I'm a bit skeptical because real source can be quite messy. Parsing C source code works because there are neither comments nor preprocessor directives to consider. You have clean input which you can map into an AST using well-defined rules. But source code you edit contain both comments and preprocessor directives. So a parser for structured editing has to acknowledge their existance and can't just ignore them, unlike a parser for a compiler. And that is hard because preprocessor directives and comments can show up almost anywhere. While comments are "mute", directives affect parsing:

    #define FOO }
    int main() {
    FOO

"No one writes code like that!" Actually, they do, and mature C code-bases are full of such preprocessing magic.