Auto merge of rust-lang#74956 - ecstatic-morse:const-option-unwrap, r=oli-obk

Make `Option::unwrap` unstably const

This is lumped into the `const_option` feature gate (rust-lang#67441), which enables a potpourri of `Option` methods.

cc @rust-lang/wg-const-eval

r? @oli-obk

Author: bors

core/src/lib.rs

@@ -81,6 +81,7 @@
 #![feature(const_fn_union)]
 #![feature(const_generics)]
 #![feature(const_option)]
+#![feature(const_precise_live_drops)]
 #![feature(const_ptr_offset)]
 #![feature(const_ptr_offset_from)]
 #![feature(const_raw_ptr_comparison)]

core/src/option.rs

@@ -380,7 +380,8 @@ impl<T> Option<T> {
     #[inline]
     #[track_caller]
     #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn unwrap(self) -> T {
+    #[rustc_const_unstable(feature = "const_option", issue = "67441")]
+    pub const fn unwrap(self) -> T {
         match self {
             Some(val) => val,
             None => panic!("called `Option::unwrap()` on a `None` value"),