---

yaml
---
r: 193485
b: refs/heads/beta
c: 9eb596c
h: refs/heads/master
i:
  193483: b78bc17
v: v3

Author: Manishearth

[refs]

@@ -31,7 +31,7 @@ refs/heads/automation-fail: 1bf06495443584539b958873e04cc2f864ab10e4
 refs/heads/issue-18208-method-dispatch-3-quick-reject: 2009f85b9f99dedcec4404418eda9ddba90258a2
 refs/heads/batch: b7fd822592a4fb577552d93010c4a4e14f314346
 refs/heads/building: 126db549b038c84269a1e4fe46f051b2c15d6970
-refs/heads/beta: e80fc10af19b1c9c4507187ab1c059b445d8f057
+refs/heads/beta: 9eb596ce8f4b70ba73e8671f9b42147c91319842
 refs/heads/windistfix: 7608dbad651f02e837ed05eef3d74a6662a6e928
 refs/tags/1.0.0-alpha: e42bd6d93a1d3433c486200587f8f9e12590a4d7
 refs/heads/tmp: de8a23bbc3a7b9cbd7574b5b91a34af59bf030e6

branches/beta/src/doc/reference.md

@@ -2555,6 +2555,14 @@ The currently implemented features of the reference compiler are:
                             types, e.g. as the return type of a public function.
                             This capability may be removed in the future.
 
+* `allow_internal_unstable` - Allows `macro_rules!` macros to be tagged with the
+                              `#[allow_internal_unstable]` attribute, designed
+                              to allow `std` macros to call
+                              `#[unstable]`/feature-gated functionality
+                              internally without imposing on callers
+                              (i.e. making them behave like function calls in
+                              terms of encapsulation).
+
 If a feature is promoted to a language feature, then all existing programs will
 start to receive compilation warnings about #[feature] directives which enabled
 the new feature (because the directive is no longer necessary). However, if a

branches/beta/src/libcore/num/mod.rs

@@ -1238,6 +1238,7 @@ pub fn from_f64<A: FromPrimitive>(n: f64) -> Option<A> {
 
 macro_rules! impl_from_primitive {
     ($T:ty, $to_ty:ident) => (
+        #[allow(deprecated)]
         impl FromPrimitive for $T {
             #[inline] fn from_int(n: int) -> Option<$T> { n.$to_ty() }
             #[inline] fn from_i8(n: i8) -> Option<$T> { n.$to_ty() }
@@ -1299,6 +1300,7 @@ macro_rules! impl_num_cast {
     ($T:ty, $conv:ident) => (
         impl NumCast for $T {
             #[inline]
+            #[allow(deprecated)]
             fn from<N: ToPrimitive>(n: N) -> Option<$T> {
                 // `$conv` could be generated using `concat_idents!`, but that
                 // macro seems to be broken at the moment

branches/beta/src/librustc/metadata/creader.rs

@@ -542,6 +542,7 @@ impl<'a> CrateReader<'a> {
                     // overridden in plugin/load.rs
                     export: false,
                     use_locally: false,
+                    allow_internal_unstable: false,
 
                     body: body,
                 });

branches/beta/src/librustc/metadata/macro_import.rs

@@ -166,6 +166,9 @@ impl<'a> MacroLoader<'a> {
                 Some(sel) => sel.contains_key(&name),
             };
             def.export = reexport.contains_key(&name);
+            def.allow_internal_unstable = attr::contains_name(&def.attrs,
+                                                              "allow_internal_unstable");
+            debug!("load_macros: loaded: {:?}", def);
             self.macros.push(def);
         }
 

branches/beta/src/librustc/middle/stability.rs

@@ -362,8 +362,6 @@ pub fn check_item(tcx: &ty::ctxt, item: &ast::Item, warn_about_defns: bool,
 /// Helper for discovering nodes to check for stability
 pub fn check_expr(tcx: &ty::ctxt, e: &ast::Expr,
                   cb: &mut FnMut(ast::DefId, Span, &Option<Stability>)) {
-    if is_internal(tcx, e.span) { return; }
-
     let span;
     let id = match e.node {
         ast::ExprMethodCall(i, _, _) => {
@@ -527,12 +525,13 @@ pub fn check_pat(tcx: &ty::ctxt, pat: &ast::Pat,
 fn maybe_do_stability_check(tcx: &ty::ctxt, id: ast::DefId, span: Span,
                             cb: &mut FnMut(ast::DefId, Span, &Option<Stability>)) {
     if !is_staged_api(tcx, id) { return  }
+    if is_internal(tcx, span) { return }
     let ref stability = lookup(tcx, id);
     cb(id, span, stability);
 }
 
 fn is_internal(tcx: &ty::ctxt, span: Span) -> bool {
-    tcx.sess.codemap().span_is_internal(span)
+    tcx.sess.codemap().span_allows_unstable(span)
 }
 
 fn is_staged_api(tcx: &ty::ctxt, id: DefId) -> bool {

branches/beta/src/librustc/plugin/registry.rs

@@ -81,8 +81,12 @@ impl<'a> Registry<'a> {
     /// This is the most general hook into `libsyntax`'s expansion behavior.
     pub fn register_syntax_extension(&mut self, name: ast::Name, extension: SyntaxExtension) {
         self.syntax_exts.push((name, match extension {
-            NormalTT(ext, _) => NormalTT(ext, Some(self.krate_span)),
-            IdentTT(ext, _) => IdentTT(ext, Some(self.krate_span)),
+            NormalTT(ext, _, allow_internal_unstable) => {
+                NormalTT(ext, Some(self.krate_span), allow_internal_unstable)
+            }
+            IdentTT(ext, _, allow_internal_unstable) => {
+                IdentTT(ext, Some(self.krate_span), allow_internal_unstable)
+            }
             Decorator(ext) => Decorator(ext),
             Modifier(ext) => Modifier(ext),
             MultiModifier(ext) => MultiModifier(ext),
@@ -99,7 +103,8 @@ impl<'a> Registry<'a> {
     /// It builds for you a `NormalTT` that calls `expander`,
     /// and also takes care of interning the macro's name.
     pub fn register_macro(&mut self, name: &str, expander: MacroExpanderFn) {
-        self.register_syntax_extension(token::intern(name), NormalTT(Box::new(expander), None));
+        self.register_syntax_extension(token::intern(name),
+                                       NormalTT(Box::new(expander), None, false));
     }
 
     /// Register a compiler lint pass.

branches/beta/src/librustc_driver/driver.rs

@@ -493,12 +493,16 @@ pub fn phase_2_configure_and_expand(sess: &Session,
         }
     );
 
-    // Needs to go *after* expansion to be able to check the results of macro expansion.
-    time(time_passes, "complete gated feature checking", (), |_| {
+    // Needs to go *after* expansion to be able to check the results
+    // of macro expansion.  This runs before #[cfg] to try to catch as
+    // much as possible (e.g. help the programmer avoid platform
+    // specific differences)
+    time(time_passes, "complete gated feature checking 1", (), |_| {
         let features =
             syntax::feature_gate::check_crate(sess.codemap(),
-                                          &sess.parse_sess.span_diagnostic,
-                                          &krate);
+                                              &sess.parse_sess.span_diagnostic,
+                                              &krate,
+                                              true);
         *sess.features.borrow_mut() = features;
         sess.abort_if_errors();
     });
@@ -521,6 +525,19 @@ pub fn phase_2_configure_and_expand(sess: &Session,
     time(time_passes, "checking that all macro invocations are gone", &krate, |krate|
          syntax::ext::expand::check_for_macros(&sess.parse_sess, krate));
 
+    // One final feature gating of the true AST that gets compiled
+    // later, to make sure we've got everything (e.g. configuration
+    // can insert new attributes via `cfg_attr`)
+    time(time_passes, "complete gated feature checking 2", (), |_| {
+        let features =
+            syntax::feature_gate::check_crate(sess.codemap(),
+                                              &sess.parse_sess.span_diagnostic,
+                                              &krate,
+                                              false);
+        *sess.features.borrow_mut() = features;
+        sess.abort_if_errors();
+    });
+
     Some(krate)
 }
 

branches/beta/src/libstd/lib.rs

@@ -125,6 +125,7 @@
 #![feature(hash)]
 #![feature(int_uint)]
 #![feature(unique)]
+#![feature(allow_internal_unstable)]
 #![cfg_attr(test, feature(test, rustc_private))]
 
 // Don't link to std. We are std.

branches/beta/src/libstd/sys/common/thread_local.rs

@@ -55,6 +55,7 @@
 //! ```
 
 #![allow(non_camel_case_types)]
+#![unstable(feature = "thread_local_internals")]
 
 use prelude::v1::*;
 
@@ -84,17 +85,14 @@ use sys::thread_local as imp;
 ///     KEY.set(1 as *mut u8);
 /// }
 /// ```
-#[stable(feature = "rust1", since = "1.0.0")]
 pub struct StaticKey {
     /// Inner static TLS key (internals), created with by `INIT_INNER` in this
     /// module.
-    #[stable(feature = "rust1", since = "1.0.0")]
     pub inner: StaticKeyInner,
     /// Destructor for the TLS value.
     ///
     /// See `Key::new` for information about when the destructor runs and how
     /// it runs.
-    #[stable(feature = "rust1", since = "1.0.0")]
     pub dtor: Option<unsafe extern fn(*mut u8)>,
 }
 
@@ -131,7 +129,6 @@ pub struct Key {
 /// Constant initialization value for static TLS keys.
 ///
 /// This value specifies no destructor by default.
-#[stable(feature = "rust1", since = "1.0.0")]
 pub const INIT: StaticKey = StaticKey {
     inner: INIT_INNER,
     dtor: None,
@@ -140,7 +137,6 @@ pub const INIT: StaticKey = StaticKey {
 /// Constant initialization value for the inner part of static TLS keys.
 ///
 /// This value allows specific configuration of the destructor for a TLS key.
-#[stable(feature = "rust1", since = "1.0.0")]
 pub const INIT_INNER: StaticKeyInner = StaticKeyInner {
     key: atomic::ATOMIC_USIZE_INIT,
 };

branches/beta/src/libstd/thread_local/mod.rs

@@ -45,7 +45,7 @@ pub mod scoped;
 
 // Sure wish we had macro hygiene, no?
 #[doc(hidden)]
-#[stable(feature = "rust1", since = "1.0.0")]
+#[unstable(feature = "thread_local_internals")]
 pub mod __impl {
     pub use super::imp::Key as KeyInner;
     pub use super::imp::destroy_value;
@@ -117,6 +117,7 @@ pub struct Key<T> {
 /// Declare a new thread local storage key of type `std::thread_local::Key`.
 #[macro_export]
 #[stable(feature = "rust1", since = "1.0.0")]
+#[allow_internal_unstable]
 macro_rules! thread_local {
     (static $name:ident: $t:ty = $init:expr) => (
         static $name: ::std::thread_local::Key<$t> = {
@@ -176,6 +177,7 @@ macro_rules! thread_local {
 
 #[macro_export]
 #[doc(hidden)]
+#[allow_internal_unstable]
 macro_rules! __thread_local_inner {
     (static $name:ident: $t:ty = $init:expr) => (
         #[cfg_attr(all(any(target_os = "macos", target_os = "linux"),
@@ -337,22 +339,22 @@ mod imp {
     use ptr;
 
     #[doc(hidden)]
-    #[stable(since = "1.0.0", feature = "rust1")]
+    #[unstable(feature = "thread_local_internals")]
     pub struct Key<T> {
         // Place the inner bits in an `UnsafeCell` to currently get around the
         // "only Sync statics" restriction. This allows any type to be placed in
         // the cell.
         //
         // Note that all access requires `T: 'static` so it can't be a type with
         // any borrowed pointers still.
-        #[stable(since = "1.0.0", feature = "rust1")]
+        #[unstable(feature = "thread_local_internals")]
         pub inner: UnsafeCell<T>,
 
         // Metadata to keep track of the state of the destructor. Remember that
         // these variables are thread-local, not global.
-        #[stable(since = "1.0.0", feature = "rust1")]
+        #[unstable(feature = "thread_local_internals")]
         pub dtor_registered: UnsafeCell<bool>, // should be Cell
-        #[stable(since = "1.0.0", feature = "rust1")]
+        #[unstable(feature = "thread_local_internals")]
         pub dtor_running: UnsafeCell<bool>, // should be Cell
     }
 
@@ -455,7 +457,7 @@ mod imp {
     }
 
     #[doc(hidden)]
-    #[stable(feature = "rust1", since = "1.0.0")]
+    #[unstable(feature = "thread_local_internals")]
     pub unsafe extern fn destroy_value<T>(ptr: *mut u8) {
         let ptr = ptr as *mut Key<T>;
         // Right before we run the user destructor be sure to flag the
@@ -477,15 +479,15 @@ mod imp {
     use sys_common::thread_local::StaticKey as OsStaticKey;
 
     #[doc(hidden)]
-    #[stable(since = "1.0.0", feature = "rust1")]
+    #[unstable(feature = "thread_local_internals")]
     pub struct Key<T> {
         // Statically allocated initialization expression, using an `UnsafeCell`
         // for the same reasons as above.
-        #[stable(since = "1.0.0", feature = "rust1")]
+        #[unstable(feature = "thread_local_internals")]
         pub inner: UnsafeCell<T>,
 
         // OS-TLS key that we'll use to key off.
-        #[stable(since = "1.0.0", feature = "rust1")]
+        #[unstable(feature = "thread_local_internals")]
         pub os: OsStaticKey,
     }
 
@@ -528,7 +530,7 @@ mod imp {
     }
 
     #[doc(hidden)]
-    #[stable(feature = "rust1", since = "1.0.0")]
+    #[unstable(feature = "thread_local_internals")]
     pub unsafe extern fn destroy_value<T: 'static>(ptr: *mut u8) {
         // The OS TLS ensures that this key contains a NULL value when this
         // destructor starts to run. We set it back to a sentinel value of 1 to

branches/beta/src/libstd/thread_local/scoped.rs

@@ -65,6 +65,7 @@ pub struct Key<T> { #[doc(hidden)] pub inner: __impl::KeyInner<T> }
 /// This macro declares a `static` item on which methods are used to get and
 /// set the value stored within.
 #[macro_export]
+#[allow_internal_unstable]
 macro_rules! scoped_thread_local {
     (static $name:ident: $t:ty) => (
         __scoped_thread_local_inner!(static $name: $t);
@@ -76,6 +77,7 @@ macro_rules! scoped_thread_local {
 
 #[macro_export]
 #[doc(hidden)]
+#[allow_internal_unstable]
 macro_rules! __scoped_thread_local_inner {
     (static $name:ident: $t:ty) => (
         #[cfg_attr(not(any(windows,

branches/beta/src/libsyntax/ast.rs

@@ -1743,6 +1743,7 @@ pub struct MacroDef {
     pub imported_from: Option<Ident>,
     pub export: bool,
     pub use_locally: bool,
+    pub allow_internal_unstable: bool,
     pub body: Vec<TokenTree>,
 }
 

branches/beta/src/libsyntax/codemap.rs

@@ -243,6 +243,10 @@ pub struct NameAndSpan {
     pub name: String,
     /// The format with which the macro was invoked.
     pub format: MacroFormat,
+    /// Whether the macro is allowed to use #[unstable]/feature-gated
+    /// features internally without forcing the whole crate to opt-in
+    /// to them.
+    pub allow_internal_unstable: bool,
     /// The span of the macro definition itself. The macro may not
     /// have a sensible definition span (e.g. something defined
     /// completely inside libsyntax) in which case this is None.
@@ -830,41 +834,43 @@ impl CodeMap {
         }
     }
 
-    /// Check if a span is "internal" to a macro. This means that it is entirely generated by a
-    /// macro expansion and contains no code that was passed in as an argument.
-    pub fn span_is_internal(&self, span: Span) -> bool {
-        // first, check if the given expression was generated by a macro or not
-        // we need to go back the expn_info tree to check only the arguments
-        // of the initial macro call, not the nested ones.
-        let mut is_internal = false;
-        let mut expnid = span.expn_id;
-        while self.with_expn_info(expnid, |expninfo| {
-            match expninfo {
-                Some(ref info) => {
-                    // save the parent expn_id for next loop iteration
-                    expnid = info.call_site.expn_id;
-                    if info.callee.name == "format_args" {
-                        // This is a hack because the format_args builtin calls unstable APIs.
-                        // I spent like 6 hours trying to solve this more generally but am stupid.
-                        is_internal = true;
-                        false
-                    } else if info.callee.span.is_none() {
-                        // it's a compiler built-in, we *really* don't want to mess with it
-                        // so we skip it, unless it was called by a regular macro, in which case
-                        // we will handle the caller macro next turn
-                        is_internal = true;
-                        true // continue looping
+    /// Check if a span is "internal" to a macro in which #[unstable]
+    /// items can be used (that is, a macro marked with
+    /// `#[allow_internal_unstable]`).
+    pub fn span_allows_unstable(&self, span: Span) -> bool {
+        debug!("span_allows_unstable(span = {:?})", span);
+        let mut allows_unstable = false;
+        let mut expn_id = span.expn_id;
+        loop {
+            let quit = self.with_expn_info(expn_id, |expninfo| {
+                debug!("span_allows_unstable: expninfo = {:?}", expninfo);
+                expninfo.map_or(/* hit the top level */ true, |info| {
+
+                    let span_comes_from_this_expansion =
+                        info.callee.span.map_or(span == info.call_site, |mac_span| {
+                            mac_span.lo <= span.lo && span.hi < mac_span.hi
+                        });
+
+                    debug!("span_allows_unstable: from this expansion? {}, allows unstable? {}",
+                           span_comes_from_this_expansion,
+                           info.callee.allow_internal_unstable);
+                    if span_comes_from_this_expansion {
+                        allows_unstable = info.callee.allow_internal_unstable;
+                        // we've found the right place, stop looking
+                        true
                     } else {
-                        // was this expression from the current macro arguments ?
-                        is_internal = !( span.lo > info.call_site.lo &&
-                                         span.hi < info.call_site.hi );
-                        true // continue looping
+                        // not the right place, keep looking
+                        expn_id = info.call_site.expn_id;
+                        false
                     }
-                },
-                _ => false // stop looping
+                })
+            });
+            if quit {
+                break
             }
-        }) { /* empty while loop body */ }
-        return is_internal;
+        }
+        debug!("span_allows_unstable? {}", allows_unstable);
+        allows_unstable
     }
 }