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Auto merge of #43017 - durka:stabilize-const-invocation, r=eddyb 

Individualize feature gates for const fn invocation

This PR changes the meaning of `#![feature(const_fn)]` so it is only required to declare a const fn but not to call one. Based on discussion at #24111. I was hoping we could have an FCP here in order to move that conversation forward.

This sets the stage for future stabilization of the constness of several functions in the standard library (listed below), so could someone please tag the lang team for review.

- `std::cell`
    - `Cell::new`
    - `RefCell::new`
    - `UnsafeCell::new`
- `std::mem`
    - `size_of`
    - `align_of`
- `std::ptr`
    - `null`
    - `null_mut`
- `std::sync`
    - `atomic`
        - `Atomic{Bool,Ptr,Isize,Usize}::new`
    - `once`
        - `Once::new`
- primitives
    - `{integer}::min_value`
    - `{integer}::max_value`

Some other functions are const but they are also unstable or hidden, e.g. `Unique::new` so they don't have to be considered at this time.

After this stabilization, the following `*_INIT` constants in the standard library can be deprecated. I wasn't sure whether to include those deprecations in the current PR.

- `std::sync`
    - `atomic`
        - `ATOMIC_{BOOL,ISIZE,USIZE}_INIT`
    - `once`
        - `ONCE_INIT`
This commit is contained in:
bors 2017-09-16 17:02:17 +00:00
parent b965d55a32 332c38cd70
commit ae8efdc87d
60 changed files with 309 additions and 99 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
src/Cargo.lock generated
View File

@ -1346,7 +1346,7 @@ dependencies = [
"lazy_static 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
"log 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
"racer 2.0.10 (registry+https://github.com/rust-lang/crates.io-index)",
"rls-analysis 0.6.5 (registry+https://github.com/rust-lang/crates.io-index)",
"rls-analysis 0.6.7 (registry+https://github.com/rust-lang/crates.io-index)",
"rls-data 0.10.0 (registry+https://github.com/rust-lang/crates.io-index)",
"rls-rustc 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
"rls-span 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
@ -1360,7 +1360,7 @@ dependencies = [
[[package]]
name = "rls-analysis"
version = "0.6.5"
version = "0.6.7"
source = "registry+https://github.com/rust-lang/crates.io-index"
dependencies = [
"derive-new 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
@ -2555,7 +2555,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
"checksum regex 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "1731164734096285ec2a5ec7fea5248ae2f5485b3feeb0115af4fda2183b2d1b"
"checksum regex-syntax 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)" = "f9ec002c35e86791825ed294b50008eea9ddfc8def4420124fbc6b08db834957"
"checksum regex-syntax 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)" = "ad890a5eef7953f55427c50575c680c42841653abd2b028b68cd223d157f62db"
"checksum rls-analysis 0.6.5 (registry+https://github.com/rust-lang/crates.io-index)" = "d2cb40c0371765897ae428b5706bb17135705ad4f6d1b8b6afbaabcf8c9b5cff"
"checksum rls-analysis 0.6.7 (registry+https://github.com/rust-lang/crates.io-index)" = "4302cc8291570d7f817945845d8c01756e833dbc93c0a87d4f6c9a0b0b7992f1"
"checksum rls-data 0.10.0 (registry+https://github.com/rust-lang/crates.io-index)" = "11d339f1888e33e74d8032de0f83c40b2bdaaaf04a8cfc03b32186c3481fb534"
"checksum rls-rustc 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "b21ea952e9bf1569929abf1bb920262cde04b7b1b26d8e0260286302807299d2"
"checksum rls-span 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "5d7c7046dc6a92f2ae02ed302746db4382e75131b9ce20ce967259f6b5867a6a"

3
src/libcore/cell.rs
View File

@ -329,6 +329,7 @@ impl<T> Cell<T> {
/// let c = Cell::new(5);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[cfg_attr(not(stage0), rustc_const_unstable(feature = "const_cell_new"))]
#[inline]
pub const fn new(value: T) -> Cell<T> {
Cell {
@ -543,6 +544,7 @@ impl<T> RefCell<T> {
/// let c = RefCell::new(5);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[cfg_attr(not(stage0), rustc_const_unstable(feature = "const_refcell_new"))]
#[inline]
pub const fn new(value: T) -> RefCell<T> {
RefCell {
@ -1188,6 +1190,7 @@ impl<T> UnsafeCell<T> {
/// let uc = UnsafeCell::new(5);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[cfg_attr(not(stage0), rustc_const_unstable(feature = "const_unsafe_cell_new"))]
#[inline]
pub const fn new(value: T) -> UnsafeCell<T> {
UnsafeCell { value: value }

18
src/libcore/lib.rs
View File

@ -85,12 +85,30 @@
#![feature(prelude_import)]
#![feature(repr_simd, platform_intrinsics)]
#![feature(rustc_attrs)]
#![cfg_attr(not(stage0), feature(rustc_const_unstable))]
#![feature(specialization)]
#![feature(staged_api)]
#![feature(unboxed_closures)]
#![feature(untagged_unions)]
#![feature(unwind_attributes)]
#![cfg_attr(not(stage0), feature(const_min_value))]
#![cfg_attr(not(stage0), feature(const_max_value))]
#![cfg_attr(not(stage0), feature(const_atomic_bool_new))]
#![cfg_attr(not(stage0), feature(const_atomic_isize_new))]
#![cfg_attr(not(stage0), feature(const_atomic_usize_new))]
#![cfg_attr(not(stage0), feature(const_atomic_i8_new))]
#![cfg_attr(not(stage0), feature(const_atomic_u8_new))]
#![cfg_attr(not(stage0), feature(const_atomic_i16_new))]
#![cfg_attr(not(stage0), feature(const_atomic_u16_new))]
#![cfg_attr(not(stage0), feature(const_atomic_i32_new))]
#![cfg_attr(not(stage0), feature(const_atomic_u32_new))]
#![cfg_attr(not(stage0), feature(const_atomic_i64_new))]
#![cfg_attr(not(stage0), feature(const_atomic_u64_new))]
#![cfg_attr(not(stage0), feature(const_unsafe_cell_new))]
#![cfg_attr(not(stage0), feature(const_cell_new))]
#![cfg_attr(not(stage0), feature(const_nonzero_new))]
#[prelude_import]
#[allow(unused)]
use prelude::v1::*;

2
src/libcore/mem.rs
View File

@ -189,6 +189,7 @@ pub fn forget<T>(t: T) {
/// ```
#[inline]
#[stable(feature = "rust1", since = "1.0.0")]
#[cfg_attr(not(stage0), rustc_const_unstable(feature = "const_size_of"))]
pub const fn size_of<T>() -> usize {
unsafe { intrinsics::size_of::<T>() }
}
@ -280,6 +281,7 @@ pub fn min_align_of_val<T: ?Sized>(val: &T) -> usize {
/// ```
#[inline]
#[stable(feature = "rust1", since = "1.0.0")]
#[cfg_attr(not(stage0), rustc_const_unstable(feature = "const_align_of"))]
pub const fn align_of<T>() -> usize {
unsafe { intrinsics::min_align_of::<T>() }
}

4
src/libcore/nonzero.rs
View File

@ -68,6 +68,10 @@ pub struct NonZero<T: Zeroable>(T);
impl<T: Zeroable> NonZero<T> {
/// Creates an instance of NonZero with the provided value.
/// You must indeed ensure that the value is actually "non-zero".
#[unstable(feature = "nonzero",
reason = "needs an RFC to flesh out the design",
issue = "27730")]
#[cfg_attr(not(stage0), rustc_const_unstable(feature = "const_nonzero_new"))]
#[inline]
pub const unsafe fn new_unchecked(inner: T) -> Self {
NonZero(inner)

4
src/libcore/num/mod.rs
View File

@ -109,6 +109,7 @@ macro_rules! int_impl {
/// assert_eq!(i8::min_value(), -128);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[cfg_attr(not(stage0), rustc_const_unstable(feature = "const_min_value"))]
#[inline]
pub const fn min_value() -> Self {
!0 ^ ((!0 as $UnsignedT) >> 1) as Self
@ -122,6 +123,7 @@ macro_rules! int_impl {
/// assert_eq!(i8::max_value(), 127);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[cfg_attr(not(stage0), rustc_const_unstable(feature = "const_max_value"))]
#[inline]
pub const fn max_value() -> Self {
!Self::min_value()
@ -1280,6 +1282,7 @@ macro_rules! uint_impl {
/// assert_eq!(u8::min_value(), 0);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[cfg_attr(not(stage0), rustc_const_unstable(feature = "const_min_value"))]
#[inline]
pub const fn min_value() -> Self { 0 }
@ -1291,6 +1294,7 @@ macro_rules! uint_impl {
/// assert_eq!(u8::max_value(), 255);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[cfg_attr(not(stage0), rustc_const_unstable(feature = "const_max_value"))]
#[inline]
pub const fn max_value() -> Self { !0 }

6
src/libcore/ptr.rs
View File

@ -76,6 +76,7 @@ pub unsafe fn drop_in_place<T: ?Sized>(to_drop: *mut T) {
/// ```
#[inline]
#[stable(feature = "rust1", since = "1.0.0")]
#[cfg_attr(not(stage0), rustc_const_unstable(feature = "const_ptr_null"))]
pub const fn null<T>() -> *const T { 0 as *const T }
/// Creates a null mutable raw pointer.
@ -90,6 +91,7 @@ pub const fn null<T>() -> *const T { 0 as *const T }
/// ```
#[inline]
#[stable(feature = "rust1", since = "1.0.0")]
#[cfg_attr(not(stage0), rustc_const_unstable(feature = "const_ptr_null_mut"))]
pub const fn null_mut<T>() -> *mut T { 0 as *mut T }
/// Swaps the values at two mutable locations of the same type, without
@ -1097,6 +1099,8 @@ impl<T: ?Sized> Unique<T> {
/// # Safety
///
/// `ptr` must be non-null.
#[unstable(feature = "unique", issue = "27730")]
#[cfg_attr(not(stage0), rustc_const_unstable(feature = "const_unique_new"))]
pub const unsafe fn new_unchecked(ptr: *mut T) -> Self {
Unique { pointer: NonZero::new_unchecked(ptr), _marker: PhantomData }
}
@ -1230,6 +1234,8 @@ impl<T: ?Sized> Shared<T> {
/// # Safety
///
/// `ptr` must be non-null.
#[unstable(feature = "shared", issue = "27730")]
#[cfg_attr(not(stage0), rustc_const_unstable(feature = "const_shared_new"))]
pub const unsafe fn new_unchecked(ptr: *mut T) -> Self {
Shared { pointer: NonZero::new_unchecked(ptr), _marker: PhantomData }
}

15
src/libcore/sync/atomic.rs
View File

@ -241,6 +241,7 @@ impl AtomicBool {
/// ```
#[inline]
#[stable(feature = "rust1", since = "1.0.0")]
#[cfg_attr(not(stage0), rustc_const_unstable(feature = "const_atomic_bool_new"))]
pub const fn new(v: bool) -> AtomicBool {
AtomicBool { v: UnsafeCell::new(v as u8) }
}
@ -649,6 +650,7 @@ impl<T> AtomicPtr<T> {
/// ```
#[inline]
#[stable(feature = "rust1", since = "1.0.0")]
#[cfg_attr(not(stage0), rustc_const_unstable(feature = "const_atomic_ptr_new"))]
pub const fn new(p: *mut T) -> AtomicPtr<T> {
AtomicPtr { p: UnsafeCell::new(p) }
}
@ -920,7 +922,7 @@ impl<T> AtomicPtr<T> {
#[cfg(target_has_atomic = "ptr")]
macro_rules! atomic_int {
($stable:meta,
($stable:meta, $const_unstable:meta,
$stable_cxchg:meta,
$stable_debug:meta,
$stable_access:meta,
@ -969,6 +971,7 @@ macro_rules! atomic_int {
/// ```
#[inline]
#[$stable]
#[cfg_attr(not(stage0), $const_unstable)]
pub const fn new(v: $int_type) -> Self {
$atomic_type {v: UnsafeCell::new(v)}
}
@ -1332,6 +1335,7 @@ macro_rules! atomic_int {
#[cfg(target_has_atomic = "8")]
atomic_int! {
unstable(feature = "integer_atomics", issue = "32976"),
rustc_const_unstable(feature = "const_atomic_i8_new"),
unstable(feature = "integer_atomics", issue = "32976"),
unstable(feature = "integer_atomics", issue = "32976"),
unstable(feature = "integer_atomics", issue = "32976"),
@ -1340,6 +1344,7 @@ atomic_int! {
#[cfg(target_has_atomic = "8")]
atomic_int! {
unstable(feature = "integer_atomics", issue = "32976"),
rustc_const_unstable(feature = "const_atomic_u8_new"),
unstable(feature = "integer_atomics", issue = "32976"),
unstable(feature = "integer_atomics", issue = "32976"),
unstable(feature = "integer_atomics", issue = "32976"),
@ -1348,6 +1353,7 @@ atomic_int! {
#[cfg(target_has_atomic = "16")]
atomic_int! {
unstable(feature = "integer_atomics", issue = "32976"),
rustc_const_unstable(feature = "const_atomic_i16_new"),
unstable(feature = "integer_atomics", issue = "32976"),
unstable(feature = "integer_atomics", issue = "32976"),
unstable(feature = "integer_atomics", issue = "32976"),
@ -1356,6 +1362,7 @@ atomic_int! {
#[cfg(target_has_atomic = "16")]
atomic_int! {
unstable(feature = "integer_atomics", issue = "32976"),
rustc_const_unstable(feature = "const_atomic_u16_new"),
unstable(feature = "integer_atomics", issue = "32976"),
unstable(feature = "integer_atomics", issue = "32976"),
unstable(feature = "integer_atomics", issue = "32976"),
@ -1364,6 +1371,7 @@ atomic_int! {
#[cfg(target_has_atomic = "32")]
atomic_int! {
unstable(feature = "integer_atomics", issue = "32976"),
rustc_const_unstable(feature = "const_atomic_i32_new"),
unstable(feature = "integer_atomics", issue = "32976"),
unstable(feature = "integer_atomics", issue = "32976"),
unstable(feature = "integer_atomics", issue = "32976"),
@ -1372,6 +1380,7 @@ atomic_int! {
#[cfg(target_has_atomic = "32")]
atomic_int! {
unstable(feature = "integer_atomics", issue = "32976"),
rustc_const_unstable(feature = "const_atomic_u32_new"),
unstable(feature = "integer_atomics", issue = "32976"),
unstable(feature = "integer_atomics", issue = "32976"),
unstable(feature = "integer_atomics", issue = "32976"),
@ -1380,6 +1389,7 @@ atomic_int! {
#[cfg(target_has_atomic = "64")]
atomic_int! {
unstable(feature = "integer_atomics", issue = "32976"),
rustc_const_unstable(feature = "const_atomic_i64_new"),
unstable(feature = "integer_atomics", issue = "32976"),
unstable(feature = "integer_atomics", issue = "32976"),
unstable(feature = "integer_atomics", issue = "32976"),
@ -1388,6 +1398,7 @@ atomic_int! {
#[cfg(target_has_atomic = "64")]
atomic_int! {
unstable(feature = "integer_atomics", issue = "32976"),
rustc_const_unstable(feature = "const_atomic_u64_new"),
unstable(feature = "integer_atomics", issue = "32976"),
unstable(feature = "integer_atomics", issue = "32976"),
unstable(feature = "integer_atomics", issue = "32976"),
@ -1396,6 +1407,7 @@ atomic_int! {
#[cfg(target_has_atomic = "ptr")]
atomic_int!{
stable(feature = "rust1", since = "1.0.0"),
rustc_const_unstable(feature = "const_atomic_isize_new"),
stable(feature = "extended_compare_and_swap", since = "1.10.0"),
stable(feature = "atomic_debug", since = "1.3.0"),
stable(feature = "atomic_access", since = "1.15.0"),
@ -1404,6 +1416,7 @@ atomic_int!{
#[cfg(target_has_atomic = "ptr")]
atomic_int!{
stable(feature = "rust1", since = "1.0.0"),
rustc_const_unstable(feature = "const_atomic_usize_new"),
stable(feature = "extended_compare_and_swap", since = "1.10.0"),
stable(feature = "atomic_debug", since = "1.3.0"),
stable(feature = "atomic_access", since = "1.15.0"),

5
src/libcore/tests/lib.rs
View File

@ -11,7 +11,6 @@
#![deny(warnings)]
#![feature(box_syntax)]
#![feature(const_fn)]
#![feature(core_float)]
#![feature(core_private_bignum)]
#![feature(core_private_diy_float)]
@ -42,6 +41,10 @@
#![feature(try_from)]
#![feature(unique)]
#![feature(const_atomic_bool_new)]
#![feature(const_atomic_usize_new)]
#![feature(const_atomic_isize_new)]
extern crate core;
extern crate test;
extern crate rand;

8
src/librustc/ich/impls_syntax.rs
View File

@ -81,7 +81,12 @@ impl_stable_hash_for!(enum ::syntax::abi::Abi {
});
impl_stable_hash_for!(struct ::syntax::attr::Deprecation { since, note });
impl_stable_hash_for!(struct ::syntax::attr::Stability { level, feature, rustc_depr });
impl_stable_hash_for!(struct ::syntax::attr::Stability {
level,
feature,
rustc_depr,
rustc_const_unstable
});
impl<'a, 'gcx, 'tcx> HashStable<StableHashingContext<'a, 'gcx, 'tcx>>
for ::syntax::attr::StabilityLevel {
@ -102,6 +107,7 @@ for ::syntax::attr::StabilityLevel {
}
impl_stable_hash_for!(struct ::syntax::attr::RustcDeprecation { since, reason });
impl_stable_hash_for!(struct ::syntax::attr::RustcConstUnstable { feature });
impl_stable_hash_for!(enum ::syntax::attr::IntType {

4
src/librustc/lib.rs
View File

@ -22,7 +22,6 @@
#![feature(box_patterns)]
#![feature(box_syntax)]
#![feature(conservative_impl_trait)]
#![feature(const_fn)]
#![feature(core_intrinsics)]
#![feature(i128_type)]
#![cfg_attr(windows, feature(libc))]
@ -36,6 +35,9 @@
#![feature(trace_macros)]
#![feature(test)]
#![cfg_attr(stage0, feature(const_fn))]
#![cfg_attr(not(stage0), feature(const_atomic_bool_new))]
#![recursion_limit="256"]
extern crate arena;

1
src/librustc/middle/stability.rs
View File

@ -427,6 +427,7 @@ impl<'a, 'tcx> Index<'tcx> {
},
feature: Symbol::intern("rustc_private"),
rustc_depr: None,
rustc_const_unstable: None,
});
annotator.parent_stab = Some(stability);
}

5
src/librustc_apfloat/lib.rs
View File

@ -45,11 +45,14 @@
#![deny(warnings)]
#![forbid(unsafe_code)]
#![feature(const_fn)]
#![feature(i128_type)]
#![feature(slice_patterns)]
#![feature(try_from)]
#![cfg_attr(stage0, feature(const_fn))]
#![cfg_attr(not(stage0), feature(const_min_value))]
#![cfg_attr(not(stage0), feature(const_max_value))]
#[macro_use]
extern crate rustc_bitflags;

4
src/librustc_const_eval/lib.rs
View File

@ -23,9 +23,11 @@
#![feature(slice_patterns)]
#![feature(box_patterns)]
#![feature(box_syntax)]
#![feature(const_fn)]
#![feature(i128_type)]
#![cfg_attr(stage0, feature(const_fn))]
#![cfg_attr(not(stage0), feature(const_min_value))]
extern crate arena;
#[macro_use] extern crate syntax;
#[macro_use] extern crate log;

5
src/librustc_const_math/lib.rs
View File

@ -19,10 +19,13 @@
html_root_url = "https://doc.rust-lang.org/nightly/")]
#![deny(warnings)]
#![feature(const_fn)]
#![feature(i128)]
#![feature(i128_type)]
#![cfg_attr(stage0, feature(const_fn))]
#![cfg_attr(not(stage0), feature(const_min_value))]
#![cfg_attr(not(stage0), feature(const_max_value))]
extern crate rustc_apfloat;
extern crate syntax;

4
src/librustc_mir/diagnostics.rs
View File

@ -384,7 +384,7 @@ static B: &'static AtomicUsize = &A; // ok!
You can also have this error while using a cell type:
```compile_fail,E0492
#![feature(const_fn)]
#![feature(const_cell_new)]
use std::cell::Cell;
@ -412,7 +412,7 @@ However, if you still wish to use these types, you can achieve this by an unsafe
wrapper:
```
#![feature(const_fn)]
#![feature(const_cell_new)]
use std::cell::Cell;
use std::marker::Sync;

54
src/librustc_mir/transform/qualify_consts.rs
View File

@ -30,6 +30,7 @@ use rustc::mir::transform::{MirPass, MirSource};
use rustc::mir::visit::{LvalueContext, Visitor};
use rustc::middle::lang_items;
use syntax::abi::Abi;
use syntax::attr;
use syntax::feature_gate::UnstableFeatures;
use syntax_pos::{Span, DUMMY_SP};
@ -713,14 +714,14 @@ impl<'a, 'tcx> Visitor<'tcx> for Qualifier<'a, 'tcx, 'tcx> {
self.visit_operand(func, location);
let fn_ty = func.ty(self.mir, self.tcx);
let (mut is_shuffle, mut is_const_fn) = (false, false);
let (mut is_shuffle, mut is_const_fn) = (false, None);
if let ty::TyFnDef(def_id, _) = fn_ty.sty {
match self.tcx.fn_sig(def_id).abi() {
Abi::RustIntrinsic |
Abi::PlatformIntrinsic => {
assert!(!self.tcx.is_const_fn(def_id));
match &self.tcx.item_name(def_id)[..] {
"size_of" | "min_align_of" => is_const_fn = true,
"size_of" | "min_align_of" => is_const_fn = Some(def_id),
name if name.starts_with("simd_shuffle") => {
is_shuffle = true;
@ -730,7 +731,9 @@ impl<'a, 'tcx> Visitor<'tcx> for Qualifier<'a, 'tcx, 'tcx> {
}
}
_ => {
is_const_fn = self.tcx.is_const_fn(def_id);
if self.tcx.is_const_fn(def_id) {
is_const_fn = Some(def_id);
}
}
}
}
@ -751,25 +754,38 @@ impl<'a, 'tcx> Visitor<'tcx> for Qualifier<'a, 'tcx, 'tcx> {
}
// Const fn calls.
if is_const_fn {
// We are in a const or static initializer,
if self.mode != Mode::Fn &&
if let Some(def_id) = is_const_fn {
// find corresponding rustc_const_unstable feature
if let Some(&attr::Stability {
rustc_const_unstable: Some(attr::RustcConstUnstable {
feature: ref feature_name
}),
.. }) = self.tcx.lookup_stability(def_id) {
// feature-gate is not enabled,
!self.tcx.sess.features.borrow().const_fn &&
// We are in a const or static initializer,
if self.mode != Mode::Fn &&
// this doesn't come from a crate with the feature-gate enabled,
self.def_id.is_local() &&
// feature-gate is not enabled,
!self.tcx.sess.features.borrow()
.declared_lib_features
.iter()
.any(|&(ref sym, _)| sym == feature_name) &&
// this doesn't come from a macro that has #[allow_internal_unstable]
!self.span.allows_unstable()
{
let mut err = self.tcx.sess.struct_span_err(self.span,
"const fns are an unstable feature");
help!(&mut err,
"in Nightly builds, add `#![feature(const_fn)]` \
to the crate attributes to enable");
err.emit();
// this doesn't come from a crate with the feature-gate enabled,
self.def_id.is_local() &&
// this doesn't come from a macro that has #[allow_internal_unstable]
!self.span.allows_unstable()
{
let mut err = self.tcx.sess.struct_span_err(self.span,
&format!("`{}` is not yet stable as a const fn",
self.tcx.item_path_str(def_id)));
help!(&mut err,
"in Nightly builds, add `#![feature({})]` \
to the crate attributes to enable",
feature_name);
err.emit();
}
}
} else {
self.qualif = Qualif::NOT_CONST;

5
src/librustc_trans/lib.rs
View File

@ -21,7 +21,6 @@
#![feature(box_patterns)]
#![feature(box_syntax)]
#![feature(const_fn)]
#![feature(custom_attribute)]
#![allow(unused_attributes)]
#![feature(i128_type)]
@ -31,6 +30,10 @@
#![feature(slice_patterns)]
#![feature(conservative_impl_trait)]
#![cfg_attr(stage0, feature(const_fn))]
#![cfg_attr(not(stage0), feature(const_atomic_bool_new))]
#![cfg_attr(not(stage0), feature(const_once_new))]
use rustc::dep_graph::WorkProduct;
use syntax_pos::symbol::Symbol;

3
src/librustc_trans_utils/lib.rs
View File

@ -19,7 +19,6 @@
#![feature(box_patterns)]
#![feature(box_syntax)]
#![feature(const_fn)]
#![feature(custom_attribute)]
#![allow(unused_attributes)]
#![feature(i128_type)]
@ -28,6 +27,8 @@
#![feature(slice_patterns)]
#![feature(conservative_impl_trait)]
#![cfg_attr(stage0, feature(const_fn))]
extern crate rustc;
extern crate syntax;
extern crate syntax_pos;

12
src/libstd/lib.rs
View File

@ -292,6 +292,7 @@
#![feature(raw)]
#![feature(repr_simd)]
#![feature(rustc_attrs)]
#![cfg_attr(not(stage0), feature(rustc_const_unstable))]
#![feature(shared)]
#![feature(sip_hash_13)]
#![feature(slice_bytes)]
@ -315,6 +316,17 @@
#![feature(doc_cfg)]
#![cfg_attr(test, feature(update_panic_count))]
#![cfg_attr(not(stage0), feature(const_max_value))]
#![cfg_attr(not(stage0), feature(const_atomic_bool_new))]
#![cfg_attr(not(stage0), feature(const_atomic_isize_new))]
#![cfg_attr(not(stage0), feature(const_atomic_usize_new))]
#![cfg_attr(all(not(stage0), windows), feature(const_atomic_ptr_new))]
#![cfg_attr(not(stage0), feature(const_unsafe_cell_new))]
#![cfg_attr(not(stage0), feature(const_cell_new))]
#![cfg_attr(not(stage0), feature(const_once_new))]
#![cfg_attr(not(stage0), feature(const_ptr_null))]
#![cfg_attr(not(stage0), feature(const_ptr_null_mut))]
#![default_lib_allocator]
// Always use alloc_system during stage0 since we don't know if the alloc_*

1
src/libstd/sync/once.rs
View File

@ -156,6 +156,7 @@ struct Finish {
impl Once {
/// Creates a new `Once` value.
#[stable(feature = "once_new", since = "1.2.0")]
#[cfg_attr(not(stage0), rustc_const_unstable(feature = "const_once_new"))]
pub const fn new() -> Once {
Once {
state: AtomicUsize::new(INCOMPLETE),

79
src/libsyntax/attr.rs
View File

@ -637,12 +637,13 @@ pub fn eval_condition<F>(cfg: &ast::MetaItem, sess: &ParseSess, eval: &mut F)
}
}
/// Represents the #[stable], #[unstable] and #[rustc_deprecated] attributes.
/// Represents the #[stable], #[unstable], #[rustc_{deprecated,const_unstable}] attributes.
#[derive(RustcEncodable, RustcDecodable, Clone, Debug, PartialEq, Eq, Hash)]
pub struct Stability {
pub level: StabilityLevel,
pub feature: Symbol,
pub rustc_depr: Option<RustcDeprecation>,
pub rustc_const_unstable: Option<RustcConstUnstable>,
}
/// The available stability levels.
@ -659,6 +660,11 @@ pub struct RustcDeprecation {
pub reason: Symbol,
}
#[derive(RustcEncodable, RustcDecodable, PartialEq, PartialOrd, Clone, Debug, Eq, Hash)]
pub struct RustcConstUnstable {
pub feature: Symbol,
}
#[derive(RustcEncodable, RustcDecodable, PartialEq, PartialOrd, Clone, Debug, Eq, Hash)]
pub struct Deprecation {
pub since: Option<Symbol>,
@ -678,9 +684,15 @@ fn find_stability_generic<'a, I>(diagnostic: &Handler,
{
let mut stab: Option<Stability> = None;
let mut rustc_depr: Option<RustcDeprecation> = None;
let mut rustc_const_unstable: Option<RustcConstUnstable> = None;
'outer: for attr in attrs_iter {
if attr.path != "rustc_deprecated" && attr.path != "unstable" && attr.path != "stable" {
if ![
"rustc_deprecated",
"rustc_const_unstable",
"unstable",
"stable",
].iter().any(|&s| attr.path == s) {
continue // not a stability level
}
@ -703,21 +715,18 @@ fn find_stability_generic<'a, I>(diagnostic: &Handler,
}
};
match &*meta.name.as_str() {
"rustc_deprecated" => {
if rustc_depr.is_some() {
span_err!(diagnostic, item_sp, E0540,
"multiple rustc_deprecated attributes");
break
}
let mut since = None;
let mut reason = None;
macro_rules! get_meta {
($($name:ident),+) => {
$(
let mut $name = None;
)+
for meta in metas {
if let Some(mi) = meta.meta_item() {
match &*mi.name().as_str() {
"since" => if !get(mi, &mut since) { continue 'outer },
"reason" => if !get(mi, &mut reason) { continue 'outer },
$(
stringify!($name)
=> if !get(mi, &mut $name) { continue 'outer },
)+
_ => {
handle_errors(diagnostic, mi.span,
AttrError::UnknownMetaItem(mi.name()));
@ -729,6 +738,18 @@ fn find_stability_generic<'a, I>(diagnostic: &Handler,
continue 'outer
}
}
}
}
match &*meta.name.as_str() {
"rustc_deprecated" => {
if rustc_depr.is_some() {
span_err!(diagnostic, item_sp, E0540,
"multiple rustc_deprecated attributes");
continue 'outer
}
get_meta!(since, reason);
match (since, reason) {
(Some(since), Some(reason)) => {
@ -747,6 +768,23 @@ fn find_stability_generic<'a, I>(diagnostic: &Handler,
}
}
}
"rustc_const_unstable" => {
if rustc_const_unstable.is_some() {
span_err!(diagnostic, item_sp, E0553,
"multiple rustc_const_unstable attributes");
continue 'outer
}
get_meta!(feature);
if let Some(feature) = feature {
rustc_const_unstable = Some(RustcConstUnstable {
feature
});
} else {
span_err!(diagnostic, attr.span(), E0629, "missing 'feature'");
continue
}
}
"unstable" => {
if stab.is_some() {
handle_errors(diagnostic, attr.span(), AttrError::MultipleStabilityLevels);
@ -791,6 +829,7 @@ fn find_stability_generic<'a, I>(diagnostic: &Handler,
},
feature,
rustc_depr: None,
rustc_const_unstable: None,
})
}
(None, _, _) => {
@ -836,6 +875,7 @@ fn find_stability_generic<'a, I>(diagnostic: &Handler,
},
feature,
rustc_depr: None,
rustc_const_unstable: None,
})
}
(None, _) => {
@ -867,6 +907,17 @@ fn find_stability_generic<'a, I>(diagnostic: &Handler,
}
}
// Merge the const-unstable info into the stability info
if let Some(rustc_const_unstable) = rustc_const_unstable {
if let Some(ref mut stab) = stab {
stab.rustc_const_unstable = Some(rustc_const_unstable);
} else {
span_err!(diagnostic, item_sp, E0630,
"rustc_const_unstable attribute must be paired with \
either stable or unstable attribute");
}
}
stab
}

3
src/libsyntax/diagnostic_list.rs
View File

@ -357,8 +357,11 @@ register_diagnostics! {
E0549, // rustc_deprecated attribute must be paired with either stable or unstable attribute
E0550, // multiple deprecated attributes
E0551, // incorrect meta item
E0553, // multiple rustc_const_unstable attributes
E0555, // malformed feature attribute, expected #![feature(...)]
E0556, // malformed feature, expected just one word
E0584, // file for module `..` found at both .. and ..
E0589, // invalid `repr(align)` attribute
E0629, // missing 'feature' (rustc_const_unstable)
E0630, // rustc_const_unstable attribute must be paired with stable/unstable attribute
}

6
src/libsyntax/feature_gate.rs
View File

@ -137,6 +137,7 @@ declare_features! (
// rustc internal
(active, rustc_diagnostic_macros, "1.0.0", None),
(active, rustc_const_unstable, "1.0.0", None),
(active, advanced_slice_patterns, "1.0.0", Some(23121)),
(active, box_syntax, "1.0.0", Some(27779)),
(active, placement_in_syntax, "1.0.0", Some(27779)),
@ -622,6 +623,11 @@ pub const BUILTIN_ATTRIBUTES: &'static [(&'static str, AttributeType, AttributeG
"the `#[rustc_on_unimplemented]` attribute \
is an experimental feature",
cfg_fn!(on_unimplemented))),
("rustc_const_unstable", Normal, Gated(Stability::Unstable,
"rustc_const_unstable",
"the `#[rustc_const_unstable]` attribute \
is an internal feature",
cfg_fn!(rustc_const_unstable))),
("global_allocator", Normal, Gated(Stability::Unstable,
"global_allocator",
"the `#[global_allocator]` attribute is \

3
src/test/compile-fail-fulldeps/dropck_tarena_cycle_checked.rs
View File

@ -16,7 +16,8 @@
// which is a reduction of this code to more directly show the reason
// for the error message we see here.)
#![feature(const_fn, rustc_private)]
#![feature(rustc_private)]
#![feature(const_atomic_usize_new)]
extern crate arena;

2
src/test/compile-fail/const-call.rs
View File

@ -8,8 +8,6 @@
// option. This file may not be copied, modified, or distributed
// except according to those terms.
#![feature(const_fn)]
fn f(x: usize) -> usize {
x
}

24
src/test/compile-fail/const-fn-feature-flags.rs Normal file
View File

@ -0,0 +1,24 @@
// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
// Test use of const fns in std using individual feature gates.
use std::cell::Cell;
const CELL: Cell<i32> = Cell::new(42); //~ERROR not yet stable as a const fn
//~^HELP #![feature(const_cell_new)]
fn main() {
let v = CELL.get();
CELL.set(v+1);
assert_eq!(CELL.get(), v);
}

2
src/test/compile-fail/dropck_trait_cycle_checked.rs
View File

@ -13,7 +13,7 @@
//
// (Compare against compile-fail/dropck_vec_cycle_checked.rs)
#![feature(const_fn)]
#![feature(const_atomic_usize_new)]
use std::cell::Cell;
use id::Id;

17
src/test/run-pass/const-fn-cross-crate.rs → src/test/compile-fail/feature-gate-rustc_const_unstable.rs
View File

@ -8,19 +8,16 @@
// option. This file may not be copied, modified, or distributed
// except according to those terms.
// aux-build:const_fn_lib.rs
// A very basic test of const fn functionality.
// Test internal const fn feature gate.
#![feature(staged_api)]
#![feature(const_fn)]
//#![feature(rustc_const_unstable)]
extern crate const_fn_lib;
use const_fn_lib::foo;
const FOO: usize = foo();
#[stable(feature="zing", since="1.0.0")]
#[rustc_const_unstable(feature="fzzzzzt")] //~ERROR internal feature
pub const fn bazinga() {}
fn main() {
assert_eq!(FOO, 22);
let _: [i32; foo()] = [42; 22];
}

2
src/test/compile-fail/functional-struct-update-respects-privacy.rs
View File

@ -10,8 +10,6 @@
// RFC 736 (and Issue 21407): functional struct update should respect privacy.
#![feature(const_fn)]
// The `foo` module attempts to maintains an invariant that each `S`
// has a unique `u64` id.
use self::foo::S;

2
src/test/compile-fail/issue-17718-const-borrow.rs
View File

@ -8,7 +8,7 @@
// option. This file may not be copied, modified, or distributed
// except according to those terms.
#![feature(const_fn)]
#![feature(const_unsafe_cell_new)]
use std::cell::UnsafeCell;

2
src/test/compile-fail/issue-43733-2.rs
View File

@ -8,7 +8,7 @@
// option. This file may not be copied, modified, or distributed
// except according to those terms.
#![feature(const_fn)]
#![feature(const_fn, const_cell_new, const_unsafe_cell_new)]
#![feature(cfg_target_thread_local, thread_local_internals)]
// On platforms *without* `#[thread_local]`, use

5
src/test/compile-fail/issue-7364.rs
View File

@ -8,9 +8,7 @@
// option. This file may not be copied, modified, or distributed
// except according to those terms.
#![feature(box_syntax)]
#![feature(const_fn)]
#![allow(warnings)]
#![feature(box_syntax, const_refcell_new)]
use std::cell::RefCell;
@ -18,5 +16,6 @@ use std::cell::RefCell;
static boxed: Box<RefCell<isize>> = box RefCell::new(0);
//~^ ERROR allocations are not allowed in statics
//~| ERROR `std::cell::RefCell<isize>: std::marker::Sync` is not satisfied
//~| WARN unsupported constant expr
fn main() { }

7
src/test/compile-fail/stability-attribute-sanity.rs
View File

@ -10,7 +10,7 @@
// Various checks that stability attributes are used correctly, per RFC 507
#![feature(staged_api)]
#![feature(const_fn, staged_api, rustc_const_unstable)]
#![stable(feature = "rust1", since = "1.0.0")]
@ -88,8 +88,11 @@ fn multiple3() { }
#[stable(feature = "a", since = "b")]
#[rustc_deprecated(since = "b", reason = "text")]
#[rustc_deprecated(since = "b", reason = "text")]
fn multiple4() { } //~ ERROR multiple rustc_deprecated attributes [E0540]
#[rustc_const_unstable(feature = "a")]
#[rustc_const_unstable(feature = "b")]
pub const fn multiple4() { } //~ ERROR multiple rustc_deprecated attributes [E0540]
//~^ ERROR Invalid stability or deprecation version found
//~| ERROR multiple rustc_const_unstable attributes
#[rustc_deprecated(since = "a", reason = "text")]
fn deprecated_without_unstable_or_stable() { }

2
src/test/debuginfo/constant-debug-locs.rs
View File

@ -15,7 +15,7 @@
#![allow(dead_code, unused_variables)]
#![feature(omit_gdb_pretty_printer_section)]
#![omit_gdb_pretty_printer_section]
#![feature(const_fn)]
#![feature(const_unsafe_cell_new)]
#![feature(static_mutex)]
// This test makes sure that the compiler doesn't crash when trying to assign

2
src/test/run-pass-valgrind/cast-enum-with-dtor.rs
View File

@ -11,7 +11,7 @@
// no-prefer-dynamic
#![allow(dead_code)]
#![feature(const_fn)]
#![feature(const_atomic_usize_new)]
// check dtor calling order when casting enums.

2
src/test/run-pass/associated-types-project-from-type-param-via-bound-in-where-clause.rs
View File

@ -12,7 +12,7 @@
// `Item` originates in a where-clause, not the declaration of
// `T`. Issue #20300.
#![feature(const_fn)]
#![feature(const_atomic_usize_new)]
use std::marker::{PhantomData};
use std::sync::atomic::{AtomicUsize};

2
src/test/run-pass/auxiliary/const_fn_lib.rs
View File

@ -13,4 +13,4 @@
#![crate_type="rlib"]
#![feature(const_fn)]
pub const fn foo() -> usize { 22 } //~ ERROR const fn is unstable
pub const fn foo() -> usize { 22 }

2
src/test/run-pass/auxiliary/issue-17718-aux.rs
View File

@ -8,7 +8,7 @@
// option. This file may not be copied, modified, or distributed
// except according to those terms.
#![feature(const_fn)]
#![feature(const_atomic_usize_new)]
use std::sync::atomic;

1
src/test/run-pass/auxiliary/thread-local-extern-static.rs
View File

@ -9,6 +9,7 @@
// except according to those terms.
#![feature(cfg_target_thread_local, const_fn, thread_local)]
#![feature(const_cell_new)]
#![crate_type = "lib"]
#[cfg(target_thread_local)]

2
src/test/run-pass/box-of-array-of-drop-1.rs
View File

@ -13,7 +13,7 @@
// ignore-emscripten no threads support
#![feature(const_fn)]
#![feature(const_atomic_usize_new)]
use std::thread;
use std::sync::atomic::{AtomicUsize, Ordering};

2
src/test/run-pass/box-of-array-of-drop-2.rs
View File

@ -13,7 +13,7 @@
// ignore-emscripten no threads support
#![feature(const_fn)]
#![feature(const_atomic_usize_new)]
use std::thread;
use std::sync::atomic::{AtomicUsize, Ordering};

25
src/test/run-pass/const-fn-feature-flags.rs Normal file
View File

@ -0,0 +1,25 @@
// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
// Test use of const fns in std using individual feature gates.
#![feature(const_cell_new)]
use std::cell::Cell;
const CELL: Cell<i32> = Cell::new(42);
fn main() {
let v = CELL.get();
CELL.set(v+1);
assert_eq!(CELL.get(), v);
}

8
src/test/compile-fail/const-fn-stability-calls.rs → src/test/run-pass/const-fn-stability-calls.rs
View File

@ -16,8 +16,8 @@ extern crate const_fn_lib;
use const_fn_lib::foo;
static FOO: usize = foo(); //~ ERROR const fns are an unstable feature
const BAR: usize = foo(); //~ ERROR const fns are an unstable feature
static FOO: usize = foo();
const BAR: usize = foo();
macro_rules! constant {
($n:ident: $t:ty = $v:expr) => {
@ -26,9 +26,9 @@ macro_rules! constant {
}
constant! {
BAZ: usize = foo() //~ ERROR const fns are an unstable feature
BAZ: usize = foo()
}
fn main() {
// let x: [usize; foo()] = [];
let x: [usize; foo()] = [42; foo()];
}

2
src/test/run-pass/const-size_of-align_of.rs
View File

@ -8,7 +8,7 @@
// option. This file may not be copied, modified, or distributed
// except according to those terms.
#![feature(const_fn)]
#![feature(const_fn, const_size_of, const_align_of)]
use std::mem;

3
src/test/run-pass/issue-17718-static-unsafe-interior.rs
View File

@ -11,8 +11,7 @@
// pretty-expanded FIXME #23616
#![feature(core)]
#![feature(const_fn)]
#![feature(const_unsafe_cell_new)]
use std::marker;
use std::cell::UnsafeCell;

2
src/test/run-pass/issue-17718.rs
View File

@ -12,7 +12,7 @@
#![feature(core)]
#![feature(const_fn)]
#![feature(const_atomic_usize_new)]
extern crate issue_17718_aux as other;

2
src/test/run-pass/issue-21486.rs
View File

@ -12,7 +12,7 @@
// created via FRU and control-flow breaks in the middle of
// construction.
#![feature(const_fn)]
#![feature(const_atomic_usize_new)]
use std::sync::atomic::{Ordering, AtomicUsize};

4
src/test/run-pass/issue-26655.rs
View File

@ -10,10 +10,10 @@
// ignore-emscripten no threads support
#![feature(const_fn)]
// Check that the destructors of simple enums are run on unwinding
#![feature(const_atomic_usize_new)]
use std::sync::atomic::{Ordering, AtomicUsize};
use std::thread;

2
src/test/run-pass/issue-27997.rs
View File

@ -8,7 +8,7 @@
// option. This file may not be copied, modified, or distributed
// except according to those terms.
#![feature(const_fn)]
#![feature(const_atomic_usize_new)]
use std::sync::atomic::{Ordering, AtomicUsize};

2
src/test/run-pass/nested-vec-3.rs
View File

@ -14,7 +14,7 @@
// the contents implement Drop and we hit a panic in the middle of
// construction.
#![feature(const_fn)]
#![feature(const_atomic_usize_new)]
use std::thread;
use std::sync::atomic::{AtomicUsize, Ordering};

3
src/test/run-pass/panic-handler-chain.rs
View File

@ -10,7 +10,8 @@
// ignore-emscripten no threads support
#![feature(panic_handler, const_fn, std_panic)]
#![feature(panic_handler, std_panic)]
#![feature(const_atomic_usize_new)]
use std::sync::atomic::{AtomicUsize, Ordering};
use std::panic;

3
src/test/run-pass/panic-handler-set-twice.rs
View File

@ -7,7 +7,8 @@
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
#![feature(panic_handler, const_fn, std_panic)]
#![feature(panic_handler, std_panic)]
#![feature(const_atomic_usize_new)]
// ignore-emscripten no threads support

2
src/test/run-pass/struct-order-of-eval-3.rs
View File

@ -11,7 +11,7 @@
// Checks that functional-record-update order-of-eval is as expected
// even when no Drop-implementations are involved.
#![feature(const_fn)]
#![feature(const_atomic_usize_new)]
use std::sync::atomic::{Ordering, AtomicUsize};

2
src/test/run-pass/struct-order-of-eval-4.rs
View File

@ -11,7 +11,7 @@
// Checks that struct-literal expression order-of-eval is as expected
// even when no Drop-implementations are involved.
#![feature(const_fn)]
#![feature(const_atomic_usize_new)]
use std::sync::atomic::{Ordering, AtomicUsize};

2
src/test/run-pass/vector-sort-panic-safe.rs
View File

@ -10,9 +10,9 @@
// ignore-emscripten no threads support
#![feature(const_fn)]
#![feature(rand)]
#![feature(sort_unstable)]
#![feature(const_atomic_usize_new)]
use std::__rand::{thread_rng, Rng};
use std::cell::Cell;

2
src/test/ui/span/dropck_arr_cycle_checked.rs
View File

@ -13,7 +13,7 @@
//
// (Compare against compile-fail/dropck_vec_cycle_checked.rs)
#![feature(const_fn)]
#![feature(const_atomic_usize_new)]
use std::cell::Cell;
use id::Id;

2
src/test/ui/span/dropck_vec_cycle_checked.rs
View File

@ -12,7 +12,7 @@
//
// (Compare against compile-fail/dropck_arr_cycle_checked.rs)
#![feature(const_fn)]
#![feature(const_atomic_usize_new)]
use std::cell::Cell;
use id::Id;

2
src/test/ui/span/vec-must-not-hide-type-from-dropck.rs
View File

@ -23,7 +23,7 @@
// conditions above to be satisfied, meaning that if the dropck is
// sound, it should reject this code.
#![feature(const_fn)]
#![feature(const_atomic_usize_new)]
use std::cell::Cell;
use id::Id;

2
src/tools/rls

@ -1 +1 @@
Subproject commit 8dd70945fb049df3f9dc7685cdc58d94e05e8ffc
Subproject commit 52d48656f93eeeb2c568e6c1048e64168e5b209f