fix set within Map child element (#105)

accessors.go

@@ -140,6 +140,10 @@ func access(current interface{}, selector string, value interface{}, isSet bool)
 		}
 
 		_, ok := curMSI[thisSel].(map[string]interface{})
+		if !ok {
+			_, ok = curMSI[thisSel].(Map)
+		}
+
 		if (curMSI[thisSel] == nil || !ok) && len(indexes) == 0 && isSet {
 			curMSI[thisSel] = map[string]interface{}{}
 		}

accessors_test.go

@@ -219,6 +219,26 @@ func TestAccessorsSet(t *testing.T) {
 	assert.Equal(t, "Mat", m.Get("name").Data())
 }
 
+func TestAccessorsSetWithinObjxMapChild(t *testing.T) {
+	m, err := objx.FromJSON(`{"a": {"b": 1}}`)
+	assert.NoError(t, err)
+
+	m.Set("a.c", 2)
+	jsonConverted, err := m.JSON()
+	assert.NoError(t, err)
+
+	m = objx.New(map[string]interface{}{
+		"a": map[string]interface{}{
+			"b": 1,
+		},
+	})
+	m.Set("a.c", 2)
+	jsonNewObj, err := m.JSON()
+
+	assert.NoError(t, err)
+	assert.Equal(t, jsonConverted, jsonNewObj)
+}
+
 func TestAccessorsNested(t *testing.T) {
 	d := objx.MustFromJSON(`{"values":[["test", "test1"], ["test2", {"name":"Mat"}, {"names": ["Captain", "Mat"]}]]}`)