Move --extern-public behind -Z unstable-options

src/librustc/session/config.rs

@@ -414,7 +414,7 @@ top_level_options!(
 
         // The list of crates to consider public for
         // checking leaked private dependency types in public interfaces
-        extern_public: Vec<String> [TRACKED],
+        extern_public: Option<Vec<String>> [TRACKED],
     }
 );
 
@@ -610,7 +610,7 @@ impl Default for Options {
             cli_forced_thinlto_off: false,
             remap_path_prefix: Vec::new(),
             edition: DEFAULT_EDITION,
-            extern_public: vec![]
+            extern_public: None
         }
     }
 }
@@ -1917,21 +1917,7 @@ pub fn build_session_options_and_crate_config(
     let crate_types = parse_crate_types_from_list(unparsed_crate_types)
         .unwrap_or_else(|e| early_error(error_format, &e[..]));
 
-    if matches.opt_present("extern-public") && !nightly_options::is_nightly_build() {
-        early_error(
-            ErrorOutputType::default(),
-            "'--extern-public' is unstable and only \
-            available for nightly builds of rustc."
-        )
-    }
-
-    let mut extern_public: Vec<String> = matches.opt_strs("extern-public").
-        iter().cloned().collect();
-
-    // FIXME - come up with a better way of handling this
-    extern_public.push("core".to_string());
-    extern_public.push("std".to_string());
-
+    
     let (lint_opts, describe_lints, lint_cap) = get_cmd_lint_options(matches, error_format);
 
     let mut debugging_opts = build_debugging_options(matches, error_format);
@@ -1950,6 +1936,24 @@ pub fn build_session_options_and_crate_config(
         );
     }
 
+    if matches.opt_present("extern-public") && !debugging_opts.unstable_options {
+        early_error(
+            ErrorOutputType::default(),
+            "'--extern-public' is unstable and only \
+            available for nightly builds of rustc."
+        )
+    }
+
+    let mut extern_public: Option<Vec<String>> = matches.opt_str("extern-public").
+        map(|s| s.split(',').map(|c| (*c).to_string()).collect());
+
+    // FIXME - come up with a better way of handling this
+    if let Some(p) = extern_public.as_mut() {
+        p.push("core".to_string());
+        p.push("std".to_string());
+    }
+
+
     let mut output_types = BTreeMap::new();
     if !debugging_opts.parse_only {
         for list in matches.opt_strs("emit") {
@@ -2488,6 +2492,7 @@ mod dep_tracking {
     impl_dep_tracking_hash_via_hash!(Option<usize>);
     impl_dep_tracking_hash_via_hash!(Option<String>);
     impl_dep_tracking_hash_via_hash!(Option<(String, u64)>);
+    impl_dep_tracking_hash_via_hash!(Option<Vec<String>>);
     impl_dep_tracking_hash_via_hash!(Option<MergeFunctions>);
     impl_dep_tracking_hash_via_hash!(Option<PanicStrategy>);
     impl_dep_tracking_hash_via_hash!(Option<RelroLevel>);

src/librustc_privacy/lib.rs

@@ -1460,7 +1460,7 @@ struct SearchInterfaceForPrivateItemsVisitor<'a, 'tcx: 'a> {
     has_pub_restricted: bool,
     has_old_errors: bool,
     in_assoc_ty: bool,
-    public_crates: FxHashSet<CrateNum>
+    public_crates: Option<FxHashSet<CrateNum>>
 }
 
 impl<'a, 'tcx: 'a> SearchInterfaceForPrivateItemsVisitor<'a, 'tcx> {
@@ -1538,13 +1538,13 @@ impl<'a, 'tcx: 'a> SearchInterfaceForPrivateItemsVisitor<'a, 'tcx> {
     /// 1. It's contained within a public type
     /// 2. It does not come from a crate marked as public
     fn leaks_private_dep(&self, item_id: DefId) -> bool {
-        // Never do any leak checking if the feature is not enabled
-        if !self.tcx.features().public_private_dependencies {
+        // Don't do any leak checking if no public crates were specified
+        if self.public_crates.is_none() {
             return false
         }
         let ret = self.required_visibility == ty::Visibility::Public &&
             !item_id.is_local() &&
-            !self.public_crates.contains(&item_id.krate);
+            !self.public_crates.as_ref().unwrap().contains(&item_id.krate);
 
 
         debug!("leaks_private_dep(item_id={:?})={}", item_id, ret);
@@ -1563,7 +1563,7 @@ struct PrivateItemsInPublicInterfacesVisitor<'a, 'tcx: 'a> {
     tcx: TyCtxt<'a, 'tcx, 'tcx>,
     has_pub_restricted: bool,
     old_error_set: &'a NodeSet,
-    public_crates: FxHashSet<CrateNum>
+    public_crates: Option<FxHashSet<CrateNum>>
 }
 
 impl<'a, 'tcx> PrivateItemsInPublicInterfacesVisitor<'a, 'tcx> {
@@ -1762,9 +1762,9 @@ fn privacy_access_levels<'tcx>(
         queries::check_mod_privacy::ensure(tcx, tcx.hir().local_def_id(module));
     }
 
-    let public_crates: FxHashSet<CrateNum> = tcx.sess.opts.extern_public.iter().flat_map(|c| {
+    let public_crates: Option<FxHashSet<CrateNum>> = tcx.sess.opts.extern_public.as_ref().map(|s| s.iter().flat_map(|c| {
         tcx.crates().iter().find(|&&krate| &tcx.crate_name(krate) == c).cloned()
-    }).collect();
+    }).collect());
 
 
     // Build up a set of all exported items in the AST. This is a set of all