Merging upstream version 1.68.2+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 36 insertions, 0 deletions

diff --git a/tests/ui/issues/issue-29746.rs b/tests/ui/issues/issue-29746.rs
new file mode 100644
index 000000000..3470a7e09
--- /dev/null
+++ b/tests/ui/issues/issue-29746.rs
@@ -0,0 +1,36 @@
+// run-pass
+// zip!(a1,a2,a3,a4) is equivalent to:
+//  a1.zip(a2).zip(a3).zip(a4).map(|(((x1,x2),x3),x4)| (x1,x2,x3,x4))
+macro_rules! zip {
+    // Entry point
+    ([$a:expr, $b:expr, $($rest:expr),*]) => {
+        zip!([$($rest),*], $a.zip($b), (x,y), [x,y])
+    };
+
+    // Intermediate steps to build the zipped expression, the match pattern
+    //  and the output tuple of the closure, using macro hygiene to repeatedly
+    //  introduce new variables named 'x'.
+    ([$a:expr, $($rest:expr),*], $zip:expr, $pat:pat, [$($flat:expr),*]) => {
+        zip!([$($rest),*], $zip.zip($a), ($pat,x), [$($flat),*, x])
+    };
+
+    // Final step
+    ([], $zip:expr, $pat:pat, [$($flat:expr),+]) => {
+        $zip.map(|$pat| ($($flat),+))
+    };
+
+    // Comma
+    ([$a:expr], $zip:expr, $pat:pat, [$($flat:expr),*]) => {
+        zip!([$a,], $zip, $pat, [$($flat),*])
+    };
+}
+
+fn main() {
+    let p1 = vec![1i32,    2].into_iter();
+    let p2 = vec!["10",    "20"].into_iter();
+    let p3 = vec![100u16,  200].into_iter();
+    let p4 = vec![1000i64, 2000].into_iter();
+
+    let e = zip!([p1,p2,p3,p4]).collect::<Vec<_>>();
+    assert_eq!(e[0], (1i32,"10",100u16,1000i64));
+}