diff --git a/library/alloc/src/lib.rs b/library/alloc/src/lib.rs
index 7881c101f9f60..0f67c57ff0946 100644
--- a/library/alloc/src/lib.rs
+++ b/library/alloc/src/lib.rs
@@ -74,6 +74,7 @@
 #![deny(unsafe_op_in_unsafe_fn)]
 #![cfg_attr(not(test), feature(generator_trait))]
 #![cfg_attr(test, feature(test))]
+#![cfg_attr(test, feature(new_uninit))]
 #![feature(allocator_api)]
 #![feature(array_chunks)]
 #![feature(array_windows)]
@@ -81,7 +82,6 @@
 #![feature(arbitrary_self_types)]
 #![feature(box_patterns)]
 #![feature(box_syntax)]
-#![feature(btree_drain_filter)]
 #![feature(cfg_sanitize)]
 #![feature(cfg_target_has_atomic)]
 #![feature(coerce_unsized)]
@@ -89,10 +89,8 @@
 #![feature(const_generics)]
 #![feature(const_in_array_repeat_expressions)]
 #![feature(cow_is_borrowed)]
-#![feature(deque_range)]
 #![feature(dispatch_from_dyn)]
 #![feature(core_intrinsics)]
-#![feature(container_error_extra)]
 #![feature(dropck_eyepatch)]
 #![feature(exact_size_is_empty)]
 #![feature(exclusive_range_pattern)]
@@ -103,13 +101,9 @@
 #![feature(inplace_iteration)]
 #![feature(lang_items)]
 #![feature(layout_for_ptr)]
-#![feature(libc)]
-#![feature(map_first_last)]
-#![feature(map_into_keys_values)]
 #![feature(maybe_uninit_ref)]
 #![feature(negative_impls)]
 #![feature(never_type)]
-#![feature(new_uninit)]
 #![feature(nll)]
 #![feature(nonnull_slice_from_raw_parts)]
 #![feature(optin_builtin_traits)]
@@ -124,10 +118,8 @@
 #![feature(slice_ptr_get)]
 #![feature(slice_ptr_len)]
 #![feature(staged_api)]
-#![feature(std_internals)]
 #![feature(str_internals)]
 #![feature(trusted_len)]
-#![feature(try_reserve)]
 #![feature(unboxed_closures)]
 #![feature(unicode_internals)]
 #![feature(unsafe_block_in_unsafe_fn)]
diff --git a/library/core/src/lib.rs b/library/core/src/lib.rs
index 3bddc3772e600..92f1f4be9560e 100644
--- a/library/core/src/lib.rs
+++ b/library/core/src/lib.rs
@@ -66,9 +66,7 @@
 #![feature(allow_internal_unstable)]
 #![feature(arbitrary_self_types)]
 #![feature(asm)]
-#![feature(bound_cloned)]
 #![feature(cfg_target_has_atomic)]
-#![feature(concat_idents)]
 #![feature(const_alloc_layout)]
 #![feature(const_discriminant)]
 #![feature(const_checked_int_methods)]
@@ -104,8 +102,6 @@
 #![feature(extern_types)]
 #![feature(fundamental)]
 #![feature(intrinsics)]
-#![feature(try_find)]
-#![feature(is_sorted)]
 #![feature(lang_items)]
 #![feature(link_llvm_intrinsics)]
 #![feature(llvm_asm)]
@@ -117,7 +113,6 @@
 #![feature(optin_builtin_traits)]
 #![feature(or_patterns)]
 #![feature(prelude_import)]
-#![feature(ptr_as_uninit)]
 #![feature(repr_simd, platform_intrinsics)]
 #![feature(rustc_attrs)]
 #![feature(simd_ffi)]
@@ -148,8 +143,6 @@
 #![feature(const_fn_transmute)]
 #![feature(abi_unadjusted)]
 #![feature(adx_target_feature)]
-#![feature(maybe_uninit_slice)]
-#![feature(maybe_uninit_extra)]
 #![feature(external_doc)]
 #![feature(associated_type_bounds)]
 #![feature(const_caller_location)]
diff --git a/library/panic_abort/src/lib.rs b/library/panic_abort/src/lib.rs
index 3b08a64b22d85..7a5c613688d42 100644
--- a/library/panic_abort/src/lib.rs
+++ b/library/panic_abort/src/lib.rs
@@ -12,7 +12,6 @@
 #![panic_runtime]
 #![allow(unused_features)]
 #![feature(core_intrinsics)]
-#![feature(libc)]
 #![feature(nll)]
 #![feature(panic_runtime)]
 #![feature(staged_api)]
diff --git a/library/panic_unwind/src/lib.rs b/library/panic_unwind/src/lib.rs
index 6f31e6dcae70d..0a193f7bf4149 100644
--- a/library/panic_unwind/src/lib.rs
+++ b/library/panic_unwind/src/lib.rs
@@ -19,7 +19,6 @@
 )]
 #![feature(core_intrinsics)]
 #![feature(lang_items)]
-#![feature(libc)]
 #![feature(nll)]
 #![feature(panic_unwind)]
 #![feature(staged_api)]
diff --git a/library/std/src/lib.rs b/library/std/src/lib.rs
index b834361b750eb..c63c3c34a88a5 100644
--- a/library/std/src/lib.rs
+++ b/library/std/src/lib.rs
@@ -228,7 +228,6 @@
 #![feature(atomic_mut_ptr)]
 #![feature(box_syntax)]
 #![feature(c_variadic)]
-#![feature(can_vector)]
 #![feature(cfg_accessible)]
 #![feature(cfg_target_has_atomic)]
 #![feature(cfg_target_thread_local)]
@@ -261,14 +260,12 @@
 #![feature(gen_future)]
 #![feature(generator_trait)]
 #![feature(global_asm)]
-#![feature(hash_raw_entry)]
 #![feature(hashmap_internals)]
 #![feature(int_error_internals)]
 #![feature(int_error_matching)]
 #![feature(integer_atomics)]
 #![feature(into_future)]
 #![feature(lang_items)]
-#![feature(libc)]
 #![feature(link_args)]
 #![feature(linkage)]
 #![feature(llvm_asm)]