Fix for issue 11888 (#11889)

std/lua/_lua/_hx_bit.lua

@@ -19,3 +19,4 @@ end
 _hx_bit.bor = function(...) return _hx_bit_clamp(_hx_bit_raw.bor(...)) end
 _hx_bit.band = function(...) return _hx_bit_clamp(_hx_bit_raw.band(...)) end
 _hx_bit.arshift = function(...) return _hx_bit_clamp(_hx_bit_raw.arshift(...)) end
+_hx_bit.lshift = function(...) return _hx_bit_clamp(_hx_bit_raw.lshift(...)) end

tests/unit/src/unit/issues/Issue11888.hx

@@ -0,0 +1,11 @@
+package unit.issues;
+
+import haxe.Int64;
+
+class Issue11888 extends unit.Test {
+	public function test() {
+		var n:Int64 = Int64.make(0,-1);
+		var result:Int64 = Int64.shl(n,1);
+		eq(-2, result.low);
+	}
+}