FWIW Sourcegraph has fully precise/semantic go-to-definition, find-references, etc. We use SCIP code indexers (a spiritual successor to LSIF, the Microsoft standard for indexing LSP servers)
Not for C++. To test my recollection I navigated to abseil-cpp/strings/str_split.h, clicked on the declaration of absl::ByString::Find, and clicked "Go to definition". I was presented with every function in Abseil named "Find" regardless of its scope or parameter types. That's not "precise code intelligence"!
In the top right corner of the tooltip it will say either "Search-based" or "Precise" - in this case, you're right, we don't have the abseil-cpp repo indexed so it falls back to search-based as you describe.
We do have a C++ code indexer in beta, https://github.com/sourcegraph/lsif-clang - it is based on clang but C++ indexing is notably harder to do automatically/without-setup due to the varying build systems that need to be understood in order to invoke the compiler.
As my colleague mentioned in a sibling comment, we have an existing indexer lsif-clang which supports C++. I just added a Chromium example to the lsif-clang README right now: (direct link) https://sourcegraph.com/github.com/chromium/chromium@cab0660...
We are also actively working on a new SCIP indexer which should support features like cross-repo references in the future. https://github.com/sourcegraph/scip-clang
Right now, Abseil doesn't have precise code navigation because no one has uploaded an index for it. In an ideal world, we would automatically have precise indexes for all the C++ code on Sourcegraph, but that's a hard problem because of the large variety in build systems, build configurations, and system dependencies that are often specified outside the build system.
