create a drop ladder for an array if any value is moved out

src/test/run-pass/dynamic-drop.rs

@@ -10,7 +10,7 @@
 
 // ignore-wasm32-bare compiled with panic=abort by default
 
-#![feature(generators, generator_trait, untagged_unions)]
+#![feature(generators, generator_trait, untagged_unions, slice_patterns, advanced_slice_patterns)]
 
 use std::cell::{Cell, RefCell};
 use std::ops::Generator;
@@ -195,6 +195,33 @@ fn vec_unreachable(a: &Allocator) {
     let _x = vec![a.alloc(), a.alloc(), a.alloc(), return];
 }
 
+fn slice_pattern_first(a: &Allocator) {
+    let[_x, ..] = [a.alloc(), a.alloc(), a.alloc()];
+}
+
+fn slice_pattern_middle(a: &Allocator) {
+    let[_, _x, _] = [a.alloc(), a.alloc(), a.alloc()];
+}
+
+fn slice_pattern_two(a: &Allocator) {
+    let[_x, _, _y, _] = [a.alloc(), a.alloc(), a.alloc(), a.alloc()];
+}
+
+fn slice_pattern_last(a: &Allocator) {
+    let[.., _y] = [a.alloc(), a.alloc(), a.alloc(), a.alloc()];
+}
+
+fn slice_pattern_one_of(a: &Allocator, i: usize) {
+    let array = [a.alloc(), a.alloc(), a.alloc(), a.alloc()];
+    let _x = match i {
+        0 => { let [a, ..] = array; a }
+        1 => { let [_, a, ..] = array; a }
+        2 => { let [_, _, a, _] = array; a }
+        3 => { let [_, _, _, a] = array; a }
+        _ => panic!("unmatched"),
+    };
+}
+
 fn run_test<F>(mut f: F)
     where F: FnMut(&Allocator)
 {
@@ -264,5 +291,14 @@ fn main() {
 
     run_test(|a| mixed_drop_and_nondrop(a));
 
+    run_test(|a| slice_pattern_first(a));
+    run_test(|a| slice_pattern_middle(a));
+    run_test(|a| slice_pattern_two(a));
+    run_test(|a| slice_pattern_last(a));
+    run_test(|a| slice_pattern_one_of(a, 0));
+    run_test(|a| slice_pattern_one_of(a, 1));
+    run_test(|a| slice_pattern_one_of(a, 2));
+    run_test(|a| slice_pattern_one_of(a, 3));
+
     run_test_nopanic(|a| union1(a));
 }