Rollup merge of rust-lang#72938 - lzutao:stabilize_option_zip, r=dtolnay

Stabilize Option::zip

This PR stabilizes the following API:

```rust
impl<T> Option<T> {
    pub fn zip<U>(self, other: Option<U>) -> Option<(T, U)>;
}
```

This API has real world usage as seen in <https://grep.app/search?q=-%3E%20Option%3C%5C%28T%2C%5Cs%3FU%5C%29%3E&regexp=true&filter[lang][0]=Rust>.

The `zip_with` method is left unstably as this API is kinda niche
and it hasn't received much usage in Rust repositories on GitHub.

cc rust-lang#70086

Author: RalfJung

src/libcore/lib.rs

@@ -145,7 +145,6 @@
 #![feature(associated_type_bounds)]
 #![feature(const_type_id)]
 #![feature(const_caller_location)]
-#![feature(option_zip)]
 #![feature(no_niche)] // rust-lang/rust#68303
 
 #[prelude_import]

src/libcore/option.rs

@@ -926,17 +926,19 @@ impl<T> Option<T> {
     /// # Examples
     ///
     /// ```
-    /// #![feature(option_zip)]
     /// let x = Some(1);
     /// let y = Some("hi");
     /// let z = None::<u8>;
     ///
     /// assert_eq!(x.zip(y), Some((1, "hi")));
     /// assert_eq!(x.zip(z), None);
     /// ```
-    #[unstable(feature = "option_zip", issue = "70086")]
+    #[stable(feature = "option_zip_option", since = "1.46.0")]
     pub fn zip<U>(self, other: Option<U>) -> Option<(T, U)> {
-        self.zip_with(other, |a, b| (a, b))
+        match (self, other) {
+            (Some(a), Some(b)) => Some((a, b)),
+            _ => None,
+        }
     }
 
     /// Zips `self` and another `Option` with function `f`.

src/librustc_trait_selection/lib.rs

@@ -16,7 +16,6 @@
 #![feature(in_band_lifetimes)]
 #![feature(crate_visibility_modifier)]
 #![feature(or_patterns)]
-#![feature(option_zip)]
 #![recursion_limit = "512"] // For rustdoc
 
 #[macro_use]

src/tools/clippy/clippy_lints/src/checked_conversions.rs

@@ -88,7 +88,7 @@ fn double_check<'a>(cx: &LateContext<'_, '_>, left: &'a Expr<'_>, right: &'a Exp
         let upper = check_upper_bound(l);
         let lower = check_lower_bound(r);
 
-        transpose(upper, lower).and_then(|(l, r)| l.combine(r, cx))
+        upper.zip(lower).and_then(|(l, r)| l.combine(r, cx))
     };
 
     upper_lower(left, right).or_else(|| upper_lower(right, left))
@@ -131,7 +131,10 @@ impl<'a> Conversion<'a> {
 
     /// Checks if the to-type is the same (if there is a type constraint)
     fn has_compatible_to_type(&self, other: &Self) -> bool {
-        transpose(self.to_type.as_ref(), other.to_type.as_ref()).map_or(true, |(l, r)| l == r)
+        match (self.to_type, other.to_type) {
+            (Some(l), Some(r)) => l == r,
+            _ => true,
+        }
     }
 
     /// Try to construct a new conversion if the conversion type is valid
@@ -322,14 +325,6 @@ fn int_ty_to_sym<'tcx>(path: &QPath<'_>) -> Option<&'tcx str> {
     }
 }
 
-/// (Option<T>, Option<U>) -> Option<(T, U)>
-fn transpose<T, U>(lhs: Option<T>, rhs: Option<U>) -> Option<(T, U)> {
-    match (lhs, rhs) {
-        (Some(l), Some(r)) => Some((l, r)),
-        _ => None,
-    }
-}
-
 /// Will return the expressions as if they were expr1 <= expr2
 fn normalize_le_ge<'a>(op: &BinOp, left: &'a Expr<'a>, right: &'a Expr<'a>) -> Option<(&'a Expr<'a>, &'a Expr<'a>)> {
     match op.node {