Revert "Auto merge of #53793 - toidiu:ak-stabalize, r=nikomatsakis"

This reverts commit 6810f52, reversing
changes made to 8586ec6.

Author: arielb1

src/doc/unstable-book/src/language-features/infer-outlives-requirements.md

@@ -0,0 +1,67 @@
+# `infer_outlives_requirements`
+
+The tracking issue for this feature is: [#44493]
+
+[#44493]: https://github.com/rust-lang/rust/issues/44493
+
+------------------------
+The `infer_outlives_requirements` feature indicates that certain
+outlives requirements can be inferred by the compiler rather than
+stating them explicitly.
+
+For example, currently generic struct definitions that contain
+references, require where-clauses of the form T: 'a. By using
+this feature the outlives predicates will be inferred, although
+they may still be written explicitly.
+
+```rust,ignore (pseudo-Rust)
+struct Foo<'a, T>
+  where T: 'a // <-- currently required
+  {
+      bar: &'a T,
+  }
+```
+
+
+## Examples:
+
+
+```rust,ignore (pseudo-Rust)
+#![feature(infer_outlives_requirements)]
+
+// Implicitly infer T: 'a
+struct Foo<'a, T> {
+    bar: &'a T,
+}
+```
+
+```rust,ignore (pseudo-Rust)
+#![feature(infer_outlives_requirements)]
+
+// Implicitly infer `U: 'b`
+struct Foo<'b, U> {
+    bar: Bar<'b, U>
+}
+
+struct Bar<'a, T> where T: 'a {
+    x: &'a (),
+    y: T,
+}
+```
+
+```rust,ignore (pseudo-Rust)
+#![feature(infer_outlives_requirements)]
+
+// Implicitly infer `b': 'a`
+struct Foo<'a, 'b, T> {
+    x: &'a &'b T
+}
+```
+
+```rust,ignore (pseudo-Rust)
+#![feature(infer_outlives_requirements)]
+
+// Implicitly infer `<T as std::iter::Iterator>::Item : 'a`
+struct Foo<'a, T: Iterator> {
+    bar: &'a T::Item
+```

src/liballoc/lib.rs

@@ -77,6 +77,7 @@
 #![cfg_attr(not(test), feature(fn_traits))]
 #![cfg_attr(not(test), feature(generator_trait))]
 #![cfg_attr(not(stage0), feature(nll))]
+#![cfg_attr(not(stage0), feature(infer_outlives_requirements))]
 #![cfg_attr(test, feature(test))]
 
 #![feature(allocator_api)]

src/liballoc_jemalloc/lib.rs

@@ -17,6 +17,7 @@
 #![feature(libc)]
 #![feature(linkage)]
 #![cfg_attr(not(stage0), feature(nll))]
+#![cfg_attr(not(stage0), feature(infer_outlives_requirements))]
 #![feature(staged_api)]
 #![feature(rustc_attrs)]
 #![cfg_attr(dummy_jemalloc, allow(dead_code, unused_extern_crates))]

src/liballoc_system/lib.rs

@@ -18,6 +18,7 @@
 #![feature(allocator_api)]
 #![feature(core_intrinsics)]
 #![cfg_attr(not(stage0), feature(nll))]
+#![cfg_attr(not(stage0), feature(infer_outlives_requirements))]
 #![feature(staged_api)]
 #![feature(rustc_attrs)]
 #![cfg_attr(any(unix, target_os = "cloudabi", target_os = "redox"), feature(libc))]

src/libarena/lib.rs

@@ -27,6 +27,7 @@
 #![feature(core_intrinsics)]
 #![feature(dropck_eyepatch)]
 #![cfg_attr(not(stage0), feature(nll))]
+#![cfg_attr(not(stage0), feature(infer_outlives_requirements))]
 #![feature(raw_vec_internals)]
 #![cfg_attr(test, feature(test))]
 

src/libcore/lib.rs

@@ -92,6 +92,7 @@
 #![feature(link_llvm_intrinsics)]
 #![feature(never_type)]
 #![cfg_attr(not(stage0), feature(nll))]
+#![cfg_attr(not(stage0), feature(infer_outlives_requirements))]
 #![feature(exhaustive_patterns)]
 #![feature(macro_at_most_once_rep)]
 #![feature(no_core)]

src/libfmt_macros/lib.rs

@@ -21,6 +21,7 @@
        test(attr(deny(warnings))))]
 
 #![cfg_attr(not(stage0), feature(nll))]
+#![cfg_attr(not(stage0), feature(infer_outlives_requirements))]
 
 pub use self::Piece::*;
 pub use self::Position::*;

src/libgraphviz/lib.rs

@@ -289,6 +289,7 @@
        test(attr(allow(unused_variables), deny(warnings))))]
 
 #![cfg_attr(not(stage0), feature(nll))]
+#![cfg_attr(not(stage0), feature(infer_outlives_requirements))]
 #![feature(str_escape)]
 
 use self::LabelText::*;

src/libpanic_abort/lib.rs

@@ -25,6 +25,7 @@
 #![feature(core_intrinsics)]
 #![feature(libc)]
 #![cfg_attr(not(stage0), feature(nll))]
+#![cfg_attr(not(stage0), feature(infer_outlives_requirements))]
 #![feature(panic_runtime)]
 #![feature(staged_api)]
 #![feature(rustc_attrs)]

src/libpanic_unwind/lib.rs

@@ -35,6 +35,7 @@
 #![feature(lang_items)]
 #![feature(libc)]
 #![cfg_attr(not(stage0), feature(nll))]
+#![cfg_attr(not(stage0), feature(infer_outlives_requirements))]
 #![feature(panic_unwind)]
 #![feature(raw)]
 #![feature(staged_api)]