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+# Generate server_gen.go
+
+`helper` generates the file `../server_gen.go` (in package
+`internal/lsp`) which contains stub declarations of server methods.
+
+To invoke it, run `go generate` in the `gopls/internal/lsp` directory.
+
+It is derived from `gopls/internal/lsp/protocol/tsserver.go`, which
+itself is generated from the protocol downloaded from VSCode, so be
+sure to run `go generate` in the protocol first. Or run `go generate
+./...` twice in the gopls directory.
+
+It decides what stubs are needed and their signatures
+by looking at the `Server` interface (`-t` flag). These all look somewhat like
+`Resolve(context.Context, *CompletionItem) (*CompletionItem, error)`.
+
+It then parses the `lsp` directory (`-u` flag) to see if there is a corresponding
+implementation function (which in this case would be named `resolve`). If so
+it discovers the parameter names needed, and generates (in `server_gen.go`) code
+like
+
+``` go
+func (s *Server) resolve(ctx context.Context, params *protocol.CompletionItem) (*protocol.CompletionItem, error) {
+    return s.resolve(ctx, params)
+}
+```
+
+If `resolve` is not defined (and it is not), then the body of the generated function is
+
+```go
+    return nil, notImplemented("resolve")
+```
+
+So to add a capability currently not implemented, just define it somewhere in `lsp`.
+In this case, just define `func (s *Server) resolve(...)` and re-generate `server_gen.go`.