Three-way diff is (probably) what you want. E.g. Intellij Idea uses it by default, and likely plenty of other IDEs and editors do too. You see original code, y

Three-way diff is (probably) what you want. E.g. Intellij Idea uses it by default, and likely plenty of other IDEs and editors do too. You see original code, you changes, and the other side's changes—and where exactly they conflict.