Make std feature to depend on alloc feature

Cargo.toml

@@ -23,6 +23,7 @@ travis-ci = { repository = "crossbeam-rs/crossbeam" }
 default = ["std"]
 nightly = ["crossbeam-epoch/nightly", "crossbeam-utils/nightly", "crossbeam-queue/nightly"]
 std = [
+  "alloc",
   "crossbeam-channel",
   "crossbeam-deque",
   "crossbeam-epoch/std",

crossbeam-epoch/Cargo.toml

@@ -18,7 +18,7 @@ categories = ["concurrency", "memory-management", "no-std"]
 [features]
 default = ["std"]
 nightly = ["crossbeam-utils/nightly"]
-std = ["crossbeam-utils/std", "lazy_static"]
+std = ["alloc", "crossbeam-utils/std", "lazy_static"]
 alloc = ["crossbeam-utils/alloc"]
 sanitize = [] # Makes it more likely to trigger any potential data races.
 

crossbeam-epoch/src/lib.rs

@@ -61,20 +61,14 @@
 
 #[macro_use]
 extern crate cfg_if;
+#[cfg(feature = "alloc")]
+extern crate alloc;
 #[cfg(feature = "std")]
 extern crate core;
 
-cfg_if! {
-    if #[cfg(feature = "alloc")] {
-        extern crate alloc;
-    } else if #[cfg(feature = "std")] {
-        extern crate std as alloc;
-    }
-}
-
 #[cfg_attr(feature = "nightly", cfg(target_has_atomic = "ptr"))]
 cfg_if! {
-    if #[cfg(any(feature = "alloc", feature = "std"))] {
+    if #[cfg(feature = "alloc")] {
         extern crate crossbeam_utils;
         #[macro_use]
         extern crate memoffset;

crossbeam-queue/Cargo.toml

@@ -17,7 +17,7 @@ categories = ["concurrency", "data-structures"]
 
 [features]
 default = ["std"]
-std = ["crossbeam-utils/std"]
+std = ["alloc", "crossbeam-utils/std"]
 alloc = ["crossbeam-utils/alloc"]
 nightly = []
 

crossbeam-queue/src/lib.rs

@@ -13,24 +13,19 @@
 #![cfg_attr(not(feature = "std"), no_std)]
 #![cfg_attr(feature = "nightly", feature(cfg_target_has_atomic))]
 
+#[cfg_attr(feature = "nightly", cfg(target_has_atomic = "ptr"))]
 #[macro_use]
 extern crate cfg_if;
+#[cfg(feature = "alloc")]
+extern crate alloc;
 #[cfg(feature = "std")]
 extern crate core;
 
-cfg_if! {
-    if #[cfg(feature = "alloc")] {
-        extern crate alloc;
-    } else if #[cfg(feature = "std")] {
-        extern crate std as alloc;
-    }
-}
-
 extern crate crossbeam_utils;
 
 #[cfg_attr(feature = "nightly", cfg(target_has_atomic = "ptr"))]
 cfg_if! {
-    if #[cfg(any(feature = "alloc", feature = "std"))] {
+    if #[cfg(feature = "alloc")] {
         mod array_queue;
         mod err;
         mod seg_queue;

crossbeam-skiplist/Cargo.toml

@@ -18,7 +18,7 @@ categories = ["algorithms", "concurrency", "data-structures", "no-std"]
 [features]
 default = ["std"]
 nightly = ["crossbeam-epoch/nightly", "crossbeam-utils/nightly"]
-std = ["crossbeam-epoch/std", "crossbeam-utils/std"]
+std = ["alloc", "crossbeam-epoch/std", "crossbeam-utils/std"]
 alloc = ["crossbeam-epoch/alloc", "crossbeam-utils/alloc"]
 
 [dependencies]

crossbeam-skiplist/src/lib.rs

@@ -7,20 +7,14 @@
 
 #[macro_use]
 extern crate cfg_if;
+#[cfg(feature = "alloc")]
+extern crate alloc;
 #[cfg(feature = "std")]
 extern crate core;
 
-cfg_if! {
-    if #[cfg(feature = "alloc")] {
-        extern crate alloc;
-    } else if #[cfg(feature = "std")] {
-        extern crate std as alloc;
-    }
-}
-
 #[cfg_attr(feature = "nightly", cfg(target_has_atomic = "ptr"))]
 cfg_if! {
-    if #[cfg(any(feature = "alloc", feature = "std"))] {
+    if #[cfg(feature = "alloc")] {
         extern crate crossbeam_epoch as epoch;
         extern crate crossbeam_utils as utils;
         extern crate scopeguard;

crossbeam-utils/Cargo.toml

@@ -18,7 +18,7 @@ categories = ["algorithms", "concurrency", "data-structures", "no-std"]
 [features]
 default = ["std"]
 nightly = []
-std = ["lazy_static"]
+std = ["alloc", "lazy_static"]
 alloc = []
 
 [dependencies]

crossbeam-utils/src/lib.rs

@@ -33,17 +33,11 @@
 
 #[macro_use]
 extern crate cfg_if;
+#[cfg(feature = "alloc")]
+extern crate alloc;
 #[cfg(feature = "std")]
 extern crate core;
 
-cfg_if! {
-    if #[cfg(feature = "alloc")] {
-        extern crate alloc;
-    } else if #[cfg(feature = "std")] {
-        extern crate std as alloc;
-    }
-}
-
 #[cfg_attr(feature = "nightly", cfg(target_has_atomic = "ptr"))]
 pub mod atomic;
 

src/lib.rs

@@ -49,17 +49,11 @@
 
 #[macro_use]
 extern crate cfg_if;
+#[cfg(feature = "alloc")]
+extern crate alloc;
 #[cfg(feature = "std")]
 extern crate core;
 
-cfg_if! {
-    if #[cfg(feature = "alloc")] {
-        extern crate alloc;
-    } else if #[cfg(feature = "std")] {
-        extern crate std as alloc;
-    }
-}
-
 mod _epoch {
     pub extern crate crossbeam_epoch;
 }
@@ -78,7 +72,7 @@ pub mod utils {
 }
 
 cfg_if! {
-    if #[cfg(any(feature = "std", feature = "alloc"))] {
+    if #[cfg(feature = "alloc")] {
         mod _queue {
             pub extern crate crossbeam_queue;
         }