fix slice of slice with sentinel on the lhs slice

example:
```zig
test {
    var foo: [2:0]u8 = .{ 1, 2 };
    _ = foo[0.. :1][0..2];
}
```

A `.slice_open` ast node will not have a end index nor sentinel.

1 files changed, 17 insertions, 0 deletions

diff --git a/test/behavior/slice.zig b/test/behavior/slice.zig
index 7c03bb8a20..52680b87f3 100644
--- a/test/behavior/slice.zig
+++ b/test/behavior/slice.zig
@@ -115,6 +115,23 @@ test "open slice of open slice with sentinel" {
     try expect(slice[1..][0.. :0][4] == 0);
 }
 
+test "open slice with sentinel of slice with end index" {
+    if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest; // TODO
+
+    var slice: [:0]const u8 = "hello";
+    _ = &slice;
+
+    comptime assert(@TypeOf(slice[0.. :0][0..5]) == *const [5]u8);
+    try expect(slice[0.. :0][0..5].len == 5);
+    try expect(slice[0.. :0][0..5][0] == 'h');
+    try expect(slice[0.. :0][0..5][4] == 'o');
+
+    comptime assert(@TypeOf(slice[0.. :0][0..5 :0]) == *const [5:0]u8);
+    try expect(slice[0.. :0][0..5 :0].len == 5);
+    try expect(slice[0.. :0][0..5 :0][0] == 'h');
+    try expect(slice[0.. :0][0..5 :0][5] == 0);
+}
+
 test "slice of type" {
     comptime {
         var types_array = [_]type{ i32, f64, type };