From 8b2092803e71180cd352f42041bf1725dc4ad1f6 Mon Sep 17 00:00:00 2001
From: Lzu Tao <taolzu@gmail.com>
Date: Sat, 13 Jun 2020 01:27:14 +0000
Subject: [PATCH] Stabilize Option::zip

---
 src/libcore/lib.rs                                |  1 -
 src/libcore/option.rs                             |  8 +++++---
 src/librustc_trait_selection/lib.rs               |  1 -
 .../clippy_lints/src/checked_conversions.rs       | 15 +++++----------
 4 files changed, 10 insertions(+), 15 deletions(-)

diff --git a/src/libcore/lib.rs b/src/libcore/lib.rs
index 7d21f9a9a66d0..fe05e914e6d44 100644
--- a/src/libcore/lib.rs
+++ b/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]
diff --git a/src/libcore/option.rs b/src/libcore/option.rs
index e8483875c97e5..5f0a12678ff43 100644
--- a/src/libcore/option.rs
+++ b/src/libcore/option.rs
@@ -926,7 +926,6 @@ impl<T> Option<T> {
     /// # Examples
     ///
     /// ```
-    /// #![feature(option_zip)]
     /// let x = Some(1);
     /// let y = Some("hi");
     /// let z = None::<u8>;
@@ -934,9 +933,12 @@ impl<T> Option<T> {
     /// 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`.
diff --git a/src/librustc_trait_selection/lib.rs b/src/librustc_trait_selection/lib.rs
index 044239b047a4e..ea886cd1f9e9b 100644
--- a/src/librustc_trait_selection/lib.rs
+++ b/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]
diff --git a/src/tools/clippy/clippy_lints/src/checked_conversions.rs b/src/tools/clippy/clippy_lints/src/checked_conversions.rs
index e845ef99c7cc0..88145015ba8bd 100644
--- a/src/tools/clippy/clippy_lints/src/checked_conversions.rs
+++ b/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 {