use Result::into_ok on infallible result.

library/alloc/src/lib.rs

@@ -160,6 +160,7 @@
 #![feature(tuple_trait)]
 #![feature(unicode_internals)]
 #![feature(unsize)]
+#![feature(unwrap_infallible)]
 #![feature(vec_pop_if)]
 // tidy-alphabetical-end
 //

library/alloc/src/vec/in_place_collect.rs

@@ -374,10 +374,8 @@ impl<T, I> SpecInPlaceCollect<T, I> for I
         // - unlike most internal iteration methods, it only takes a &mut self
         // - it lets us thread the write pointer through its innards and get it back in the end
         let sink = InPlaceDrop { inner: dst_buf, dst: dst_buf };
-        let sink = match self.try_fold::<_, _, Result<_, !>>(sink, write_in_place_with_drop(end)) {
-            Ok(sink) => sink,
-            Err(never) => match never {},
-        };
+        let sink =
+            self.try_fold::<_, _, Result<_, !>>(sink, write_in_place_with_drop(end)).into_ok();
         // iteration succeeded, don't drop head
         unsafe { ManuallyDrop::new(sink).dst.sub_ptr(dst_buf) }
     }