Add version detection for stabilized atomics and checked_add

Cargo.toml

@@ -18,6 +18,9 @@ lock_api = { path = "lock_api", version = "0.2" }
 rand = "0.6"
 lazy_static = "1.0"
 
+[build-dependencies]
+rustc_version = "0.2"
+
 [features]
 default = []
 owning_ref = ["lock_api/owning_ref"]

build.rs

@@ -0,0 +1,9 @@
+use rustc_version::{version, Version};
+
+fn main() {
+    if version().unwrap() >= Version::parse("1.34.0").unwrap() {
+        println!("cargo:rustc-cfg=has_sized_atomics");
+        println!("cargo:rustc-cfg=has_checked_instant");
+    }
+}
+

core/Cargo.toml

@@ -17,6 +17,9 @@ petgraph = { version = "0.4.5", optional = true }
 thread-id = { version = "3.2.0", optional = true }
 backtrace = { version = "0.3.2", optional = true }
 
+[build-dependencies]
+rustc_version = "0.2"
+
 [target.'cfg(unix)'.dependencies]
 libc = "0.2.27"
 

core/build.rs

@@ -0,0 +1,8 @@
+use rustc_version::{version, Version};
+
+fn main() {
+    if version().unwrap() >= Version::parse("1.34.0").unwrap() {
+        println!("cargo:rustc-cfg=has_sized_atomics");
+    }
+}
+

core/src/lib.rs

@@ -72,7 +72,7 @@ mod libstd {
 }
 
 cfg_if! {
-    if #[cfg(all(any(feature = "i-am-libstd", feature = "nightly"), target_os = "linux"))] {
+    if #[cfg(all(any(feature = "i-am-libstd", has_sized_atomics), target_os = "linux"))] {
         #[path = "thread_parker/linux.rs"]
         mod thread_parker;
     } else if #[cfg(unix)] {
@@ -81,7 +81,7 @@ cfg_if! {
     } else if #[cfg(windows)] {
         #[path = "thread_parker/windows/mod.rs"]
         mod thread_parker;
-    } else if #[cfg(all(any(feature = "i-am-libstd", feature = "nightly"), target_os = "redox"))] {
+    } else if #[cfg(all(any(feature = "i-am-libstd", has_sized_atomics), target_os = "redox"))] {
         #[path = "thread_parker/redox.rs"]
         mod thread_parker;
     } else if #[cfg(all(target_env = "sgx", target_vendor = "fortanix"))] {

src/once.rs

@@ -5,13 +5,13 @@
 // http://opensource.org/licenses/MIT>, at your option. This file may not be
 // copied, modified, or distributed except according to those terms.
 
-#[cfg(any(feature = "nightly", feature = "i-am-libstd"))]
+#[cfg(any(has_sized_atomics, feature = "i-am-libstd"))]
 use core::sync::atomic::AtomicU8;
-#[cfg(any(feature = "nightly", feature = "i-am-libstd"))]
+#[cfg(any(has_sized_atomics, feature = "i-am-libstd"))]
 type U8 = u8;
-#[cfg(not(any(feature = "nightly", feature = "i-am-libstd")))]
+#[cfg(not(any(has_sized_atomics, feature = "i-am-libstd")))]
 use core::sync::atomic::AtomicUsize as AtomicU8;
-#[cfg(not(any(feature = "nightly", feature = "i-am-libstd")))]
+#[cfg(not(any(has_sized_atomics, feature = "i-am-libstd")))]
 type U8 = usize;
 use super::parking_lot_core::{self, SpinWait, DEFAULT_PARK_TOKEN, DEFAULT_UNPARK_TOKEN};
 use super::util::UncheckedOptionExt;

src/raw_mutex.rs

@@ -5,14 +5,14 @@
 // http://opensource.org/licenses/MIT>, at your option. This file may not be
 // copied, modified, or distributed except according to those terms.
 
-#[cfg(any(feature = "nightly", feature = "i-am-libstd"))]
+#[cfg(any(has_sized_atomics, feature = "i-am-libstd"))]
 use core::sync::atomic::AtomicU8;
 use core::sync::atomic::Ordering;
-#[cfg(any(feature = "nightly", feature = "i-am-libstd"))]
+#[cfg(any(has_sized_atomics, feature = "i-am-libstd"))]
 type U8 = u8;
-#[cfg(not(any(feature = "nightly", feature = "i-am-libstd")))]
+#[cfg(not(any(has_sized_atomics, feature = "i-am-libstd")))]
 use core::sync::atomic::AtomicUsize as AtomicU8;
-#[cfg(not(any(feature = "nightly", feature = "i-am-libstd")))]
+#[cfg(not(any(has_sized_atomics, feature = "i-am-libstd")))]
 type U8 = usize;
 use super::libstd::time::{Duration, Instant};
 use super::lock_api::{GuardNoSend, RawMutex as RawMutexTrait, RawMutexFair, RawMutexTimed};

src/util.rs

@@ -35,9 +35,9 @@ unsafe fn unreachable() -> ! {
 
 #[inline]
 pub fn to_deadline(timeout: Duration) -> Option<Instant> {
-    #[cfg(any(feature = "nightly", feature = "i-am-libstd"))]
+    #[cfg(any(has_checked_instant, feature = "i-am-libstd"))]
     let deadline = Instant::now().checked_add(timeout);
-    #[cfg(not(any(feature = "nightly", feature = "i-am-libstd")))]
+    #[cfg(not(any(has_checked_instant, feature = "i-am-libstd")))]
     let deadline = Some(Instant::now() + timeout);
 
     deadline