Add unwrap_unsafe_binder and wrap_unsafe_binder macro operators

core/src/lib.rs

@@ -354,6 +354,8 @@ pub mod random;
 pub mod range;
 pub mod result;
 pub mod sync;
+#[unstable(feature = "unsafe_binders", issue = "130516")]
+pub mod unsafe_binder;
 
 pub mod fmt;
 pub mod hash;

core/src/unsafe_binder.rs

@@ -0,0 +1,25 @@
+//! Operators used to turn types into unsafe binders and back.
+
+/// Unwrap an unsafe binder into its underlying type.
+#[allow_internal_unstable(builtin_syntax)]
+#[unstable(feature = "unsafe_binders", issue = "130516")]
+pub macro unwrap_binder {
+    ($expr:expr) => {
+        builtin # unwrap_binder ( $expr )
+    },
+    ($expr:expr ; $ty:ty) => {
+        builtin # unwrap_binder ( $expr, $ty )
+    },
+}
+
+/// Wrap a type into an unsafe binder.
+#[allow_internal_unstable(builtin_syntax)]
+#[unstable(feature = "unsafe_binders", issue = "130516")]
+pub macro wrap_binder {
+    ($expr:expr) => {
+        builtin # wrap_binder ( $expr )
+    },
+    ($expr:expr ; $ty:ty) => {
+        builtin # wrap_binder ( $expr, $ty )
+    },
+}

std/src/lib.rs

@@ -544,6 +544,8 @@ pub use core::u64;
 #[stable(feature = "i128", since = "1.26.0")]
 #[allow(deprecated, deprecated_in_future)]
 pub use core::u128;
+#[unstable(feature = "unsafe_binders", issue = "130516")]
+pub use core::unsafe_binder;
 #[stable(feature = "rust1", since = "1.0.0")]
 #[allow(deprecated, deprecated_in_future)]
 pub use core::usize;