introduce crate rustc_feature and move active, accepted, and removed to it

30 files changed, 73 insertions, 52 deletions

diff --git a/src/librustc/Cargo.toml b/src/librustc/Cargo.toml
index 6c1695a4eac..fb30d6c519c 100644
--- a/src/librustc/Cargo.toml
+++ b/src/librustc/Cargo.toml
@@ -22,6 +22,7 @@ rustc-rayon = "0.3.0"
 rustc-rayon-core = "0.3.0"
 polonius-engine  = "0.10.0"
 rustc_apfloat = { path = "../librustc_apfloat" }
+rustc_feature = { path = "../librustc_feature" }
 rustc_target = { path = "../librustc_target" }
 rustc_macros = { path = "../librustc_macros" }
 rustc_data_structures = { path = "../librustc_data_structures" }
diff --git a/src/librustc/arena.rs b/src/librustc/arena.rs
index 9b13a910c61..c3b810d04eb 100644
--- a/src/librustc/arena.rs
+++ b/src/librustc/arena.rs
@@ -100,7 +100,7 @@ macro_rules! arena_types {
             [few] resolve_lifetimes: rustc::middle::resolve_lifetime::ResolveLifetimes,
             [few] lint_levels: rustc::lint::LintLevelMap,
             [few] stability_index: rustc::middle::stability::Index<'tcx>,
-            [few] features: syntax::feature_gate::Features,
+            [few] features: rustc_feature::Features,
             [few] all_traits: Vec<rustc::hir::def_id::DefId>,
             [few] privacy_access_levels: rustc::middle::privacy::AccessLevels,
             [few] target_features_whitelist: rustc_data_structures::fx::FxHashMap<
diff --git a/src/librustc/ich/impls_syntax.rs b/src/librustc/ich/impls_syntax.rs
index 144980c53eb..6499e56325a 100644
--- a/src/librustc/ich/impls_syntax.rs
+++ b/src/librustc/ich/impls_syntax.rs
@@ -4,7 +4,6 @@
 use crate::ich::StableHashingContext;
 
 use syntax::ast;
-use syntax::feature_gate;
 use syntax_pos::SourceFile;
 
 use crate::hir::def_id::{DefId, CrateNum, CRATE_DEF_INDEX};
@@ -156,7 +155,7 @@ fn stable_normalized_pos(np: ::syntax_pos::NormalizedPos,
 }
 
 
-impl<'tcx> HashStable<StableHashingContext<'tcx>> for feature_gate::Features {
+impl<'tcx> HashStable<StableHashingContext<'tcx>> for rustc_feature::Features {
     fn hash_stable(&self, hcx: &mut StableHashingContext<'tcx>, hasher: &mut StableHasher) {
         // Unfortunately we cannot exhaustively list fields here, since the
         // struct is macro generated.
diff --git a/src/librustc/query/mod.rs b/src/librustc/query/mod.rs
index cd93fed8e1e..d715ddb1b81 100644
--- a/src/librustc/query/mod.rs
+++ b/src/librustc/query/mod.rs
@@ -1130,7 +1130,7 @@ rustc_queries! {
             desc { |tcx| "estimating size for `{}`", tcx.def_path_str(def.def_id()) }
         }
 
-        query features_query(_: CrateNum) -> &'tcx feature_gate::Features {
+        query features_query(_: CrateNum) -> &'tcx rustc_feature::Features {
             eval_always
             desc { "looking up enabled feature gates" }
         }
diff --git a/src/librustc/session/mod.rs b/src/librustc/session/mod.rs
index af6522df61e..0ee8107cb14 100644
--- a/src/librustc/session/mod.rs
+++ b/src/librustc/session/mod.rs
@@ -21,7 +21,6 @@ use errors::emitter::{Emitter, EmitterWriter};
 use errors::emitter::HumanReadableErrorType;
 use errors::annotate_snippet_emitter_writer::{AnnotateSnippetEmitterWriter};
 use syntax::edition::Edition;
-use syntax::feature_gate;
 use errors::json::JsonEmitter;
 use syntax::source_map;
 use syntax::sess::ParseSess;
@@ -86,7 +85,7 @@ pub struct Session {
     /// `rustc_codegen_llvm::back::symbol_names` module for more information.
     pub crate_disambiguator: Once<CrateDisambiguator>,
 
-    features: Once<feature_gate::Features>,
+    features: Once<rustc_feature::Features>,
 
     /// The maximum recursion limit for potentially infinitely recursive
     /// operations such as auto-dereference and monomorphization.
@@ -473,11 +472,11 @@ impl Session {
     /// DO NOT USE THIS METHOD if there is a TyCtxt available, as it circumvents
     /// dependency tracking. Use tcx.features() instead.
     #[inline]
-    pub fn features_untracked(&self) -> &feature_gate::Features {
+    pub fn features_untracked(&self) -> &rustc_feature::Features {
         self.features.get()
     }
 
-    pub fn init_features(&self, features: feature_gate::Features) {
+    pub fn init_features(&self, features: rustc_feature::Features) {
         self.features.set(features);
     }
 
diff --git a/src/librustc/ty/context.rs b/src/librustc/ty/context.rs
index 95456581169..d2f9312a482 100644
--- a/src/librustc/ty/context.rs
+++ b/src/librustc/ty/context.rs
@@ -72,7 +72,6 @@ use rustc_macros::HashStable;
 use syntax::ast;
 use syntax::attr;
 use syntax::source_map::MultiSpan;
-use syntax::feature_gate;
 use syntax::symbol::{Symbol, kw, sym};
 use syntax_pos::Span;
 use syntax::expand::allocator::AllocatorKind;
@@ -1315,7 +1314,7 @@ impl<'tcx> TyCtxt<'tcx> {
         self.cstore.allocator_kind()
     }
 
-    pub fn features(self) -> &'tcx feature_gate::Features {
+    pub fn features(self) -> &'tcx rustc_feature::Features {
         self.features_query(LOCAL_CRATE)
     }
 
diff --git a/src/librustc/ty/query/mod.rs b/src/librustc/ty/query/mod.rs
index a1eb1c43335..5b4a6ac8a2d 100644
--- a/src/librustc/ty/query/mod.rs
+++ b/src/librustc/ty/query/mod.rs
@@ -56,7 +56,6 @@ use std::any::type_name;
 use syntax_pos::{Span, DUMMY_SP};
 use syntax::attr;
 use syntax::ast;
-use syntax::feature_gate;
 use syntax::symbol::Symbol;
 
 #[macro_use]
diff --git a/src/librustc_feature/Cargo.toml b/src/librustc_feature/Cargo.toml
new file mode 100644
index 00000000000..22e8366804b
--- /dev/null
+++ b/src/librustc_feature/Cargo.toml
@@ -0,0 +1,13 @@
+[package]
+authors = ["The Rust Project Developers"]
+name = "rustc_feature"
+version = "0.0.0"
+edition = "2018"
+
+[lib]
+name = "rustc_feature"
+path = "lib.rs"
+doctest = false
+
+[dependencies]
+syntax_pos = { path = "../libsyntax_pos" }
diff --git a/src/libsyntax/feature_gate/accepted.rs b/src/librustc_feature/accepted.rs
index dab83f48a03..fec5a7f1a45 100644
--- a/src/libsyntax/feature_gate/accepted.rs
+++ b/src/librustc_feature/accepted.rs
@@ -1,7 +1,7 @@
 //! List of the accepted feature gates.
 
-use crate::symbol::sym;
 use super::{State, Feature};
+use syntax_pos::symbol::sym;
 
 macro_rules! declare_features {
     ($(
diff --git a/src/libsyntax/feature_gate/active.rs b/src/librustc_feature/active.rs
index b04b30aa6bc..fc1f770e226 100644
--- a/src/libsyntax/feature_gate/active.rs
+++ b/src/librustc_feature/active.rs
@@ -2,10 +2,9 @@
 
 use super::{State, Feature};
 
-use crate::edition::Edition;
-use crate::symbol::{Symbol, sym};
-
+use syntax_pos::edition::Edition;
 use syntax_pos::Span;
+use syntax_pos::symbol::{Symbol, sym};
 
 macro_rules! set {
     ($field: ident) => {{
diff --git a/src/libsyntax/feature_gate/mod.rs b/src/librustc_feature/lib.rs
index c4418c0f0f6..c6388f47cfe 100644
--- a/src/libsyntax/feature_gate/mod.rs
+++ b/src/librustc_feature/lib.rs
@@ -15,13 +15,10 @@
 mod accepted;
 mod removed;
 mod active;
-mod builtin_attrs;
-mod check;
 
-use crate::{edition::Edition, symbol::Symbol};
 use std::fmt;
 use std::num::NonZeroU32;
-use syntax_pos::Span;
+use syntax_pos::{Span, edition::Edition, symbol::Symbol};
 
 #[derive(Clone, Copy)]
 pub enum State {
@@ -44,28 +41,21 @@ impl fmt::Debug for State {
 
 #[derive(Debug, Clone)]
 pub struct Feature {
-    state: State,
-    name: Symbol,
-    since: &'static str,
+    pub state: State,
+    pub name: Symbol,
+    pub since: &'static str,
     issue: Option<u32>,  // FIXME: once #58732 is done make this an Option<NonZeroU32>
-    edition: Option<Edition>,
+    pub edition: Option<Edition>,
     description: &'static str,
 }
 
 impl Feature {
-    fn issue(&self) -> Option<NonZeroU32> {
+    // FIXME(Centril): privatize again.
+    pub fn issue(&self) -> Option<NonZeroU32> {
         self.issue.and_then(|i| NonZeroU32::new(i))
     }
 }
 
-pub use active::{Features, INCOMPLETE_FEATURES};
-pub use builtin_attrs::{
-    AttributeGate, AttributeType, GatedCfg,
-    BuiltinAttribute, BUILTIN_ATTRIBUTES, BUILTIN_ATTRIBUTE_MAP,
-    deprecated_attributes, is_builtin_attr,  is_builtin_attr_name,
-};
-pub use check::{
-    check_crate, check_attribute, get_features, feature_err, emit_feature_err,
-    Stability, GateIssue, UnstableFeatures,
-    EXPLAIN_STMT_ATTR_SYNTAX, EXPLAIN_UNSIZED_TUPLE_COERCION,
-};
+pub use accepted::ACCEPTED_FEATURES;
+pub use active::{ACTIVE_FEATURES, Features, INCOMPLETE_FEATURES};
+pub use removed::{REMOVED_FEATURES, STABLE_REMOVED_FEATURES};
diff --git a/src/libsyntax/feature_gate/removed.rs b/src/librustc_feature/removed.rs
index f0aa74c65df..340bd32fb8a 100644
--- a/src/libsyntax/feature_gate/removed.rs
+++ b/src/librustc_feature/removed.rs
@@ -1,7 +1,7 @@
 //! List of the removed feature gates.
 
-use crate::symbol::sym;
 use super::{State, Feature};
+use syntax_pos::symbol::sym;
 
 macro_rules! declare_features {
     ($(
diff --git a/src/librustc_lint/Cargo.toml b/src/librustc_lint/Cargo.toml
index d26d8791f66..ed38243581b 100644
--- a/src/librustc_lint/Cargo.toml
+++ b/src/librustc_lint/Cargo.toml
@@ -15,5 +15,6 @@ rustc_target = { path = "../librustc_target" }
 syntax = { path = "../libsyntax" }
 syntax_pos = { path = "../libsyntax_pos" }
 rustc_data_structures = { path = "../librustc_data_structures" }
+rustc_feature = { path = "../librustc_feature" }
 rustc_index = { path = "../librustc_index" }
 rustc_error_codes = { path = "../librustc_error_codes" }
diff --git a/src/librustc_lint/builtin.rs b/src/librustc_lint/builtin.rs
index 38624034022..3515ef13e79 100644
--- a/src/librustc_lint/builtin.rs
+++ b/src/librustc_lint/builtin.rs
@@ -41,7 +41,7 @@ use syntax::ptr::P;
 use syntax::attr::{self, HasAttrs, AttributeTemplate};
 use syntax::source_map::Spanned;
 use syntax::edition::Edition;
-use syntax::feature_gate::{self, AttributeGate, AttributeType};
+use syntax::feature_gate::{AttributeGate, AttributeType};
 use syntax::feature_gate::{Stability, deprecated_attributes};
 use syntax_pos::{BytePos, Span};
 use syntax::symbol::{Symbol, kw, sym};
@@ -1850,7 +1850,7 @@ impl EarlyLintPass for IncompleteFeatures {
         features.declared_lang_features
             .iter().map(|(name, span, _)| (name, span))
             .chain(features.declared_lib_features.iter().map(|(name, span)| (name, span)))
-            .filter(|(name, _)| feature_gate::INCOMPLETE_FEATURES.iter().any(|f| name == &f))
+            .filter(|(name, _)| rustc_feature::INCOMPLETE_FEATURES.iter().any(|f| name == &f))
             .for_each(|(name, &span)| {
                 cx.struct_span_lint(
                     INCOMPLETE_FEATURES,
diff --git a/src/librustc_parse/Cargo.toml b/src/librustc_parse/Cargo.toml
index a9175487a75..95b3256f53a 100644
--- a/src/librustc_parse/Cargo.toml
+++ b/src/librustc_parse/Cargo.toml
@@ -16,6 +16,7 @@ syntax_pos = { path = "../libsyntax_pos" }
 syntax = { path = "../libsyntax" }
 errors = { path = "../librustc_errors", package = "rustc_errors" }
 rustc_data_structures = { path = "../librustc_data_structures" }
+rustc_feature = { path = "../librustc_feature" }
 rustc_lexer = { path = "../librustc_lexer" }
 rustc_target = { path = "../librustc_target" }
 smallvec = { version = "1.0", features = ["union", "may_dangle"] }
diff --git a/src/librustc_parse/config.rs b/src/librustc_parse/config.rs
index 7ce555ed57a..9c309f60515 100644
--- a/src/librustc_parse/config.rs
+++ b/src/librustc_parse/config.rs
@@ -9,11 +9,11 @@
 //! [#64197]: https://github.com/rust-lang/rust/issues/64197
 
 use crate::validate_attr;
+use rustc_feature::Features;
 use syntax::attr::HasAttrs;
 use syntax::feature_gate::{
     feature_err,
     EXPLAIN_STMT_ATTR_SYNTAX,
-    Features,
     get_features,
     GateIssue,
 };
diff --git a/src/librustc_passes/Cargo.toml b/src/librustc_passes/Cargo.toml
index 7a98734bdbe..bb2f7c67418 100644
--- a/src/librustc_passes/Cargo.toml
+++ b/src/librustc_passes/Cargo.toml
@@ -12,6 +12,7 @@ path = "lib.rs"
 log = "0.4"
 rustc = { path = "../librustc" }
 rustc_data_structures = { path = "../librustc_data_structures" }
+rustc_feature = { path = "../librustc_feature" }
 rustc_index = { path = "../librustc_index" }
 rustc_parse = { path = "../librustc_parse" }
 rustc_target = { path = "../librustc_target" }
diff --git a/src/librustc_passes/check_const.rs b/src/librustc_passes/check_const.rs
index 24bc088e24a..697a3ae873c 100644
--- a/src/librustc_passes/check_const.rs
+++ b/src/librustc_passes/check_const.rs
@@ -13,8 +13,9 @@ use rustc::hir::map::Map;
 use rustc::hir;
 use rustc::ty::TyCtxt;
 use rustc::ty::query::Providers;
+use rustc_feature::Features;
 use syntax::ast::Mutability;
-use syntax::feature_gate::{emit_feature_err, Features, GateIssue};
+use syntax::feature_gate::{emit_feature_err, GateIssue};
 use syntax::span_err;
 use syntax_pos::{sym, Span};
 use rustc_error_codes::*;
diff --git a/src/librustdoc/clean/cfg.rs b/src/librustdoc/clean/cfg.rs
index 09f4873967e..078948cc63b 100644
--- a/src/librustdoc/clean/cfg.rs
+++ b/src/librustdoc/clean/cfg.rs
@@ -7,10 +7,10 @@ use std::mem;
 use std::fmt::{self, Write};
 use std::ops;
 
+use rustc_feature::Features;
 use syntax::symbol::{Symbol, sym};
 use syntax::ast::{MetaItem, MetaItemKind, NestedMetaItem, LitKind};
 use syntax::sess::ParseSess;
-use syntax::feature_gate::Features;
 
 use syntax_pos::Span;
 
diff --git a/src/librustdoc/lib.rs b/src/librustdoc/lib.rs
index 69d9748bb88..be3644ecf96 100644
--- a/src/librustdoc/lib.rs
+++ b/src/librustdoc/lib.rs
@@ -24,6 +24,7 @@ extern crate env_logger;
 extern crate rustc;
 extern crate rustc_data_structures;
 extern crate rustc_driver;
+extern crate rustc_feature;
 extern crate rustc_error_codes;
 extern crate rustc_index;
 extern crate rustc_resolve;
diff --git a/src/libsyntax/Cargo.toml b/src/libsyntax/Cargo.toml
index dff23076c82..085c1760c80 100644
--- a/src/libsyntax/Cargo.toml
+++ b/src/libsyntax/Cargo.toml
@@ -18,6 +18,7 @@ lazy_static = "1.0.0"
 syntax_pos = { path = "../libsyntax_pos" }
 errors = { path = "../librustc_errors", package = "rustc_errors" }
 rustc_data_structures = { path = "../librustc_data_structures" }
+rustc_feature = { path = "../librustc_feature" }
 rustc_index = { path = "../librustc_index" }
 rustc_lexer = { path = "../librustc_lexer" }
 rustc_macros = { path = "../librustc_macros" }
diff --git a/src/libsyntax/attr/builtin.rs b/src/libsyntax/attr/builtin.rs
index c10541c8c7e..eaa4a64025a 100644
--- a/src/libsyntax/attr/builtin.rs
+++ b/src/libsyntax/attr/builtin.rs
@@ -1,14 +1,15 @@
 //! Parsing and validation of builtin attributes
 
 use crate::ast::{self, Attribute, MetaItem, NestedMetaItem};
-use crate::feature_gate::{Features, GatedCfg};
 use crate::print::pprust;
+use crate::feature_gate::GatedCfg;
 use crate::sess::ParseSess;
 
 use errors::{Applicability, Handler};
 use std::num::NonZeroU32;
 use syntax_pos::hygiene::Transparency;
 use syntax_pos::{symbol::Symbol, symbol::sym, Span};
+use rustc_feature::Features;
 use rustc_macros::HashStable_Generic;
 
 use super::{mark_used, MetaItemKind};
diff --git a/src/libsyntax/feature_gate/builtin_attrs.rs b/src/libsyntax/feature_gate/builtin_attrs.rs
index a9f41633f30..e6f61e8fcbe 100644
--- a/src/libsyntax/feature_gate/builtin_attrs.rs
+++ b/src/libsyntax/feature_gate/builtin_attrs.rs
@@ -5,13 +5,13 @@ use AttributeGate::*;
 
 use super::check::{emit_feature_err, GateIssue};
 use super::check::{Stability, EXPLAIN_ALLOW_INTERNAL_UNSAFE, EXPLAIN_ALLOW_INTERNAL_UNSTABLE};
-use super::active::Features;
+use rustc_feature::Features;
 
 use crate::ast;
 use crate::attr::AttributeTemplate;
 use crate::sess::ParseSess;
-use crate::symbol::{Symbol, sym};
 
+use syntax_pos::symbol::{Symbol, sym};
 use syntax_pos::Span;
 use rustc_data_structures::fx::FxHashMap;
 use lazy_static::lazy_static;
diff --git a/src/libsyntax/feature_gate/check.rs b/src/libsyntax/feature_gate/check.rs
index ec0eaa56812..7d959756f23 100644
--- a/src/libsyntax/feature_gate/check.rs
+++ b/src/libsyntax/feature_gate/check.rs
@@ -1,6 +1,5 @@
-use super::{active::{ACTIVE_FEATURES, Features}, Feature, State as FeatureState};
-use super::accepted::ACCEPTED_FEATURES;
-use super::removed::{REMOVED_FEATURES, STABLE_REMOVED_FEATURES};
+use rustc_feature::{ACCEPTED_FEATURES, ACTIVE_FEATURES, Features, Feature, State as FeatureState};
+use rustc_feature::{REMOVED_FEATURES, STABLE_REMOVED_FEATURES};
 use super::builtin_attrs::{AttributeGate, BUILTIN_ATTRIBUTE_MAP};
 
 use crate::ast::{self, AssocTyConstraint, AssocTyConstraintKind, NodeId};
diff --git a/src/libsyntax/lib.rs b/src/libsyntax/lib.rs
index 22b49862f49..f0d857673e7 100644
--- a/src/libsyntax/lib.rs
+++ b/src/libsyntax/lib.rs
@@ -92,7 +92,20 @@ pub mod attr;
 pub mod expand;
 pub use syntax_pos::source_map;
 pub mod entry;
-pub mod feature_gate;
+pub mod feature_gate {
+    mod check;
+    pub use check::{
+        check_crate, check_attribute, get_features, feature_err, emit_feature_err,
+        Stability, GateIssue, UnstableFeatures,
+        EXPLAIN_STMT_ATTR_SYNTAX, EXPLAIN_UNSIZED_TUPLE_COERCION,
+    };
+    mod builtin_attrs;
+    pub use builtin_attrs::{
+        AttributeGate, AttributeType, GatedCfg,
+        BuiltinAttribute, BUILTIN_ATTRIBUTES, BUILTIN_ATTRIBUTE_MAP,
+        deprecated_attributes, is_builtin_attr,  is_builtin_attr_name,
+    };
+}
 pub mod mut_visit;
 pub mod ptr;
 pub mod show_span;
diff --git a/src/libsyntax_expand/Cargo.toml b/src/libsyntax_expand/Cargo.toml
index 653b87f0d82..897d5a65ba3 100644
--- a/src/libsyntax_expand/Cargo.toml
+++ b/src/libsyntax_expand/Cargo.toml
@@ -16,6 +16,7 @@ log = "0.4"
 syntax_pos = { path = "../libsyntax_pos" }
 errors = { path = "../librustc_errors", package = "rustc_errors" }
 rustc_data_structures = { path = "../librustc_data_structures" }
+rustc_feature = { path = "../librustc_feature" }
 rustc_lexer = { path = "../librustc_lexer" }
 rustc_parse = { path = "../librustc_parse" }
 smallvec = { version = "1.0", features = ["union", "may_dangle"] }
diff --git a/src/libsyntax_expand/expand.rs b/src/libsyntax_expand/expand.rs
index 4f05b0147bf..d8033759033 100644
--- a/src/libsyntax_expand/expand.rs
+++ b/src/libsyntax_expand/expand.rs
@@ -4,8 +4,9 @@ use crate::hygiene::{ExpnId, SyntaxContext, ExpnData, ExpnKind};
 use crate::mbe::macro_rules::annotate_err_with_kind;
 use crate::placeholders::{placeholder, PlaceholderExpander};
 use crate::config::StripUnconfigured;
-use rustc_parse::configure;
 
+use rustc_feature::Features;
+use rustc_parse::configure;
 use rustc_parse::DirectoryOwnership;
 use rustc_parse::parser::Parser;
 use rustc_parse::validate_attr;
@@ -13,7 +14,7 @@ use syntax::ast::{self, AttrItem, Block, Ident, LitKind, NodeId, PatKind, Path};
 use syntax::ast::{MacStmtStyle, StmtKind, ItemKind};
 use syntax::attr::{self, HasAttrs};
 use syntax::source_map::respan;
-use syntax::feature_gate::{self, Features, GateIssue, is_builtin_attr, emit_feature_err};
+use syntax::feature_gate::{self, GateIssue, is_builtin_attr, emit_feature_err};
 use syntax::mut_visit::*;
 use syntax::print::pprust;
 use syntax::ptr::P;
diff --git a/src/libsyntax_expand/mbe/macro_rules.rs b/src/libsyntax_expand/mbe/macro_rules.rs
index a1d8b5a5338..b191527df19 100644
--- a/src/libsyntax_expand/mbe/macro_rules.rs
+++ b/src/libsyntax_expand/mbe/macro_rules.rs
@@ -8,12 +8,12 @@ use crate::mbe::macro_parser::{Error, Failure, Success};
 use crate::mbe::macro_parser::{MatchedNonterminal, MatchedSeq, NamedParseResult};
 use crate::mbe::transcribe::transcribe;
 
+use rustc_feature::Features;
 use rustc_parse::parser::Parser;
 use rustc_parse::Directory;
 use syntax::ast;
 use syntax::attr::{self, TransparencyError};
 use syntax::edition::Edition;
-use syntax::feature_gate::Features;
 use syntax::print::pprust;
 use syntax::sess::ParseSess;
 use syntax::symbol::{kw, sym, Symbol};
diff --git a/src/libsyntax_ext/Cargo.toml b/src/libsyntax_ext/Cargo.toml
index 2ebdac8ef7c..d73a9ea6cdb 100644
--- a/src/libsyntax_ext/Cargo.toml
+++ b/src/libsyntax_ext/Cargo.toml
@@ -14,6 +14,7 @@ errors = { path = "../librustc_errors", package = "rustc_errors" }
 fmt_macros = { path = "../libfmt_macros" }
 log = "0.4"
 rustc_data_structures = { path = "../librustc_data_structures" }
+rustc_feature = { path = "../librustc_feature" }
 rustc_parse = { path = "../librustc_parse" }
 rustc_target = { path = "../librustc_target" }
 smallvec = { version = "1.0", features = ["union", "may_dangle"] }
diff --git a/src/libsyntax_ext/test_harness.rs b/src/libsyntax_ext/test_harness.rs
index 659780d7a43..4c1eec38c6e 100644
--- a/src/libsyntax_ext/test_harness.rs
+++ b/src/libsyntax_ext/test_harness.rs
@@ -2,13 +2,13 @@
 
 use log::debug;
 use smallvec::{smallvec, SmallVec};
+use rustc_feature::Features;
 use rustc_target::spec::PanicStrategy;
 use syntax::ast::{self, Ident};
 use syntax::attr;
 use syntax::entry::{self, EntryPointType};
 use syntax_expand::base::{ExtCtxt, Resolver};
 use syntax_expand::expand::{AstFragment, ExpansionConfig};
-use syntax::feature_gate::Features;
 use syntax::mut_visit::{*, ExpectOne};
 use syntax::ptr::P;
 use syntax::sess::ParseSess;