Parse `unsafe impl` but don't do anything particularly interesting with the results.

28 files changed, 97 insertions, 57 deletions

diff --git a/src/librustc/lint/builtin.rs b/src/librustc/lint/builtin.rs
index 5af7fec4181..3040125d97e 100644
--- a/src/librustc/lint/builtin.rs
+++ b/src/librustc/lint/builtin.rs
@@ -1729,7 +1729,7 @@ impl LintPass for Stability {
                     }
                 }
             }
-            ast::ItemImpl(_, Some(ref t), _, _) => {
+            ast::ItemImpl(_, _, Some(ref t), _, _) => {
                 let id = ty::trait_ref_to_def_id(cx.tcx, t);
                 self.lint(cx, id, t.path.span);
             }
diff --git a/src/librustc/metadata/decoder.rs b/src/librustc/metadata/decoder.rs
index 37124286398..b78112f1f78 100644
--- a/src/librustc/metadata/decoder.rs
+++ b/src/librustc/metadata/decoder.rs
@@ -361,6 +361,15 @@ fn item_to_def_like(item: rbml::Doc, did: ast::DefId, cnum: ast::CrateNum)
     }
 }
 
+fn parse_unsafety(item_doc: rbml::Doc) -> ast::Unsafety {
+    let unsafety_doc = reader::get_doc(item_doc, tag_unsafety);
+    if reader::doc_as_u8(unsafety_doc) != 0 {
+        ast::Unsafety::Unsafe
+    } else {
+        ast::Unsafety::Normal
+    }
+}
+
 pub fn get_trait_def<'tcx>(cdata: Cmd,
                            item_id: ast::NodeId,
                            tcx: &ty::ctxt<'tcx>) -> ty::TraitDef<'tcx>
@@ -368,10 +377,7 @@ pub fn get_trait_def<'tcx>(cdata: Cmd,
     let item_doc = lookup_item(item_id, cdata.data());
     let generics = doc_generics(item_doc, tcx, cdata, tag_item_generics);
     let bounds = trait_def_bounds(item_doc, tcx, cdata);
-    let unsafety = match reader::maybe_get_doc(item_doc, tag_unsafety) {
-        Some(_) => ast::Unsafety::Unsafe,
-        None => ast::Unsafety::Normal,
-    };
+    let unsafety = parse_unsafety(item_doc);
 
     ty::TraitDef {
         unsafety: unsafety,
diff --git a/src/librustc/metadata/encoder.rs b/src/librustc/metadata/encoder.rs
index cb8de256448..a1f04b7412b 100644
--- a/src/librustc/metadata/encoder.rs
+++ b/src/librustc/metadata/encoder.rs
@@ -1205,7 +1205,7 @@ fn encode_info_for_item(ecx: &EncodeContext,
             None => {}
         }
       }
-      ast::ItemImpl(_, ref opt_trait, ref ty, ref ast_items) => {
+      ast::ItemImpl(unsafety, _, ref opt_trait, ref ty, ref ast_items) => {
         // We need to encode information about the default methods we
         // have inherited, so we drive this based on the impl structure.
         let impl_items = tcx.impl_items.borrow();
@@ -1218,6 +1218,7 @@ fn encode_info_for_item(ecx: &EncodeContext,
         encode_bounds_and_type(rbml_w, ecx, &lookup_item_type(tcx, def_id));
         encode_name(rbml_w, item.ident.name);
         encode_attributes(rbml_w, item.attrs.as_slice());
+        encode_unsafety(rbml_w, unsafety);
         match ty.node {
             ast::TyPath(ref path, _) if path.segments
                                                         .len() == 1 => {
@@ -1315,15 +1316,7 @@ fn encode_info_for_item(ecx: &EncodeContext,
         encode_family(rbml_w, 'I');
         encode_item_variances(rbml_w, ecx, item.id);
         let trait_def = ty::lookup_trait_def(tcx, def_id);
-
-        match trait_def.unsafety {
-            ast::Unsafety::Unsafe => {
-                rbml_w.start_tag(tag_unsafety);
-                rbml_w.end_tag();
-            }
-            ast::Unsafety::Normal => { }
-        }
-
+        encode_unsafety(rbml_w, trait_def.unsafety);
         encode_generics(rbml_w, ecx, &trait_def.generics, tag_item_generics);
         encode_trait_ref(rbml_w, ecx, &*trait_def.trait_ref, tag_item_trait_ref);
         encode_name(rbml_w, item.ident.name);
@@ -1683,6 +1676,14 @@ fn encode_attributes(rbml_w: &mut Encoder, attrs: &[ast::Attribute]) {
     rbml_w.end_tag();
 }
 
+fn encode_unsafety(rbml_w: &mut Encoder, unsafety: ast::Unsafety) {
+    let byte: u8 = match unsafety {
+        ast::Unsafety::Normal => 0,
+        ast::Unsafety::Unsafe => 1,
+    };
+    rbml_w.wr_tagged_u8(tag_unsafety, byte);
+}
+
 fn encode_crate_deps(rbml_w: &mut Encoder, cstore: &cstore::CStore) {
     fn get_ordered_deps(cstore: &cstore::CStore) -> Vec<decoder::CrateDep> {
         // Pull the cnums and name,vers,hash out of cstore
@@ -1864,7 +1865,7 @@ struct ImplVisitor<'a, 'b:'a, 'c:'a, 'tcx:'b> {
 
 impl<'a, 'b, 'c, 'tcx, 'v> Visitor<'v> for ImplVisitor<'a, 'b, 'c, 'tcx> {
     fn visit_item(&mut self, item: &ast::Item) {
-        if let ast::ItemImpl(_, Some(ref trait_ref), _, _) = item.node {
+        if let ast::ItemImpl(_, _, Some(ref trait_ref), _, _) = item.node {
             let def_map = &self.ecx.tcx.def_map;
             let trait_def = def_map.borrow()[trait_ref.ref_id].clone();
             let def_id = trait_def.def_id();
diff --git a/src/librustc/middle/dead.rs b/src/librustc/middle/dead.rs
index d2f43faa003..939775e7507 100644
--- a/src/librustc/middle/dead.rs
+++ b/src/librustc/middle/dead.rs
@@ -355,7 +355,7 @@ impl<'v> Visitor<'v> for LifeSeeder {
             ast::ItemEnum(ref enum_def, _) if allow_dead_code => {
                 self.worklist.extend(enum_def.variants.iter().map(|variant| variant.node.id));
             }
-            ast::ItemImpl(_, Some(ref _trait_ref), _, ref impl_items) => {
+            ast::ItemImpl(_, _, Some(ref _trait_ref), _, ref impl_items) => {
                 for impl_item in impl_items.iter() {
                     match *impl_item {
                         ast::MethodImplItem(ref method) => {
diff --git a/src/librustc/middle/infer/error_reporting.rs b/src/librustc/middle/infer/error_reporting.rs
index c638182d7f3..5c2944f898e 100644
--- a/src/librustc/middle/infer/error_reporting.rs
+++ b/src/librustc/middle/infer/error_reporting.rs
@@ -1690,7 +1690,7 @@ fn lifetimes_in_scope(tcx: &ty::ctxt,
         match tcx.map.find(parent) {
             Some(node) => match node {
                 ast_map::NodeItem(item) => match item.node {
-                    ast::ItemImpl(ref gen, _, _, _) => {
+                    ast::ItemImpl(_, ref gen, _, _, _) => {
                         taken.push_all(gen.lifetimes.as_slice());
                     }
                     _ => ()
diff --git a/src/librustc/middle/privacy.rs b/src/librustc/middle/privacy.rs
index 352c2add000..8cce1321d72 100644
--- a/src/librustc/middle/privacy.rs
+++ b/src/librustc/middle/privacy.rs
@@ -241,7 +241,7 @@ impl<'a, 'tcx, 'v> Visitor<'v> for EmbargoVisitor<'a, 'tcx> {
             //   undefined symbols at linkage time if this case is not handled.
             //
             // * Private trait impls for private types can be completely ignored
-            ast::ItemImpl(_, _, ref ty, ref impl_items) => {
+            ast::ItemImpl(_, _, _, ref ty, ref impl_items) => {
                 let public_ty = match ty.node {
                     ast::TyPath(_, id) => {
                         match self.tcx.def_map.borrow()[id].clone() {
@@ -611,7 +611,7 @@ impl<'a, 'tcx> PrivacyVisitor<'a, 'tcx> {
                     // invoked, and the struct/enum itself is private. Crawl
                     // back up the chains to find the relevant struct/enum that
                     // was private.
-                    ast::ItemImpl(_, _, ref ty, _) => {
+                    ast::ItemImpl(_, _, _, ref ty, _) => {
                         let id = match ty.node {
                             ast::TyPath(_, id) => id,
                             _ => return Some((err_span, err_msg, None)),
@@ -1096,7 +1096,7 @@ impl<'a, 'tcx> SanePrivacyVisitor<'a, 'tcx> {
         match item.node {
             // implementations of traits don't need visibility qualifiers because
             // that's controlled by having the trait in scope.
-            ast::ItemImpl(_, Some(..), _, ref impl_items) => {
+            ast::ItemImpl(_, _, Some(..), _, ref impl_items) => {
                 check_inherited(item.span, item.vis,
                                 "visibility qualifiers have no effect on trait \
                                  impls");
@@ -1175,7 +1175,7 @@ impl<'a, 'tcx> SanePrivacyVisitor<'a, 'tcx> {
         };
         check_inherited(tcx, item.span, item.vis);
         match item.node {
-            ast::ItemImpl(_, _, _, ref impl_items) => {
+            ast::ItemImpl(_, _, _, _, ref impl_items) => {
                 for impl_item in impl_items.iter() {
                     match *impl_item {
                         ast::MethodImplItem(ref m) => {
@@ -1320,7 +1320,7 @@ impl<'a, 'tcx, 'v> Visitor<'v> for VisiblePrivateTypesVisitor<'a, 'tcx> {
             // (i.e. we could just return here to not check them at
             // all, or some worse estimation of whether an impl is
             // publicly visible.
-            ast::ItemImpl(ref g, ref trait_ref, ref self_, ref impl_items) => {
+            ast::ItemImpl(_, ref g, ref trait_ref, ref self_, ref impl_items) => {
                 // `impl [... for] Private` is never visible.
                 let self_contains_private;
                 // impl [... for] Public<...>, but not `impl [... for]
diff --git a/src/librustc/middle/reachable.rs b/src/librustc/middle/reachable.rs
index fa02c940aa7..38d3b859c9d 100644
--- a/src/librustc/middle/reachable.rs
+++ b/src/librustc/middle/reachable.rs
@@ -55,7 +55,7 @@ fn item_might_be_inlined(item: &ast::Item) -> bool {
     }
 
     match item.node {
-        ast::ItemImpl(ref generics, _, _, _) |
+        ast::ItemImpl(_, ref generics, _, _, _) |
         ast::ItemFn(_, _, _, ref generics, _) => {
             generics_require_inlining(generics)
         }
@@ -216,7 +216,7 @@ impl<'a, 'tcx> ReachableContext<'a, 'tcx> {
                                       .map
                                       .expect_item(impl_did.node)
                                       .node {
-                                ast::ItemImpl(ref generics, _, _, _) => {
+                                ast::ItemImpl(_, ref generics, _, _, _) => {
                                     generics_require_inlining(generics)
                                 }
                                 _ => false
diff --git a/src/librustc/middle/resolve.rs b/src/librustc/middle/resolve.rs
index 2e52bab2ae3..c6fdd845ea7 100644
--- a/src/librustc/middle/resolve.rs
+++ b/src/librustc/middle/resolve.rs
@@ -1432,7 +1432,7 @@ impl<'a> Resolver<'a> {
                 parent
             }
 
-            ItemImpl(_, None, ref ty, ref impl_items) => {
+            ItemImpl(_, _, None, ref ty, ref impl_items) => {
                 // If this implements an anonymous trait, then add all the
                 // methods within to a new module, if the type was defined
                 // within this module.
@@ -1581,7 +1581,7 @@ impl<'a> Resolver<'a> {
                 parent
             }
 
-            ItemImpl(_, Some(_), _, _) => parent,
+            ItemImpl(_, _, Some(_), _, _) => parent,
 
             ItemTrait(_, _, _, _, ref items) => {
                 let name_bindings =
@@ -4230,7 +4230,8 @@ impl<'a> Resolver<'a> {
                 });
             }
 
-            ItemImpl(ref generics,
+            ItemImpl(_,
+                     ref generics,
                      ref implemented_traits,
                      ref self_type,
                      ref impl_items) => {
diff --git a/src/librustc/middle/resolve_lifetime.rs b/src/librustc/middle/resolve_lifetime.rs
index 683948cd2e7..48d6ac847d8 100644
--- a/src/librustc/middle/resolve_lifetime.rs
+++ b/src/librustc/middle/resolve_lifetime.rs
@@ -114,7 +114,7 @@ impl<'a, 'v> Visitor<'v> for LifetimeContext<'a> {
                     visit::walk_item(this, item);
                 });
             }
-            ast::ItemImpl(ref generics, _, _, _) => {
+            ast::ItemImpl(_, ref generics, _, _, _) => {
                 // Impls have both early- and late-bound lifetimes.
                 self.visit_early_late(subst::TypeSpace, generics, |this| {
                     this.check_lifetime_defs(&generics.lifetimes);
diff --git a/src/librustc/middle/ty.rs b/src/librustc/middle/ty.rs
index 4c4df698f33..d6fd3d9a943 100644
--- a/src/librustc/middle/ty.rs
+++ b/src/librustc/middle/ty.rs
@@ -4741,7 +4741,7 @@ pub fn impl_trait_ref<'tcx>(cx: &ctxt<'tcx>, id: ast::DefId)
             match cx.map.find(id.node) {
                 Some(ast_map::NodeItem(item)) => {
                     match item.node {
-                        ast::ItemImpl(_, ref opt_trait, _, _) => {
+                        ast::ItemImpl(_, _, ref opt_trait, _, _) => {
                             match opt_trait {
                                 &Some(ref t) => {
                                     Some(ty::node_id_to_trait_ref(cx, t.ref_id))
@@ -5722,7 +5722,7 @@ pub fn trait_id_of_impl(tcx: &ctxt,
     match node {
         ast_map::NodeItem(item) => {
             match item.node {
-                ast::ItemImpl(_, Some(ref trait_ref), _, _) => {
+                ast::ItemImpl(_, _, Some(ref trait_ref), _, _) => {
                     Some(node_id_to_trait_ref(tcx, trait_ref.ref_id).def_id)
                 }
                 _ => None
diff --git a/src/librustc_trans/save/mod.rs b/src/librustc_trans/save/mod.rs
index 779fcd70864..712d6217dde 100644
--- a/src/librustc_trans/save/mod.rs
+++ b/src/librustc_trans/save/mod.rs
@@ -282,7 +282,7 @@ impl <'l, 'tcx> DxrVisitor<'l, 'tcx> {
                 NodeItem(item) => {
                     scope_id = item.id;
                     match item.node {
-                        ast::ItemImpl(_, _, ref ty, _) => {
+                        ast::ItemImpl(_, _, _, ref ty, _) => {
                             let mut result = String::from_str("<");
                             result.push_str(ty_to_string(&**ty).as_slice());
 
@@ -1040,7 +1040,8 @@ impl<'l, 'tcx, 'v> Visitor<'v> for DxrVisitor<'l, 'tcx> {
                 self.process_const(item, &**typ, &**expr),
             ast::ItemStruct(ref def, ref ty_params) => self.process_struct(item, &**def, ty_params),
             ast::ItemEnum(ref def, ref ty_params) => self.process_enum(item, def, ty_params),
-            ast::ItemImpl(ref ty_params,
+            ast::ItemImpl(_,
+                          ref ty_params,
                           ref trait_ref,
                           ref typ,
                           ref impl_items) => {
diff --git a/src/librustc_trans/trans/base.rs b/src/librustc_trans/trans/base.rs
index b2578fdbc05..83779ffbe16 100644
--- a/src/librustc_trans/trans/base.rs
+++ b/src/librustc_trans/trans/base.rs
@@ -2304,7 +2304,7 @@ pub fn trans_item(ccx: &CrateContext, item: &ast::Item) {
         let mut v = TransItemVisitor{ ccx: ccx };
         v.visit_block(&**body);
       }
-      ast::ItemImpl(ref generics, _, _, ref impl_items) => {
+      ast::ItemImpl(_, ref generics, _, _, ref impl_items) => {
         meth::trans_impl(ccx,
                          item.ident,
                          impl_items.as_slice(),
diff --git a/src/librustc_typeck/check/mod.rs b/src/librustc_typeck/check/mod.rs
index c64519c96dd..e0df94745d6 100644
--- a/src/librustc_typeck/check/mod.rs
+++ b/src/librustc_typeck/check/mod.rs
@@ -595,7 +595,7 @@ pub fn check_item(ccx: &CrateCtxt, it: &ast::Item) {
         let param_env = ParameterEnvironment::for_item(ccx.tcx, it.id);
         check_bare_fn(ccx, &**decl, &**body, it.id, fn_pty.ty, param_env);
       }
-      ast::ItemImpl(_, ref opt_trait_ref, _, ref impl_items) => {
+      ast::ItemImpl(_, _, ref opt_trait_ref, _, ref impl_items) => {
         debug!("ItemImpl {} with id {}", token::get_ident(it.ident), it.id);
 
         let impl_pty = ty::lookup_item_type(ccx.tcx, ast_util::local_def(it.id));
diff --git a/src/librustc_typeck/coherence/mod.rs b/src/librustc_typeck/coherence/mod.rs
index defad95f749..7bc79d6e4a4 100644
--- a/src/librustc_typeck/coherence/mod.rs
+++ b/src/librustc_typeck/coherence/mod.rs
@@ -145,7 +145,7 @@ impl<'a, 'tcx, 'v> visit::Visitor<'v> for CoherenceCheckVisitor<'a, 'tcx> {
         //debug!("(checking coherence) item '{}'", token::get_ident(item.ident));
 
         match item.node {
-            ItemImpl(_, ref opt_trait, _, _) => {
+            ItemImpl(_, _, ref opt_trait, _, _) => {
                 match opt_trait.clone() {
                     Some(opt_trait) => {
                         self.cc.check_implementation(item, &[opt_trait]);
@@ -325,7 +325,7 @@ impl<'a, 'tcx> CoherenceChecker<'a, 'tcx> {
     // Converts an implementation in the AST to a vector of items.
     fn create_impl_from_item(&self, item: &Item) -> Vec<ImplOrTraitItemId> {
         match item.node {
-            ItemImpl(_, ref trait_refs, _, ref ast_items) => {
+            ItemImpl(_, _, ref trait_refs, _, ref ast_items) => {
                 let mut items: Vec<ImplOrTraitItemId> =
                         ast_items.iter()
                                  .map(|ast_item| {
diff --git a/src/librustc_typeck/coherence/orphan.rs b/src/librustc_typeck/coherence/orphan.rs
index dc3afaae35f..1803bf766dd 100644
--- a/src/librustc_typeck/coherence/orphan.rs
+++ b/src/librustc_typeck/coherence/orphan.rs
@@ -44,7 +44,7 @@ impl<'cx, 'tcx,'v> visit::Visitor<'v> for OrphanChecker<'cx, 'tcx> {
     fn visit_item(&mut self, item: &'v ast::Item) {
         let def_id = ast_util::local_def(item.id);
         match item.node {
-            ast::ItemImpl(_, None, _, _) => {
+            ast::ItemImpl(_, _, None, _, _) => {
                 // For inherent impls, self type must be a nominal type
                 // defined in this crate.
                 debug!("coherence2::orphan check: inherent impl {}", item.repr(self.tcx));
@@ -64,7 +64,7 @@ impl<'cx, 'tcx,'v> visit::Visitor<'v> for OrphanChecker<'cx, 'tcx> {
                     }
                 }
             }
-            ast::ItemImpl(_, Some(_), _, _) => {
+            ast::ItemImpl(_, _, Some(_), _, _) => {
                 // "Trait" impl
                 debug!("coherence2::orphan check: trait impl {}", item.repr(self.tcx));
                 if traits::is_orphan_impl(self.tcx, def_id) {
diff --git a/src/librustc_typeck/collect.rs b/src/librustc_typeck/collect.rs
index 643d8eb60ce..61b8e6c956c 100644
--- a/src/librustc_typeck/collect.rs
+++ b/src/librustc_typeck/collect.rs
@@ -1045,7 +1045,8 @@ pub fn convert(ccx: &CrateCtxt, it: &ast::Item) {
                                    enum_definition.variants.as_slice(),
                                    generics);
         },
-        ast::ItemImpl(ref generics,
+        ast::ItemImpl(_,
+                      ref generics,
                       ref opt_trait_ref,
                       ref selfty,
                       ref impl_items) => {
diff --git a/src/librustdoc/doctree.rs b/src/librustdoc/doctree.rs
index 79f04e91260..6592ca498dc 100644
--- a/src/librustdoc/doctree.rs
+++ b/src/librustdoc/doctree.rs
@@ -184,6 +184,7 @@ pub struct Trait {
 }
 
 pub struct Impl {
+    pub unsafety: ast::Unsafety,
     pub generics: ast::Generics,
     pub trait_: Option<ast::TraitRef>,
     pub for_: P<ast::Ty>,
diff --git a/src/librustdoc/visit_ast.rs b/src/librustdoc/visit_ast.rs
index f94e647b1cf..4374ce5deef 100644
--- a/src/librustdoc/visit_ast.rs
+++ b/src/librustdoc/visit_ast.rs
@@ -338,8 +338,9 @@ impl<'a, 'tcx> RustdocVisitor<'a, 'tcx> {
                 };
                 om.traits.push(t);
             },
-            ast::ItemImpl(ref gen, ref tr, ref ty, ref items) => {
+            ast::ItemImpl(unsafety, ref gen, ref tr, ref ty, ref items) => {
                 let i = Impl {
+                    unsafety: unsafety,
                     generics: gen.clone(),
                     trait_: tr.clone(),
                     for_: ty.clone(),
diff --git a/src/libsyntax/ast.rs b/src/libsyntax/ast.rs
index 1cc6b6feee8..206fb26eb55 100644
--- a/src/libsyntax/ast.rs
+++ b/src/libsyntax/ast.rs
@@ -1617,7 +1617,8 @@ pub enum Item_ {
                                 // Currently, only Sized makes sense here.
               TyParamBounds,
               Vec<TraitItem>),
-    ItemImpl(Generics,
+    ItemImpl(Unsafety,
+             Generics,
              Option<TraitRef>, // (optional) trait this impl implements
              P<Ty>, // self
              Vec<ImplItem>),
diff --git a/src/libsyntax/ast_map/mod.rs b/src/libsyntax/ast_map/mod.rs
index a2cdc4d2fbc..6089f39e828 100644
--- a/src/libsyntax/ast_map/mod.rs
+++ b/src/libsyntax/ast_map/mod.rs
@@ -755,7 +755,7 @@ impl<'ast> Visitor<'ast> for NodeCollector<'ast> {
         let parent = self.parent;
         self.parent = i.id;
         match i.node {
-            ItemImpl(_, _, _, ref impl_items) => {
+            ItemImpl(_, _, _, _, ref impl_items) => {
                 for impl_item in impl_items.iter() {
                     match *impl_item {
                         MethodImplItem(ref m) => {
diff --git a/src/libsyntax/config.rs b/src/libsyntax/config.rs
index ee651592117..d2185a00876 100644
--- a/src/libsyntax/config.rs
+++ b/src/libsyntax/config.rs
@@ -133,11 +133,11 @@ fn fold_item_underscore<F>(cx: &mut Context<F>, item: ast::Item_) -> ast::Item_
     F: FnMut(&[ast::Attribute]) -> bool
 {
     let item = match item {
-        ast::ItemImpl(a, b, c, impl_items) => {
+        ast::ItemImpl(u, a, b, c, impl_items) => {
             let impl_items = impl_items.into_iter()
                                        .filter(|ii| impl_item_in_cfg(cx, ii))
                                        .collect();
-            ast::ItemImpl(a, b, c, impl_items)
+            ast::ItemImpl(u, a, b, c, impl_items)
         }
         ast::ItemTrait(u, a, b, c, methods) => {
             let methods = methods.into_iter()
diff --git a/src/libsyntax/ext/deriving/generic/mod.rs b/src/libsyntax/ext/deriving/generic/mod.rs
index 820ff08a255..f40be823a1a 100644
--- a/src/libsyntax/ext/deriving/generic/mod.rs
+++ b/src/libsyntax/ext/deriving/generic/mod.rs
@@ -462,7 +462,8 @@ impl<'a> TraitDef<'a> {
             self.span,
             ident,
             a,
-            ast::ItemImpl(trait_generics,
+            ast::ItemImpl(ast::Unsafety::Normal,
+                          trait_generics,
                           opt_trait_ref,
                           self_type,
                           methods.into_iter()
diff --git a/src/libsyntax/feature_gate.rs b/src/libsyntax/feature_gate.rs
index 66fe672c3e5..9656629e14d 100644
--- a/src/libsyntax/feature_gate.rs
+++ b/src/libsyntax/feature_gate.rs
@@ -215,7 +215,7 @@ impl<'a, 'v> Visitor<'v> for Context<'a> {
                 }
             }
 
-            ast::ItemImpl(_, _, _, ref items) => {
+            ast::ItemImpl(_, _, _, _, ref items) => {
                 if attr::contains_name(i.attrs.as_slice(),
                                        "unsafe_destructor") {
                     self.gate_feature("unsafe_destructor",
diff --git a/src/libsyntax/fold.rs b/src/libsyntax/fold.rs
index daed014f4eb..8a578c2cb05 100644
--- a/src/libsyntax/fold.rs
+++ b/src/libsyntax/fold.rs
@@ -1008,7 +1008,7 @@ pub fn noop_fold_item_underscore<T: Folder>(i: Item_, folder: &mut T) -> Item_ {
             let struct_def = folder.fold_struct_def(struct_def);
             ItemStruct(struct_def, folder.fold_generics(generics))
         }
-        ItemImpl(generics, ifce, ty, impl_items) => {
+        ItemImpl(unsafety, generics, ifce, ty, impl_items) => {
             let mut new_impl_items = Vec::new();
             for impl_item in impl_items.iter() {
                 match *impl_item {
@@ -1030,7 +1030,8 @@ pub fn noop_fold_item_underscore<T: Folder>(i: Item_, folder: &mut T) -> Item_ {
                     Some(folder.fold_trait_ref((*trait_ref).clone()))
                 }
             };
-            ItemImpl(folder.fold_generics(generics),
+            ItemImpl(unsafety,
+                     folder.fold_generics(generics),
                      ifce,
                      folder.fold_ty(ty),
                      new_impl_items)
@@ -1160,7 +1161,7 @@ pub fn noop_fold_item_simple<T: Folder>(Item {id, ident, attrs, node, vis, span}
     let node = folder.fold_item_underscore(node);
     let ident = match node {
         // The node may have changed, recompute the "pretty" impl name.
-        ItemImpl(_, ref maybe_trait, ref ty, _) => {
+        ItemImpl(_, _, ref maybe_trait, ref ty, _) => {
             ast_util::impl_pretty_name(maybe_trait, &**ty)
         }
         _ => ident
diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index b2c30797cac..d1991c0463f 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -4667,7 +4667,7 @@ impl<'a> Parser<'a> {
     /// Parses two variants (with the region/type params always optional):
     ///    impl<T> Foo { ... }
     ///    impl<T> ToString for ~[T] { ... }
-    fn parse_item_impl(&mut self) -> ItemInfo {
+    fn parse_item_impl(&mut self, unsafety: ast::Unsafety) -> ItemInfo {
         // First, parse type parameters if necessary.
         let mut generics = self.parse_generics();
 
@@ -4706,7 +4706,7 @@ impl<'a> Parser<'a> {
         let ident = ast_util::impl_pretty_name(&opt_trait, &*ty);
 
         (ident,
-         ItemImpl(generics, opt_trait, ty, impl_items),
+         ItemImpl(unsafety, generics, opt_trait, ty, impl_items),
          Some(attrs))
     }
 
@@ -5556,6 +5556,22 @@ impl<'a> Parser<'a> {
                                     maybe_append(attrs, extra_attrs));
             return IoviItem(item);
         }
+        if self.token.is_keyword(keywords::Unsafe) &&
+            self.look_ahead(1u, |t| t.is_keyword(keywords::Impl))
+        {
+            // IMPL ITEM
+            self.expect_keyword(keywords::Unsafe);
+            self.expect_keyword(keywords::Impl);
+            let (ident, item_, extra_attrs) = self.parse_item_impl(ast::Unsafety::Unsafe);
+            let last_span = self.last_span;
+            let item = self.mk_item(lo,
+                                    last_span.hi,
+                                    ident,
+                                    item_,
+                                    visibility,
+                                    maybe_append(attrs, extra_attrs));
+            return IoviItem(item);
+        }
         if self.token.is_keyword(keywords::Fn) &&
                 self.look_ahead(1, |f| !Parser::fn_expr_lookahead(f)) {
             // FUNCTION ITEM
@@ -5644,7 +5660,7 @@ impl<'a> Parser<'a> {
         }
         if self.eat_keyword(keywords::Impl) {
             // IMPL ITEM
-            let (ident, item_, extra_attrs) = self.parse_item_impl();
+            let (ident, item_, extra_attrs) = self.parse_item_impl(ast::Unsafety::Normal);
             let last_span = self.last_span;
             let item = self.mk_item(lo,
                                     last_span.hi,
diff --git a/src/libsyntax/print/pprust.rs b/src/libsyntax/print/pprust.rs
index 037118b145f..db122f271a9 100644
--- a/src/libsyntax/print/pprust.rs
+++ b/src/libsyntax/print/pprust.rs
@@ -917,12 +917,16 @@ impl<'a> State<'a> {
                 try!(self.print_struct(&**struct_def, generics, item.ident, item.span));
             }
 
-            ast::ItemImpl(ref generics,
+            ast::ItemImpl(unsafety,
+                          ref generics,
                           ref opt_trait,
                           ref ty,
                           ref impl_items) => {
-                try!(self.head(visibility_qualified(item.vis,
-                                                    "impl").as_slice()));
+                try!(self.head(""));
+                try!(self.print_visibility(item.vis));
+                try!(self.print_unsafety(unsafety));
+                try!(self.word_nbsp("impl"));
+
                 if generics.is_parameterized() {
                     try!(self.print_generics(generics));
                     try!(space(&mut self.s));
diff --git a/src/libsyntax/visit.rs b/src/libsyntax/visit.rs
index 7bb79a15f45..3535c6e267e 100644
--- a/src/libsyntax/visit.rs
+++ b/src/libsyntax/visit.rs
@@ -282,7 +282,8 @@ pub fn walk_item<'v, V: Visitor<'v>>(visitor: &mut V, item: &'v Item) {
             visitor.visit_generics(type_parameters);
             walk_enum_def(visitor, enum_definition, type_parameters)
         }
-        ItemImpl(ref type_parameters,
+        ItemImpl(_,
+                 ref type_parameters,
                  ref trait_reference,
                  ref typ,
                  ref impl_items) => {
diff --git a/src/test/pretty/trait-safety.rs b/src/test/pretty/trait-safety.rs
index 42e578482e6..b96dbbf3cc9 100644
--- a/src/test/pretty/trait-safety.rs
+++ b/src/test/pretty/trait-safety.rs
@@ -14,6 +14,10 @@ unsafe trait UnsafeTrait {
     fn foo(&self);
 }
 
+unsafe impl UnsafeTrait for int {
+    fn foo(&self) { }
+}
+
 pub unsafe trait PubUnsafeTrait {
     fn foo(&self);
 }