core: Split apart the global `core` feature

This commit shards the broad `core` feature of the libcore library into finer
grained features. This split groups together similar APIs and enables tracking
each API separately, giving a better sense of where each feature is within the
stabilization process.

A few minor APIs were deprecated along the way:

* Iterator::reverse_in_place
* marker::NoCopy

7 files changed, 34 insertions, 23 deletions

diff --git a/src/libcore/num/f32.rs b/src/libcore/num/f32.rs
index 50dd3f1661a..229414fe766 100644
--- a/src/libcore/num/f32.rs
+++ b/src/libcore/num/f32.rs
@@ -71,7 +71,8 @@ pub mod consts {
     pub const PI: f32 = 3.14159265358979323846264338327950288_f32;
 
     /// pi * 2.0
-    #[unstable(feature = "core", reason = "unclear naming convention/usefulness")]
+    #[unstable(feature = "float_consts",
+               reason = "unclear naming convention/usefulness")]
     pub const PI_2: f32 = 6.28318530717958647692528676655900576_f32;
 
     /// pi/2.0
@@ -135,7 +136,6 @@ pub mod consts {
     pub const LN_10: f32 = 2.30258509299404568401799145468436421_f32;
 }
 
-#[unstable(feature = "core", reason = "trait is unstable")]
 impl Float for f32 {
     #[inline]
     fn nan() -> f32 { NAN }
diff --git a/src/libcore/num/f64.rs b/src/libcore/num/f64.rs
index 62b566e7eb4..bbc1bdacde7 100644
--- a/src/libcore/num/f64.rs
+++ b/src/libcore/num/f64.rs
@@ -71,7 +71,8 @@ pub mod consts {
     pub const PI: f64 = 3.14159265358979323846264338327950288_f64;
 
     /// pi * 2.0
-    #[unstable(feature = "core", reason = "unclear naming convention/usefulness")]
+    #[unstable(feature = "float_consts",
+               reason = "unclear naming convention/usefulness")]
     pub const PI_2: f64 = 6.28318530717958647692528676655900576_f64;
 
     /// pi/2.0
@@ -135,7 +136,6 @@ pub mod consts {
     pub const LN_10: f64 = 2.30258509299404568401799145468436421_f64;
 }
 
-#[unstable(feature = "core", reason = "trait is unstable")]
 impl Float for f64 {
     #[inline]
     fn nan() -> f64 { NAN }
diff --git a/src/libcore/num/flt2dec/mod.rs b/src/libcore/num/flt2dec/mod.rs
index f51dcf54a19..f3a7e8f09a9 100644
--- a/src/libcore/num/flt2dec/mod.rs
+++ b/src/libcore/num/flt2dec/mod.rs
@@ -126,6 +126,8 @@ functions.
 // while this is extensively documented, this is in principle private which is
 // only made public for testing. do not expose us.
 #![doc(hidden)]
+#![unstable(feature = "flt2dec",
+            reason = "internal routines only exposed for testing")]
 
 use prelude::*;
 use i16;
diff --git a/src/libcore/num/int_macros.rs b/src/libcore/num/int_macros.rs
index 3113521e0af..efc91238809 100644
--- a/src/libcore/num/int_macros.rs
+++ b/src/libcore/num/int_macros.rs
@@ -14,11 +14,13 @@ macro_rules! int_module { ($T:ty, $bits:expr) => (
 
 // FIXME(#11621): Should be deprecated once CTFE is implemented in favour of
 // calling the `mem::size_of` function.
-#[unstable(feature = "core")]
+#[unstable(feature = "num_bits_bytes",
+           reason = "may want to be an associated function")]
 pub const BITS : usize = $bits;
 // FIXME(#11621): Should be deprecated once CTFE is implemented in favour of
 // calling the `mem::size_of` function.
-#[unstable(feature = "core")]
+#[unstable(feature = "num_bits_bytes",
+           reason = "may want to be an associated function")]
 pub const BYTES : usize = ($bits / 8);
 
 // FIXME(#11621): Should be deprecated once CTFE is implemented in favour of
diff --git a/src/libcore/num/mod.rs b/src/libcore/num/mod.rs
index bf26022692d..c8a0ae47637 100644
--- a/src/libcore/num/mod.rs
+++ b/src/libcore/num/mod.rs
@@ -41,10 +41,7 @@ use str::{FromStr, StrExt};
 #[derive(PartialEq, Eq, PartialOrd, Ord, Clone, Copy, Debug)]
 pub struct Wrapping<T>(#[stable(feature = "rust1", since = "1.0.0")] pub T);
 
-#[unstable(feature = "core", reason = "may be removed or relocated")]
 pub mod wrapping;
-
-#[unstable(feature = "core", reason = "internal routines only exposed for testing")]
 pub mod flt2dec;
 
 /// Types that have a "zero" value.
@@ -471,7 +468,7 @@ macro_rules! int_impl {
         /// to `-MIN`, a positive value that is too large to represent
         /// in the type. In such a case, this function returns `MIN`
         /// itself..
-        #[unstable(feature = "core", since = "1.0.0")]
+        #[unstable(feature = "num_wrapping")]
         #[inline(always)]
         pub fn wrapping_div(self, rhs: Self) -> Self {
             self.overflowing_div(rhs).0
@@ -484,7 +481,7 @@ macro_rules! int_impl {
         /// implementation artifacts make `x % y` illegal for `MIN /
         /// -1` on a signed type illegal (where `MIN` is the negative
         /// minimal value). In such a case, this function returns `0`.
-        #[unstable(feature = "core", since = "1.0.0")]
+        #[unstable(feature = "num_wrapping")]
         #[inline(always)]
         pub fn wrapping_rem(self, rhs: Self) -> Self {
             self.overflowing_rem(rhs).0
@@ -498,7 +495,7 @@ macro_rules! int_impl {
         /// negative minimal value for the type); this is a positive
         /// value that is too large to represent in the type. In such
         /// a case, this function returns `MIN` itself.
-        #[unstable(feature = "core", since = "1.0.0")]
+        #[unstable(feature = "num_wrapping")]
         #[inline(always)]
         pub fn wrapping_neg(self) -> Self {
             self.overflowing_neg().0
@@ -507,7 +504,7 @@ macro_rules! int_impl {
         /// Panic-free bitwise shift-left; yields `self << mask(rhs)`,
         /// where `mask` removes any high-order bits of `rhs` that
         /// would cause the shift to exceed the bitwidth of the type.
-        #[unstable(feature = "core", since = "1.0.0")]
+        #[unstable(feature = "num_wrapping")]
         #[inline(always)]
         pub fn wrapping_shl(self, rhs: u32) -> Self {
             self.overflowing_shl(rhs).0
@@ -516,7 +513,7 @@ macro_rules! int_impl {
         /// Panic-free bitwise shift-left; yields `self >> mask(rhs)`,
         /// where `mask` removes any high-order bits of `rhs` that
         /// would cause the shift to exceed the bitwidth of the type.
-        #[unstable(feature = "core", since = "1.0.0")]
+        #[unstable(feature = "num_wrapping")]
         #[inline(always)]
         pub fn wrapping_shr(self, rhs: u32) -> Self {
             self.overflowing_shr(rhs).0
@@ -1041,7 +1038,7 @@ macro_rules! uint_impl {
         /// to `-MIN`, a positive value that is too large to represent
         /// in the type. In such a case, this function returns `MIN`
         /// itself..
-        #[unstable(feature = "core", since = "1.0.0")]
+        #[unstable(feature = "num_wrapping")]
         #[inline(always)]
         pub fn wrapping_div(self, rhs: Self) -> Self {
             self.overflowing_div(rhs).0
@@ -1054,7 +1051,7 @@ macro_rules! uint_impl {
         /// implementation artifacts make `x % y` illegal for `MIN /
         /// -1` on a signed type illegal (where `MIN` is the negative
         /// minimal value). In such a case, this function returns `0`.
-        #[unstable(feature = "core", since = "1.0.0")]
+        #[unstable(feature = "num_wrapping")]
         #[inline(always)]
         pub fn wrapping_rem(self, rhs: Self) -> Self {
             self.overflowing_rem(rhs).0
@@ -1068,7 +1065,7 @@ macro_rules! uint_impl {
         /// negative minimal value for the type); this is a positive
         /// value that is too large to represent in the type. In such
         /// a case, this function returns `MIN` itself.
-        #[unstable(feature = "core", since = "1.0.0")]
+        #[unstable(feature = "num_wrapping")]
         #[inline(always)]
         pub fn wrapping_neg(self) -> Self {
             self.overflowing_neg().0
@@ -1077,7 +1074,7 @@ macro_rules! uint_impl {
         /// Panic-free bitwise shift-left; yields `self << mask(rhs)`,
         /// where `mask` removes any high-order bits of `rhs` that
         /// would cause the shift to exceed the bitwidth of the type.
-        #[unstable(feature = "core", since = "1.0.0")]
+        #[unstable(feature = "num_wrapping")]
         #[inline(always)]
         pub fn wrapping_shl(self, rhs: u32) -> Self {
             self.overflowing_shl(rhs).0
@@ -1086,7 +1083,7 @@ macro_rules! uint_impl {
         /// Panic-free bitwise shift-left; yields `self >> mask(rhs)`,
         /// where `mask` removes any high-order bits of `rhs` that
         /// would cause the shift to exceed the bitwidth of the type.
-        #[unstable(feature = "core", since = "1.0.0")]
+        #[unstable(feature = "num_wrapping")]
         #[inline(always)]
         pub fn wrapping_shr(self, rhs: u32) -> Self {
             self.overflowing_shr(rhs).0
@@ -1262,6 +1259,8 @@ pub enum FpCategory {
 
 /// A built-in floating point number.
 #[doc(hidden)]
+#[unstable(feature = "core_float",
+           reason = "stable interface is via `impl f{32,64}` in later crates")]
 pub trait Float {
     /// Returns the NaN value.
     fn nan() -> Self;
@@ -1512,7 +1511,9 @@ enum IntErrorKind {
 }
 
 impl ParseIntError {
-    #[unstable(feature = "core", reason = "available through Error trait")]
+    #[unstable(feature = "int_error_internals",
+               reason = "available through Error trait and this method should \
+                         not be exposed publicly")]
     pub fn description(&self) -> &str {
         match self.kind {
             IntErrorKind::Empty => "cannot parse integer from empty string",
@@ -1535,10 +1536,14 @@ impl fmt::Display for ParseIntError {
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct ParseFloatError {
     #[doc(hidden)]
+    #[unstable(feature = "float_error_internals",
+               reason = "should not be exposed publicly")]
     pub __kind: FloatErrorKind
 }
 
 #[derive(Debug, Clone, PartialEq)]
+#[unstable(feature = "float_error_internals",
+           reason = "should not be exposed publicly")]
 pub enum FloatErrorKind {
     Empty,
     Invalid,
diff --git a/src/libcore/num/uint_macros.rs b/src/libcore/num/uint_macros.rs
index 86782950745..0719d7c17cc 100644
--- a/src/libcore/num/uint_macros.rs
+++ b/src/libcore/num/uint_macros.rs
@@ -12,9 +12,11 @@
 
 macro_rules! uint_module { ($T:ty, $T_SIGNED:ty, $bits:expr) => (
 
-#[unstable(feature = "core")]
+#[unstable(feature = "num_bits_bytes",
+           reason = "may want to be an associated function")]
 pub const BITS : usize = $bits;
-#[unstable(feature = "core")]
+#[unstable(feature = "num_bits_bytes",
+           reason = "may want to be an associated function")]
 pub const BYTES : usize = ($bits / 8);
 
 #[stable(feature = "rust1", since = "1.0.0")]
diff --git a/src/libcore/num/wrapping.rs b/src/libcore/num/wrapping.rs
index 69c22229490..748ed29e3a3 100644
--- a/src/libcore/num/wrapping.rs
+++ b/src/libcore/num/wrapping.rs
@@ -10,6 +10,7 @@
 
 #![allow(missing_docs)]
 #![allow(deprecated)]
+#![unstable(feature = "wrapping", reason = "may be removed or relocated")]
 
 use super::Wrapping;
 
@@ -30,7 +31,6 @@ use intrinsics::{i64_mul_with_overflow, u64_mul_with_overflow};
 
 use ::{i8,i16,i32,i64};
 
-#[unstable(feature = "core", reason = "may be removed, renamed, or relocated")]
 pub trait OverflowingOps {
     fn overflowing_add(self, rhs: Self) -> (Self, bool);
     fn overflowing_sub(self, rhs: Self) -> (Self, bool);