refactor away get_unstable_features_setting

src/librustc/session/config.rs

@@ -37,7 +37,6 @@ use std::collections::btree_map::Iter as BTreeMapIter;
 use std::collections::btree_map::Keys as BTreeMapKeysIter;
 use std::collections::btree_map::Values as BTreeMapValuesIter;
 
-use std::env;
 use std::fmt;
 use std::hash::{Hasher, SipHasher};
 use std::iter::FromIterator;
@@ -1525,27 +1524,12 @@ pub fn build_session_options_and_crate_config(matches: &getopts::Matches)
         crate_name: crate_name,
         alt_std_name: None,
         libs: libs,
-        unstable_features: get_unstable_features_setting(),
+        unstable_features: UnstableFeatures::from_environment(),
         debug_assertions: debug_assertions,
     },
     cfg)
 }
 
-pub fn get_unstable_features_setting() -> UnstableFeatures {
-    // Whether this is a feature-staged build, i.e. on the beta or stable channel
-    let disable_unstable_features = option_env!("CFG_DISABLE_UNSTABLE_FEATURES").is_some();
-    // The secret key needed to get through the rustc build itself by
-    // subverting the unstable features lints
-    let bootstrap_secret_key = option_env!("CFG_BOOTSTRAP_KEY");
-    // The matching key to the above, only known by the build system
-    let bootstrap_provided_key = env::var("RUSTC_BOOTSTRAP_KEY").ok();
-    match (disable_unstable_features, bootstrap_secret_key, bootstrap_provided_key) {
-        (_, Some(ref s), Some(ref p)) if s == p => UnstableFeatures::Cheat,
-        (true, ..) => UnstableFeatures::Disallow,
-        (false, ..) => UnstableFeatures::Allow
-    }
-}
-
 pub fn parse_crate_types_from_list(list_list: Vec<String>) -> Result<Vec<CrateType>, String> {
     let mut crate_types: Vec<CrateType> = Vec::new();
     for unparsed_crate_type in &list_list {
@@ -1575,7 +1559,7 @@ pub fn parse_crate_types_from_list(list_list: Vec<String>) -> Result<Vec<CrateTy
 pub mod nightly_options {
     use getopts;
     use syntax::feature_gate::UnstableFeatures;
-    use super::{ErrorOutputType, OptionStability, RustcOptGroup, get_unstable_features_setting};
+    use super::{ErrorOutputType, OptionStability, RustcOptGroup};
     use session::{early_error, early_warn};
 
     pub fn is_unstable_enabled(matches: &getopts::Matches) -> bool {
@@ -1588,7 +1572,7 @@ pub mod nightly_options {
 
     pub fn check_nightly_options(matches: &getopts::Matches, flags: &[RustcOptGroup]) {
         let has_z_unstable_option = matches.opt_strs("Z").iter().any(|x| *x == "unstable-options");
-        let really_allows_unstable_options = match get_unstable_features_setting() {
+        let really_allows_unstable_options = match UnstableFeatures::from_environment() {
             UnstableFeatures::Disallow => false,
             _ => true,
         };

src/librustc_driver/lib.rs

@@ -73,7 +73,7 @@ use rustc_trans::back::write::{create_target_machine, RELOC_MODEL_ARGS, CODE_GEN
 use rustc::dep_graph::DepGraph;
 use rustc::session::{self, config, Session, build_session, CompileResult};
 use rustc::session::config::{Input, PrintRequest, OutputType, ErrorOutputType};
-use rustc::session::config::{get_unstable_features_setting, nightly_options};
+use rustc::session::config::nightly_options;
 use rustc::lint::Lint;
 use rustc::lint;
 use rustc_metadata::loader;
@@ -649,7 +649,7 @@ impl RustcDefaultCalls {
                     }
                 }
                 PrintRequest::Cfg => {
-                    let allow_unstable_cfg = match get_unstable_features_setting() {
+                    let allow_unstable_cfg = match UnstableFeatures::from_environment() {
                         UnstableFeatures::Disallow => false,
                         _ => true,
                     };

src/librustdoc/html/markdown.rs

@@ -27,7 +27,6 @@
 #![allow(non_camel_case_types)]
 
 use libc;
-use rustc::session::config::get_unstable_features_setting;
 use std::ascii::AsciiExt;
 use std::cell::RefCell;
 use std::default::Default;
@@ -478,7 +477,7 @@ impl LangString {
         let mut data = LangString::all_false();
         let mut allow_compile_fail = false;
         let mut allow_error_code_check = false;
-        match get_unstable_features_setting() {
+        match UnstableFeatures::from_environment() {
             UnstableFeatures::Allow | UnstableFeatures::Cheat => {
                 allow_compile_fail = true;
                 allow_error_code_check = true;

src/librustdoc/html/render.rs

@@ -58,7 +58,6 @@ use syntax::feature_gate::UnstableFeatures;
 use rustc::hir::def_id::{CrateNum, CRATE_DEF_INDEX, DefId, LOCAL_CRATE};
 use rustc::middle::privacy::AccessLevels;
 use rustc::middle::stability;
-use rustc::session::config::get_unstable_features_setting;
 use rustc::hir;
 use rustc::util::nodemap::{FnvHashMap, FnvHashSet};
 use rustc_data_structures::flock;
@@ -1971,7 +1970,7 @@ fn item_static(w: &mut fmt::Formatter, cx: &Context, it: &clean::Item,
 fn item_function(w: &mut fmt::Formatter, cx: &Context, it: &clean::Item,
                  f: &clean::Function) -> fmt::Result {
     // FIXME(#24111): remove when `const_fn` is stabilized
-    let vis_constness = match get_unstable_features_setting() {
+    let vis_constness = match UnstableFeatures::from_environment() {
         UnstableFeatures::Allow => f.constness,
         _ => hir::Constness::NotConst
     };
@@ -2250,7 +2249,7 @@ fn render_assoc_item(w: &mut fmt::Formatter,
             }
         };
         // FIXME(#24111): remove when `const_fn` is stabilized
-        let vis_constness = match get_unstable_features_setting() {
+        let vis_constness = match UnstableFeatures::from_environment() {
             UnstableFeatures::Allow => constness,
             _ => hir::Constness::NotConst
         };

src/librustdoc/test.rs

@@ -25,8 +25,7 @@ use rustc_lint;
 use rustc::dep_graph::DepGraph;
 use rustc::hir::map as hir_map;
 use rustc::session::{self, config};
-use rustc::session::config::{get_unstable_features_setting, OutputType,
-                             OutputTypes, Externs};
+use rustc::session::config::{OutputType, OutputTypes, Externs};
 use rustc::session::search_paths::{SearchPaths, PathKind};
 use rustc_back::dynamic_lib::DynamicLibrary;
 use rustc_back::tempdir::TempDir;
@@ -35,6 +34,7 @@ use rustc_driver::driver::phase_2_configure_and_expand;
 use rustc_metadata::cstore::CStore;
 use rustc_resolve::MakeGlobMap;
 use syntax::codemap::CodeMap;
+use syntax::feature_gate::UnstableFeatures;
 use errors;
 use errors::emitter::ColorConfig;
 
@@ -68,7 +68,7 @@ pub fn run(input: &str,
         search_paths: libs.clone(),
         crate_types: vec!(config::CrateTypeDylib),
         externs: externs.clone(),
-        unstable_features: get_unstable_features_setting(),
+        unstable_features: UnstableFeatures::from_environment(),
         ..config::basic_options().clone()
     };
 
@@ -197,7 +197,7 @@ fn runtest(test: &str, cratename: &str, cfgs: Vec<String>, libs: SearchPaths,
             .. config::basic_codegen_options()
         },
         test: as_test_harness,
-        unstable_features: get_unstable_features_setting(),
+        unstable_features: UnstableFeatures::from_environment(),
         ..config::basic_options().clone()
     };