[skybrian]

I'm not sure what you mean by "semantic/type binds", but if you're writing a plugin, IDE's like Eclipse and IDEA do give you access to program syntax via a Java API, and for many languages there is also type-aware indexing. Typically this is exposed to the user as specific queries (such as "go to definition" or "find all usages") and updates ("rename method"). From a UI perspective, more features can be added by writing more plugins and/or improving them.

But this indexing is only on one user's workstation and tends not to scale up well. Updating dependencies or switching to a different branch means rebuilding large parts of the index.

Also, part of the problem is that there is little standardization. Many ecosystems are language, platform, build tool, and/or editor-specific. When you do something new you end up reinventing the wheel.