* code completion (with both signature help and snippets)
* definition/references, and other cross references
* cross reference extensions: $ccls/call $ccls/inheritance $ccls/member $ccls/vars ...
* formatting
* hierarchies: call (caller/callee) hierarchy, inheritance (base/derived) hierarchy, member hierarchy
* symbol rename
* document symbols and approximate search of workspace symbol
* hover information
* diagnostics and code actions (clang FixIts)
* semantic highlighting and preprocessor skipped regions
* semantic navigation: $ccls/navigate