Sort tests.

test/libsolidity/semanticTests/structs/struct_copy.sol

@@ -0,0 +1,48 @@
+contract c {
+    struct Nested {
+        uint256 x;
+        uint256 y;
+    }
+    struct Struct {
+        uint256 a;
+        mapping(uint256 => Struct) b;
+        Nested nested;
+        uint256 c;
+    }
+    mapping(uint256 => Struct) data;
+
+    function set(uint256 k) public returns (bool) {
+        data[k].a = 1;
+        data[k].nested.x = 3;
+        data[k].nested.y = 4;
+        data[k].c = 2;
+        return true;
+    }
+
+    function copy(uint256 from, uint256 to) public returns (bool) {
+        data[to] = data[from];
+        return true;
+    }
+
+    function retrieve(uint256 k)
+        public
+        returns (uint256 a, uint256 x, uint256 y, uint256 c)
+    {
+        a = data[k].a;
+        x = data[k].nested.x;
+        y = data[k].nested.y;
+        c = data[k].c;
+    }
+}
+
+// ----
+// set(uint256): 7 -> true
+// retrieve(uint256): 7 -> 1, 3, 4, 2
+// copy(uint256,uint256): 7, 8 -> true
+// retrieve(uint256): 7 -> 1, 3, 4, 2
+// retrieve(uint256): 8 -> 1, 3, 4, 2
+// copy(uint256,uint256): 0, 7 -> true
+// retrieve(uint256): 7 -> 0, 0, 0, 0
+// retrieve(uint256): 8 -> 1, 3, 4, 2
+// copy(uint256,uint256): 7, 8 -> true
+// retrieve(uint256): 8 -> 0, 0, 0, 0