6 files changed, 88 insertions, 84 deletions

diff --git a/crates/ra_lsp_server/src/cargo_target_spec.rs b/crates/ra_lsp_server/src/cargo_target_spec.rs
index cdf2ec10b..742361155 100644
--- a/crates/ra_lsp_server/src/cargo_target_spec.rs
+++ b/crates/ra_lsp_server/src/cargo_target_spec.rs
@@ -1,13 +1,13 @@
 use crate::{
     project_model::{self, TargetKind},
-    server_world::ServerWorld,
+    world::WorldSnapshot,
     Result
 };
 
 use ra_ide_api::{FileId, RunnableKind};
 
 pub(crate) fn runnable_args(
-    world: &ServerWorld,
+    world: &WorldSnapshot,
     file_id: FileId,
     kind: &RunnableKind,
 ) -> Result<Vec<String>> {
@@ -58,7 +58,7 @@ pub struct CargoTargetSpec {
 }
 
 impl CargoTargetSpec {
-    pub fn for_file(world: &ServerWorld, file_id: FileId) -> Result<Option<CargoTargetSpec>> {
+    pub fn for_file(world: &WorldSnapshot, file_id: FileId) -> Result<Option<CargoTargetSpec>> {
         let &crate_id = match world.analysis().crate_for(file_id)?.first() {
             Some(crate_id) => crate_id,
             None => return Ok(None),
diff --git a/crates/ra_lsp_server/src/conv.rs b/crates/ra_lsp_server/src/conv.rs
index 1b349d02a..88d29b256 100644
--- a/crates/ra_lsp_server/src/conv.rs
+++ b/crates/ra_lsp_server/src/conv.rs
@@ -12,7 +12,7 @@ use ra_ide_api::{
 use ra_syntax::{SyntaxKind, TextRange, TextUnit};
 use ra_text_edit::{AtomTextEdit, TextEdit};
 
-use crate::{req, server_world::ServerWorld, Result};
+use crate::{req, world::WorldSnapshot, Result};
 
 pub trait Conv {
     type Output;
@@ -228,49 +228,49 @@ impl<T: ConvWith> ConvWith for Option<T> {
 }
 
 impl<'a> TryConvWith for &'a Url {
-    type Ctx = ServerWorld;
+    type Ctx = WorldSnapshot;
     type Output = FileId;
-    fn try_conv_with(self, world: &ServerWorld) -> Result<FileId> {
+    fn try_conv_with(self, world: &WorldSnapshot) -> Result<FileId> {
         world.uri_to_file_id(self)
     }
 }
 
 impl TryConvWith for FileId {
-    type Ctx = ServerWorld;
+    type Ctx = WorldSnapshot;
     type Output = Url;
-    fn try_conv_with(self, world: &ServerWorld) -> Result<Url> {
+    fn try_conv_with(self, world: &WorldSnapshot) -> Result<Url> {
         world.file_id_to_uri(self)
     }
 }
 
 impl<'a> TryConvWith for &'a TextDocumentItem {
-    type Ctx = ServerWorld;
+    type Ctx = WorldSnapshot;
     type Output = FileId;
-    fn try_conv_with(self, world: &ServerWorld) -> Result<FileId> {
+    fn try_conv_with(self, world: &WorldSnapshot) -> Result<FileId> {
         self.uri.try_conv_with(world)
     }
 }
 
 impl<'a> TryConvWith for &'a VersionedTextDocumentIdentifier {
-    type Ctx = ServerWorld;
+    type Ctx = WorldSnapshot;
     type Output = FileId;
-    fn try_conv_with(self, world: &ServerWorld) -> Result<FileId> {
+    fn try_conv_with(self, world: &WorldSnapshot) -> Result<FileId> {
         self.uri.try_conv_with(world)
     }
 }
 
 impl<'a> TryConvWith for &'a TextDocumentIdentifier {
-    type Ctx = ServerWorld;
+    type Ctx = WorldSnapshot;
     type Output = FileId;
-    fn try_conv_with(self, world: &ServerWorld) -> Result<FileId> {
+    fn try_conv_with(self, world: &WorldSnapshot) -> Result<FileId> {
         world.uri_to_file_id(&self.uri)
     }
 }
 
 impl<'a> TryConvWith for &'a TextDocumentPositionParams {
-    type Ctx = ServerWorld;
+    type Ctx = WorldSnapshot;
     type Output = FilePosition;
-    fn try_conv_with(self, world: &ServerWorld) -> Result<FilePosition> {
+    fn try_conv_with(self, world: &WorldSnapshot) -> Result<FilePosition> {
         let file_id = self.text_document.try_conv_with(world)?;
         let line_index = world.analysis().file_line_index(file_id);
         let offset = self.position.conv_with(&line_index);
@@ -279,9 +279,9 @@ impl<'a> TryConvWith for &'a TextDocumentPositionParams {
 }
 
 impl<'a> TryConvWith for (&'a TextDocumentIdentifier, Range) {
-    type Ctx = ServerWorld;
+    type Ctx = WorldSnapshot;
     type Output = FileRange;
-    fn try_conv_with(self, world: &ServerWorld) -> Result<FileRange> {
+    fn try_conv_with(self, world: &WorldSnapshot) -> Result<FileRange> {
         let file_id = self.0.try_conv_with(world)?;
         let line_index = world.analysis().file_line_index(file_id);
         let range = self.1.conv_with(&line_index);
@@ -302,9 +302,9 @@ impl<T: TryConvWith> TryConvWith for Vec<T> {
 }
 
 impl TryConvWith for SourceChange {
-    type Ctx = ServerWorld;
+    type Ctx = WorldSnapshot;
     type Output = req::SourceChange;
-    fn try_conv_with(self, world: &ServerWorld) -> Result<req::SourceChange> {
+    fn try_conv_with(self, world: &WorldSnapshot) -> Result<req::SourceChange> {
         let cursor_position = match self.cursor_position {
             None => None,
             Some(pos) => {
@@ -342,9 +342,9 @@ impl TryConvWith for SourceChange {
 }
 
 impl TryConvWith for SourceFileEdit {
-    type Ctx = ServerWorld;
+    type Ctx = WorldSnapshot;
     type Output = TextDocumentEdit;
-    fn try_conv_with(self, world: &ServerWorld) -> Result<TextDocumentEdit> {
+    fn try_conv_with(self, world: &WorldSnapshot) -> Result<TextDocumentEdit> {
         let text_document = VersionedTextDocumentIdentifier {
             uri: self.file_id.try_conv_with(world)?,
             version: None,
@@ -356,9 +356,9 @@ impl TryConvWith for SourceFileEdit {
 }
 
 impl TryConvWith for FileSystemEdit {
-    type Ctx = ServerWorld;
+    type Ctx = WorldSnapshot;
     type Output = ResourceOp;
-    fn try_conv_with(self, world: &ServerWorld) -> Result<ResourceOp> {
+    fn try_conv_with(self, world: &WorldSnapshot) -> Result<ResourceOp> {
         let res = match self {
             FileSystemEdit::CreateFile { source_root, path } => {
                 let uri = world.path_to_uri(source_root, &path)?;
@@ -375,9 +375,9 @@ impl TryConvWith for FileSystemEdit {
 }
 
 impl TryConvWith for &NavigationTarget {
-    type Ctx = ServerWorld;
+    type Ctx = WorldSnapshot;
     type Output = Location;
-    fn try_conv_with(self, world: &ServerWorld) -> Result<Location> {
+    fn try_conv_with(self, world: &WorldSnapshot) -> Result<Location> {
         let line_index = world.analysis().file_line_index(self.file_id());
         let range = self.range();
         to_location(self.file_id(), range, &world, &line_index)
@@ -386,7 +386,7 @@ impl TryConvWith for &NavigationTarget {
 
 pub fn to_location_link(
     target: &RangeInfo<NavigationTarget>,
-    world: &ServerWorld,
+    world: &WorldSnapshot,
     // line index for original range file
     line_index: &LineIndex,
 ) -> Result<LocationLink> {
@@ -410,7 +410,7 @@ pub fn to_location_link(
 pub fn to_location(
     file_id: FileId,
     range: TextRange,
-    world: &ServerWorld,
+    world: &WorldSnapshot,
     line_index: &LineIndex,
 ) -> Result<Location> {
     let url = file_id.try_conv_with(world)?;
diff --git a/crates/ra_lsp_server/src/lib.rs b/crates/ra_lsp_server/src/lib.rs
index 113883bdd..aabde420b 100644
--- a/crates/ra_lsp_server/src/lib.rs
+++ b/crates/ra_lsp_server/src/lib.rs
@@ -7,7 +7,7 @@ mod project_model;
 mod vfs_filter;
 pub mod req;
 pub mod init;
-mod server_world;
+mod world;
 
 pub type Result<T> = ::std::result::Result<T, ::failure::Error>;
 pub use crate::{caps::server_capabilities, main_loop::main_loop, main_loop::LspError, init::InitializationOptions};
diff --git a/crates/ra_lsp_server/src/main_loop.rs b/crates/ra_lsp_server/src/main_loop.rs
index 452499497..6080a3a4e 100644
--- a/crates/ra_lsp_server/src/main_loop.rs
+++ b/crates/ra_lsp_server/src/main_loop.rs
@@ -24,7 +24,7 @@ use crate::{
     },
     project_model::workspace_loader,
     req,
-    server_world::{ServerWorld, ServerWorldState},
+    world::{WorldSnapshot, WorldState},
     Result,
     InitializationOptions,
 };
@@ -73,12 +73,11 @@ pub fn main_loop(
         loaded_workspaces
     };
 
-    let mut state = ServerWorldState::new(ws_roots, workspaces);
+    let mut state = WorldState::new(ws_roots, workspaces);
 
     let pool = ThreadPool::new(THREADPOOL_SIZE);
     let (task_sender, task_receiver) = unbounded::<Task>();
     let mut pending_requests = PendingRequests::default();
-    let mut subs = Subscriptions::default();
 
     log::info!("server initialized, serving requests");
     let main_res = main_loop_inner(
@@ -90,7 +89,6 @@ pub fn main_loop(
         task_receiver.clone(),
         &mut state,
         &mut pending_requests,
-        &mut subs,
     );
 
     log::info!("waiting for tasks to finish...");
@@ -163,10 +161,10 @@ fn main_loop_inner(
     msg_receiver: &Receiver<RawMessage>,
     task_sender: Sender<Task>,
     task_receiver: Receiver<Task>,
-    state: &mut ServerWorldState,
+    state: &mut WorldState,
     pending_requests: &mut PendingRequests,
-    subs: &mut Subscriptions,
 ) -> Result<()> {
+    let mut subs = Subscriptions::default();
     // We try not to index more than MAX_IN_FLIGHT_LIBS libraries at the same
     // time to always have a thread ready to react to input.
     let mut in_flight_libraries = 0;
@@ -230,7 +228,7 @@ fn main_loop_inner(
                     )?
                 }
                 RawMessage::Notification(not) => {
-                    on_notification(msg_sender, state, pending_requests, subs, not)?;
+                    on_notification(msg_sender, state, pending_requests, &mut subs, not)?;
                     state_changed = true;
                 }
                 RawMessage::Response(resp) => log::error!("unexpected response: {:?}", resp),
@@ -280,7 +278,7 @@ fn on_task(
     task: Task,
     msg_sender: &Sender<RawMessage>,
     pending_requests: &mut PendingRequests,
-    state: &mut ServerWorldState,
+    state: &mut WorldState,
 ) {
     match task {
         Task::Respond(response) => {
@@ -297,7 +295,7 @@ fn on_task(
 }
 
 fn on_request(
-    world: &mut ServerWorldState,
+    world: &mut WorldState,
     pending_requests: &mut PendingRequests,
     pool: &ThreadPool,
     sender: &Sender<Task>,
@@ -354,7 +352,7 @@ fn on_request(
 
 fn on_notification(
     msg_sender: &Sender<RawMessage>,
-    state: &mut ServerWorldState,
+    state: &mut WorldState,
     pending_requests: &mut PendingRequests,
     subs: &mut Subscriptions,
     not: RawNotification,
@@ -424,7 +422,7 @@ fn on_notification(
 struct PoolDispatcher<'a> {
     req: Option<RawRequest>,
     pool: &'a ThreadPool,
-    world: &'a mut ServerWorldState,
+    world: &'a mut WorldState,
     pending_requests: &'a mut PendingRequests,
     msg_sender: &'a Sender<RawMessage>,
     sender: &'a Sender<Task>,
@@ -435,7 +433,7 @@ impl<'a> PoolDispatcher<'a> {
     /// Dispatches the request onto the current thread
     fn on_sync<R>(
         &mut self,
-        f: fn(&mut ServerWorldState, R::Params) -> Result<R::Result>,
+        f: fn(&mut WorldState, R::Params) -> Result<R::Result>,
     ) -> Result<&mut Self>
     where
         R: req::Request + 'static,
@@ -455,7 +453,7 @@ impl<'a> PoolDispatcher<'a> {
     }
 
     /// Dispatches the request onto thread pool
-    fn on<R>(&mut self, f: fn(ServerWorld, R::Params) -> Result<R::Result>) -> Result<&mut Self>
+    fn on<R>(&mut self, f: fn(WorldSnapshot, R::Params) -> Result<R::Result>) -> Result<&mut Self>
     where
         R: req::Request + 'static,
         R::Params: DeserializeOwned + Send + 'static,
@@ -559,7 +557,7 @@ where
 
 fn update_file_notifications_on_threadpool(
     pool: &ThreadPool,
-    world: ServerWorld,
+    world: WorldSnapshot,
     publish_decorations: bool,
     sender: Sender<Task>,
     subscriptions: Vec<FileId>,
diff --git a/crates/ra_lsp_server/src/main_loop/handlers.rs b/crates/ra_lsp_server/src/main_loop/handlers.rs
index 8cfb6a192..6373240d5 100644
--- a/crates/ra_lsp_server/src/main_loop/handlers.rs
+++ b/crates/ra_lsp_server/src/main_loop/handlers.rs
@@ -24,11 +24,11 @@ use crate::{
     cargo_target_spec::{runnable_args, CargoTargetSpec},
     conv::{to_location, to_location_link, Conv, ConvWith, MapConvWith, TryConvWith},
     req::{self, Decoration},
-    server_world::ServerWorld,
+    world::WorldSnapshot,
     LspError, Result,
 };
 
-pub fn handle_analyzer_status(world: ServerWorld, _: ()) -> Result<String> {
+pub fn handle_analyzer_status(world: WorldSnapshot, _: ()) -> Result<String> {
     let mut buf = world.status();
     writeln!(buf, "\n\nrequests:").unwrap();
     let requests = world.latest_requests.read();
@@ -39,7 +39,7 @@ pub fn handle_analyzer_status(world: ServerWorld, _: ()) -> Result<String> {
     Ok(buf)
 }
 
-pub fn handle_syntax_tree(world: ServerWorld, params: req::SyntaxTreeParams) -> Result<String> {
+pub fn handle_syntax_tree(world: WorldSnapshot, params: req::SyntaxTreeParams) -> Result<String> {
     let id = params.text_document.try_conv_with(&world)?;
     let line_index = world.analysis().file_line_index(id);
     let text_range = params.range.map(|p| p.conv_with(&line_index));
@@ -49,7 +49,7 @@ pub fn handle_syntax_tree(world: ServerWorld, params: req::SyntaxTreeParams) ->
 
 // FIXME: drop this API
 pub fn handle_extend_selection(
-    world: ServerWorld,
+    world: WorldSnapshot,
     params: req::ExtendSelectionParams,
 ) -> Result<req::ExtendSelectionResult> {
     log::error!(
@@ -69,7 +69,7 @@ pub fn handle_extend_selection(
 }
 
 pub fn handle_selection_range(
-    world: ServerWorld,
+    world: WorldSnapshot,
     params: req::SelectionRangeParams,
 ) -> Result<Vec<req::SelectionRange>> {
     let _p = profile("handle_selection_range");
@@ -110,7 +110,7 @@ pub fn handle_selection_range(
 }
 
 pub fn handle_find_matching_brace(
-    world: ServerWorld,
+    world: WorldSnapshot,
     params: req::FindMatchingBraceParams,
 ) -> Result<Vec<Position>> {
     let _p = profile("handle_find_matching_brace");
@@ -129,7 +129,7 @@ pub fn handle_find_matching_brace(
 }
 
 pub fn handle_join_lines(
-    world: ServerWorld,
+    world: WorldSnapshot,
     params: req::JoinLinesParams,
 ) -> Result<req::SourceChange> {
     let _p = profile("handle_join_lines");
@@ -138,7 +138,7 @@ pub fn handle_join_lines(
 }
 
 pub fn handle_on_enter(
-    world: ServerWorld,
+    world: WorldSnapshot,
     params: req::TextDocumentPositionParams,
 ) -> Result<Option<req::SourceChange>> {
     let _p = profile("handle_on_enter");
@@ -150,7 +150,7 @@ pub fn handle_on_enter(
 }
 
 pub fn handle_on_type_formatting(
-    world: ServerWorld,
+    world: WorldSnapshot,
     params: req::DocumentOnTypeFormattingParams,
 ) -> Result<Option<Vec<TextEdit>>> {
     let _p = profile("handle_on_type_formatting");
@@ -181,7 +181,7 @@ pub fn handle_on_type_formatting(
 }
 
 pub fn handle_document_symbol(
-    world: ServerWorld,
+    world: WorldSnapshot,
     params: req::DocumentSymbolParams,
 ) -> Result<Option<req::DocumentSymbolResponse>> {
     let file_id = params.text_document.try_conv_with(&world)?;
@@ -219,7 +219,7 @@ pub fn handle_document_symbol(
 }
 
 pub fn handle_workspace_symbol(
-    world: ServerWorld,
+    world: WorldSnapshot,
     params: req::WorkspaceSymbolParams,
 ) -> Result<Option<Vec<SymbolInformation>>> {
     let all_symbols = params.query.contains('#');
@@ -245,7 +245,7 @@ pub fn handle_workspace_symbol(
 
     return Ok(Some(res));
 
-    fn exec_query(world: &ServerWorld, query: Query) -> Result<Vec<SymbolInformation>> {
+    fn exec_query(world: &WorldSnapshot, query: Query) -> Result<Vec<SymbolInformation>> {
         let mut res = Vec::new();
         for nav in world.analysis().symbol_search(query)? {
             let info = SymbolInformation {
@@ -262,7 +262,7 @@ pub fn handle_workspace_symbol(
 }
 
 pub fn handle_goto_definition(
-    world: ServerWorld,
+    world: WorldSnapshot,
     params: req::TextDocumentPositionParams,
 ) -> Result<Option<req::GotoDefinitionResponse>> {
     let position = params.try_conv_with(&world)?;
@@ -282,7 +282,7 @@ pub fn handle_goto_definition(
 }
 
 pub fn handle_goto_implementation(
-    world: ServerWorld,
+    world: WorldSnapshot,
     params: req::TextDocumentPositionParams,
 ) -> Result<Option<req::GotoImplementationResponse>> {
     let position = params.try_conv_with(&world)?;
@@ -302,7 +302,7 @@ pub fn handle_goto_implementation(
 }
 
 pub fn handle_goto_type_definition(
-    world: ServerWorld,
+    world: WorldSnapshot,
     params: req::TextDocumentPositionParams,
 ) -> Result<Option<req::GotoTypeDefinitionResponse>> {
     let position = params.try_conv_with(&world)?;
@@ -322,7 +322,7 @@ pub fn handle_goto_type_definition(
 }
 
 pub fn handle_parent_module(
-    world: ServerWorld,
+    world: WorldSnapshot,
     params: req::TextDocumentPositionParams,
 ) -> Result<Vec<Location>> {
     let position = params.try_conv_with(&world)?;
@@ -335,7 +335,7 @@ pub fn handle_parent_module(
 }
 
 pub fn handle_runnables(
-    world: ServerWorld,
+    world: WorldSnapshot,
     params: req::RunnablesParams,
 ) -> Result<Vec<req::Runnable>> {
     let file_id = params.text_document.try_conv_with(&world)?;
@@ -396,7 +396,7 @@ pub fn handle_runnables(
 }
 
 pub fn handle_decorations(
-    world: ServerWorld,
+    world: WorldSnapshot,
     params: TextDocumentIdentifier,
 ) -> Result<Vec<Decoration>> {
     let file_id = params.try_conv_with(&world)?;
@@ -404,7 +404,7 @@ pub fn handle_decorations(
 }
 
 pub fn handle_completion(
-    world: ServerWorld,
+    world: WorldSnapshot,
     params: req::CompletionParams,
 ) -> Result<Option<req::CompletionResponse>> {
     let _p = profile("handle_completion");
@@ -447,7 +447,7 @@ pub fn handle_completion(
 }
 
 pub fn handle_folding_range(
-    world: ServerWorld,
+    world: WorldSnapshot,
     params: FoldingRangeParams,
 ) -> Result<Option<Vec<FoldingRange>>> {
     let file_id = params.text_document.try_conv_with(&world)?;
@@ -481,7 +481,7 @@ pub fn handle_folding_range(
 }
 
 pub fn handle_signature_help(
-    world: ServerWorld,
+    world: WorldSnapshot,
     params: req::TextDocumentPositionParams,
 ) -> Result<Option<req::SignatureHelp>> {
     let position = params.try_conv_with(&world)?;
@@ -500,7 +500,7 @@ pub fn handle_signature_help(
 }
 
 pub fn handle_hover(
-    world: ServerWorld,
+    world: WorldSnapshot,
     params: req::TextDocumentPositionParams,
 ) -> Result<Option<Hover>> {
     let position = params.try_conv_with(&world)?;
@@ -522,7 +522,7 @@ pub fn handle_hover(
 
 /// Test doc comment
 pub fn handle_prepare_rename(
-    world: ServerWorld,
+    world: WorldSnapshot,
     params: req::TextDocumentPositionParams,
 ) -> Result<Option<PrepareRenameResponse>> {
     let position = params.try_conv_with(&world)?;
@@ -543,7 +543,7 @@ pub fn handle_prepare_rename(
     Ok(Some(PrepareRenameResponse::Range(loc.range)))
 }
 
-pub fn handle_rename(world: ServerWorld, params: RenameParams) -> Result<Option<WorkspaceEdit>> {
+pub fn handle_rename(world: WorldSnapshot, params: RenameParams) -> Result<Option<WorkspaceEdit>> {
     let file_id = params.text_document.try_conv_with(&world)?;
     let line_index = world.analysis().file_line_index(file_id);
     let offset = params.position.conv_with(&line_index);
@@ -569,7 +569,7 @@ pub fn handle_rename(world: ServerWorld, params: RenameParams) -> Result<Option<
 }
 
 pub fn handle_references(
-    world: ServerWorld,
+    world: WorldSnapshot,
     params: req::ReferenceParams,
 ) -> Result<Option<Vec<Location>>> {
     let file_id = params.text_document.try_conv_with(&world)?;
@@ -597,7 +597,7 @@ pub fn handle_references(
 }
 
 pub fn handle_formatting(
-    world: ServerWorld,
+    world: WorldSnapshot,
     params: DocumentFormattingParams,
 ) -> Result<Option<Vec<TextEdit>>> {
     let file_id = params.text_document.try_conv_with(&world)?;
@@ -641,7 +641,7 @@ pub fn handle_formatting(
 }
 
 pub fn handle_code_action(
-    world: ServerWorld,
+    world: WorldSnapshot,
     params: req::CodeActionParams,
 ) -> Result<Option<CodeActionResponse>> {
     let _p = profile("handle_code_action");
@@ -704,7 +704,7 @@ pub fn handle_code_action(
 }
 
 pub fn handle_code_lens(
-    world: ServerWorld,
+    world: WorldSnapshot,
     params: req::CodeLensParams,
 ) -> Result<Option<Vec<CodeLens>>> {
     let file_id = params.text_document.try_conv_with(&world)?;
@@ -781,7 +781,7 @@ enum CodeLensResolveData {
     Impls(req::TextDocumentPositionParams),
 }
 
-pub fn handle_code_lens_resolve(world: ServerWorld, code_lens: CodeLens) -> Result<CodeLens> {
+pub fn handle_code_lens_resolve(world: WorldSnapshot, code_lens: CodeLens) -> Result<CodeLens> {
     let data = code_lens.data.unwrap();
     let resolve = serde_json::from_value(data)?;
     match resolve {
@@ -826,7 +826,7 @@ pub fn handle_code_lens_resolve(world: ServerWorld, code_lens: CodeLens) -> Resu
 }
 
 pub fn handle_document_highlight(
-    world: ServerWorld,
+    world: WorldSnapshot,
     params: req::TextDocumentPositionParams,
 ) -> Result<Option<Vec<DocumentHighlight>>> {
     let file_id = params.text_document.try_conv_with(&world)?;
@@ -845,7 +845,7 @@ pub fn handle_document_highlight(
 }
 
 pub fn publish_diagnostics(
-    world: &ServerWorld,
+    world: &WorldSnapshot,
     file_id: FileId,
 ) -> Result<req::PublishDiagnosticsParams> {
     let uri = world.file_id_to_uri(file_id)?;
@@ -867,14 +867,14 @@ pub fn publish_diagnostics(
 }
 
 pub fn publish_decorations(
-    world: &ServerWorld,
+    world: &WorldSnapshot,
     file_id: FileId,
 ) -> Result<req::PublishDecorationsParams> {
     let uri = world.file_id_to_uri(file_id)?;
     Ok(req::PublishDecorationsParams { uri, decorations: highlight(&world, file_id)? })
 }
 
-fn highlight(world: &ServerWorld, file_id: FileId) -> Result<Vec<Decoration>> {
+fn highlight(world: &WorldSnapshot, file_id: FileId) -> Result<Vec<Decoration>> {
     let line_index = world.analysis().file_line_index(file_id);
     let res = world
         .analysis()
diff --git a/crates/ra_lsp_server/src/server_world.rs b/crates/ra_lsp_server/src/world.rs
index 6076a6cd6..e0d2f6306 100644
--- a/crates/ra_lsp_server/src/server_world.rs
+++ b/crates/ra_lsp_server/src/world.rs
@@ -22,8 +22,13 @@ use crate::{
     LspError,
 };
 
+/// `WorldState` is the primary mutable state of the language server
+///
+/// The most interesting components are `vfs`, which stores a consistent
+/// snapshot of the file systems, and `analysis_host`, which stores our
+/// incremental salsa database.
 #[derive(Debug)]
-pub struct ServerWorldState {
+pub struct WorldState {
     pub roots_to_scan: usize,
     pub roots: Vec<PathBuf>,
     pub workspaces: Arc<Vec<ProjectWorkspace>>,
@@ -32,15 +37,16 @@ pub struct ServerWorldState {
     pub latest_requests: Arc<RwLock<LatestRequests>>,
 }
 
-pub struct ServerWorld {
+/// An immutable snapshot of the world's state at a point in time.
+pub struct WorldSnapshot {
     pub workspaces: Arc<Vec<ProjectWorkspace>>,
     pub analysis: Analysis,
     pub vfs: Arc<RwLock<Vfs>>,
     pub latest_requests: Arc<RwLock<LatestRequests>>,
 }
 
-impl ServerWorldState {
-    pub fn new(folder_roots: Vec<PathBuf>, workspaces: Vec<ProjectWorkspace>) -> ServerWorldState {
+impl WorldState {
+    pub fn new(folder_roots: Vec<PathBuf>, workspaces: Vec<ProjectWorkspace>) -> WorldState {
         let mut change = AnalysisChange::new();
 
         let mut roots = Vec::new();
@@ -70,7 +76,7 @@ impl ServerWorldState {
 
         let mut analysis_host = AnalysisHost::default();
         analysis_host.apply_change(change);
-        ServerWorldState {
+        WorldState {
             roots_to_scan,
             roots: folder_roots,
             workspaces: Arc::new(workspaces),
@@ -136,8 +142,8 @@ impl ServerWorldState {
         self.analysis_host.apply_change(change);
     }
 
-    pub fn snapshot(&self) -> ServerWorld {
-        ServerWorld {
+    pub fn snapshot(&self) -> WorldSnapshot {
+        WorldSnapshot {
             workspaces: Arc::clone(&self.workspaces),
             analysis: self.analysis_host.analysis(),
             vfs: Arc::clone(&self.vfs),
@@ -158,7 +164,7 @@ impl ServerWorldState {
     }
 }
 
-impl ServerWorld {
+impl WorldSnapshot {
     pub fn analysis(&self) -> &Analysis {
         &self.analysis
     }