Add test for inplace collection of Result<Vec<_>,_>

Author: SkiFire13

library/core/tests/iter/mod.rs

@@ -100,3 +100,29 @@ pub fn extend_for_unit() {
     }
     assert_eq!(x, 5);
 }
+
+#[test]
+pub fn inplace_result_collect() {
+    let src = vec![0usize; 256];
+    let srcptr = src.as_ptr();
+    let sink = src.into_iter().map(|i| Ok(i)).collect::<Result<Vec<_>, ()>>().unwrap();
+    let sinkptr = sink.as_ptr();
+    assert_eq!(srcptr, sinkptr);
+
+    let src: Vec<usize> = vec![0usize; 256];
+    let srcptr = src.as_ptr();
+    let iter = src
+        .into_iter()
+        .enumerate()
+        .map(|i| i.0 + i.1)
+        .zip(std::iter::repeat(1usize))
+        .map(|(a, b)| a + b)
+        .map_while(Option::Some)
+        .peekable()
+        .skip(1)
+        .map(|e| std::num::NonZeroUsize::new(e))
+        .map(|z| z.map(|u| u.get()).ok_or(()));
+    let sink = iter.collect::<Result<Vec<_>, _>>().unwrap();
+    let sinkptr = sink.as_ptr();
+    assert_eq!(srcptr, sinkptr as *const usize);
+}