From 4d7c0b68cf2df93158747180bef0c7c6724e4dd3 Mon Sep 17 00:00:00 2001
From: achernyak <artemchernyak@gmail.com>
Date: Wed, 3 May 2017 08:17:54 -0500
Subject: [PATCH 01/17] all queries use dep nodes

---
 src/librustc/dep_graph/dep_node.rs |  6 ++++++
 src/librustc/ty/maps.rs            | 10 +++-------
 2 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/src/librustc/dep_graph/dep_node.rs b/src/librustc/dep_graph/dep_node.rs
index 37b8a56d9166b..1c71079e94b27 100644
--- a/src/librustc/dep_graph/dep_node.rs
+++ b/src/librustc/dep_graph/dep_node.rs
@@ -154,6 +154,9 @@ pub enum DepNode<D: Clone + Debug> {
     DefSpan(D),
     Stability(D),
     Deprecation(D),
+    ItemBodyNestedBodies(D),
+    ConstIsRvaluePromotableToStatic(D),
+    IsMirAvailable(D),
 }
 
 impl<D: Clone + Debug> DepNode<D> {
@@ -264,6 +267,9 @@ impl<D: Clone + Debug> DepNode<D> {
             DefSpan(ref d) => op(d).map(DefSpan),
             Stability(ref d) => op(d).map(Stability),
             Deprecation(ref d) => op(d).map(Deprecation),
+            ItemBodyNestedBodies(ref d) => op(d).map(ItemBodyNestedBodies),
+            ConstIsRvaluePromotableToStatic(ref d) => op(d).map(ConstIsRvaluePromotableToStatic),
+            IsMirAvailable(ref d) => op(d).map(IsMirAvailable),
         }
     }
 }
diff --git a/src/librustc/ty/maps.rs b/src/librustc/ty/maps.rs
index 66df8dc050a24..513240a4ec345 100644
--- a/src/librustc/ty/maps.rs
+++ b/src/librustc/ty/maps.rs
@@ -783,9 +783,9 @@ define_maps! { <'tcx>
     [] def_span: DefSpan(DefId) -> Span,
     [] stability: Stability(DefId) -> Option<attr::Stability>,
     [] deprecation: Deprecation(DefId) -> Option<attr::Deprecation>,
-    [] item_body_nested_bodies: metadata_dep_node(DefId) -> Rc<BTreeMap<hir::BodyId, hir::Body>>,
-    [] const_is_rvalue_promotable_to_static: metadata_dep_node(DefId) -> bool,
-    [] is_mir_available: metadata_dep_node(DefId) -> bool,
+    [] item_body_nested_bodies: ItemBodyNestedBodies(DefId) -> Rc<BTreeMap<hir::BodyId, hir::Body>>,
+    [] const_is_rvalue_promotable_to_static: ConstIsRvaluePromotableToStatic(DefId) -> bool,
+    [] is_mir_available: IsMirAvailable(DefId) -> bool,
 }
 
 fn coherent_trait_dep_node((_, def_id): (CrateNum, DefId)) -> DepNode<DefId> {
@@ -800,10 +800,6 @@ fn reachability_dep_node(_: CrateNum) -> DepNode<DefId> {
     DepNode::Reachability
 }
 
-fn metadata_dep_node(def_id: DefId) -> DepNode<DefId> {
-    DepNode::MetaData(def_id)
-}
-
 fn mir_shim_dep_node(instance: ty::InstanceDef) -> DepNode<DefId> {
     instance.dep_node()
 }

From a12a55f519baea94c049fcda6d14dcd56110f39d Mon Sep 17 00:00:00 2001
From: achernyak <artemchernyak@gmail.com>
Date: Wed, 3 May 2017 08:40:32 -0500
Subject: [PATCH 02/17] item_attrs

---
 src/librustc/dep_graph/dep_node.rs   | 2 ++
 src/librustc/middle/cstore.rs        | 2 --
 src/librustc/ty/maps.rs              | 8 ++++++++
 src/librustc/ty/mod.rs               | 2 +-
 src/librustc_metadata/cstore_impl.rs | 7 +------
 5 files changed, 12 insertions(+), 9 deletions(-)

diff --git a/src/librustc/dep_graph/dep_node.rs b/src/librustc/dep_graph/dep_node.rs
index 1c71079e94b27..fb8678ce93eae 100644
--- a/src/librustc/dep_graph/dep_node.rs
+++ b/src/librustc/dep_graph/dep_node.rs
@@ -157,6 +157,7 @@ pub enum DepNode<D: Clone + Debug> {
     ItemBodyNestedBodies(D),
     ConstIsRvaluePromotableToStatic(D),
     IsMirAvailable(D),
+    ItemAttrs(D),
 }
 
 impl<D: Clone + Debug> DepNode<D> {
@@ -267,6 +268,7 @@ impl<D: Clone + Debug> DepNode<D> {
             DefSpan(ref d) => op(d).map(DefSpan),
             Stability(ref d) => op(d).map(Stability),
             Deprecation(ref d) => op(d).map(Deprecation),
+            ItemAttrs(ref d) => op(d).map(ItemAttrs),
             ItemBodyNestedBodies(ref d) => op(d).map(ItemBodyNestedBodies),
             ConstIsRvaluePromotableToStatic(ref d) => op(d).map(ConstIsRvaluePromotableToStatic),
             IsMirAvailable(ref d) => op(d).map(IsMirAvailable),
diff --git a/src/librustc/middle/cstore.rs b/src/librustc/middle/cstore.rs
index 303c5059e7cf3..e30b4b2818e5e 100644
--- a/src/librustc/middle/cstore.rs
+++ b/src/librustc/middle/cstore.rs
@@ -182,7 +182,6 @@ pub trait CrateStore {
     fn visibility(&self, def: DefId) -> ty::Visibility;
     fn visible_parent_map<'a>(&'a self) -> ::std::cell::Ref<'a, DefIdMap<DefId>>;
     fn item_generics_cloned(&self, def: DefId) -> ty::Generics;
-    fn item_attrs(&self, def_id: DefId) -> Rc<[ast::Attribute]>;
     fn fn_arg_names(&self, did: DefId) -> Vec<ast::Name>;
 
     // trait info
@@ -309,7 +308,6 @@ impl CrateStore for DummyCrateStore {
     }
     fn item_generics_cloned(&self, def: DefId) -> ty::Generics
         { bug!("item_generics_cloned") }
-    fn item_attrs(&self, def_id: DefId) -> Rc<[ast::Attribute]> { bug!("item_attrs") }
     fn fn_arg_names(&self, did: DefId) -> Vec<ast::Name> { bug!("fn_arg_names") }
 
     // trait info
diff --git a/src/librustc/ty/maps.rs b/src/librustc/ty/maps.rs
index 513240a4ec345..948df61786751 100644
--- a/src/librustc/ty/maps.rs
+++ b/src/librustc/ty/maps.rs
@@ -34,6 +34,7 @@ use std::ops::Deref;
 use std::rc::Rc;
 use syntax_pos::{Span, DUMMY_SP};
 use syntax::attr;
+use syntax::ast;
 use syntax::symbol::Symbol;
 
 pub trait Key: Clone + Hash + Eq + Debug {
@@ -334,6 +335,12 @@ impl<'tcx> QueryDescription for queries::deprecation<'tcx> {
     }
 }
 
+impl<'tcx> QueryDescription for queries::item_attrs<'tcx> {
+    fn describe(_: TyCtxt, _: DefId) -> String {
+        bug!("item_attrs")
+    }
+}
+
 impl<'tcx> QueryDescription for queries::item_body_nested_bodies<'tcx> {
     fn describe(tcx: TyCtxt, def_id: DefId) -> String {
         format!("nested item bodies of `{}`", tcx.item_path_str(def_id))
@@ -783,6 +790,7 @@ define_maps! { <'tcx>
     [] def_span: DefSpan(DefId) -> Span,
     [] stability: Stability(DefId) -> Option<attr::Stability>,
     [] deprecation: Deprecation(DefId) -> Option<attr::Deprecation>,
+    [] item_attrs: ItemAttrs(DefId) -> Rc<[ast::Attribute]>,
     [] item_body_nested_bodies: ItemBodyNestedBodies(DefId) -> Rc<BTreeMap<hir::BodyId, hir::Body>>,
     [] const_is_rvalue_promotable_to_static: ConstIsRvaluePromotableToStatic(DefId) -> bool,
     [] is_mir_available: IsMirAvailable(DefId) -> bool,
diff --git a/src/librustc/ty/mod.rs b/src/librustc/ty/mod.rs
index 55466b1f36dac..3cc250f0814ef 100644
--- a/src/librustc/ty/mod.rs
+++ b/src/librustc/ty/mod.rs
@@ -2357,7 +2357,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         if let Some(id) = self.hir.as_local_node_id(did) {
             Attributes::Borrowed(self.hir.attrs(id))
         } else {
-            Attributes::Owned(self.sess.cstore.item_attrs(did))
+            Attributes::Owned(self.item_attrs(did))
         }
     }
 
diff --git a/src/librustc_metadata/cstore_impl.rs b/src/librustc_metadata/cstore_impl.rs
index a1794ec2d82ca..c7a52922e2a09 100644
--- a/src/librustc_metadata/cstore_impl.rs
+++ b/src/librustc_metadata/cstore_impl.rs
@@ -113,6 +113,7 @@ provide! { <'tcx> tcx, def_id, cdata
     def_span => { cdata.get_span(def_id.index, &tcx.sess) }
     stability => { cdata.get_stability(def_id.index) }
     deprecation => { cdata.get_deprecation(def_id.index) }
+    item_attrs => { cdata.get_item_attrs(def_id.index) }
     item_body_nested_bodies => {
         let map: BTreeMap<_, _> = cdata.entry(def_id.index).ast.into_iter().flat_map(|ast| {
             ast.decode(cdata).nested_bodies.decode(cdata).map(|body| (body.id(), body))
@@ -145,12 +146,6 @@ impl CrateStore for cstore::CStore {
         self.get_crate_data(def.krate).get_generics(def.index)
     }
 
-    fn item_attrs(&self, def_id: DefId) -> Rc<[ast::Attribute]>
-    {
-        self.dep_graph.read(DepNode::MetaData(def_id));
-        self.get_crate_data(def_id.krate).get_item_attrs(def_id.index)
-    }
-
     fn fn_arg_names(&self, did: DefId) -> Vec<ast::Name>
     {
         // FIXME(#38501) We've skipped a `read` on the `HirBody` of

From c72a16b8e2e1febb300cab5b97fc3265a463e775 Mon Sep 17 00:00:00 2001
From: achernyak <artemchernyak@gmail.com>
Date: Wed, 3 May 2017 09:01:49 -0500
Subject: [PATCH 03/17] fn_arg_names

---
 src/librustc/dep_graph/dep_node.rs   |  2 ++
 src/librustc/middle/cstore.rs        |  2 --
 src/librustc/ty/maps.rs              |  7 +++++++
 src/librustc_metadata/cstore_impl.rs | 15 +++++----------
 src/librustdoc/clean/mod.rs          |  2 +-
 5 files changed, 15 insertions(+), 13 deletions(-)

diff --git a/src/librustc/dep_graph/dep_node.rs b/src/librustc/dep_graph/dep_node.rs
index fb8678ce93eae..591c128a16559 100644
--- a/src/librustc/dep_graph/dep_node.rs
+++ b/src/librustc/dep_graph/dep_node.rs
@@ -158,6 +158,7 @@ pub enum DepNode<D: Clone + Debug> {
     ConstIsRvaluePromotableToStatic(D),
     IsMirAvailable(D),
     ItemAttrs(D),
+    FnArgNames(D),
 }
 
 impl<D: Clone + Debug> DepNode<D> {
@@ -269,6 +270,7 @@ impl<D: Clone + Debug> DepNode<D> {
             Stability(ref d) => op(d).map(Stability),
             Deprecation(ref d) => op(d).map(Deprecation),
             ItemAttrs(ref d) => op(d).map(ItemAttrs),
+            FnArgNames(ref d) => op(d).map(FnArgNames),
             ItemBodyNestedBodies(ref d) => op(d).map(ItemBodyNestedBodies),
             ConstIsRvaluePromotableToStatic(ref d) => op(d).map(ConstIsRvaluePromotableToStatic),
             IsMirAvailable(ref d) => op(d).map(IsMirAvailable),
diff --git a/src/librustc/middle/cstore.rs b/src/librustc/middle/cstore.rs
index e30b4b2818e5e..00904f5406172 100644
--- a/src/librustc/middle/cstore.rs
+++ b/src/librustc/middle/cstore.rs
@@ -182,7 +182,6 @@ pub trait CrateStore {
     fn visibility(&self, def: DefId) -> ty::Visibility;
     fn visible_parent_map<'a>(&'a self) -> ::std::cell::Ref<'a, DefIdMap<DefId>>;
     fn item_generics_cloned(&self, def: DefId) -> ty::Generics;
-    fn fn_arg_names(&self, did: DefId) -> Vec<ast::Name>;
 
     // trait info
     fn implementations_of_trait(&self, filter: Option<DefId>) -> Vec<DefId>;
@@ -308,7 +307,6 @@ impl CrateStore for DummyCrateStore {
     }
     fn item_generics_cloned(&self, def: DefId) -> ty::Generics
         { bug!("item_generics_cloned") }
-    fn fn_arg_names(&self, did: DefId) -> Vec<ast::Name> { bug!("fn_arg_names") }
 
     // trait info
     fn implementations_of_trait(&self, filter: Option<DefId>) -> Vec<DefId> { vec![] }
diff --git a/src/librustc/ty/maps.rs b/src/librustc/ty/maps.rs
index 948df61786751..43f6c94b8b095 100644
--- a/src/librustc/ty/maps.rs
+++ b/src/librustc/ty/maps.rs
@@ -341,6 +341,12 @@ impl<'tcx> QueryDescription for queries::item_attrs<'tcx> {
     }
 }
 
+impl<'tcx> QueryDescription for queries::fn_arg_names<'tcx> {
+    fn describe(_: TyCtxt, _: DefId) -> String {
+        bug!("fn_arg_names")
+    }
+}
+
 impl<'tcx> QueryDescription for queries::item_body_nested_bodies<'tcx> {
     fn describe(tcx: TyCtxt, def_id: DefId) -> String {
         format!("nested item bodies of `{}`", tcx.item_path_str(def_id))
@@ -791,6 +797,7 @@ define_maps! { <'tcx>
     [] stability: Stability(DefId) -> Option<attr::Stability>,
     [] deprecation: Deprecation(DefId) -> Option<attr::Deprecation>,
     [] item_attrs: ItemAttrs(DefId) -> Rc<[ast::Attribute]>,
+    [] fn_arg_names: FnArgNames(DefId) -> Vec<ast::Name>,
     [] item_body_nested_bodies: ItemBodyNestedBodies(DefId) -> Rc<BTreeMap<hir::BodyId, hir::Body>>,
     [] const_is_rvalue_promotable_to_static: ConstIsRvaluePromotableToStatic(DefId) -> bool,
     [] is_mir_available: IsMirAvailable(DefId) -> bool,
diff --git a/src/librustc_metadata/cstore_impl.rs b/src/librustc_metadata/cstore_impl.rs
index c7a52922e2a09..325ba14da9c8a 100644
--- a/src/librustc_metadata/cstore_impl.rs
+++ b/src/librustc_metadata/cstore_impl.rs
@@ -114,6 +114,11 @@ provide! { <'tcx> tcx, def_id, cdata
     stability => { cdata.get_stability(def_id.index) }
     deprecation => { cdata.get_deprecation(def_id.index) }
     item_attrs => { cdata.get_item_attrs(def_id.index) }
+    // FIXME(#38501) We've skipped a `read` on the `HirBody` of
+    // a `fn` when encoding, so the dep-tracking wouldn't work.
+    // This is only used by rustdoc anyway, which shouldn't have
+    // incremental recompilation ever enabled.
+    fn_arg_names => { cdata.get_fn_arg_names(def_id.index) }
     item_body_nested_bodies => {
         let map: BTreeMap<_, _> = cdata.entry(def_id.index).ast.into_iter().flat_map(|ast| {
             ast.decode(cdata).nested_bodies.decode(cdata).map(|body| (body.id(), body))
@@ -146,16 +151,6 @@ impl CrateStore for cstore::CStore {
         self.get_crate_data(def.krate).get_generics(def.index)
     }
 
-    fn fn_arg_names(&self, did: DefId) -> Vec<ast::Name>
-    {
-        // FIXME(#38501) We've skipped a `read` on the `HirBody` of
-        // a `fn` when encoding, so the dep-tracking wouldn't work.
-        // This is only used by rustdoc anyway, which shouldn't have
-        // incremental recompilation ever enabled.
-        assert!(!self.dep_graph.is_fully_enabled());
-        self.get_crate_data(did.krate).get_fn_arg_names(did.index)
-    }
-
     fn implementations_of_trait(&self, filter: Option<DefId>) -> Vec<DefId>
     {
         if let Some(def_id) = filter {
diff --git a/src/librustdoc/clean/mod.rs b/src/librustdoc/clean/mod.rs
index 0a74848724432..78b96e1833b6d 100644
--- a/src/librustdoc/clean/mod.rs
+++ b/src/librustdoc/clean/mod.rs
@@ -1179,7 +1179,7 @@ impl<'a, 'tcx> Clean<FnDecl> for (DefId, ty::PolyFnSig<'tcx>) {
         let mut names = if cx.tcx.hir.as_local_node_id(did).is_some() {
             vec![].into_iter()
         } else {
-            cx.tcx.sess.cstore.fn_arg_names(did).into_iter()
+            cx.tcx.fn_arg_names(did).into_iter()
         }.peekable();
         FnDecl {
             output: Return(sig.skip_binder().output().clean(cx)),

From aa5a5320466d4a6ac7125cb01956307e63d9918b Mon Sep 17 00:00:00 2001
From: achernyak <artemchernyak@gmail.com>
Date: Thu, 4 May 2017 08:27:48 -0500
Subject: [PATCH 04/17] trait_of_item

---
 src/librustc/dep_graph/dep_node.rs   |  2 ++
 src/librustc/middle/cstore.rs        |  2 --
 src/librustc/ty/maps.rs              |  7 ++++++
 src/librustc/ty/mod.rs               | 34 +++++++++++++++-------------
 src/librustc_const_eval/eval.rs      |  2 +-
 src/librustc_metadata/cstore_impl.rs |  6 +----
 6 files changed, 29 insertions(+), 24 deletions(-)

diff --git a/src/librustc/dep_graph/dep_node.rs b/src/librustc/dep_graph/dep_node.rs
index 591c128a16559..0e462b95d820e 100644
--- a/src/librustc/dep_graph/dep_node.rs
+++ b/src/librustc/dep_graph/dep_node.rs
@@ -156,6 +156,7 @@ pub enum DepNode<D: Clone + Debug> {
     Deprecation(D),
     ItemBodyNestedBodies(D),
     ConstIsRvaluePromotableToStatic(D),
+    TraitOfItem(D),
     IsMirAvailable(D),
     ItemAttrs(D),
     FnArgNames(D),
@@ -271,6 +272,7 @@ impl<D: Clone + Debug> DepNode<D> {
             Deprecation(ref d) => op(d).map(Deprecation),
             ItemAttrs(ref d) => op(d).map(ItemAttrs),
             FnArgNames(ref d) => op(d).map(FnArgNames),
+            TraitOfItem(ref d) => op(d).map(TraitOfItem),
             ItemBodyNestedBodies(ref d) => op(d).map(ItemBodyNestedBodies),
             ConstIsRvaluePromotableToStatic(ref d) => op(d).map(ConstIsRvaluePromotableToStatic),
             IsMirAvailable(ref d) => op(d).map(IsMirAvailable),
diff --git a/src/librustc/middle/cstore.rs b/src/librustc/middle/cstore.rs
index 00904f5406172..11a2dfc6685a1 100644
--- a/src/librustc/middle/cstore.rs
+++ b/src/librustc/middle/cstore.rs
@@ -191,7 +191,6 @@ pub trait CrateStore {
     fn impl_parent(&self, impl_def_id: DefId) -> Option<DefId>;
 
     // trait/impl-item info
-    fn trait_of_item(&self, def_id: DefId) -> Option<DefId>;
     fn associated_item_cloned(&self, def: DefId) -> ty::AssociatedItem;
 
     // flags
@@ -316,7 +315,6 @@ impl CrateStore for DummyCrateStore {
     fn impl_parent(&self, def: DefId) -> Option<DefId> { bug!("impl_parent") }
 
     // trait/impl-item info
-    fn trait_of_item(&self, def_id: DefId) -> Option<DefId> { bug!("trait_of_item") }
     fn associated_item_cloned(&self, def: DefId) -> ty::AssociatedItem
         { bug!("associated_item_cloned") }
 
diff --git a/src/librustc/ty/maps.rs b/src/librustc/ty/maps.rs
index 43f6c94b8b095..5d1b16c3d2e1c 100644
--- a/src/librustc/ty/maps.rs
+++ b/src/librustc/ty/maps.rs
@@ -347,6 +347,12 @@ impl<'tcx> QueryDescription for queries::fn_arg_names<'tcx> {
     }
 }
 
+impl<'tcx> QueryDescription for queries::trait_of_item<'tcx> {
+    fn describe(_: TyCtxt, _: DefId) -> String {
+        bug!("trait_of_item")
+    }
+}
+
 impl<'tcx> QueryDescription for queries::item_body_nested_bodies<'tcx> {
     fn describe(tcx: TyCtxt, def_id: DefId) -> String {
         format!("nested item bodies of `{}`", tcx.item_path_str(def_id))
@@ -798,6 +804,7 @@ define_maps! { <'tcx>
     [] deprecation: Deprecation(DefId) -> Option<attr::Deprecation>,
     [] item_attrs: ItemAttrs(DefId) -> Rc<[ast::Attribute]>,
     [] fn_arg_names: FnArgNames(DefId) -> Vec<ast::Name>,
+    [] trait_of_item: TraitOfItem(DefId) -> Option<DefId>,
     [] item_body_nested_bodies: ItemBodyNestedBodies(DefId) -> Rc<BTreeMap<hir::BodyId, hir::Body>>,
     [] const_is_rvalue_promotable_to_static: ConstIsRvaluePromotableToStatic(DefId) -> bool,
     [] is_mir_available: IsMirAvailable(DefId) -> bool,
diff --git a/src/librustc/ty/mod.rs b/src/librustc/ty/mod.rs
index 3cc250f0814ef..00f81c9dcf7bc 100644
--- a/src/librustc/ty/mod.rs
+++ b/src/librustc/ty/mod.rs
@@ -2430,22 +2430,6 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         }
     }
 
-    /// If the given def ID describes an item belonging to a trait,
-    /// return the ID of the trait that the trait item belongs to.
-    /// Otherwise, return `None`.
-    pub fn trait_of_item(self, def_id: DefId) -> Option<DefId> {
-        if def_id.krate != LOCAL_CRATE {
-            return self.sess.cstore.trait_of_item(def_id);
-        }
-        self.opt_associated_item(def_id)
-            .and_then(|associated_item| {
-                match associated_item.container {
-                    TraitContainer(def_id) => Some(def_id),
-                    ImplContainer(_) => None
-                }
-            })
-    }
-
     /// Construct a parameter environment suitable for static contexts or other contexts where there
     /// are no free type/lifetime parameters in scope.
     pub fn empty_parameter_environment(self) -> ParameterEnvironment<'tcx> {
@@ -2693,6 +2677,23 @@ fn def_span<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Span {
     tcx.hir.span_if_local(def_id).unwrap()
 }
 
+/// If the given def ID describes an item belonging to a trait,
+/// return the ID of the trait that the trait item belongs to.
+/// Otherwise, return `None`.
+fn trait_of_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Option<DefId> {
+    if def_id.krate != LOCAL_CRATE {
+        return None
+    }
+    tcx.opt_associated_item(def_id)
+        .and_then(|associated_item| {
+            match associated_item.container {
+                TraitContainer(def_id) => Some(def_id),
+                ImplContainer(_) => None
+            }
+        })
+}
+
+
 pub fn provide(providers: &mut ty::maps::Providers) {
     *providers = ty::maps::Providers {
         associated_item,
@@ -2700,6 +2701,7 @@ pub fn provide(providers: &mut ty::maps::Providers) {
         adt_sized_constraint,
         adt_dtorck_constraint,
         def_span,
+        trait_of_item,
         ..*providers
     };
 }
diff --git a/src/librustc_const_eval/eval.rs b/src/librustc_const_eval/eval.rs
index 8b1aa0708807b..e79f23aee1145 100644
--- a/src/librustc_const_eval/eval.rs
+++ b/src/librustc_const_eval/eval.rs
@@ -74,7 +74,7 @@ pub fn lookup_const_by_id<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                 // constants, we only try to find the expression for a
                 // trait-associated const if the caller gives us the
                 // substitutions for the reference to it.
-                if tcx.sess.cstore.trait_of_item(def_id).is_some() {
+                if tcx.trait_of_item(def_id).is_some() {
                     resolve_trait_associated_const(tcx, def_id, substs)
                 } else {
                     Some((def_id, substs))
diff --git a/src/librustc_metadata/cstore_impl.rs b/src/librustc_metadata/cstore_impl.rs
index 325ba14da9c8a..b07dd1ec7b0b8 100644
--- a/src/librustc_metadata/cstore_impl.rs
+++ b/src/librustc_metadata/cstore_impl.rs
@@ -119,6 +119,7 @@ provide! { <'tcx> tcx, def_id, cdata
     // This is only used by rustdoc anyway, which shouldn't have
     // incremental recompilation ever enabled.
     fn_arg_names => { cdata.get_fn_arg_names(def_id.index) }
+    trait_of_item => { cdata.get_trait_of_item(def_id.index) }
     item_body_nested_bodies => {
         let map: BTreeMap<_, _> = cdata.entry(def_id.index).ast.into_iter().flat_map(|ast| {
             ast.decode(cdata).nested_bodies.decode(cdata).map(|body| (body.id(), body))
@@ -174,11 +175,6 @@ impl CrateStore for cstore::CStore {
         self.get_crate_data(impl_def.krate).get_parent_impl(impl_def.index)
     }
 
-    fn trait_of_item(&self, def_id: DefId) -> Option<DefId> {
-        self.dep_graph.read(DepNode::MetaData(def_id));
-        self.get_crate_data(def_id.krate).get_trait_of_item(def_id.index)
-    }
-
     fn associated_item_cloned(&self, def: DefId) -> ty::AssociatedItem
     {
         self.dep_graph.read(DepNode::MetaData(def));

From 03fe10d91d3361144ab5c8a142daf63bc0ff143e Mon Sep 17 00:00:00 2001
From: achernyak <artemchernyak@gmail.com>
Date: Thu, 4 May 2017 09:37:34 -0500
Subject: [PATCH 05/17] impl_parent

---
 src/librustc/dep_graph/dep_node.rs   | 2 ++
 src/librustc/middle/cstore.rs        | 2 --
 src/librustc/ty/maps.rs              | 7 +++++++
 src/librustc/ty/mod.rs               | 2 +-
 src/librustc_metadata/cstore_impl.rs | 6 +-----
 5 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/src/librustc/dep_graph/dep_node.rs b/src/librustc/dep_graph/dep_node.rs
index 0e462b95d820e..de1531bbd54d3 100644
--- a/src/librustc/dep_graph/dep_node.rs
+++ b/src/librustc/dep_graph/dep_node.rs
@@ -156,6 +156,7 @@ pub enum DepNode<D: Clone + Debug> {
     Deprecation(D),
     ItemBodyNestedBodies(D),
     ConstIsRvaluePromotableToStatic(D),
+    ImplParent(D),
     TraitOfItem(D),
     IsMirAvailable(D),
     ItemAttrs(D),
@@ -272,6 +273,7 @@ impl<D: Clone + Debug> DepNode<D> {
             Deprecation(ref d) => op(d).map(Deprecation),
             ItemAttrs(ref d) => op(d).map(ItemAttrs),
             FnArgNames(ref d) => op(d).map(FnArgNames),
+            ImplParent(ref d) => op(d).map(ImplParent),
             TraitOfItem(ref d) => op(d).map(TraitOfItem),
             ItemBodyNestedBodies(ref d) => op(d).map(ItemBodyNestedBodies),
             ConstIsRvaluePromotableToStatic(ref d) => op(d).map(ConstIsRvaluePromotableToStatic),
diff --git a/src/librustc/middle/cstore.rs b/src/librustc/middle/cstore.rs
index 11a2dfc6685a1..e50072043d5f7 100644
--- a/src/librustc/middle/cstore.rs
+++ b/src/librustc/middle/cstore.rs
@@ -188,7 +188,6 @@ pub trait CrateStore {
 
     // impl info
     fn impl_defaultness(&self, def: DefId) -> hir::Defaultness;
-    fn impl_parent(&self, impl_def_id: DefId) -> Option<DefId>;
 
     // trait/impl-item info
     fn associated_item_cloned(&self, def: DefId) -> ty::AssociatedItem;
@@ -312,7 +311,6 @@ impl CrateStore for DummyCrateStore {
 
     // impl info
     fn impl_defaultness(&self, def: DefId) -> hir::Defaultness { bug!("impl_defaultness") }
-    fn impl_parent(&self, def: DefId) -> Option<DefId> { bug!("impl_parent") }
 
     // trait/impl-item info
     fn associated_item_cloned(&self, def: DefId) -> ty::AssociatedItem
diff --git a/src/librustc/ty/maps.rs b/src/librustc/ty/maps.rs
index 5d1b16c3d2e1c..1dfd7bc976082 100644
--- a/src/librustc/ty/maps.rs
+++ b/src/librustc/ty/maps.rs
@@ -347,6 +347,12 @@ impl<'tcx> QueryDescription for queries::fn_arg_names<'tcx> {
     }
 }
 
+impl<'tcx> QueryDescription for queries::impl_parent<'tcx> {
+    fn describe(_: TyCtxt, _: DefId) -> String {
+        bug!("impl_parent")
+    }
+}
+
 impl<'tcx> QueryDescription for queries::trait_of_item<'tcx> {
     fn describe(_: TyCtxt, _: DefId) -> String {
         bug!("trait_of_item")
@@ -804,6 +810,7 @@ define_maps! { <'tcx>
     [] deprecation: Deprecation(DefId) -> Option<attr::Deprecation>,
     [] item_attrs: ItemAttrs(DefId) -> Rc<[ast::Attribute]>,
     [] fn_arg_names: FnArgNames(DefId) -> Vec<ast::Name>,
+    [] impl_parent: ImplParent(DefId) -> Option<DefId>,
     [] trait_of_item: TraitOfItem(DefId) -> Option<DefId>,
     [] item_body_nested_bodies: ItemBodyNestedBodies(DefId) -> Rc<BTreeMap<hir::BodyId, hir::Body>>,
     [] const_is_rvalue_promotable_to_static: ConstIsRvaluePromotableToStatic(DefId) -> bool,
diff --git a/src/librustc/ty/mod.rs b/src/librustc/ty/mod.rs
index 00f81c9dcf7bc..1c3e74d4fb965 100644
--- a/src/librustc/ty/mod.rs
+++ b/src/librustc/ty/mod.rs
@@ -2393,7 +2393,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
             let trait_ref = self.impl_trait_ref(impl_def_id).unwrap();
 
             // Record the trait->implementation mapping.
-            let parent = self.sess.cstore.impl_parent(impl_def_id).unwrap_or(trait_id);
+            let parent = self.impl_parent(impl_def_id).unwrap_or(trait_id);
             def.record_remote_impl(self, impl_def_id, trait_ref, parent);
         }
 
diff --git a/src/librustc_metadata/cstore_impl.rs b/src/librustc_metadata/cstore_impl.rs
index b07dd1ec7b0b8..b54db55c0e12a 100644
--- a/src/librustc_metadata/cstore_impl.rs
+++ b/src/librustc_metadata/cstore_impl.rs
@@ -119,6 +119,7 @@ provide! { <'tcx> tcx, def_id, cdata
     // This is only used by rustdoc anyway, which shouldn't have
     // incremental recompilation ever enabled.
     fn_arg_names => { cdata.get_fn_arg_names(def_id.index) }
+    impl_parent => { cdata.get_parent_impl(def_id.index) }
     trait_of_item => { cdata.get_trait_of_item(def_id.index) }
     item_body_nested_bodies => {
         let map: BTreeMap<_, _> = cdata.entry(def_id.index).ast.into_iter().flat_map(|ast| {
@@ -170,11 +171,6 @@ impl CrateStore for cstore::CStore {
         self.get_crate_data(def.krate).get_impl_defaultness(def.index)
     }
 
-    fn impl_parent(&self, impl_def: DefId) -> Option<DefId> {
-        self.dep_graph.read(DepNode::MetaData(impl_def));
-        self.get_crate_data(impl_def.krate).get_parent_impl(impl_def.index)
-    }
-
     fn associated_item_cloned(&self, def: DefId) -> ty::AssociatedItem
     {
         self.dep_graph.read(DepNode::MetaData(def));

From 5b71d769ffe751399b538fb0fdb51ec88345061b Mon Sep 17 00:00:00 2001
From: achernyak <artemchernyak@gmail.com>
Date: Thu, 4 May 2017 12:45:56 -0500
Subject: [PATCH 06/17] moved metadata provider impls to decoder

---
 src/librustc_metadata/cstore_impl.rs | 18 +++---------------
 src/librustc_metadata/decoder.rs     | 23 ++++++++++++++++++++---
 2 files changed, 23 insertions(+), 18 deletions(-)

diff --git a/src/librustc_metadata/cstore_impl.rs b/src/librustc_metadata/cstore_impl.rs
index b54db55c0e12a..a0c887e95d6c7 100644
--- a/src/librustc_metadata/cstore_impl.rs
+++ b/src/librustc_metadata/cstore_impl.rs
@@ -41,8 +41,6 @@ use rustc::hir::svh::Svh;
 use rustc_back::target::Target;
 use rustc::hir;
 
-use std::collections::BTreeMap;
-
 macro_rules! provide {
     (<$lt:tt> $tcx:ident, $def_id:ident, $cdata:ident $($name:ident => $compute:block)*) => {
         pub fn provide<$lt>(providers: &mut Providers<$lt>) {
@@ -121,21 +119,11 @@ provide! { <'tcx> tcx, def_id, cdata
     fn_arg_names => { cdata.get_fn_arg_names(def_id.index) }
     impl_parent => { cdata.get_parent_impl(def_id.index) }
     trait_of_item => { cdata.get_trait_of_item(def_id.index) }
-    item_body_nested_bodies => {
-        let map: BTreeMap<_, _> = cdata.entry(def_id.index).ast.into_iter().flat_map(|ast| {
-            ast.decode(cdata).nested_bodies.decode(cdata).map(|body| (body.id(), body))
-        }).collect();
-
-        Rc::new(map)
-    }
+    item_body_nested_bodies => { Rc::new(cdata.item_body_nested_bodies(def_id.index)) }
     const_is_rvalue_promotable_to_static => {
-        cdata.entry(def_id.index).ast.expect("const item missing `ast`")
-            .decode(cdata).rvalue_promotable_to_static
-    }
-    is_mir_available => {
-        !cdata.is_proc_macro(def_id.index) &&
-        cdata.maybe_entry(def_id.index).and_then(|item| item.decode(cdata).mir).is_some()
+        cdata.const_is_rvalue_promotable_to_static(def_id.index)
     }
+    is_mir_available => { cdata.is_item_mir_available(def_id.index) }
 }
 
 impl CrateStore for cstore::CStore {
diff --git a/src/librustc_metadata/decoder.rs b/src/librustc_metadata/decoder.rs
index ae755adcf5fbb..b89b5181e7bb7 100644
--- a/src/librustc_metadata/decoder.rs
+++ b/src/librustc_metadata/decoder.rs
@@ -29,6 +29,7 @@ use rustc::mir::Mir;
 
 use std::borrow::Cow;
 use std::cell::Ref;
+use std::collections::BTreeMap;
 use std::io;
 use std::mem;
 use std::rc::Rc;
@@ -448,16 +449,16 @@ impl<'tcx> EntryKind<'tcx> {
 }
 
 impl<'a, 'tcx> CrateMetadata {
-    pub fn is_proc_macro(&self, id: DefIndex) -> bool {
+    fn is_proc_macro(&self, id: DefIndex) -> bool {
         self.proc_macros.is_some() && id != CRATE_DEF_INDEX
     }
 
-    pub fn maybe_entry(&self, item_id: DefIndex) -> Option<Lazy<Entry<'tcx>>> {
+    fn maybe_entry(&self, item_id: DefIndex) -> Option<Lazy<Entry<'tcx>>> {
         assert!(!self.is_proc_macro(item_id));
         self.root.index.lookup(self.blob.raw_bytes(), item_id)
     }
 
-    pub fn entry(&self, item_id: DefIndex) -> Entry<'tcx> {
+    fn entry(&self, item_id: DefIndex) -> Entry<'tcx> {
         match self.maybe_entry(item_id) {
             None => {
                 bug!("entry: id not found: {:?} in crate {:?} with number {}",
@@ -779,6 +780,22 @@ impl<'a, 'tcx> CrateMetadata {
         tcx.alloc_tables(ast.tables.decode((self, tcx)))
     }
 
+    pub fn item_body_nested_bodies(&self, id: DefIndex) -> BTreeMap<hir::BodyId, hir::Body> {
+        self.entry(id).ast.into_iter().flat_map(|ast| {
+            ast.decode(self).nested_bodies.decode(self).map(|body| (body.id(), body))
+        }).collect()
+    }
+
+    pub fn const_is_rvalue_promotable_to_static(&self, id: DefIndex) -> bool {
+        self.entry(id).ast.expect("const item missing `ast`")
+            .decode(self).rvalue_promotable_to_static
+    }
+
+    pub fn is_item_mir_available(&self, id: DefIndex) -> bool {
+        !self.is_proc_macro(id) &&
+        self.maybe_entry(id).and_then(|item| item.decode(self).mir).is_some()
+    }
+
     pub fn maybe_get_optimized_mir(&self,
                                    tcx: TyCtxt<'a, 'tcx, 'tcx>,
                                    id: DefIndex)

From 5a7946df703f2d9149adc0ca5c7e0b116e82a98d Mon Sep 17 00:00:00 2001
From: achernyak <artemchernyak@gmail.com>
Date: Fri, 5 May 2017 08:15:08 -0500
Subject: [PATCH 07/17] is_foreign_item

---
 src/librustc/middle/cstore.rs           | 2 --
 src/librustc/middle/effect.rs           | 2 +-
 src/librustc_metadata/cstore_impl.rs    | 4 ----
 src/librustc_trans/back/symbol_names.rs | 2 +-
 src/librustc_trans/collector.rs         | 2 +-
 src/librustc_trans/consts.rs            | 2 +-
 6 files changed, 4 insertions(+), 10 deletions(-)

diff --git a/src/librustc/middle/cstore.rs b/src/librustc/middle/cstore.rs
index e50072043d5f7..d9ce40a0d7de2 100644
--- a/src/librustc/middle/cstore.rs
+++ b/src/librustc/middle/cstore.rs
@@ -195,7 +195,6 @@ pub trait CrateStore {
     // flags
     fn is_const_fn(&self, did: DefId) -> bool;
     fn is_default_impl(&self, impl_did: DefId) -> bool;
-    fn is_foreign_item(&self, did: DefId) -> bool;
     fn is_dllimport_foreign_item(&self, def: DefId) -> bool;
     fn is_statically_included_foreign_item(&self, def_id: DefId) -> bool;
     fn is_exported_symbol(&self, def_id: DefId) -> bool;
@@ -319,7 +318,6 @@ impl CrateStore for DummyCrateStore {
     // flags
     fn is_const_fn(&self, did: DefId) -> bool { bug!("is_const_fn") }
     fn is_default_impl(&self, impl_did: DefId) -> bool { bug!("is_default_impl") }
-    fn is_foreign_item(&self, did: DefId) -> bool { bug!("is_foreign_item") }
     fn is_dllimport_foreign_item(&self, id: DefId) -> bool { false }
     fn is_statically_included_foreign_item(&self, def_id: DefId) -> bool { false }
     fn is_exported_symbol(&self, def_id: DefId) -> bool { false }
diff --git a/src/librustc/middle/effect.rs b/src/librustc/middle/effect.rs
index d2b8ed8c29707..4bbf37b21edbf 100644
--- a/src/librustc/middle/effect.rs
+++ b/src/librustc/middle/effect.rs
@@ -205,7 +205,7 @@ impl<'a, 'tcx> Visitor<'tcx> for EffectCheckVisitor<'a, 'tcx> {
                     } else if match self.tcx.hir.get_if_local(def_id) {
                         Some(hir::map::NodeForeignItem(..)) => true,
                         Some(..) => false,
-                        None => self.tcx.sess.cstore.is_foreign_item(def_id),
+                        None => self.tcx.is_foreign_item(def_id),
                     } {
                         self.require_unsafe_ext(expr.id, expr.span, "use of extern static", true);
                     }
diff --git a/src/librustc_metadata/cstore_impl.rs b/src/librustc_metadata/cstore_impl.rs
index a0c887e95d6c7..7bd431ff44621 100644
--- a/src/librustc_metadata/cstore_impl.rs
+++ b/src/librustc_metadata/cstore_impl.rs
@@ -176,10 +176,6 @@ impl CrateStore for cstore::CStore {
         self.get_crate_data(impl_did.krate).is_default_impl(impl_did.index)
     }
 
-    fn is_foreign_item(&self, did: DefId) -> bool {
-        self.get_crate_data(did.krate).is_foreign_item(did.index)
-    }
-
     fn is_statically_included_foreign_item(&self, def_id: DefId) -> bool
     {
         self.do_is_statically_included_foreign_item(def_id)
diff --git a/src/librustc_trans/back/symbol_names.rs b/src/librustc_trans/back/symbol_names.rs
index aef9140ba4556..1aed293294802 100644
--- a/src/librustc_trans/back/symbol_names.rs
+++ b/src/librustc_trans/back/symbol_names.rs
@@ -223,7 +223,7 @@ fn compute_symbol_name<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, instance: Instance
             _ => false
         }
     } else {
-        tcx.sess.cstore.is_foreign_item(def_id)
+        tcx.is_foreign_item(def_id)
     };
 
     if let Some(name) = weak_lang_items::link_name(&attrs) {
diff --git a/src/librustc_trans/collector.rs b/src/librustc_trans/collector.rs
index 6d7d95f548721..f0be0941ccf36 100644
--- a/src/librustc_trans/collector.rs
+++ b/src/librustc_trans/collector.rs
@@ -653,7 +653,7 @@ fn should_trans_locally<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, instance: &Instan
         Some(_) => true,
         None => {
             if tcx.sess.cstore.is_exported_symbol(def_id) ||
-                tcx.sess.cstore.is_foreign_item(def_id)
+                tcx.is_foreign_item(def_id)
             {
                 // We can link to the item in question, no instance needed
                 // in this crate
diff --git a/src/librustc_trans/consts.rs b/src/librustc_trans/consts.rs
index 6afb340107d66..eac0a06256719 100644
--- a/src/librustc_trans/consts.rs
+++ b/src/librustc_trans/consts.rs
@@ -186,7 +186,7 @@ pub fn get_static(ccx: &CrateContext, def_id: DefId) -> ValueRef {
                 llvm::set_thread_local(g, true);
             }
         }
-        if ccx.use_dll_storage_attrs() && !ccx.sess().cstore.is_foreign_item(def_id) {
+        if ccx.use_dll_storage_attrs() && !ccx.tcx().is_foreign_item(def_id) {
             // This item is external but not foreign, i.e. it originates from an external Rust
             // crate. Since we don't know whether this crate will be linked dynamically or
             // statically in the final application, we always mark such symbols as 'dllimport'.

From d561d4c9eb808cbca28fd641934825fdf96fb762 Mon Sep 17 00:00:00 2001
From: achernyak <artemchernyak@gmail.com>
Date: Fri, 5 May 2017 14:40:26 -0500
Subject: [PATCH 08/17] propper trait of item impl

---
 src/librustc/ty/mod.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/librustc/ty/mod.rs b/src/librustc/ty/mod.rs
index 1c3e74d4fb965..9f43ed9bf5bb5 100644
--- a/src/librustc/ty/mod.rs
+++ b/src/librustc/ty/mod.rs
@@ -2682,7 +2682,7 @@ fn def_span<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Span {
 /// Otherwise, return `None`.
 fn trait_of_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Option<DefId> {
     if def_id.krate != LOCAL_CRATE {
-        return None
+        return tcx.trait_of_item(def_id)
     }
     tcx.opt_associated_item(def_id)
         .and_then(|associated_item| {

From 1f532bfed5e0a80bf145f5db504601dc037367a1 Mon Sep 17 00:00:00 2001
From: achernyak <artemchernyak@gmail.com>
Date: Sun, 7 May 2017 21:05:31 -0500
Subject: [PATCH 09/17] is_exported_symbol

---
 src/librustc/dep_graph/dep_node.rs   | 2 ++
 src/librustc/middle/cstore.rs        | 2 --
 src/librustc/ty/maps.rs              | 7 +++++++
 src/librustc_metadata/cstore_impl.rs | 5 +----
 src/librustc_trans/collector.rs      | 2 +-
 5 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/src/librustc/dep_graph/dep_node.rs b/src/librustc/dep_graph/dep_node.rs
index de1531bbd54d3..712ada4ec65bb 100644
--- a/src/librustc/dep_graph/dep_node.rs
+++ b/src/librustc/dep_graph/dep_node.rs
@@ -158,6 +158,7 @@ pub enum DepNode<D: Clone + Debug> {
     ConstIsRvaluePromotableToStatic(D),
     ImplParent(D),
     TraitOfItem(D),
+    IsExportedSymbol(D),
     IsMirAvailable(D),
     ItemAttrs(D),
     FnArgNames(D),
@@ -275,6 +276,7 @@ impl<D: Clone + Debug> DepNode<D> {
             FnArgNames(ref d) => op(d).map(FnArgNames),
             ImplParent(ref d) => op(d).map(ImplParent),
             TraitOfItem(ref d) => op(d).map(TraitOfItem),
+            IsExportedSymbol(ref d) => op(d).map(IsExportedSymbol),
             ItemBodyNestedBodies(ref d) => op(d).map(ItemBodyNestedBodies),
             ConstIsRvaluePromotableToStatic(ref d) => op(d).map(ConstIsRvaluePromotableToStatic),
             IsMirAvailable(ref d) => op(d).map(IsMirAvailable),
diff --git a/src/librustc/middle/cstore.rs b/src/librustc/middle/cstore.rs
index d9ce40a0d7de2..6f0a990ca4126 100644
--- a/src/librustc/middle/cstore.rs
+++ b/src/librustc/middle/cstore.rs
@@ -197,7 +197,6 @@ pub trait CrateStore {
     fn is_default_impl(&self, impl_did: DefId) -> bool;
     fn is_dllimport_foreign_item(&self, def: DefId) -> bool;
     fn is_statically_included_foreign_item(&self, def_id: DefId) -> bool;
-    fn is_exported_symbol(&self, def_id: DefId) -> bool;
 
     // crate metadata
     fn dylib_dependency_formats(&self, cnum: CrateNum)
@@ -320,7 +319,6 @@ impl CrateStore for DummyCrateStore {
     fn is_default_impl(&self, impl_did: DefId) -> bool { bug!("is_default_impl") }
     fn is_dllimport_foreign_item(&self, id: DefId) -> bool { false }
     fn is_statically_included_foreign_item(&self, def_id: DefId) -> bool { false }
-    fn is_exported_symbol(&self, def_id: DefId) -> bool { false }
 
     // crate metadata
     fn dylib_dependency_formats(&self, cnum: CrateNum)
diff --git a/src/librustc/ty/maps.rs b/src/librustc/ty/maps.rs
index 1dfd7bc976082..80783a547bf42 100644
--- a/src/librustc/ty/maps.rs
+++ b/src/librustc/ty/maps.rs
@@ -341,6 +341,12 @@ impl<'tcx> QueryDescription for queries::item_attrs<'tcx> {
     }
 }
 
+impl<'tcx> QueryDescription for queries::is_exported_symbol<'tcx> {
+    fn describe(_: TyCtxt, _: DefId) -> String {
+        bug!("is_exported_symbol")
+    }
+}
+
 impl<'tcx> QueryDescription for queries::fn_arg_names<'tcx> {
     fn describe(_: TyCtxt, _: DefId) -> String {
         bug!("fn_arg_names")
@@ -812,6 +818,7 @@ define_maps! { <'tcx>
     [] fn_arg_names: FnArgNames(DefId) -> Vec<ast::Name>,
     [] impl_parent: ImplParent(DefId) -> Option<DefId>,
     [] trait_of_item: TraitOfItem(DefId) -> Option<DefId>,
+    [] is_exported_symbol: IsExportedSymbol(DefId) -> bool,
     [] item_body_nested_bodies: ItemBodyNestedBodies(DefId) -> Rc<BTreeMap<hir::BodyId, hir::Body>>,
     [] const_is_rvalue_promotable_to_static: ConstIsRvaluePromotableToStatic(DefId) -> bool,
     [] is_mir_available: IsMirAvailable(DefId) -> bool,
diff --git a/src/librustc_metadata/cstore_impl.rs b/src/librustc_metadata/cstore_impl.rs
index 7bd431ff44621..d29fa8f081497 100644
--- a/src/librustc_metadata/cstore_impl.rs
+++ b/src/librustc_metadata/cstore_impl.rs
@@ -119,6 +119,7 @@ provide! { <'tcx> tcx, def_id, cdata
     fn_arg_names => { cdata.get_fn_arg_names(def_id.index) }
     impl_parent => { cdata.get_parent_impl(def_id.index) }
     trait_of_item => { cdata.get_trait_of_item(def_id.index) }
+    is_exported_symbol => { cdata.exported_symbols.contains(&def_id.index) }
     item_body_nested_bodies => { Rc::new(cdata.item_body_nested_bodies(def_id.index)) }
     const_is_rvalue_promotable_to_static => {
         cdata.const_is_rvalue_promotable_to_static(def_id.index)
@@ -181,10 +182,6 @@ impl CrateStore for cstore::CStore {
         self.do_is_statically_included_foreign_item(def_id)
     }
 
-    fn is_exported_symbol(&self, def_id: DefId) -> bool {
-        self.get_crate_data(def_id.krate).exported_symbols.contains(&def_id.index)
-    }
-
     fn is_dllimport_foreign_item(&self, def_id: DefId) -> bool {
         if def_id.krate == LOCAL_CRATE {
             self.dllimport_foreign_items.borrow().contains(&def_id.index)
diff --git a/src/librustc_trans/collector.rs b/src/librustc_trans/collector.rs
index f0be0941ccf36..5f8b79a994a55 100644
--- a/src/librustc_trans/collector.rs
+++ b/src/librustc_trans/collector.rs
@@ -652,7 +652,7 @@ fn should_trans_locally<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, instance: &Instan
         }
         Some(_) => true,
         None => {
-            if tcx.sess.cstore.is_exported_symbol(def_id) ||
+            if tcx.is_exported_symbol(def_id) ||
                 tcx.is_foreign_item(def_id)
             {
                 // We can link to the item in question, no instance needed

From dfb740f83ca1d6f2056f5cf8de1adbe81b973438 Mon Sep 17 00:00:00 2001
From: achernyak <artemchernyak@gmail.com>
Date: Mon, 8 May 2017 14:30:30 -0500
Subject: [PATCH 10/17] removed unnecessary if

---
 src/librustc/ty/mod.rs | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/src/librustc/ty/mod.rs b/src/librustc/ty/mod.rs
index 9f43ed9bf5bb5..a065dd6a592f2 100644
--- a/src/librustc/ty/mod.rs
+++ b/src/librustc/ty/mod.rs
@@ -2681,9 +2681,6 @@ fn def_span<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Span {
 /// return the ID of the trait that the trait item belongs to.
 /// Otherwise, return `None`.
 fn trait_of_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Option<DefId> {
-    if def_id.krate != LOCAL_CRATE {
-        return tcx.trait_of_item(def_id)
-    }
     tcx.opt_associated_item(def_id)
         .and_then(|associated_item| {
             match associated_item.container {

From 84a40c14430566b94a238d5399929bc16867f519 Mon Sep 17 00:00:00 2001
From: Michael Woerister <michaelwoerister@posteo.net>
Date: Wed, 10 May 2017 11:00:08 +0200
Subject: [PATCH 11/17] ICH: Handle case of removed FileMaps.

---
 src/librustc_incremental/persist/hash.rs      |  6 +++-
 .../remove_source_file/auxiliary/mod.rs       | 13 ++++++++
 .../incremental/remove_source_file/main.rs    | 31 +++++++++++++++++++
 3 files changed, 49 insertions(+), 1 deletion(-)
 create mode 100644 src/test/incremental/remove_source_file/auxiliary/mod.rs
 create mode 100644 src/test/incremental/remove_source_file/main.rs

diff --git a/src/librustc_incremental/persist/hash.rs b/src/librustc_incremental/persist/hash.rs
index 5bc442deafa2b..2f727a80f016e 100644
--- a/src/librustc_incremental/persist/hash.rs
+++ b/src/librustc_incremental/persist/hash.rs
@@ -79,7 +79,11 @@ impl<'a, 'tcx> HashContext<'a, 'tcx> {
 
             DepNode::FileMap(def_id, ref name) => {
                 if def_id.is_local() {
-                    Some(self.incremental_hashes_map[dep_node])
+                    // We will have been able to retrace the DefId (which is
+                    // always the local CRATE_DEF_INDEX), but the file with the
+                    // given name might have been removed, so we use get() in
+                    // order to allow for that case.
+                    self.incremental_hashes_map.get(dep_node).map(|x| *x)
                 } else {
                     Some(self.metadata_hash(DepNode::FileMap(def_id, name.clone()),
                                             def_id.krate,
diff --git a/src/test/incremental/remove_source_file/auxiliary/mod.rs b/src/test/incremental/remove_source_file/auxiliary/mod.rs
new file mode 100644
index 0000000000000..a2cea65a309ce
--- /dev/null
+++ b/src/test/incremental/remove_source_file/auxiliary/mod.rs
@@ -0,0 +1,13 @@
+// Copyright 2017 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.
+
+pub fn print_hello() {
+    println!("hello");
+}
diff --git a/src/test/incremental/remove_source_file/main.rs b/src/test/incremental/remove_source_file/main.rs
new file mode 100644
index 0000000000000..4ba33f3bb3d62
--- /dev/null
+++ b/src/test/incremental/remove_source_file/main.rs
@@ -0,0 +1,31 @@
+// Copyright 2017 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.
+
+// This test case makes sure that the compiler doesn't crash due to a failing
+// table lookup when a source file is removed.
+
+// revisions:rpass1 rpass2
+
+// Note that we specify -g so that the FileMaps actually get referenced by the
+// incr. comp. cache:
+// compile-flags: -Z query-dep-graph -g
+
+#[cfg(rpass1)]
+mod auxiliary;
+
+#[cfg(rpass1)]
+fn main() {
+    auxiliary::print_hello();
+}
+
+#[cfg(rpass2)]
+fn main() {
+    println!("hello");
+}

From d23a65077add9da538e7ba2c2d3c3baae7a8597e Mon Sep 17 00:00:00 2001
From: Eduard-Mihai Burtescu <edy.burt@gmail.com>
Date: Wed, 10 May 2017 14:37:29 +0300
Subject: [PATCH 12/17] compiletest: force GDB to print values in the Rust
 format.

---
 src/tools/compiletest/src/runtest.rs | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/tools/compiletest/src/runtest.rs b/src/tools/compiletest/src/runtest.rs
index a044282666da0..461cb59bf7dfa 100644
--- a/src/tools/compiletest/src/runtest.rs
+++ b/src/tools/compiletest/src/runtest.rs
@@ -647,6 +647,11 @@ actual:\n\
                                              exe_file.to_str().unwrap()
                                              .replace(r"\", r"\\")));
 
+                // Force GDB to print values in the Rust format.
+                if self.config.gdb_native_rust {
+                    script_str.push_str("set language rust\n");
+                }
+
                 // Add line breakpoints
                 for line in &breakpoint_lines {
                     script_str.push_str(&format!("break '{}':{}\n",

From 76127275a09d970169952bcf616f966faa9ed6db Mon Sep 17 00:00:00 2001
From: Zack Weinberg <zackw@panix.com>
Date: Sat, 21 Jan 2017 13:38:11 -0500
Subject: [PATCH 13/17] Add `eprint!` and `eprintln!` macros to the prelude.

These are exactly the same as `print!` and `println!` except that
they write to stderr instead of stdout.  Issue #39228.
---
 src/libstd/io/mod.rs                          |  2 +
 src/libstd/io/stdio.rs                        | 36 +++++++++++++++
 src/libstd/macros.rs                          | 45 +++++++++++++++++++
 .../run-pass/print-stdout-eprint-stderr.rs    | 40 +++++++++++++++++
 4 files changed, 123 insertions(+)
 create mode 100644 src/test/run-pass/print-stdout-eprint-stderr.rs

diff --git a/src/libstd/io/mod.rs b/src/libstd/io/mod.rs
index e2832873e2e67..b6d3c920fb942 100644
--- a/src/libstd/io/mod.rs
+++ b/src/libstd/io/mod.rs
@@ -290,6 +290,8 @@ pub use self::util::{copy, sink, Sink, empty, Empty, repeat, Repeat};
 pub use self::stdio::{stdin, stdout, stderr, _print, Stdin, Stdout, Stderr};
 #[stable(feature = "rust1", since = "1.0.0")]
 pub use self::stdio::{StdoutLock, StderrLock, StdinLock};
+#[unstable(feature = "eprint", issue="39228")]
+pub use self::stdio::_eprint;
 #[unstable(feature = "libstd_io_internals", issue = "0")]
 #[doc(no_inline, hidden)]
 pub use self::stdio::{set_panic, set_print};
diff --git a/src/libstd/io/stdio.rs b/src/libstd/io/stdio.rs
index 38ad23e14b3eb..de80cb4980421 100644
--- a/src/libstd/io/stdio.rs
+++ b/src/libstd/io/stdio.rs
@@ -694,6 +694,42 @@ pub fn _print(args: fmt::Arguments) {
     }
 }
 
+#[unstable(feature = "eprint_internal",
+           reason = "implementation detail which may disappear or be replaced at any time",
+           issue = "0")]
+#[doc(hidden)]
+pub fn _eprint(args: fmt::Arguments) {
+    // As an implementation of the `eprintln!` macro, we want to try our best to
+    // not panic wherever possible and get the output somewhere. There are
+    // currently two possible vectors for panics we take care of here:
+    //
+    // 1. If the TLS key for the local stderr has been destroyed, accessing it
+    //    would cause a panic. Note that we just lump in the uninitialized case
+    //    here for convenience, we're not trying to avoid a panic.
+    // 2. If the local stderr is currently in use (e.g. we're in the middle of
+    //    already printing) then accessing again would cause a panic.
+    //
+    // If, however, the actual I/O causes an error, we do indeed panic.
+    use panicking::LOCAL_STDERR;
+    let result = match LOCAL_STDERR.state() {
+        LocalKeyState::Uninitialized |
+        LocalKeyState::Destroyed => stderr().write_fmt(args),
+        LocalKeyState::Valid => {
+            LOCAL_STDERR.with(|s| {
+                if let Ok(mut borrowed) = s.try_borrow_mut() {
+                    if let Some(w) = borrowed.as_mut() {
+                        return w.write_fmt(args);
+                    }
+                }
+                stderr().write_fmt(args)
+            })
+        }
+    };
+    if let Err(e) = result {
+        panic!("failed printing to stderr: {}", e);
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use thread;
diff --git a/src/libstd/macros.rs b/src/libstd/macros.rs
index a1f092621cb44..d1c304ec46e79 100644
--- a/src/libstd/macros.rs
+++ b/src/libstd/macros.rs
@@ -68,6 +68,9 @@ macro_rules! panic {
 /// necessary to use `io::stdout().flush()` to ensure the output is emitted
 /// immediately.
 ///
+/// Use `print!` only for the primary output of your program.  Use
+/// `eprint!` instead to print error and progress messages.
+///
 /// # Panics
 ///
 /// Panics if writing to `io::stdout()` fails.
@@ -105,6 +108,9 @@ macro_rules! print {
 /// Use the `format!` syntax to write data to the standard output.
 /// See `std::fmt` for more information.
 ///
+/// Use `println!` only for the primary output of your program.  Use
+/// `eprintln!` instead to print error and progress messages.
+///
 /// # Panics
 ///
 /// Panics if writing to `io::stdout()` fails.
@@ -124,6 +130,45 @@ macro_rules! println {
     ($fmt:expr, $($arg:tt)*) => (print!(concat!($fmt, "\n"), $($arg)*));
 }
 
+/// Macro for printing to the standard error.
+///
+/// Equivalent to the `print!` macro, except that output goes to
+/// `io::stderr()` instead of `io::stdout()`.  See `print!` for
+/// example usage.
+///
+/// Use `eprint!` only for error and progress messages.  Use `print!`
+/// instead for the primary output of your program.
+///
+/// # Panics
+///
+/// Panics if writing to `io::stderr()` fails.
+#[macro_export]
+#[unstable(feature = "eprint", issue="39228")]
+#[allow_internal_unstable]
+macro_rules! eprint {
+    ($($arg:tt)*) => ($crate::io::_eprint(format_args!($($arg)*)));
+}
+
+/// Macro for printing to the standard error, with a newline.
+///
+/// Equivalent to the `println!` macro, except that output goes to
+/// `io::stderr()` instead of `io::stdout()`.  See `println!` for
+/// example usage.
+///
+/// Use `eprintln!` only for error and progress messages.  Use `println!`
+/// instead for the primary output of your program.
+///
+/// # Panics
+///
+/// Panics if writing to `io::stderr()` fails.
+#[macro_export]
+#[unstable(feature = "eprint", issue="39228")]
+macro_rules! eprintln {
+    () => (eprint!("\n"));
+    ($fmt:expr) => (eprint!(concat!($fmt, "\n")));
+    ($fmt:expr, $($arg:tt)*) => (eprint!(concat!($fmt, "\n"), $($arg)*));
+}
+
 /// A macro to select an event from a number of receivers.
 ///
 /// This macro is used to wait for the first event to occur on a number of
diff --git a/src/test/run-pass/print-stdout-eprint-stderr.rs b/src/test/run-pass/print-stdout-eprint-stderr.rs
new file mode 100644
index 0000000000000..8ca6e1c63567e
--- /dev/null
+++ b/src/test/run-pass/print-stdout-eprint-stderr.rs
@@ -0,0 +1,40 @@
+// Copyright 2017 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.
+
+#![feature(eprint)]
+
+use std::{env, process};
+
+fn child() {
+    print!("[stdout 0]");
+    print!("[stdout {}]", 1);
+    println!("[stdout {}]", 2);
+    println!();
+    eprint!("[stderr 0]");
+    eprint!("[stderr {}]", 1);
+    eprintln!("[stderr {}]", 2);
+    eprintln!();
+}
+
+fn parent() {
+    let this = env::args().next().unwrap();
+    let output = process::Command::new(this).arg("-").output().unwrap();
+    assert!(output.status.success());
+
+    let stdout = String::from_utf8(output.stdout).unwrap();
+    let stderr = String::from_utf8(output.stderr).unwrap();
+
+    assert_eq!(stdout, "[stdout 0][stdout 1][stdout 2]\n\n");
+    assert_eq!(stderr, "[stderr 0][stderr 1][stderr 2]\n\n");
+}
+
+fn main() {
+    if env::args().count() == 2 { child() } else { parent() }
+}

From 07766f675caaabc1d64ef59db6ddfa43e72e6d4f Mon Sep 17 00:00:00 2001
From: Zack Weinberg <zackw@panix.com>
Date: Thu, 13 Apr 2017 10:48:09 -0400
Subject: [PATCH 14/17] Revise the eprint(ln)! feature.

 * Factor out the nigh-identical bodies of `_print` and `_eprint` to a helper
   function `print_to` (I was sorely tempted to call it `_doprnt`).
 * Update the issue number for the unstable `eprint` feature.
 * Add entries to the "unstable book" for `eprint` and `eprint_internal`.
 * Style corrections to the documentation.
---
 src/doc/unstable-book/src/SUMMARY.md          |  2 +
 .../src/library-features/eprint-internal.md   |  5 ++
 .../src/library-features/eprint.md            | 13 +++
 src/libstd/io/mod.rs                          |  2 +-
 src/libstd/io/stdio.rs                        | 79 +++++++------------
 src/libstd/macros.rs                          | 14 ++--
 6 files changed, 57 insertions(+), 58 deletions(-)
 create mode 100644 src/doc/unstable-book/src/library-features/eprint-internal.md
 create mode 100644 src/doc/unstable-book/src/library-features/eprint.md

diff --git a/src/doc/unstable-book/src/SUMMARY.md b/src/doc/unstable-book/src/SUMMARY.md
index 3d9e7c7fd860d..9229f445297df 100644
--- a/src/doc/unstable-book/src/SUMMARY.md
+++ b/src/doc/unstable-book/src/SUMMARY.md
@@ -130,6 +130,8 @@
     - [derive_eq](library-features/derive-eq.md)
     - [discriminant_value](library-features/discriminant-value.md)
     - [error_type_id](library-features/error-type-id.md)
+    - [eprint](library-features/eprint.md)
+    - [eprint_internal](library-features/eprint-internal.md)
     - [exact_size_is_empty](library-features/exact-size-is-empty.md)
     - [fd](library-features/fd.md)
     - [fd_read](library-features/fd-read.md)
diff --git a/src/doc/unstable-book/src/library-features/eprint-internal.md b/src/doc/unstable-book/src/library-features/eprint-internal.md
new file mode 100644
index 0000000000000..d3230d8bfa83e
--- /dev/null
+++ b/src/doc/unstable-book/src/library-features/eprint-internal.md
@@ -0,0 +1,5 @@
+# `eprint_internal`
+
+This feature is internal to the Rust compiler and is not intended for general use.
+
+------------------------
diff --git a/src/doc/unstable-book/src/library-features/eprint.md b/src/doc/unstable-book/src/library-features/eprint.md
new file mode 100644
index 0000000000000..69f781b224167
--- /dev/null
+++ b/src/doc/unstable-book/src/library-features/eprint.md
@@ -0,0 +1,13 @@
+# `eprint`
+
+The tracking issue for this feature is: [#40528]
+
+[#40528]: https://github.com/rust-lang/rust/issues/40528
+
+------------------------
+
+This feature enables the `eprint!` and `eprintln!` global macros,
+which are just like `print!` and `println!`, respectively, except that
+they send output to the standard _error_ stream, rather than standard
+output.  (`panic!` messages have always been written to standard error.)
+
diff --git a/src/libstd/io/mod.rs b/src/libstd/io/mod.rs
index b6d3c920fb942..9320bfe9abee5 100644
--- a/src/libstd/io/mod.rs
+++ b/src/libstd/io/mod.rs
@@ -290,7 +290,7 @@ pub use self::util::{copy, sink, Sink, empty, Empty, repeat, Repeat};
 pub use self::stdio::{stdin, stdout, stderr, _print, Stdin, Stdout, Stderr};
 #[stable(feature = "rust1", since = "1.0.0")]
 pub use self::stdio::{StdoutLock, StderrLock, StdinLock};
-#[unstable(feature = "eprint", issue="39228")]
+#[unstable(feature = "eprint", issue="40528")]
 pub use self::stdio::_eprint;
 #[unstable(feature = "libstd_io_internals", issue = "0")]
 #[doc(no_inline, hidden)]
diff --git a/src/libstd/io/stdio.rs b/src/libstd/io/stdio.rs
index de80cb4980421..363c99c666e3a 100644
--- a/src/libstd/io/stdio.rs
+++ b/src/libstd/io/stdio.rs
@@ -17,7 +17,7 @@ use io::{self, BufReader, LineWriter};
 use sync::{Arc, Mutex, MutexGuard};
 use sys::stdio;
 use sys_common::remutex::{ReentrantMutex, ReentrantMutexGuard};
-use thread::LocalKeyState;
+use thread::{LocalKey, LocalKeyState};
 
 /// Stdout used by print! and println! macros
 thread_local! {
@@ -659,75 +659,54 @@ pub fn set_print(sink: Option<Box<Write + Send>>) -> Option<Box<Write + Send>> {
     })
 }
 
-#[unstable(feature = "print",
-           reason = "implementation detail which may disappear or be replaced at any time",
-           issue = "0")]
-#[doc(hidden)]
-pub fn _print(args: fmt::Arguments) {
-    // As an implementation of the `println!` macro, we want to try our best to
-    // not panic wherever possible and get the output somewhere. There are
-    // currently two possible vectors for panics we take care of here:
-    //
-    // 1. If the TLS key for the local stdout has been destroyed, accessing it
-    //    would cause a panic. Note that we just lump in the uninitialized case
-    //    here for convenience, we're not trying to avoid a panic.
-    // 2. If the local stdout is currently in use (e.g. we're in the middle of
-    //    already printing) then accessing again would cause a panic.
-    //
-    // If, however, the actual I/O causes an error, we do indeed panic.
-    let result = match LOCAL_STDOUT.state() {
+/// Write `args` to output stream `local_s` if possible, `global_s`
+/// otherwise. `label` identifies the stream in a panic message.
+///
+/// This function is used to print error messages, so it takes extra
+/// care to avoid causing a panic when `local_stream` is unusable.
+/// For instance, if the TLS key for the local stream is uninitialized
+/// or already destroyed, or if the local stream is locked by another
+/// thread, it will just fall back to the global stream.
+///
+/// However, if the actual I/O causes an error, this function does panic.
+fn print_to<T>(args: fmt::Arguments,
+               local_s: &'static LocalKey<RefCell<Option<Box<Write+Send>>>>,
+               global_s: fn() -> T,
+               label: &str) where T: Write {
+    let result = match local_s.state() {
         LocalKeyState::Uninitialized |
-        LocalKeyState::Destroyed => stdout().write_fmt(args),
+        LocalKeyState::Destroyed => global_s().write_fmt(args),
         LocalKeyState::Valid => {
-            LOCAL_STDOUT.with(|s| {
+            local_s.with(|s| {
                 if let Ok(mut borrowed) = s.try_borrow_mut() {
                     if let Some(w) = borrowed.as_mut() {
                         return w.write_fmt(args);
                     }
                 }
-                stdout().write_fmt(args)
+                global_s().write_fmt(args)
             })
         }
     };
     if let Err(e) = result {
-        panic!("failed printing to stdout: {}", e);
+        panic!("failed printing to {}: {}", label, e);
     }
 }
 
+#[unstable(feature = "print",
+           reason = "implementation detail which may disappear or be replaced at any time",
+           issue = "0")]
+#[doc(hidden)]
+pub fn _print(args: fmt::Arguments) {
+    print_to(args, &LOCAL_STDOUT, stdout, "stdout");
+}
+
 #[unstable(feature = "eprint_internal",
            reason = "implementation detail which may disappear or be replaced at any time",
            issue = "0")]
 #[doc(hidden)]
 pub fn _eprint(args: fmt::Arguments) {
-    // As an implementation of the `eprintln!` macro, we want to try our best to
-    // not panic wherever possible and get the output somewhere. There are
-    // currently two possible vectors for panics we take care of here:
-    //
-    // 1. If the TLS key for the local stderr has been destroyed, accessing it
-    //    would cause a panic. Note that we just lump in the uninitialized case
-    //    here for convenience, we're not trying to avoid a panic.
-    // 2. If the local stderr is currently in use (e.g. we're in the middle of
-    //    already printing) then accessing again would cause a panic.
-    //
-    // If, however, the actual I/O causes an error, we do indeed panic.
     use panicking::LOCAL_STDERR;
-    let result = match LOCAL_STDERR.state() {
-        LocalKeyState::Uninitialized |
-        LocalKeyState::Destroyed => stderr().write_fmt(args),
-        LocalKeyState::Valid => {
-            LOCAL_STDERR.with(|s| {
-                if let Ok(mut borrowed) = s.try_borrow_mut() {
-                    if let Some(w) = borrowed.as_mut() {
-                        return w.write_fmt(args);
-                    }
-                }
-                stderr().write_fmt(args)
-            })
-        }
-    };
-    if let Err(e) = result {
-        panic!("failed printing to stderr: {}", e);
-    }
+    print_to(args, &LOCAL_STDERR, stderr, "stderr");
 }
 
 #[cfg(test)]
diff --git a/src/libstd/macros.rs b/src/libstd/macros.rs
index d1c304ec46e79..98c635d127f7d 100644
--- a/src/libstd/macros.rs
+++ b/src/libstd/macros.rs
@@ -113,7 +113,7 @@ macro_rules! print {
 ///
 /// # Panics
 ///
-/// Panics if writing to `io::stdout()` fails.
+/// Panics if writing to `io::stdout` fails.
 ///
 /// # Examples
 ///
@@ -133,7 +133,7 @@ macro_rules! println {
 /// Macro for printing to the standard error.
 ///
 /// Equivalent to the `print!` macro, except that output goes to
-/// `io::stderr()` instead of `io::stdout()`.  See `print!` for
+/// `io::stderr` instead of `io::stdout`.  See `print!` for
 /// example usage.
 ///
 /// Use `eprint!` only for error and progress messages.  Use `print!`
@@ -141,9 +141,9 @@ macro_rules! println {
 ///
 /// # Panics
 ///
-/// Panics if writing to `io::stderr()` fails.
+/// Panics if writing to `io::stderr` fails.
 #[macro_export]
-#[unstable(feature = "eprint", issue="39228")]
+#[unstable(feature = "eprint", issue="40528")]
 #[allow_internal_unstable]
 macro_rules! eprint {
     ($($arg:tt)*) => ($crate::io::_eprint(format_args!($($arg)*)));
@@ -152,7 +152,7 @@ macro_rules! eprint {
 /// Macro for printing to the standard error, with a newline.
 ///
 /// Equivalent to the `println!` macro, except that output goes to
-/// `io::stderr()` instead of `io::stdout()`.  See `println!` for
+/// `io::stderr` instead of `io::stdout`.  See `println!` for
 /// example usage.
 ///
 /// Use `eprintln!` only for error and progress messages.  Use `println!`
@@ -160,9 +160,9 @@ macro_rules! eprint {
 ///
 /// # Panics
 ///
-/// Panics if writing to `io::stderr()` fails.
+/// Panics if writing to `io::stderr` fails.
 #[macro_export]
-#[unstable(feature = "eprint", issue="39228")]
+#[unstable(feature = "eprint", issue="40528")]
 macro_rules! eprintln {
     () => (eprint!("\n"));
     ($fmt:expr) => (eprint!(concat!($fmt, "\n")));

From 4ab3bcb9ca137ad6e6ee4ae4a70a234d92b6d4ab Mon Sep 17 00:00:00 2001
From: Zack Weinberg <zackw@panix.com>
Date: Thu, 20 Apr 2017 17:37:12 -0400
Subject: [PATCH 15/17] Fix up stability annotations per feedback.

---
 src/doc/unstable-book/src/SUMMARY.md                |  4 +---
 .../unstable-book/src/library-features/eprint.md    | 13 -------------
 .../{eprint-internal.md => print-internals.md}      |  2 +-
 src/doc/unstable-book/src/library-features/print.md |  5 -----
 src/libstd/io/mod.rs                                |  6 +++---
 src/libstd/io/stdio.rs                              |  4 ++--
 src/libstd/macros.rs                                |  4 ++--
 src/test/run-pass/print-stdout-eprint-stderr.rs     |  2 --
 8 files changed, 9 insertions(+), 31 deletions(-)
 delete mode 100644 src/doc/unstable-book/src/library-features/eprint.md
 rename src/doc/unstable-book/src/library-features/{eprint-internal.md => print-internals.md} (84%)
 delete mode 100644 src/doc/unstable-book/src/library-features/print.md

diff --git a/src/doc/unstable-book/src/SUMMARY.md b/src/doc/unstable-book/src/SUMMARY.md
index 9229f445297df..8f26e4d36cda2 100644
--- a/src/doc/unstable-book/src/SUMMARY.md
+++ b/src/doc/unstable-book/src/SUMMARY.md
@@ -130,8 +130,6 @@
     - [derive_eq](library-features/derive-eq.md)
     - [discriminant_value](library-features/discriminant-value.md)
     - [error_type_id](library-features/error-type-id.md)
-    - [eprint](library-features/eprint.md)
-    - [eprint_internal](library-features/eprint-internal.md)
     - [exact_size_is_empty](library-features/exact-size-is-empty.md)
     - [fd](library-features/fd.md)
     - [fd_read](library-features/fd-read.md)
@@ -180,7 +178,7 @@
     - [peek](library-features/peek.md)
     - [placement_in](library-features/placement-in.md)
     - [placement_new_protocol](library-features/placement-new-protocol.md)
-    - [print](library-features/print.md)
+    - [print_internals](library-features/print-internals.md)
     - [proc_macro_internals](library-features/proc-macro-internals.md)
     - [process_try_wait](library-features/process-try-wait.md)
     - [question_mark_carrier](library-features/question-mark-carrier.md)
diff --git a/src/doc/unstable-book/src/library-features/eprint.md b/src/doc/unstable-book/src/library-features/eprint.md
deleted file mode 100644
index 69f781b224167..0000000000000
--- a/src/doc/unstable-book/src/library-features/eprint.md
+++ /dev/null
@@ -1,13 +0,0 @@
-# `eprint`
-
-The tracking issue for this feature is: [#40528]
-
-[#40528]: https://github.com/rust-lang/rust/issues/40528
-
-------------------------
-
-This feature enables the `eprint!` and `eprintln!` global macros,
-which are just like `print!` and `println!`, respectively, except that
-they send output to the standard _error_ stream, rather than standard
-output.  (`panic!` messages have always been written to standard error.)
-
diff --git a/src/doc/unstable-book/src/library-features/eprint-internal.md b/src/doc/unstable-book/src/library-features/print-internals.md
similarity index 84%
rename from src/doc/unstable-book/src/library-features/eprint-internal.md
rename to src/doc/unstable-book/src/library-features/print-internals.md
index d3230d8bfa83e..a68557872af55 100644
--- a/src/doc/unstable-book/src/library-features/eprint-internal.md
+++ b/src/doc/unstable-book/src/library-features/print-internals.md
@@ -1,4 +1,4 @@
-# `eprint_internal`
+# `print_internals`
 
 This feature is internal to the Rust compiler and is not intended for general use.
 
diff --git a/src/doc/unstable-book/src/library-features/print.md b/src/doc/unstable-book/src/library-features/print.md
deleted file mode 100644
index dc25cb237e3b5..0000000000000
--- a/src/doc/unstable-book/src/library-features/print.md
+++ /dev/null
@@ -1,5 +0,0 @@
-# `print`
-
-This feature is internal to the Rust compiler and is not intended for general use.
-
-------------------------
diff --git a/src/libstd/io/mod.rs b/src/libstd/io/mod.rs
index 9320bfe9abee5..c872a8e526114 100644
--- a/src/libstd/io/mod.rs
+++ b/src/libstd/io/mod.rs
@@ -287,11 +287,11 @@ pub use self::error::{Result, Error, ErrorKind};
 #[stable(feature = "rust1", since = "1.0.0")]
 pub use self::util::{copy, sink, Sink, empty, Empty, repeat, Repeat};
 #[stable(feature = "rust1", since = "1.0.0")]
-pub use self::stdio::{stdin, stdout, stderr, _print, Stdin, Stdout, Stderr};
+pub use self::stdio::{stdin, stdout, stderr, Stdin, Stdout, Stderr};
 #[stable(feature = "rust1", since = "1.0.0")]
 pub use self::stdio::{StdoutLock, StderrLock, StdinLock};
-#[unstable(feature = "eprint", issue="40528")]
-pub use self::stdio::_eprint;
+#[unstable(feature = "print_internals", issue = "0")]
+pub use self::stdio::{_print, _eprint};
 #[unstable(feature = "libstd_io_internals", issue = "0")]
 #[doc(no_inline, hidden)]
 pub use self::stdio::{set_panic, set_print};
diff --git a/src/libstd/io/stdio.rs b/src/libstd/io/stdio.rs
index 363c99c666e3a..a8b0bf0071a22 100644
--- a/src/libstd/io/stdio.rs
+++ b/src/libstd/io/stdio.rs
@@ -692,7 +692,7 @@ fn print_to<T>(args: fmt::Arguments,
     }
 }
 
-#[unstable(feature = "print",
+#[unstable(feature = "print_internals",
            reason = "implementation detail which may disappear or be replaced at any time",
            issue = "0")]
 #[doc(hidden)]
@@ -700,7 +700,7 @@ pub fn _print(args: fmt::Arguments) {
     print_to(args, &LOCAL_STDOUT, stdout, "stdout");
 }
 
-#[unstable(feature = "eprint_internal",
+#[unstable(feature = "print_internals",
            reason = "implementation detail which may disappear or be replaced at any time",
            issue = "0")]
 #[doc(hidden)]
diff --git a/src/libstd/macros.rs b/src/libstd/macros.rs
index 98c635d127f7d..ef78ea6dfe8ee 100644
--- a/src/libstd/macros.rs
+++ b/src/libstd/macros.rs
@@ -143,7 +143,7 @@ macro_rules! println {
 ///
 /// Panics if writing to `io::stderr` fails.
 #[macro_export]
-#[unstable(feature = "eprint", issue="40528")]
+#[stable(feature = "eprint", since="1.18.0")]
 #[allow_internal_unstable]
 macro_rules! eprint {
     ($($arg:tt)*) => ($crate::io::_eprint(format_args!($($arg)*)));
@@ -162,7 +162,7 @@ macro_rules! eprint {
 ///
 /// Panics if writing to `io::stderr` fails.
 #[macro_export]
-#[unstable(feature = "eprint", issue="40528")]
+#[stable(feature = "eprint", since="1.18.0")]
 macro_rules! eprintln {
     () => (eprint!("\n"));
     ($fmt:expr) => (eprint!(concat!($fmt, "\n")));
diff --git a/src/test/run-pass/print-stdout-eprint-stderr.rs b/src/test/run-pass/print-stdout-eprint-stderr.rs
index 8ca6e1c63567e..f65d841700efa 100644
--- a/src/test/run-pass/print-stdout-eprint-stderr.rs
+++ b/src/test/run-pass/print-stdout-eprint-stderr.rs
@@ -8,8 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![feature(eprint)]
-
 use std::{env, process};
 
 fn child() {

From a06f9a66dff42965a47e9c8d99b059707347b998 Mon Sep 17 00:00:00 2001
From: est31 <MTest31@outlook.com>
Date: Wed, 10 May 2017 18:20:23 +0200
Subject: [PATCH 16/17] Remove debug message

---
 src/librustc_lint/builtin.rs | 1 -
 1 file changed, 1 deletion(-)

diff --git a/src/librustc_lint/builtin.rs b/src/librustc_lint/builtin.rs
index 715a769158bc3..3b6516af35a05 100644
--- a/src/librustc_lint/builtin.rs
+++ b/src/librustc_lint/builtin.rs
@@ -718,7 +718,6 @@ fn fl_lit_check_expr(cx: &EarlyContext, expr: &ast::Expr) {
                     cx.span_lint(ILLEGAL_FLOATING_POINT_LITERAL_PATTERN,
                                  l.span,
                                  "floating-point literals cannot be used in patterns");
-                    error!("span mc spanspam");
                     },
                 _ => (),
             }

From 72588a2b2a1af655b81fcd3c1c467707d9c237c2 Mon Sep 17 00:00:00 2001
From: Zack Weinberg <zackw@panix.com>
Date: Wed, 10 May 2017 15:28:25 -0400
Subject: [PATCH 17/17] Skip print-stdout-eprint-stderr test on emscripten

---
 src/test/run-pass/print-stdout-eprint-stderr.rs | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/test/run-pass/print-stdout-eprint-stderr.rs b/src/test/run-pass/print-stdout-eprint-stderr.rs
index f65d841700efa..0a0f30aba72c2 100644
--- a/src/test/run-pass/print-stdout-eprint-stderr.rs
+++ b/src/test/run-pass/print-stdout-eprint-stderr.rs
@@ -8,6 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+// ignore-emscripten spawning processes is not supported
+
 use std::{env, process};
 
 fn child() {