir::BodyId,
                             Option<hir::Defaultness>) {
     fn clean(&self, cx: &DocContext<'_>) -> Method {
@@ -2262,66 +1996,6 @@ impl Clean<PathSegment> for hir::PathSegment {
     }
 }
 
-fn strip_type(ty: Type) -> Type {
-    match ty {
-        Type::ResolvedPath { path, param_names, did, is_generic } => {
-            Type::ResolvedPath { path: strip_path(&path), param_names, did, is_generic }
-        }
-        Type::Tuple(inner_tys) => {
-            Type::Tuple(inner_tys.iter().map(|t| strip_type(t.clone())).collect())
-        }
-        Type::Slice(inner_ty) => Type::Slice(Box::new(strip_type(*inner_ty))),
-        Type::Array(inner_ty, s) => Type::Array(Box::new(strip_type(*inner_ty)), s),
-        Type::RawPointer(m, inner_ty) => Type::RawPointer(m, Box::new(strip_type(*inner_ty))),
-        Type::BorrowedRef { lifetime, mutability, type_ } => {
-            Type::BorrowedRef { lifetime, mutability, type_: Box::new(strip_type(*type_)) }
-        }
-        Type::QPath { name, self_type, trait_ } => {
-            Type::QPath {
-                name,
-                self_type: Box::new(strip_type(*self_type)), trait_: Box::new(strip_type(*trait_))
-            }
-        }
-        _ => ty
-    }
-}
-
-fn strip_path(path: &Path) -> Path {
-    let segments = path.segments.iter().map(|s| {
-        PathSegment {
-            name: s.name.clone(),
-            args: GenericArgs::AngleBracketed {
-                args: vec![],
-                bindings: vec![],
-            }
-        }
-    }).collect();
-
-    Path {
-        global: path.global,
-        res: path.res.clone(),
-        segments,
-    }
-}
-
-fn qpath_to_string(p: &hir::QPath) -> String {
-    let segments = match *p {
-        hir::QPath::Resolved(_, ref path) => &path.segments,
-        hir::QPath::TypeRelative(_, ref segment) => return segment.ident.to_string(),
-    };
-
-    let mut s = String::new();
-    for (i, seg) in segments.iter().enumerate() {
-        if i > 0 {
-            s.push_str("::");
-        }
-        if seg.ident.name != kw::PathRoot {
-            s.push_str(&seg.ident.as_str());
-        }
-    }
-    s
-}
-
 impl Clean<String> for Ident {
     #[inline]
     fn clean(&self, cx: &DocContext<'_>) -> String {
@@ -2444,15 +2118,6 @@ impl Clean<ImplPolarity> for ty::ImplPolarity {
     }
 }
 
-pub fn get_auto_trait_and_blanket_impls(
-    cx: &DocContext<'tcx>,
-    ty: Ty<'tcx>,
-    param_env_def_id: DefId,
-) -> impl Iterator<Item = Item> {
-    AutoTraitFinder::new(cx).get_auto_trait_impls(ty, param_env_def_id).into_iter()
-        .chain(BlanketImplFinder::new(cx).get_blanket_impls(ty, param_env_def_id))
-}
-
 impl Clean<Vec<Item>> for doctree::Impl<'_> {
     fn clean(&self, cx: &DocContext<'_>) -> Vec<Item> {
         let mut ret = Vec::new();
@@ -2497,63 +2162,6 @@ impl Clean<Vec<Item>> for doctree::Impl<'_> {
     }
 }
 
-fn build_deref_target_impls(cx: &DocContext<'_>,
-                            items: &[Item],
-                            ret: &mut Vec<Item>) {
-    use self::PrimitiveType::*;
-    let tcx = cx.tcx;
-
-    for item in items {
-        let target = match item.inner {
-            TypedefItem(ref t, true) => &t.type_,
-            _ => continue,
-        };
-        let primitive = match *target {
-            ResolvedPath { did, .. } if did.is_local() => continue,
-            ResolvedPath { did, .. } => {
-                ret.extend(inline::build_impls(cx, did, None));
-                continue
-            }
-            _ => match target.primitive_type() {
-                Some(prim) => prim,
-                None => continue,
-            }
-        };
-        let did = match primitive {
-            Isize => tcx.lang_items().isize_impl(),
-            I8 => tcx.lang_items().i8_impl(),
-            I16 => tcx.lang_items().i16_impl(),
-            I32 => tcx.lang_items().i32_impl(),
-            I64 => tcx.lang_items().i64_impl(),
-            I128 => tcx.lang_items().i128_impl(),
-            Usize => tcx.lang_items().usize_impl(),
-            U8 => tcx.lang_items().u8_impl(),
-            U16 => tcx.lang_items().u16_impl(),
-            U32 => tcx.lang_items().u32_impl(),
-            U64 => tcx.lang_items().u64_impl(),
-            U128 => tcx.lang_items().u128_impl(),
-            F32 => tcx.lang_items().f32_impl(),
-            F64 => tcx.lang_items().f64_impl(),
-            Char => tcx.lang_items().char_impl(),
-            Bool => tcx.lang_items().bool_impl(),
-            Str => tcx.lang_items().str_impl(),
-            Slice => tcx.lang_items().slice_impl(),
-            Array => tcx.lang_items().slice_impl(),
-            Tuple => None,
-            Unit => None,
-            RawPointer => tcx.lang_items().const_ptr_impl(),
-            Reference => None,
-            Fn => None,
-            Never => None,
-        };
-        if let Some(did) = did {
-            if !did.is_local() {
-                inline::build_impl(cx, did, None, ret);
-            }
-        }
-    }
-}
-
 impl Clean<Vec<Item>> for doctree::ExternCrate<'_> {
     fn clean(&self, cx: &DocContext<'_>) -> Vec<Item> {
 
@@ -2710,170 +2318,6 @@ impl Clean<Item> for doctree::ForeignItem<'_> {
     }
 }
 
-// Utilities
-
-pub trait ToSource {
-    fn to_src(&self, cx: &DocContext<'_>) -> String;
-}
-
-impl ToSource for syntax_pos::Span {
-    fn to_src(&self, cx: &DocContext<'_>) -> String {
-        debug!("converting span {:?} to snippet", self.clean(cx));
-        let sn = match cx.sess().source_map().span_to_snippet(*self) {
-            Ok(x) => x,
-            Err(_) => String::new()
-        };
-        debug!("got snippet {}", sn);
-        sn
-    }
-}
-
-fn name_from_pat(p: &hir::Pat) -> String {
-    use rustc::hir::*;
-    debug!("trying to get a name from pattern: {:?}", p);
-
-    match p.kind {
-        PatKind::Wild => "_".to_string(),
-        PatKind::Binding(_, _, ident, _) => ident.to_string(),
-        PatKind::TupleStruct(ref p, ..) | PatKind::Path(ref p) => qpath_to_string(p),
-        PatKind::Struct(ref name, ref fields, etc) => {
-            format!("{} {{ {}{} }}", qpath_to_string(name),
-                fields.iter().map(|fp| format!("{}: {}", fp.ident, name_from_pat(&fp.pat)))
-                             .collect::<Vec<String>>().join(", "),
-                if etc { ", .." } else { "" }
-            )
-        }
-        PatKind::Or(ref pats) => {
-            pats.iter().map(|p| name_from_pat(&**p)).collect::<Vec<String>>().join(" | ")
-        }
-        PatKind::Tuple(ref elts, _) => format!("({})", elts.iter().map(|p| name_from_pat(&**p))
-                                            .collect::<Vec<String>>().join(", ")),
-        PatKind::Box(ref p) => name_from_pat(&**p),
-        PatKind::Ref(ref p, _) => name_from_pat(&**p),
-        PatKind::Lit(..) => {
-            warn!("tried to get argument name from PatKind::Lit, \
-                  which is silly in function arguments");
-            "()".to_string()
-        },
-        PatKind::Range(..) => panic!("tried to get argument name from PatKind::Range, \
-                              which is not allowed in function arguments"),
-        PatKind::Slice(ref begin, ref mid, ref end) => {
-            let begin = begin.iter().map(|p| name_from_pat(&**p));
-            let mid = mid.as_ref().map(|p| format!("..{}", name_from_pat(&**p))).into_iter();
-            let end = end.iter().map(|p| name_from_pat(&**p));
-            format!("[{}]", begin.chain(mid).chain(end).collect::<Vec<_>>().join(", "))
-        },
-    }
-}
-
-fn print_const(cx: &DocContext<'_>, n: &ty::Const<'_>) -> String {
-    match n.val {
-        ty::ConstKind::Unevaluated(def_id, _) => {
-            if let Some(hir_id) = cx.tcx.hir().as_local_hir_id(def_id) {
-                print_const_expr(cx, cx.tcx.hir().body_owned_by(hir_id))
-            } else {
-                inline::print_inlined_const(cx, def_id)
-            }
-        },
-        _ => {
-            let mut s = n.to_string();
-            // array lengths are obviously usize
-            if s.ends_with("usize") {
-                let n = s.len() - "usize".len();
-                s.truncate(n);
-                if s.ends_with(": ") {
-                    let n = s.len() - ": ".len();
-                    s.truncate(n);
-                }
-            }
-            s
-        },
-    }
-}
-
-fn print_const_expr(cx: &DocContext<'_>, body: hir::BodyId) -> String {
-    cx.tcx.hir().hir_to_pretty_string(body.hir_id)
-}
-
-/// Given a type Path, resolve it to a Type using the TyCtxt
-fn resolve_type(cx: &DocContext<'_>,
-                path: Path,
-                id: hir::HirId) -> Type {
-    if id == hir::DUMMY_HIR_ID {
-        debug!("resolve_type({:?})", path);
-    } else {
-        debug!("resolve_type({:?},{:?})", path, id);
-    }
-
-    let is_generic = match path.res {
-        Res::PrimTy(p) => match p {
-            hir::Str => return Primitive(PrimitiveType::Str),
-            hir::Bool => return Primitive(PrimitiveType::Bool),
-            hir::Char => return Primitive(PrimitiveType::Char),
-            hir::Int(int_ty) => return Primitive(int_ty.into()),
-            hir::Uint(uint_ty) => return Primitive(uint_ty.into()),
-            hir::Float(float_ty) => return Primitive(float_ty.into()),
-        },
-        Res::SelfTy(..) if path.segments.len() == 1 => {
-            return Generic(kw::SelfUpper.to_string());
-        }
-        Res::Def(DefKind::TyParam, _) if path.segments.len() == 1 => {
-            return Generic(format!("{:#}", path.print()));
-        }
-        Res::SelfTy(..)
-        | Res::Def(DefKind::TyParam, _)
-        | Res::Def(DefKind::AssocTy, _) => true,
-        _ => false,
-    };
-    let did = register_res(&*cx, path.res);
-    ResolvedPath { path, param_names: None, did, is_generic }
-}
-
-pub fn register_res(cx: &DocContext<'_>, res: Res) -> DefId {
-    debug!("register_res({:?})", res);
-
-    let (did, kind) = match res {
-        Res::Def(DefKind::Fn, i) => (i, TypeKind::Function),
-        Res::Def(DefKind::TyAlias, i) => (i, TypeKind::Typedef),
-        Res::Def(DefKind::Enum, i) => (i, TypeKind::Enum),
-        Res::Def(DefKind::Trait, i) => (i, TypeKind::Trait),
-        Res::Def(DefKind::Struct, i) => (i, TypeKind::Struct),
-        Res::Def(DefKind::Union, i) => (i, TypeKind::Union),
-        Res::Def(DefKind::Mod, i) => (i, TypeKind::Module),
-        Res::Def(DefKind::ForeignTy, i) => (i, TypeKind::Foreign),
-        Res::Def(DefKind::Const, i) => (i, TypeKind::Const),
-        Res::Def(DefKind::Static, i) => (i, TypeKind::Static),
-        Res::Def(DefKind::Variant, i) => (cx.tcx.parent(i).expect("cannot get parent def id"),
-                            TypeKind::Enum),
-        Res::Def(DefKind::Macro(mac_kind), i) => match mac_kind {
-            MacroKind::Bang => (i, TypeKind::Macro),
-            MacroKind::Attr => (i, TypeKind::Attr),
-            MacroKind::Derive => (i, TypeKind::Derive),
-        },
-        Res::Def(DefKind::TraitAlias, i) => (i, TypeKind::TraitAlias),
-        Res::SelfTy(Some(def_id), _) => (def_id, TypeKind::Trait),
-        Res::SelfTy(_, Some(impl_def_id)) => return impl_def_id,
-        _ => return res.def_id()
-    };
-    if did.is_local() { return did }
-    inline::record_extern_fqn(cx, did, kind);
-    if let TypeKind::Trait = kind {
-        inline::record_extern_trait(cx, did);
-    }
-    did
-}
-
-fn resolve_use_source(cx: &DocContext<'_>, path: Path) -> ImportSource {
-    ImportSource {
-        did: if path.res.opt_def_id().is_none() {
-            None
-        } else {
-            Some(register_res(cx, path.res))
-        },
-        path,
-    }
-}
-
 impl Clean<Item> for doctree::Macro<'_> {
     fn clean(&self, cx: &DocContext<'_>) -> Item {
         let name = self.name.clean(cx);
@@ -2981,29 +2425,6 @@ impl Clean<TypeBindingKind> for hir::TypeBindingKind {
     }
 }
 
-pub fn enter_impl_trait<F, R>(cx: &DocContext<'_>, f: F) -> R
-where
-    F: FnOnce() -> R,
-{
-    let old_bounds = mem::take(&mut *cx.impl_trait_bounds.borrow_mut());
-    let r = f();
-    assert!(cx.impl_trait_bounds.borrow().is_empty());
-    *cx.impl_trait_bounds.borrow_mut() = old_bounds;
-    r
-}
-
-#[derive(Eq, PartialEq, Hash, Copy, Clone, Debug)]
-enum RegionTarget<'tcx> {
-    Region(Region<'tcx>),
-    RegionVid(RegionVid)
-}
-
-#[derive(Default, Debug, Clone)]
-struct RegionDeps<'tcx> {
-    larger: FxHashSet<RegionTarget<'tcx>>,
-    smaller: FxHashSet<RegionTarget<'tcx>>
-}
-
 enum SimpleBound {
     TraitBound(Vec<PathSegment>, Vec<SimpleBound>, Vec<GenericParamDef>, hir::TraitBoundModifier),
     Outlives(Lifetime),

src/librustdoc/clean/utils.rs

@@ -0,0 +1,585 @@
+use crate::core::DocContext;
+use crate::clean::{
+    Clean, Crate, Deprecation, ExternalCrate, FnDecl, FunctionRetTy, Generic, GenericArg,
+    GenericArgs, Generics, GenericBound, GetDefId, ImportSource, Item, ItemEnum, MacroKind, Path,
+    PathSegment, Primitive, PrimitiveType, ResolvedPath, Span, Stability, Type, TypeBinding,
+    TypeKind, Visibility, WherePredicate, inline,
+};
+use crate::clean::blanket_impl::BlanketImplFinder;
+use crate::clean::auto_trait::AutoTraitFinder;
+
+use rustc::hir;
+use rustc::hir::def::{DefKind, Res};
+use rustc::hir::def_id::{DefId, LOCAL_CRATE};
+use rustc::ty::{self, DefIdTree, Ty};
+use rustc::ty::subst::{SubstsRef, GenericArgKind};
+use rustc::util::nodemap::FxHashSet;
+use syntax_pos;
+use syntax_pos::symbol::{Symbol, kw, sym};
+
+use std::mem;
+
+pub fn krate(mut cx: &mut DocContext<'_>) -> Crate {
+    use crate::visit_lib::LibEmbargoVisitor;
+
+    let krate = cx.tcx.hir().krate();
+    let module = crate::visit_ast::RustdocVisitor::new(&mut cx).visit(krate);
+
+    let mut r = cx.renderinfo.get_mut();
+    r.deref_trait_did = cx.tcx.lang_items().deref_trait();
+    r.deref_mut_trait_did = cx.tcx.lang_items().deref_mut_trait();
+    r.owned_box_did = cx.tcx.lang_items().owned_box();
+
+    let mut externs = Vec::new();
+    for &cnum in cx.tcx.crates().iter() {
+        externs.push((cnum, cnum.clean(cx)));
+        // Analyze doc-reachability for extern items
+        LibEmbargoVisitor::new(&mut cx).visit_lib(cnum);
+    }
+    externs.sort_by(|&(a, _), &(b, _)| a.cmp(&b));
+
+    // Clean the crate, translating the entire libsyntax AST to one that is
+    // understood by rustdoc.
+    let mut module = module.clean(cx);
+    let mut masked_crates = FxHashSet::default();
+
+    match module.inner {
+        ItemEnum::ModuleItem(ref module) => {
+            for it in &module.items {
+                // `compiler_builtins` should be masked too, but we can't apply
+                // `#[doc(masked)]` to the injected `extern crate` because it's unstable.
+                if it.is_extern_crate()
+                    && (it.attrs.has_doc_flag(sym::masked)
+                        || cx.tcx.is_compiler_builtins(it.def_id.krate))
+                {
+                    masked_crates.insert(it.def_id.krate);
+                }
+            }
+        }
+        _ => unreachable!(),
+    }
+
+    let ExternalCrate { name, src, primitives, keywords, .. } = LOCAL_CRATE.clean(cx);
+    {
+        let m = match module.inner {
+            ItemEnum::ModuleItem(ref mut m) => m,
+            _ => unreachable!(),
+        };
+        m.items.extend(primitives.iter().map(|&(def_id, prim, ref attrs)| {
+            Item {
+                source: Span::empty(),
+                name: Some(prim.to_url_str().to_string()),
+                attrs: attrs.clone(),
+                visibility: Visibility::Public,
+                stability: get_stability(cx, def_id),
+                deprecation: get_deprecation(cx, def_id),
+                def_id,
+                inner: ItemEnum::PrimitiveItem(prim),
+            }
+        }));
+        m.items.extend(keywords.into_iter().map(|(def_id, kw, attrs)| {
+            Item {
+                source: Span::empty(),
+                name: Some(kw.clone()),
+                attrs,
+                visibility: Visibility::Public,
+                stability: get_stability(cx, def_id),
+                deprecation: get_deprecation(cx, def_id),
+                def_id,
+                inner: ItemEnum::KeywordItem(kw),
+            }
+        }));
+    }
+
+    Crate {
+        name,
+        version: None,
+        src,
+        module: Some(module),
+        externs,
+        primitives,
+        external_traits: cx.external_traits.clone(),
+        masked_crates,
+        collapsed: false,
+    }
+}
+
+// extract the stability index for a node from tcx, if possible
+pub fn get_stability(cx: &DocContext<'_>, def_id: DefId) -> Option<Stability> {
+    cx.tcx.lookup_stability(def_id).clean(cx)
+}
+
+pub fn get_deprecation(cx: &DocContext<'_>, def_id: DefId) -> Option<Deprecation> {
+    cx.tcx.lookup_deprecation(def_id).clean(cx)
+}
+
+pub fn external_generic_args(
+    cx: &DocContext<'_>,
+    trait_did: Option<DefId>,
+    has_self: bool,
+    bindings: Vec<TypeBinding>,
+    substs: SubstsRef<'_>,
+) -> GenericArgs {
+    let mut skip_self = has_self;
+    let mut ty_kind = None;
+    let args: Vec<_> = substs.iter().filter_map(|kind| match kind.unpack() {
+        GenericArgKind::Lifetime(lt) => {
+            lt.clean(cx).and_then(|lt| Some(GenericArg::Lifetime(lt)))
+        }
+        GenericArgKind::Type(_) if skip_self => {
+            skip_self = false;
+            None
+        }
+        GenericArgKind::Type(ty) => {
+            ty_kind = Some(&ty.kind);
+            Some(GenericArg::Type(ty.clean(cx)))
+        }
+        GenericArgKind::Const(ct) => Some(GenericArg::Const(ct.clean(cx))),
+    }).collect();
+
+    match trait_did {
+        // Attempt to sugar an external path like Fn<(A, B,), C> to Fn(A, B) -> C
+        Some(did) if cx.tcx.lang_items().fn_trait_kind(did).is_some() => {
+            assert!(ty_kind.is_some());
+            let inputs = match ty_kind {
+                Some(ty::Tuple(ref tys)) => tys.iter().map(|t| t.expect_ty().clean(cx)).collect(),
+                _ => return GenericArgs::AngleBracketed { args, bindings },
+            };
+            let output = None;
+            // FIXME(#20299) return type comes from a projection now
+            // match types[1].kind {
+            //     ty::Tuple(ref v) if v.is_empty() => None, // -> ()
+            //     _ => Some(types[1].clean(cx))
+            // };
+            GenericArgs::Parenthesized { inputs, output }
+        },
+        _ => {
+            GenericArgs::AngleBracketed { args, bindings }
+        }
+    }
+}
+
+// trait_did should be set to a trait's DefId if called on a TraitRef, in order to sugar
+// from Fn<(A, B,), C> to Fn(A, B) -> C
+pub fn external_path(cx: &DocContext<'_>, name: Symbol, trait_did: Option<DefId>, has_self: bool,
+                     bindings: Vec<TypeBinding>, substs: SubstsRef<'_>) -> Path {
+    Path {
+        global: false,
+        res: Res::Err,
+        segments: vec![PathSegment {
+            name: name.to_string(),
+            args: external_generic_args(cx, trait_did, has_self, bindings, substs)
+        }],
+    }
+}
+
+/// The point of this function is to replace bounds with types.
+///
+/// i.e. `[T, U]` when you have the following bounds: `T: Display, U: Option<T>` will return
+/// `[Display, Option]` (we just returns the list of the types, we don't care about the
+/// wrapped types in here).
+pub fn get_real_types(
+    generics: &Generics,
+    arg: &Type,
+    cx: &DocContext<'_>,
+    recurse: i32,
+) -> FxHashSet<Type> {
+    let arg_s = arg.print().to_string();
+    let mut res = FxHashSet::default();
+    if recurse >= 10 { // FIXME: remove this whole recurse thing when the recursion bug is fixed
+        return res;
+    }
+    if arg.is_full_generic() {
+        if let Some(where_pred) = generics.where_predicates.iter().find(|g| {
+            match g {
+                &WherePredicate::BoundPredicate { ref ty, .. } => ty.def_id() == arg.def_id(),
+                _ => false,
+            }
+        }) {
+            let bounds = where_pred.get_bounds().unwrap_or_else(|| &[]);
+            for bound in bounds.iter() {
+                match *bound {
+                    GenericBound::TraitBound(ref poly_trait, _) => {
+                        for x in poly_trait.generic_params.iter() {
+                            if !x.is_type() {
+                                continue
+                            }
+                            if let Some(ty) = x.get_type() {
+                                let adds = get_real_types(generics, &ty, cx, recurse + 1);
+                                if !adds.is_empty() {
+                                    res.extend(adds);
+                                } else if !ty.is_full_generic() {
+                                    res.insert(ty);
+                                }
+                            }
+                        }
+                    }
+                    _ => {}
+                }
+            }
+        }
+        if let Some(bound) = generics.params.iter().find(|g| {
+            g.is_type() && g.name == arg_s
+        }) {
+            for bound in bound.get_bounds().unwrap_or_else(|| &[]) {
+                if let Some(ty) = bound.get_trait_type() {
+                    let adds = get_real_types(generics, &ty, cx, recurse + 1);
+                    if !adds.is_empty() {
+                        res.extend(adds);
+                    } else if !ty.is_full_generic() {
+                        res.insert(ty.clone());
+                    }
+                }
+            }
+        }
+    } else {
+        res.insert(arg.clone());
+        if let Some(gens) = arg.generics() {
+            for gen in gens.iter() {
+                if gen.is_full_generic() {
+                    let adds = get_real_types(generics, gen, cx, recurse + 1);
+                    if !adds.is_empty() {
+                        res.extend(adds);
+                    }
+                } else {
+                    res.insert(gen.clone());
+                }
+            }
+        }
+    }
+    res
+}
+
+/// Return the full list of types when bounds have been resolved.
+///
+/// i.e. `fn foo<A: Display, B: Option<A>>(x: u32, y: B)` will return
+/// `[u32, Display, Option]`.
+pub fn get_all_types(
+    generics: &Generics,
+    decl: &FnDecl,
+    cx: &DocContext<'_>,
+) -> (Vec<Type>, Vec<Type>) {
+    let mut all_types = FxHashSet::default();
+    for arg in decl.inputs.values.iter() {
+        if arg.type_.is_self_type() {
+            continue;
+        }
+        let args = get_real_types(generics, &arg.type_, cx, 0);
+        if !args.is_empty() {
+            all_types.extend(args);
+        } else {
+            all_types.insert(arg.type_.clone());
+        }
+    }
+
+    let ret_types = match decl.output {
+        FunctionRetTy::Return(ref return_type) => {
+            let mut ret = get_real_types(generics, &return_type, cx, 0);
+            if ret.is_empty() {
+                ret.insert(return_type.clone());
+            }
+            ret.into_iter().collect()
+        }
+        _ => Vec::new(),
+    };
+    (all_types.into_iter().collect(), ret_types)
+}
+
+pub fn strip_type(ty: Type) -> Type {
+    match ty {
+        Type::ResolvedPath { path, param_names, did, is_generic } => {
+            Type::ResolvedPath { path: strip_path(&path), param_names, did, is_generic }
+        }
+        Type::Tuple(inner_tys) => {
+            Type::Tuple(inner_tys.iter().map(|t| strip_type(t.clone())).collect())
+        }
+        Type::Slice(inner_ty) => Type::Slice(Box::new(strip_type(*inner_ty))),
+        Type::Array(inner_ty, s) => Type::Array(Box::new(strip_type(*inner_ty)), s),
+        Type::RawPointer(m, inner_ty) => Type::RawPointer(m, Box::new(strip_type(*inner_ty))),
+        Type::BorrowedRef { lifetime, mutability, type_ } => {
+            Type::BorrowedRef { lifetime, mutability, type_: Box::new(strip_type(*type_)) }
+        }
+        Type::QPath { name, self_type, trait_ } => {
+            Type::QPath {
+                name,
+                self_type: Box::new(strip_type(*self_type)), trait_: Box::new(strip_type(*trait_))
+            }
+        }
+        _ => ty
+    }
+}
+
+pub fn strip_path(path: &Path) -> Path {
+    let segments = path.segments.iter().map(|s| {
+        PathSegment {
+            name: s.name.clone(),
+            args: GenericArgs::AngleBracketed {
+                args: vec![],
+                bindings: vec![],
+            }
+        }
+    }).collect();
+
+    Path {
+        global: path.global,
+        res: path.res.clone(),
+        segments,
+    }
+}
+
+pub fn qpath_to_string(p: &hir::QPath) -> String {
+    let segments = match *p {
+        hir::QPath::Resolved(_, ref path) => &path.segments,
+        hir::QPath::TypeRelative(_, ref segment) => return segment.ident.to_string(),
+    };
+
+    let mut s = String::new();
+    for (i, seg) in segments.iter().enumerate() {
+        if i > 0 {
+            s.push_str("::");
+        }
+        if seg.ident.name != kw::PathRoot {
+            s.push_str(&seg.ident.as_str());
+        }
+    }
+    s
+}
+
+pub fn build_deref_target_impls(cx: &DocContext<'_>,
+                                items: &[Item],
+                                ret: &mut Vec<Item>) {
+    use self::PrimitiveType::*;
+    let tcx = cx.tcx;
+
+    for item in items {
+        let target = match item.inner {
+            ItemEnum::TypedefItem(ref t, true) => &t.type_,
+            _ => continue,
+        };
+        let primitive = match *target {
+            ResolvedPath { did, .. } if did.is_local() => continue,
+            ResolvedPath { did, .. } => {
+                ret.extend(inline::build_impls(cx, did, None));
+                continue
+            }
+            _ => match target.primitive_type() {
+                Some(prim) => prim,
+                None => continue,
+            }
+        };
+        let did = match primitive {
+            Isize => tcx.lang_items().isize_impl(),
+            I8 => tcx.lang_items().i8_impl(),
+            I16 => tcx.lang_items().i16_impl(),
+            I32 => tcx.lang_items().i32_impl(),
+            I64 => tcx.lang_items().i64_impl(),
+            I128 => tcx.lang_items().i128_impl(),
+            Usize => tcx.lang_items().usize_impl(),
+            U8 => tcx.lang_items().u8_impl(),
+            U16 => tcx.lang_items().u16_impl(),
+            U32 => tcx.lang_items().u32_impl(),
+            U64 => tcx.lang_items().u64_impl(),
+            U128 => tcx.lang_items().u128_impl(),
+            F32 => tcx.lang_items().f32_impl(),
+            F64 => tcx.lang_items().f64_impl(),
+            Char => tcx.lang_items().char_impl(),
+            Bool => tcx.lang_items().bool_impl(),
+            Str => tcx.lang_items().str_impl(),
+            Slice => tcx.lang_items().slice_impl(),
+            Array => tcx.lang_items().slice_impl(),
+            Tuple => None,
+            Unit => None,
+            RawPointer => tcx.lang_items().const_ptr_impl(),
+            Reference => None,
+            Fn => None,
+            Never => None,
+        };
+        if let Some(did) = did {
+            if !did.is_local() {
+                inline::build_impl(cx, did, None, ret);
+            }
+        }
+    }
+}
+
+pub trait ToSource {
+    fn to_src(&self, cx: &DocContext<'_>) -> String;
+}
+
+impl ToSource for syntax_pos::Span {
+    fn to_src(&self, cx: &DocContext<'_>) -> String {
+        debug!("converting span {:?} to snippet", self.clean(cx));
+        let sn = match cx.sess().source_map().span_to_snippet(*self) {
+            Ok(x) => x,
+            Err(_) => String::new()
+        };
+        debug!("got snippet {}", sn);
+        sn
+    }
+}
+
+pub fn name_from_pat(p: &hir::Pat) -> String {
+    use rustc::hir::*;
+    debug!("trying to get a name from pattern: {:?}", p);
+
+    match p.kind {
+        PatKind::Wild => "_".to_string(),
+        PatKind::Binding(_, _, ident, _) => ident.to_string(),
+        PatKind::TupleStruct(ref p, ..) | PatKind::Path(ref p) => qpath_to_string(p),
+        PatKind::Struct(ref name, ref fields, etc) => {
+            format!("{} {{ {}{} }}", qpath_to_string(name),
+                fields.iter().map(|fp| format!("{}: {}", fp.ident, name_from_pat(&fp.pat)))
+                             .collect::<Vec<String>>().join(", "),
+                if etc { ", .." } else { "" }
+            )
+        }
+        PatKind::Or(ref pats) => {
+            pats.iter().map(|p| name_from_pat(&**p)).collect::<Vec<String>>().join(" | ")
+        }
+        PatKind::Tuple(ref elts, _) => format!("({})", elts.iter().map(|p| name_from_pat(&**p))
+                                            .collect::<Vec<String>>().join(", ")),
+        PatKind::Box(ref p) => name_from_pat(&**p),
+        PatKind::Ref(ref p, _) => name_from_pat(&**p),
+        PatKind::Lit(..) => {
+            warn!("tried to get argument name from PatKind::Lit, \
+                  which is silly in function arguments");
+            "()".to_string()
+        },
+        PatKind::Range(..) => panic!("tried to get argument name from PatKind::Range, \
+                              which is not allowed in function arguments"),
+        PatKind::Slice(ref begin, ref mid, ref end) => {
+            let begin = begin.iter().map(|p| name_from_pat(&**p));
+            let mid = mid.as_ref().map(|p| format!("..{}", name_from_pat(&**p))).into_iter();
+            let end = end.iter().map(|p| name_from_pat(&**p));
+            format!("[{}]", begin.chain(mid).chain(end).collect::<Vec<_>>().join(", "))
+        },
+    }
+}
+
+pub fn print_const(cx: &DocContext<'_>, n: &ty::Const<'_>) -> String {
+    match n.val {
+        ty::ConstKind::Unevaluated(def_id, _) => {
+            if let Some(hir_id) = cx.tcx.hir().as_local_hir_id(def_id) {
+                print_const_expr(cx, cx.tcx.hir().body_owned_by(hir_id))
+            } else {
+                inline::print_inlined_const(cx, def_id)
+            }
+        },
+        _ => {
+            let mut s = n.to_string();
+            // array lengths are obviously usize
+            if s.ends_with("usize") {
+                let n = s.len() - "usize".len();
+                s.truncate(n);
+                if s.ends_with(": ") {
+                    let n = s.len() - ": ".len();
+                    s.truncate(n);
+                }
+            }
+            s
+        },
+    }
+}
+
+pub fn print_const_expr(cx: &DocContext<'_>, body: hir::BodyId) -> String {
+    cx.tcx.hir().hir_to_pretty_string(body.hir_id)
+}
+
+/// Given a type Path, resolve it to a Type using the TyCtxt
+pub fn resolve_type(cx: &DocContext<'_>,
+                    path: Path,
+                    id: hir::HirId) -> Type {
+    if id == hir::DUMMY_HIR_ID {
+        debug!("resolve_type({:?})", path);
+    } else {
+        debug!("resolve_type({:?},{:?})", path, id);
+    }
+
+    let is_generic = match path.res {
+        Res::PrimTy(p) => match p {
+            hir::Str => return Primitive(PrimitiveType::Str),
+            hir::Bool => return Primitive(PrimitiveType::Bool),
+            hir::Char => return Primitive(PrimitiveType::Char),
+            hir::Int(int_ty) => return Primitive(int_ty.into()),
+            hir::Uint(uint_ty) => return Primitive(uint_ty.into()),
+            hir::Float(float_ty) => return Primitive(float_ty.into()),
+        },
+        Res::SelfTy(..) if path.segments.len() == 1 => {
+            return Generic(kw::SelfUpper.to_string());
+        }
+        Res::Def(DefKind::TyParam, _) if path.segments.len() == 1 => {
+            return Generic(format!("{:#}", path.print()));
+        }
+        Res::SelfTy(..)
+        | Res::Def(DefKind::TyParam, _)
+        | Res::Def(DefKind::AssocTy, _) => true,
+        _ => false,
+    };
+    let did = register_res(&*cx, path.res);
+    ResolvedPath { path, param_names: None, did, is_generic }
+}
+
+pub fn get_auto_trait_and_blanket_impls(
+    cx: &DocContext<'tcx>,
+    ty: Ty<'tcx>,
+    param_env_def_id: DefId,
+) -> impl Iterator<Item = Item> {
+    AutoTraitFinder::new(cx).get_auto_trait_impls(ty, param_env_def_id).into_iter()
+        .chain(BlanketImplFinder::new(cx).get_blanket_impls(ty, param_env_def_id))
+}
+
+pub fn register_res(cx: &DocContext<'_>, res: Res) -> DefId {
+    debug!("register_res({:?})", res);
+
+    let (did, kind) = match res {
+        Res::Def(DefKind::Fn, i) => (i, TypeKind::Function),
+        Res::Def(DefKind::TyAlias, i) => (i, TypeKind::Typedef),
+        Res::Def(DefKind::Enum, i) => (i, TypeKind::Enum),
+        Res::Def(DefKind::Trait, i) => (i, TypeKind::Trait),
+        Res::Def(DefKind::Struct, i) => (i, TypeKind::Struct),
+        Res::Def(DefKind::Union, i) => (i, TypeKind::Union),
+        Res::Def(DefKind::Mod, i) => (i, TypeKind::Module),
+        Res::Def(DefKind::ForeignTy, i) => (i, TypeKind::Foreign),
+        Res::Def(DefKind::Const, i) => (i, TypeKind::Const),
+        Res::Def(DefKind::Static, i) => (i, TypeKind::Static),
+        Res::Def(DefKind::Variant, i) => (cx.tcx.parent(i).expect("cannot get parent def id"),
+                            TypeKind::Enum),
+        Res::Def(DefKind::Macro(mac_kind), i) => match mac_kind {
+            MacroKind::Bang => (i, TypeKind::Macro),
+            MacroKind::Attr => (i, TypeKind::Attr),
+            MacroKind::Derive => (i, TypeKind::Derive),
+        },
+        Res::Def(DefKind::TraitAlias, i) => (i, TypeKind::TraitAlias),
+        Res::SelfTy(Some(def_id), _) => (def_id, TypeKind::Trait),
+        Res::SelfTy(_, Some(impl_def_id)) => return impl_def_id,
+        _ => return res.def_id()
+    };
+    if did.is_local() { return did }
+    inline::record_extern_fqn(cx, did, kind);
+    if let TypeKind::Trait = kind {
+        inline::record_extern_trait(cx, did);
+    }
+    did
+}
+
+pub fn resolve_use_source(cx: &DocContext<'_>, path: Path) -> ImportSource {
+    ImportSource {
+        did: if path.res.opt_def_id().is_none() {
+            None
+        } else {
+            Some(register_res(cx, path.res))
+        },
+        path,
+    }
+}
+
+pub fn enter_impl_trait<F, R>(cx: &DocContext<'_>, f: F) -> R
+where
+    F: FnOnce() -> R,
+{
+    let old_bounds = mem::take(&mut *cx.impl_trait_bounds.borrow_mut());
+    let r = f();
+    assert!(cx.impl_trait_bounds.borrow().is_empty());
+    *cx.impl_trait_bounds.borrow_mut() = old_bounds;
+    r
+}

src/librustdoc/html/format.rs

@@ -63,6 +63,13 @@ impl Buffer {
         }
     }
 
+    crate fn new() -> Buffer {
+        Buffer {
+            for_html: false,
+            buffer: String::new(),
+        }
+    }
+
     crate fn is_empty(&self) -> bool {
         self.buffer.is_empty()
     }
@@ -106,6 +113,10 @@ impl Buffer {
             write!(self, "{:#}", t);
         }
     }
+
+    crate fn is_for_html(&self) -> bool {
+        self.for_html
+    }
 }
 
 /// Wrapper struct for properly emitting a function or method declaration.

src/librustdoc/html/render.rs

@@ -2282,12 +2282,23 @@ fn render_implementor(cx: &Context, implementor: &Impl, w: &mut Buffer,
 fn render_impls(cx: &Context, w: &mut Buffer,
                 traits: &[&&Impl],
                 containing_item: &clean::Item) {
-    for i in traits {
+    let mut impls = traits.iter()
+        .map(|i| {
             let did = i.trait_did().unwrap();
             let assoc_link = AssocItemLink::GotoSource(did, &i.inner_impl().provided_trait_methods);
-        render_impl(w, cx, i, assoc_link,
+            let mut buffer = if w.is_for_html() {
-                    RenderMode::Normal, containing_item.stable_since(), true, None, false, true);
+                Buffer::html()
-    }
+            } else {
+                Buffer::new()
+            };
+            render_impl(&mut buffer, cx, i, assoc_link,
+                        RenderMode::Normal, containing_item.stable_since(),
+                        true, None, false, true);
+            buffer.into_inner()
+        })
+        .collect::<Vec<_>>();
+    impls.sort();
+    w.write_str(&impls.join(""));
 }
 
 fn bounds(t_bounds: &[clean::GenericBound], trait_alias: bool) -> String {

src/libstd/collections/mod.rs

@@ -433,7 +433,7 @@ mod hash;
 
 #[stable(feature = "rust1", since = "1.0.0")]
 pub mod hash_map {
-    //! A hash map implemented with linear probing and Robin Hood bucket stealing.
+    //! A hash map implemented with quadratic probing and SIMD lookup.
     #[stable(feature = "rust1", since = "1.0.0")]
     pub use super::hash::map::*;
 }

src/test/ui/consts/assoc_const_generic_impl.rs

@@ -0,0 +1,19 @@
+#![warn(const_err)]
+
+trait ZeroSized: Sized {
+    const I_AM_ZERO_SIZED: ();
+    fn requires_zero_size(self);
+}
+
+impl<T: Sized> ZeroSized for T {
+    const I_AM_ZERO_SIZED: ()  = [()][std::mem::size_of::<Self>()]; //~ WARN any use of this value
+    fn requires_zero_size(self) {
+        let () = Self::I_AM_ZERO_SIZED; //~ ERROR erroneous constant encountered
+        println!("requires_zero_size called");
+    }
+}
+
+fn main() {
+    ().requires_zero_size();
+    42_u32.requires_zero_size();
+}

src/test/ui/consts/assoc_const_generic_impl.stderr

@@ -0,0 +1,22 @@
+warning: any use of this value will cause an error
+  --> $DIR/assoc_const_generic_impl.rs:9:34
+   |
+LL |     const I_AM_ZERO_SIZED: ()  = [()][std::mem::size_of::<Self>()];
+   |     -----------------------------^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^-
+   |                                  |
+   |                                  index out of bounds: the len is 1 but the index is 4
+   |
+note: lint level defined here
+  --> $DIR/assoc_const_generic_impl.rs:1:9
+   |
+LL | #![warn(const_err)]
+   |         ^^^^^^^^^
+
+error: erroneous constant encountered
+  --> $DIR/assoc_const_generic_impl.rs:11:18
+   |
+LL |         let () = Self::I_AM_ZERO_SIZED;
+   |                  ^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to previous error
+