Make std feature list sorted

This helps to avoid merge conflicts when concurrent PRs append
features to the end of the list.

src/libstd/lib.rs

@@ -215,16 +215,22 @@
 // std may use features in a platform-specific way
 #![allow(unused_features)]
 
+#![cfg_attr(test, feature(test, update_panic_count))]
+#![cfg_attr(all(target_vendor = "fortanix", target_env = "sgx"),
+            feature(global_asm, range_contains, slice_index_methods,
+                    decl_macro, coerce_unsized, sgx_platform, ptr_wrapping_offset_from))]
+
 // std is implemented with unstable features, many of which are internal
 // compiler details that will never be stable
-#![cfg_attr(test, feature(test, update_panic_count))]
-#![feature(alloc)]
+// NB: the following list is sorted to minimize merge conflicts.
+#![feature(align_offset)]
 #![feature(alloc_error_handler)]
+#![feature(alloc_layout_extra)]
+#![feature(alloc)]
 #![feature(allocator_api)]
 #![feature(allocator_internals)]
 #![feature(allow_internal_unsafe)]
 #![feature(allow_internal_unstable)]
-#![feature(align_offset)]
 #![feature(arbitrary_self_types)]
 #![feature(array_error_internals)]
 #![feature(asm)]
@@ -233,72 +239,69 @@
 #![feature(cfg_target_has_atomic)]
 #![feature(cfg_target_thread_local)]
 #![feature(char_error_internals)]
+#![feature(checked_duration_since)]
 #![feature(compiler_builtins_lib)]
 #![feature(concat_idents)]
-#![feature(const_raw_ptr_deref)]
 #![feature(const_cstr_unchecked)]
+#![feature(const_raw_ptr_deref)]
 #![feature(core_intrinsics)]
+#![feature(doc_alias)]
+#![feature(doc_cfg)]
+#![feature(doc_keyword)]
+#![feature(doc_masked)]
+#![feature(doc_spotlight)]
 #![feature(dropck_eyepatch)]
 #![feature(duration_constants)]
 #![feature(exact_size_is_empty)]
+#![feature(exhaustive_patterns)]
 #![feature(external_doc)]
 #![feature(fixed_size_array)]
 #![feature(fn_traits)]
 #![feature(fnbox)]
 #![feature(futures_api)]
 #![feature(generator_trait)]
+#![feature(hash_raw_entry)]
 #![feature(hashmap_internals)]
 #![feature(int_error_internals)]
 #![feature(integer_atomics)]
 #![feature(lang_items)]
 #![feature(libc)]
 #![feature(link_args)]
 #![feature(linkage)]
+#![feature(maybe_uninit)]
 #![feature(needs_panic_runtime)]
 #![feature(never_type)]
 #![feature(nll)]
-#![feature(exhaustive_patterns)]
+#![feature(non_exhaustive)]
 #![feature(on_unimplemented)]
 #![feature(optin_builtin_traits)]
+#![feature(panic_info_message)]
 #![feature(panic_internals)]
 #![feature(panic_unwind)]
 #![feature(prelude_import)]
 #![feature(ptr_internals)]
 #![feature(raw)]
-#![feature(hash_raw_entry)]
+#![feature(renamed_spin_loop)]
 #![feature(rustc_attrs)]
 #![feature(rustc_const_unstable)]
-#![feature(std_internals)]
-#![feature(stdsimd)]
+#![feature(rustc_private)]
 #![feature(shrink_to)]
 #![feature(slice_concat_ext)]
 #![feature(slice_internals)]
 #![feature(slice_patterns)]
 #![feature(staged_api)]
+#![feature(std_internals)]
+#![feature(stdsimd)]
 #![feature(stmt_expr_attributes)]
 #![feature(str_internals)]
-#![feature(renamed_spin_loop)]
-#![feature(rustc_private)]
 #![feature(thread_local)]
 #![feature(toowned_clone_into)]
 #![feature(try_from)]
 #![feature(try_reserve)]
 #![feature(unboxed_closures)]
 #![feature(untagged_unions)]
 #![feature(unwind_attributes)]
-#![feature(doc_cfg)]
-#![feature(doc_masked)]
-#![feature(doc_spotlight)]
-#![feature(doc_alias)]
-#![feature(doc_keyword)]
-#![feature(panic_info_message)]
-#![feature(non_exhaustive)]
-#![feature(alloc_layout_extra)]
-#![feature(maybe_uninit)]
-#![feature(checked_duration_since)]
-#![cfg_attr(all(target_vendor = "fortanix", target_env = "sgx"),
-            feature(global_asm, range_contains, slice_index_methods,
-                    decl_macro, coerce_unsized, sgx_platform, ptr_wrapping_offset_from))]
+// NB: the above list is sorted to minimize merge conflicts.
 
 #![default_lib_allocator]