diff --git a/Sources/LanguageServerProtocol/Requests/CodeActionRequest.swift b/Sources/LanguageServerProtocol/Requests/CodeActionRequest.swift
index 205456f0..4a777f62 100644
--- a/Sources/LanguageServerProtocol/Requests/CodeActionRequest.swift
+++ b/Sources/LanguageServerProtocol/Requests/CodeActionRequest.swift
@@ -11,7 +11,7 @@
 //===----------------------------------------------------------------------===//
 
 public typealias CodeActionProviderCompletion = (LSPResult<[CodeAction]>) -> Void
-public typealias CodeActionProvider = (CodeActionRequest, @escaping CodeActionProviderCompletion) async -> Void
+public typealias CodeActionProvider = (CodeActionRequest, @escaping CodeActionProviderCompletion) -> Void
 
 /// Request for returning all possible code actions for a given text document and range.
 ///
diff --git a/Sources/SKCore/BuildServerBuildSystem.swift b/Sources/SKCore/BuildServerBuildSystem.swift
index b9dd23c1..7bbef467 100644
--- a/Sources/SKCore/BuildServerBuildSystem.swift
+++ b/Sources/SKCore/BuildServerBuildSystem.swift
@@ -65,9 +65,6 @@ public final class BuildServerBuildSystem: MessageHandler {
   /// Delegate to handle any build system events.
   public weak var delegate: BuildSystemDelegate?
 
-  /// The build settings that have been received from the build server.
-  private var buildSettings: [DocumentURI: FileBuildSettings] = [:]
-
   public init(projectRoot: AbsolutePath, buildFolder: AbsolutePath?, fileSystem: FileSystem = localFileSystem) throws {
     let configPath = projectRoot.appending(component: "buildServer.json")
     let config = try loadBuildServerConfig(path: configPath, fileSystem: fileSystem)
@@ -198,18 +195,7 @@ public final class BuildServerBuildSystem: MessageHandler {
     let result = notification.params.updatedOptions
     let settings = FileBuildSettings(
         compilerArguments: result.options, workingDirectory: result.workingDirectory)
-    self.buildSettingsChanged(for: notification.params.uri, settings: settings)
-  }
-
-  /// Record the new build settings for the given document and inform the delegate
-  /// about the changed build settings.
-  private func buildSettingsChanged(for document: DocumentURI, settings: FileBuildSettings?) {
-    buildSettings[document] = settings
-    if let settings {
-      self.delegate?.fileBuildSettingsChanged([document: .modified(settings)])
-    } else {
-      self.delegate?.fileBuildSettingsChanged([document: .removedOrUnavailable])
-    }
+    self.delegate?.fileBuildSettingsChanged([notification.params.uri: .modified(settings)])
   }
 }
 
@@ -222,14 +208,19 @@ private func readReponseDataKey(data: LSPAny?, key: String) -> String? {
   return nil
 }
 
-extension BuildServerBuildSystem: BuildSystem {
-  /// The build settings for the given file.
-  ///
-  /// Returns `nil` if no build settings have been received from the build
-  /// server yet or if no build settings are available for this file.
-  public func buildSettings(for document: DocumentURI, language: Language) async throws -> FileBuildSettings? {
-    return buildSettings[document]
+extension BuildServerBuildSystem {
+  /// Exposed for *testing*.
+  public func _settings(for uri: DocumentURI) -> FileBuildSettings? {
+    if let response = try? self.buildServer?.sendSync(SourceKitOptions(uri: uri)) {
+      return FileBuildSettings(
+        compilerArguments: response.options,
+        workingDirectory: response.workingDirectory)
+    }
+    return nil
   }
+}
+
+extension BuildServerBuildSystem: BuildSystem {
 
   public func registerForChangeNotifications(for uri: DocumentURI, language: Language) {
     let request = RegisterForChanges(uri: uri, action: .register)
@@ -239,7 +230,7 @@ extension BuildServerBuildSystem: BuildSystem {
 
         // BuildServer registration failed, so tell our delegate that no build
         // settings are available.
-        self.buildSettingsChanged(for: uri, settings: nil)
+        self.delegate?.fileBuildSettingsChanged([uri: .removedOrUnavailable])
       }
     })
   }
diff --git a/Sources/SKCore/BuildSystem.swift b/Sources/SKCore/BuildSystem.swift
index 05d76572..dee92d51 100644
--- a/Sources/SKCore/BuildSystem.swift
+++ b/Sources/SKCore/BuildSystem.swift
@@ -51,13 +51,6 @@ public protocol BuildSystem: AnyObject {
   /// initial reports as well as changes.
   var delegate: BuildSystemDelegate? { get set }
 
-  /// Retrieve build settings for the given document with the given source
-  /// language.
-  ///
-  /// Returns `nil` if the build system can't provide build settings for this
-  /// file or if it hasn't computed build settings for the file yet.
-  func buildSettings(for document: DocumentURI, language: Language) async throws -> FileBuildSettings?
-
   /// Register the given file for build-system level change notifications, such
   /// as command line flag changes, dependency changes, etc.
   ///
diff --git a/Sources/SKCore/BuildSystemManager.swift b/Sources/SKCore/BuildSystemManager.swift
index 4c29920c..1e811f6d 100644
--- a/Sources/SKCore/BuildSystemManager.swift
+++ b/Sources/SKCore/BuildSystemManager.swift
@@ -146,41 +146,6 @@ extension BuildSystemManager {
     set { queue.sync { _mainFilesProvider = newValue } }
   }
 
-  /// Get the build settings for the given document, assuming it has the given
-  /// language.
-  ///
-  /// Returns `nil` if no build settings are availabe in the build system and
-  /// no fallback build settings can be computed.
-  ///
-  /// `isFallback` is `true` if the build settings couldn't be computed and
-  /// fallback settings are used. These fallback settings are most likely not
-  /// correct and provide limited semantic functionality.
-  public func buildSettings(
-    for document: DocumentURI,
-    language: Language
-  ) async -> (buildSettings: FileBuildSettings, isFallback: Bool)? {
-    do {
-      // FIXME: (async) We should only wait `fallbackSettingsTimeout` for build
-      // settings and return fallback afterwards. I am not sure yet, how best to
-      // implement that with Swift concurrency.
-      // For now, this should be fine because all build systems return
-      // very quickly from `settings(for:language:)`.
-      if let settings = try await buildSystem?.buildSettings(for: document, language: language) {
-        return (buildSettings: settings, isFallback: false)
-      }
-    } catch {
-      log("Getting build settings failed: \(error)")
-    }
-    if let settings = fallbackBuildSystem?.buildSettings(for: document, language: language) {
-      // If there is no build system and we onlyl have the fallback build system,
-      // we will never get real build settings. Consider the build settings
-      // non-fallback.
-      return (buildSettings: settings, isFallback: buildSystem != nil)
-    } else {
-      return nil
-    }
-  }
-
   public func registerForChangeNotifications(for uri: DocumentURI, language: Language) {
     return queue.async {
       log("registerForChangeNotifications(\(uri.pseudoPath))")
@@ -257,7 +222,7 @@ extension BuildSystemManager {
     } else if let fallback = self.fallbackBuildSystem {
       // Only have a fallback build system. We consider it be a primary build
       // system that functions synchronously.
-      if let settings = fallback.buildSettings(for: mainFile, language: language) {
+      if let settings = fallback.settings(for: mainFile, language) {
         newStatus = .primary(settings)
       } else {
         newStatus = .unsupported
@@ -318,7 +283,7 @@ extension BuildSystemManager {
     guard let status = self.mainFileStatuses[mainFile], status == .waiting else {
       return
     }
-    if let settings = fallback.buildSettings(for: mainFile, language: language) {
+    if let settings = fallback.settings(for: mainFile, language) {
       self.updateAndNotifyStatuses(changes: [mainFile: .waitingUsingFallback(settings)])
     } else {
       // Keep the status as waiting.
@@ -373,7 +338,7 @@ extension BuildSystemManager: BuildSystemDelegate {
           // FIXME: we need to stop threading the language everywhere, or we need the build system
           // itself to pass it in here. Or alteratively cache the fallback settings/language earlier?
           let language = firstWatch.value.language
-          if let settings = fallback.buildSettings(for: mainFile, language: language) {
+          if let settings = fallback.settings(for: mainFile, language) {
             newStatus = .fallback(settings)
           } else {
             newStatus = .unsupported
diff --git a/Sources/SKCore/CompilationDatabaseBuildSystem.swift b/Sources/SKCore/CompilationDatabaseBuildSystem.swift
index 34f36f48..10735178 100644
--- a/Sources/SKCore/CompilationDatabaseBuildSystem.swift
+++ b/Sources/SKCore/CompilationDatabaseBuildSystem.swift
@@ -93,15 +93,6 @@ extension CompilationDatabaseBuildSystem: BuildSystem {
 
   public var indexPrefixMappings: [PathPrefixMapping] { return [] }
 
-  public func buildSettings(for document: DocumentURI, language: Language) async throws -> FileBuildSettings? {
-    // FIXME: (async) Convert this to an async function once `CompilationDatabaseBuildSystem` is an actor.
-    return await withCheckedContinuation { continuation in
-      self.queue.async {
-        continuation.resume(returning: self.settings(for: document))
-      }
-    }
-  }
-
   public func registerForChangeNotifications(for uri: DocumentURI, language: Language) {
     queue.async {
       self.watchedFiles[uri] = language
diff --git a/Sources/SKCore/FallbackBuildSystem.swift b/Sources/SKCore/FallbackBuildSystem.swift
index 67c81423..30183e04 100644
--- a/Sources/SKCore/FallbackBuildSystem.swift
+++ b/Sources/SKCore/FallbackBuildSystem.swift
@@ -44,7 +44,7 @@ public final class FallbackBuildSystem: BuildSystem {
 
   public var indexPrefixMappings: [PathPrefixMapping] { return [] }
 
-  public func buildSettings(for uri: DocumentURI, language: Language) -> FileBuildSettings? {
+  public func settings(for uri: DocumentURI, _ language: Language) -> FileBuildSettings? {
     switch language {
     case .swift:
       return settingsSwift(uri.pseudoPath)
@@ -58,7 +58,7 @@ public final class FallbackBuildSystem: BuildSystem {
   public func registerForChangeNotifications(for uri: DocumentURI, language: Language) {
     guard let delegate = self.delegate else { return }
 
-    let settings = self.buildSettings(for: uri, language: language)
+    let settings = self.settings(for: uri, language)
     DispatchQueue.global().async {
       delegate.fileBuildSettingsChanged([uri: FileBuildSettingsChange(settings)])
     }
diff --git a/Sources/SKSwiftPMWorkspace/SwiftPMWorkspace.swift b/Sources/SKSwiftPMWorkspace/SwiftPMWorkspace.swift
index 940d3e28..2ca18dc5 100644
--- a/Sources/SKSwiftPMWorkspace/SwiftPMWorkspace.swift
+++ b/Sources/SKSwiftPMWorkspace/SwiftPMWorkspace.swift
@@ -290,18 +290,6 @@ extension SwiftPMWorkspace: SKCore.BuildSystem {
     }
   }
 
-  public func buildSettings(for document: DocumentURI, language: Language) async throws -> FileBuildSettings? {
-    return try await withCheckedThrowingContinuation { continuation in
-      queue.async {
-        do {
-          continuation.resume(returning: try self.settings(for: document, language))
-        } catch {
-          continuation.resume(throwing: error)
-        }
-      }
-    }
-  }
-
   /// Must only be called on `queue`.
   private func settings(
     for uri: DocumentURI,
diff --git a/Sources/SourceKitLSP/Clang/ClangLanguageServer.swift b/Sources/SourceKitLSP/Clang/ClangLanguageServer.swift
index 953a5d18..01b17dd8 100644
--- a/Sources/SourceKitLSP/Clang/ClangLanguageServer.swift
+++ b/Sources/SourceKitLSP/Clang/ClangLanguageServer.swift
@@ -118,8 +118,7 @@ final class ClangLanguageServerShim: ToolchainLanguageServer, MessageHandler {
     toolchain: Toolchain,
     options: SourceKitServer.Options,
     workspace: Workspace,
-    reopenDocuments: @escaping (ToolchainLanguageServer) -> Void,
-    workspaceForDocument: @escaping (DocumentURI) async -> Workspace?
+    reopenDocuments: @escaping (ToolchainLanguageServer) -> Void
   ) throws {
     guard let clangdPath = toolchain.clangd else {
       return nil
diff --git a/Sources/SourceKitLSP/SourceKitServer.swift b/Sources/SourceKitLSP/SourceKitServer.swift
index f32d4532..3b1826c9 100644
--- a/Sources/SourceKitLSP/SourceKitServer.swift
+++ b/Sources/SourceKitLSP/SourceKitServer.swift
@@ -414,10 +414,6 @@ public actor SourceKitServer {
           Task {
             await self.reopenDocuments(for: toolchainLanguageServer)
           }
-        },
-        workspaceForDocument: { [weak self] document in
-          guard let self else { return nil }
-          return await self.workspaceForDocument(uri: document)
         }
       )
 
@@ -2012,8 +2008,7 @@ func languageService(
   options: SourceKitServer.Options,
   client: MessageHandler,
   in workspace: Workspace,
-  reopenDocuments: @escaping (ToolchainLanguageServer) -> Void,
-  workspaceForDocument: @escaping (DocumentURI) async -> Workspace?
+  reopenDocuments: @escaping (ToolchainLanguageServer) -> Void
 ) throws -> ToolchainLanguageServer? {
   let connectionToClient = LocalConnection()
 
@@ -2022,8 +2017,7 @@ func languageService(
     toolchain: toolchain,
     options: options,
     workspace: workspace,
-    reopenDocuments: reopenDocuments,
-    workspaceForDocument: workspaceForDocument
+    reopenDocuments: reopenDocuments
   )
   connectionToClient.start(handler: client)
   return server
diff --git a/Sources/SourceKitLSP/Swift/CodeCompletion.swift b/Sources/SourceKitLSP/Swift/CodeCompletion.swift
index bdce13c5..b95e01ec 100644
--- a/Sources/SourceKitLSP/Swift/CodeCompletion.swift
+++ b/Sources/SourceKitLSP/Swift/CodeCompletion.swift
@@ -17,7 +17,7 @@ import Foundation
 
 extension SwiftLanguageServer {
 
-  public func completion(_ req: Request<CompletionRequest>) async {
+  public func completion(_ req: Request<CompletionRequest>) {
     guard let snapshot = documentManager.latestSnapshot(req.params.textDocument.uri) else {
       log("failed to find snapshot for url \(req.params.textDocument.uri)")
       req.reply(CompletionList(isIncomplete: true, items: []))
@@ -39,13 +39,14 @@ extension SwiftLanguageServer {
     let options = req.params.sourcekitlspOptions ?? serverOptions.completionOptions
 
     if options.serverSideFiltering {
-      await _completionWithServerFiltering(offset: offset, completionPos: completionPos, snapshot: snapshot, request: req, options: options)
+      _completionWithServerFiltering(offset: offset, completionPos: completionPos, snapshot: snapshot, request: req, options: options)
     } else {
-      await _completionWithClientFiltering(offset: offset, completionPos: completionPos, snapshot: snapshot, request: req, options: options)
+      _completionWithClientFiltering(offset: offset, completionPos: completionPos, snapshot: snapshot, request: req, options: options)
     }
   }
 
-  func _completionWithServerFiltering(offset: Int, completionPos: Position, snapshot: DocumentSnapshot, request req: Request<CompletionRequest>, options: SKCompletionOptions) async {
+  /// Must be called on `queue`.
+  func _completionWithServerFiltering(offset: Int, completionPos: Position, snapshot: DocumentSnapshot, request req: Request<CompletionRequest>, options: SKCompletionOptions) {
     guard let start = snapshot.indexOf(utf8Offset: offset),
           let end = snapshot.index(of: req.params.position) else {
       log("invalid completion position \(req.params.position)")
@@ -73,7 +74,7 @@ extension SwiftLanguageServer {
         snapshot: snapshot,
         utf8Offset: offset,
         position: completionPos,
-        compileCommand: await buildSettings(for: snapshot.document.uri))
+        compileCommand: commandsByFile[snapshot.document.uri])
 
       currentCompletionSession?.close()
       currentCompletionSession = session
@@ -82,7 +83,8 @@ extension SwiftLanguageServer {
     session.update(filterText: filterText, position: req.params.position, in: snapshot, options: options, completion: req.reply)
   }
 
-  func _completionWithClientFiltering(offset: Int, completionPos: Position, snapshot: DocumentSnapshot, request req: Request<CompletionRequest>, options: SKCompletionOptions) async {
+  /// Must be called on `queue`.
+  func _completionWithClientFiltering(offset: Int, completionPos: Position, snapshot: DocumentSnapshot, request req: Request<CompletionRequest>, options: SKCompletionOptions) {
     let skreq = SKDRequestDictionary(sourcekitd: sourcekitd)
     skreq[keys.request] = requests.codecomplete
     skreq[keys.offset] = offset
@@ -94,7 +96,7 @@ extension SwiftLanguageServer {
     skreq[keys.codecomplete_options] = skreqOptions
 
     // FIXME: SourceKit should probably cache this for us.
-    if let compileCommand = await buildSettings(for: snapshot.document.uri) {
+    if let compileCommand = commandsByFile[snapshot.document.uri] {
       skreq[keys.compilerargs] = compileCommand.compilerArgs
     }
 
diff --git a/Sources/SourceKitLSP/Swift/CursorInfo.swift b/Sources/SourceKitLSP/Swift/CursorInfo.swift
index 7701896e..69472f64 100644
--- a/Sources/SourceKitLSP/Swift/CursorInfo.swift
+++ b/Sources/SourceKitLSP/Swift/CursorInfo.swift
@@ -84,7 +84,7 @@ extension SwiftLanguageServer {
     _ uri: DocumentURI,
     _ range: Range<Position>,
     additionalParameters appendAdditionalParameters: ((SKDRequestDictionary) -> Void)? = nil,
-    _ completion: @escaping (Swift.Result<CursorInfo?, CursorInfoError>) -> Void) async
+    _ completion: @escaping (Swift.Result<CursorInfo?, CursorInfoError>) -> Void)
   {
     guard let snapshot = documentManager.latestSnapshot(uri) else {
        return completion(.failure(.unknownDocument(uri)))
@@ -105,7 +105,7 @@ extension SwiftLanguageServer {
     skreq[keys.sourcefile] = snapshot.document.uri.pseudoPath
 
     // FIXME: SourceKit should probably cache this for us.
-    if let compileCommand = await self.buildSettings(for: uri) {
+    if let compileCommand = self.commandsByFile[uri] {
       skreq[keys.compilerargs] = compileCommand.compilerArgs
     }
 
diff --git a/Sources/SourceKitLSP/Swift/ExpressionTypeInfo.swift b/Sources/SourceKitLSP/Swift/ExpressionTypeInfo.swift
index 68aac791..bc1ade78 100644
--- a/Sources/SourceKitLSP/Swift/ExpressionTypeInfo.swift
+++ b/Sources/SourceKitLSP/Swift/ExpressionTypeInfo.swift
@@ -57,7 +57,7 @@ extension SwiftLanguageServer {
   func expressionTypeInfos(
     _ uri: DocumentURI,
     _ completion: @escaping (Swift.Result<[ExpressionTypeInfo], ExpressionTypeInfoError>) -> Void
-  ) async {
+  ) {
     guard let snapshot = documentManager.latestSnapshot(uri) else {
       return completion(.failure(.unknownDocument(uri)))
     }
@@ -69,7 +69,7 @@ extension SwiftLanguageServer {
     skreq[keys.sourcefile] = snapshot.document.uri.pseudoPath
 
     // FIXME: SourceKit should probably cache this for us.
-    if let compileCommand = await self.buildSettings(for: uri) {
+    if let compileCommand = self.commandsByFile[uri] {
       skreq[keys.compilerargs] = compileCommand.compilerArgs
     }
 
diff --git a/Sources/SourceKitLSP/Swift/OpenInterface.swift b/Sources/SourceKitLSP/Swift/OpenInterface.swift
index 0d36cf94..d488ee93 100644
--- a/Sources/SourceKitLSP/Swift/OpenInterface.swift
+++ b/Sources/SourceKitLSP/Swift/OpenInterface.swift
@@ -25,7 +25,7 @@ struct FindUSRInfo {
 }
 
 extension SwiftLanguageServer {
-  public func openInterface(_ request: LanguageServerProtocol.Request<LanguageServerProtocol.OpenInterfaceRequest>) async {
+  public func openInterface(_ request: LanguageServerProtocol.Request<LanguageServerProtocol.OpenInterfaceRequest>) {
     let uri = request.params.textDocument.uri
     let moduleName = request.params.moduleName
     let name = request.params.name
@@ -37,7 +37,7 @@ extension SwiftLanguageServer {
       self._findUSRAndRespond(request: request, uri: interfaceDocURI, snapshot: snapshot, symbol: symbol)
     } else {
       // generate interface
-      await self._openInterface(request: request, uri: uri, name: moduleName, interfaceURI: interfaceDocURI) { result in
+      self._openInterface(request: request, uri: uri, name: moduleName, interfaceURI: interfaceDocURI) { result in
         switch result {
         case .success(let interfaceInfo):
           do {
@@ -69,7 +69,7 @@ extension SwiftLanguageServer {
                               uri: DocumentURI,
                               name: String,
                               interfaceURI: DocumentURI,
-                              completion: @escaping (Swift.Result<InterfaceInfo, SKDError>) -> Void) async {
+                              completion: @escaping (Swift.Result<InterfaceInfo, SKDError>) -> Void) {
     let keys = self.keys
     let skreq = SKDRequestDictionary(sourcekitd: sourcekitd)
     skreq[keys.request] = requests.editor_open_interface
@@ -79,7 +79,7 @@ extension SwiftLanguageServer {
     }
     skreq[keys.name] = interfaceURI.pseudoPath
     skreq[keys.synthesizedextensions] = 1
-    if let compileCommand = await self.buildSettings(for: uri) {
+    if let compileCommand = self.commandsByFile[uri] {
       skreq[keys.compilerargs] = compileCommand.compilerArgs
     }
     
diff --git a/Sources/SourceKitLSP/Swift/SemanticRefactoring.swift b/Sources/SourceKitLSP/Swift/SemanticRefactoring.swift
index 700cc720..167b53de 100644
--- a/Sources/SourceKitLSP/Swift/SemanticRefactoring.swift
+++ b/Sources/SourceKitLSP/Swift/SemanticRefactoring.swift
@@ -126,7 +126,7 @@ extension SwiftLanguageServer {
   ///   - completion: Completion block to asynchronously receive the SemanticRefactoring data, or error.
   func semanticRefactoring(
     _ refactorCommand: SemanticRefactorCommand,
-    _ completion: @escaping (Result<SemanticRefactoring, SemanticRefactoringError>) -> Void) async
+    _ completion: @escaping (Result<SemanticRefactoring, SemanticRefactoringError>) -> Void)
   {
     let keys = self.keys
 
@@ -156,7 +156,7 @@ extension SwiftLanguageServer {
     skreq[keys.actionuid] = self.sourcekitd.api.uid_get_from_cstr(refactorCommand.actionString)!
 
     // FIXME: SourceKit should probably cache this for us.
-    if let compileCommand = await self.buildSettings(for: snapshot.document.uri) {
+    if let compileCommand = self.commandsByFile[snapshot.document.uri] {
       skreq[keys.compilerargs] = compileCommand.compilerArgs
     }
 
diff --git a/Sources/SourceKitLSP/Swift/SwiftLanguageServer.swift b/Sources/SourceKitLSP/Swift/SwiftLanguageServer.swift
index 5a5a7f34..c17489ad 100644
--- a/Sources/SourceKitLSP/Swift/SwiftLanguageServer.swift
+++ b/Sources/SourceKitLSP/Swift/SwiftLanguageServer.swift
@@ -124,6 +124,8 @@ public actor SwiftLanguageServer: ToolchainLanguageServer {
 
   var currentCompletionSession: CodeCompletionSession? = nil
 
+  var commandsByFile: [DocumentURI: SwiftCompileCommand] = [:]
+  
   /// *For Testing*
   public var reusedNodeCallback: ReusedNodeCallback?
 
@@ -152,12 +154,6 @@ public actor SwiftLanguageServer: ToolchainLanguageServer {
   /// A callback with which `SwiftLanguageServer` can request its owner to reopen all documents in case it has crashed.
   private let reopenDocuments: (ToolchainLanguageServer) -> Void
 
-  /// Get the workspace that the document with the given URI belongs to.
-  ///
-  /// This is used to find the `BuildSystemManager` that is able to deliver
-  /// build settings for this document.
-  private let workspaceForDocument: (DocumentURI) async -> Workspace?
-
   /// Creates a language server for the given client using the sourcekitd dylib specified in `toolchain`.
   /// `reopenDocuments` is a closure that will be called if sourcekitd crashes and the `SwiftLanguageServer` asks its parent server to reopen all of its documents.
   /// Returns `nil` if `sourcektid` couldn't be found.
@@ -166,8 +162,7 @@ public actor SwiftLanguageServer: ToolchainLanguageServer {
     toolchain: Toolchain,
     options: SourceKitServer.Options,
     workspace: Workspace,
-    reopenDocuments: @escaping (ToolchainLanguageServer) -> Void,
-    workspaceForDocument: @escaping (DocumentURI) async -> Workspace?
+    reopenDocuments: @escaping (ToolchainLanguageServer) -> Void
   ) throws {
     guard let sourcekitd = toolchain.sourcekitd else { return nil }
     self.client = client
@@ -177,22 +172,10 @@ public actor SwiftLanguageServer: ToolchainLanguageServer {
     self.documentManager = DocumentManager()
     self.state = .connected
     self.reopenDocuments = reopenDocuments
-    self.workspaceForDocument = workspaceForDocument
     self.generatedInterfacesPath = options.generatedInterfacesPath.asURL
     try FileManager.default.createDirectory(at: generatedInterfacesPath, withIntermediateDirectories: true)
   }
 
-  func buildSettings(for document: DocumentURI) async -> SwiftCompileCommand? {
-    guard let workspace = await self.workspaceForDocument(document) else {
-      return nil
-    }
-    if let settings = await workspace.buildSystemManager.buildSettings(for: document, language: .swift) {
-      return SwiftCompileCommand(settings.buildSettings, isFallback: settings.isFallback)
-    } else {
-      return nil
-    }
-  }
-
   public nonisolated func canHandle(workspace: Workspace) -> Bool {
     // We have a single sourcekitd instance for all workspaces.
     return true
@@ -305,15 +288,10 @@ public actor SwiftLanguageServer: ToolchainLanguageServer {
 
   /// Register the diagnostics returned from sourcekitd in `currentDiagnostics`
   /// and returns the corresponding LSP diagnostics.
-  ///
-  /// If `isFromFallbackBuildSettings` is `true`, then only parse diagnostics are
-  /// stored and any semantic diagnostics are ignored since they are probably
-  /// incorrect in the absence of build settings.
   private func registerDiagnostics(
     sourcekitdDiagnostics: SKDResponseArray?,
     snapshot: DocumentSnapshot,
-    stage: DiagnosticStage,
-    isFromFallbackBuildSettings: Bool
+    stage: DiagnosticStage
   ) -> [Diagnostic] {
     let supportsCodeDescription = capabilityRegistry.clientHasDiagnosticsCodeDescriptionSupport
 
@@ -329,7 +307,7 @@ public actor SwiftLanguageServer: ToolchainLanguageServer {
       old: currentDiagnostics[snapshot.document.uri] ?? [],
       new: newDiags,
       stage: stage,
-      isFallback: isFromFallbackBuildSettings
+      isFallback: self.commandsByFile[snapshot.document.uri]?.isFallback ?? true
     )
     currentDiagnostics[snapshot.document.uri] = result
 
@@ -356,8 +334,7 @@ public actor SwiftLanguageServer: ToolchainLanguageServer {
     let diagnostics = registerDiagnostics(
       sourcekitdDiagnostics: response[keys.diagnostics],
       snapshot: snapshot,
-      stage: stage,
-      isFromFallbackBuildSettings: compileCommand?.isFallback ?? true
+      stage: stage
     )
 
     client.send(
@@ -369,11 +346,11 @@ public actor SwiftLanguageServer: ToolchainLanguageServer {
     )
   }
 
-  func handleDocumentUpdate(uri: DocumentURI) async {
+  func handleDocumentUpdate(uri: DocumentURI) {
     guard let snapshot = documentManager.latestSnapshot(uri) else {
       return
     }
-    let compileCommand = await self.buildSettings(for: uri)
+    let compileCommand = self.commandsByFile[uri]
 
     // Make the magic 0,0 replacetext request to update diagnostics and semantic tokens.
 
@@ -488,7 +465,16 @@ extension SwiftLanguageServer {
     self.updateSyntacticTokens(for: snapshot)
   }
 
-  public func documentUpdatedBuildSettings(_ uri: DocumentURI, change: FileBuildSettingsChange) async {
+  public func documentUpdatedBuildSettings(_ uri: DocumentURI, change: FileBuildSettingsChange) {
+    let compileCommand = SwiftCompileCommand(change: change)
+    // Confirm that the compile commands actually changed, otherwise we don't need to do anything.
+    // This includes when the compiler arguments are the same but the command is no longer
+    // considered to be fallback.
+    guard self.commandsByFile[uri] != compileCommand else {
+      return
+    }
+    self.commandsByFile[uri] = compileCommand
+
     // We may not have a snapshot if this is called just before `openDocument`.
     guard let snapshot = self.documentManager.latestSnapshot(uri) else {
       return
@@ -496,22 +482,22 @@ extension SwiftLanguageServer {
 
     // Close and re-open the document internally to inform sourcekitd to update the compile
     // command. At the moment there's no better way to do this.
-    self.reopenDocument(snapshot, await self.buildSettings(for: uri))
+    self.reopenDocument(snapshot, compileCommand)
   }
 
-  public func documentDependenciesUpdated(_ uri: DocumentURI) async {
+  public func documentDependenciesUpdated(_ uri: DocumentURI) {
     guard let snapshot = self.documentManager.latestSnapshot(uri) else {
       return
     }
 
     // Forcefully reopen the document since the `BuildSystem` has informed us
     // that the dependencies have changed and the AST needs to be reloaded.
-    await self.reopenDocument(snapshot, self.buildSettings(for: uri))
+    self.reopenDocument(snapshot, self.commandsByFile[uri])
   }
 
   // MARK: - Text synchronization
 
-  public func openDocument(_ note: DidOpenTextDocumentNotification) async {
+  public func openDocument(_ note: DidOpenTextDocumentNotification) {
     let keys = self.keys
 
     guard let snapshot = self.documentManager.open(note) else {
@@ -525,7 +511,7 @@ extension SwiftLanguageServer {
     req[keys.name] = note.textDocument.uri.pseudoPath
     req[keys.sourcetext] = snapshot.text
 
-    let compileCommand = await self.buildSettings(for: uri)
+    let compileCommand = self.commandsByFile[uri]
 
     if let compilerArgs = compileCommand?.compilerArgs {
       req[keys.compilerargs] = compilerArgs
@@ -551,12 +537,13 @@ extension SwiftLanguageServer {
     req[keys.name] = uri.pseudoPath
 
     // Clear settings that should not be cached for closed documents.
+    self.commandsByFile[uri] = nil
     self.currentDiagnostics[uri] = nil
 
     _ = try? self.sourcekitd.sendSync(req)
   }
 
-  public func changeDocument(_ note: DidChangeTextDocumentNotification) async {
+  public func changeDocument(_ note: DidChangeTextDocumentNotification) {
     let keys = self.keys
     var edits: [IncrementalEdit] = []
 
@@ -602,7 +589,7 @@ extension SwiftLanguageServer {
     }
 
     if let dict = lastResponse, let snapshot = snapshot {
-      let compileCommand = await self.buildSettings(for: note.textDocument.uri)
+      let compileCommand = self.commandsByFile[note.textDocument.uri]
       self.publishDiagnostics(response: dict, for: snapshot, compileCommand: compileCommand)
     }
   }
@@ -628,10 +615,10 @@ extension SwiftLanguageServer {
     return false
   }
 
-  public func hover(_ req: Request<HoverRequest>) async {
+  public func hover(_ req: Request<HoverRequest>) {
     let uri = req.params.textDocument.uri
     let position = req.params.position
-    await cursorInfo(uri, position..<position) { result in
+    cursorInfo(uri, position..<position) { result in
       guard let cursorInfo: CursorInfo = result.success ?? nil else {
         if let error = result.failure, error != .responseError(.serverCancelled) {
           log("cursor info failed \(uri):\(position): \(error)", level: .warning)
@@ -668,10 +655,10 @@ extension SwiftLanguageServer {
     }
   }
 
-  public func symbolInfo(_ req: Request<SymbolInfoRequest>) async {
+  public func symbolInfo(_ req: Request<SymbolInfoRequest>) {
     let uri = req.params.textDocument.uri
     let position = req.params.position
-    await cursorInfo(uri, position..<position) { result in
+    cursorInfo(uri, position..<position) { result in
       guard let cursorInfo: CursorInfo = result.success ?? nil else {
         if let error = result.failure {
           log("cursor info failed \(uri):\(position): \(error)", level: .warning)
@@ -928,7 +915,7 @@ extension SwiftLanguageServer {
     req.reply([presentation])
   }
 
-  public func documentSymbolHighlight(_ req: Request<DocumentHighlightRequest>) async {
+  public func documentSymbolHighlight(_ req: Request<DocumentHighlightRequest>) {
     let keys = self.keys
 
     guard let snapshot = self.documentManager.latestSnapshot(req.params.textDocument.uri) else {
@@ -949,7 +936,7 @@ extension SwiftLanguageServer {
     skreq[keys.sourcefile] = snapshot.document.uri.pseudoPath
 
     // FIXME: SourceKit should probably cache this for us.
-    if let compileCommand = await self.buildSettings(for: snapshot.document.uri) {
+    if let compileCommand = self.commandsByFile[snapshot.document.uri] {
       skreq[keys.compilerargs] = compileCommand.compilerArgs
     }
 
@@ -1241,14 +1228,12 @@ extension SwiftLanguageServer {
           // FIXME: (async) Migrate `CodeActionProvider` to be async so that we
           // don't need to do the `withCheckedContinuation` dance here.
           await withCheckedContinuation { continuation in
-            Task {
-              await provider(req.params) {
-                switch $0 {
-                case .success(let actions):
-                  continuation.resume(returning: actions)
-                case .failure:
-                  continuation.resume(returning: [])
-                }
+            provider(req.params) {
+              switch $0 {
+              case .success(let actions):
+                continuation.resume(returning: actions)
+              case .failure:
+                continuation.resume(returning: [])
               }
             }
           }
@@ -1263,12 +1248,12 @@ extension SwiftLanguageServer {
     completion(.success(codeActions))
   }
 
-  func retrieveRefactorCodeActions(_ params: CodeActionRequest, completion: @escaping CodeActionProviderCompletion) async {
+  func retrieveRefactorCodeActions(_ params: CodeActionRequest, completion: @escaping CodeActionProviderCompletion) {
     let additionalCursorInfoParameters: ((SKDRequestDictionary) -> Void) = { skreq in
       skreq[self.keys.retrieve_refactor_actions] = 1
     }
 
-    await cursorInfo(
+    cursorInfo(
       params.textDocument.uri,
       params.range,
       additionalParameters: additionalCursorInfoParameters)
@@ -1356,9 +1341,9 @@ extension SwiftLanguageServer {
     completion(.success(codeActions))
   }
 
-  public func inlayHint(_ req: Request<InlayHintRequest>) async {
+  public func inlayHint(_ req: Request<InlayHintRequest>) {
     let uri = req.params.textDocument.uri
-    await variableTypeInfos(uri, req.params.range) { infosResult in
+    variableTypeInfos(uri, req.params.range) { infosResult in
       do {
         let infos = try infosResult.get()
         let hints = infos
@@ -1393,7 +1378,7 @@ extension SwiftLanguageServer {
   public func documentDiagnostic(
     _ uri: DocumentURI,
     _ completion: @escaping (Result<[Diagnostic], ResponseError>) -> Void
-  ) async {
+  ) {
     guard let snapshot = documentManager.latestSnapshot(uri) else {
       let msg = "failed to find snapshot for url \(uri)"
       log(msg)
@@ -1407,12 +1392,8 @@ extension SwiftLanguageServer {
     skreq[keys.sourcefile] = snapshot.document.uri.pseudoPath
 
     // FIXME: SourceKit should probably cache this for us.
-    let areFallbackBuildSettings: Bool
-    if let buildSettings = await self.buildSettings(for: uri) {
-      skreq[keys.compilerargs] = buildSettings.compilerArgs
-      areFallbackBuildSettings = buildSettings.isFallback
-    } else {
-      areFallbackBuildSettings = true
+    if let compileCommand = self.commandsByFile[uri] {
+      skreq[keys.compilerargs] = compileCommand.compilerArgs
     }
 
     let handle = self.sourcekitd.send(skreq, self.queue) { response in
@@ -1423,8 +1404,7 @@ extension SwiftLanguageServer {
       let diagnostics = self.registerDiagnostics(
         sourcekitdDiagnostics: dict[keys.diagnostics],
         snapshot: snapshot,
-        stage: .sema,
-        isFromFallbackBuildSettings: areFallbackBuildSettings
+        stage: .sema
       )
 
       completion(.success(diagnostics))
@@ -1434,9 +1414,9 @@ extension SwiftLanguageServer {
     _ = handle
   }
 
-  public func documentDiagnostic(_ req: Request<DocumentDiagnosticsRequest>) async {
+  public func documentDiagnostic(_ req: Request<DocumentDiagnosticsRequest>) {
     let uri = req.params.textDocument.uri
-    await documentDiagnostic(req.params.textDocument.uri) { result in
+    documentDiagnostic(req.params.textDocument.uri) { result in
       switch result {
         case .success(let diagnostics):
           req.reply(.full(.init(items: diagnostics)))
@@ -1449,7 +1429,7 @@ extension SwiftLanguageServer {
     }
   }
 
-  public func executeCommand(_ req: Request<ExecuteCommandRequest>) async {
+  public func executeCommand(_ req: Request<ExecuteCommandRequest>) {
     let params = req.params
     //TODO: If there's support for several types of commands, we might need to structure this similarly to the code actions request.
     guard let swiftCommand = params.swiftCommand(ofType: SemanticRefactorCommand.self) else {
@@ -1458,7 +1438,7 @@ extension SwiftLanguageServer {
       return req.reply(.failure(.unknown(message)))
     }
     let uri = swiftCommand.textDocument.uri
-    await semanticRefactoring(swiftCommand) { result in
+    semanticRefactoring(swiftCommand) { result in
       switch result {
       case .success(let refactor):
         let edit = refactor.edit
@@ -1511,7 +1491,7 @@ extension SwiftLanguageServer: SKDNotificationHandler {
     }
   }
 
-  public func notificationImpl(_ notification: SKDResponse) async {
+  public func notificationImpl(_ notification: SKDResponse) {
     // Check if we need to update our `state` based on the contents of the notification.
     if notification.value?[self.keys.notification] == self.values.notification_sema_enabled {
       self.state = .connected
@@ -1569,7 +1549,7 @@ extension SwiftLanguageServer: SKDNotificationHandler {
       } else {
         uri = DocumentURI(string: name)
       }
-      await self.handleDocumentUpdate(uri: uri)
+      self.handleDocumentUpdate(uri: uri)
     }
   }
 }
diff --git a/Sources/SourceKitLSP/Swift/VariableTypeInfo.swift b/Sources/SourceKitLSP/Swift/VariableTypeInfo.swift
index 172ca0a5..43c227d9 100644
--- a/Sources/SourceKitLSP/Swift/VariableTypeInfo.swift
+++ b/Sources/SourceKitLSP/Swift/VariableTypeInfo.swift
@@ -93,7 +93,7 @@ extension SwiftLanguageServer {
     _ uri: DocumentURI,
     _ range: Range<Position>? = nil,
     _ completion: @escaping (Swift.Result<[VariableTypeInfo], VariableTypeInfoError>) -> Void
-  ) async {
+  ) {
     guard let snapshot = documentManager.latestSnapshot(uri) else {
       return completion(.failure(.unknownDocument(uri)))
     }
@@ -112,7 +112,7 @@ extension SwiftLanguageServer {
     }
 
     // FIXME: SourceKit should probably cache this for us
-    if let compileCommand = await self.buildSettings(for: uri) {
+    if let compileCommand = self.commandsByFile[uri] {
       skreq[keys.compilerargs] = compileCommand.compilerArgs
     }
 
diff --git a/Sources/SourceKitLSP/ToolchainLanguageServer.swift b/Sources/SourceKitLSP/ToolchainLanguageServer.swift
index e2da6bf3..2a67dfd4 100644
--- a/Sources/SourceKitLSP/ToolchainLanguageServer.swift
+++ b/Sources/SourceKitLSP/ToolchainLanguageServer.swift
@@ -34,8 +34,7 @@ public protocol ToolchainLanguageServer: AnyObject {
     toolchain: Toolchain,
     options: SourceKitServer.Options,
     workspace: Workspace,
-    reopenDocuments: @escaping (ToolchainLanguageServer) -> Void,
-    workspaceForDocument: @escaping (DocumentURI) async -> Workspace?
+    reopenDocuments: @escaping (ToolchainLanguageServer) -> Void
   ) throws
 
   /// Returns `true` if this instance of the language server can handle opening documents in `workspace`.
diff --git a/Tests/SKCoreTests/BuildServerBuildSystemTests.swift b/Tests/SKCoreTests/BuildServerBuildSystemTests.swift
index a4324425..aafaa689 100644
--- a/Tests/SKCoreTests/BuildServerBuildSystemTests.swift
+++ b/Tests/SKCoreTests/BuildServerBuildSystemTests.swift
@@ -40,6 +40,24 @@ final class BuildServerBuildSystemTests: XCTestCase {
     )
   }
 
+  func testSettings() throws {
+#if os(Windows)
+    try XCTSkipIf(true, "hang")
+#endif
+    let buildSystem = try BuildServerBuildSystem(projectRoot: root, buildFolder: buildFolder)
+
+    // test settings with a response
+    let fileURL = URL(fileURLWithPath: "/path/to/some/file.swift")
+    let settings = buildSystem._settings(for: DocumentURI(fileURL))
+    XCTAssertNotNil(settings)
+    XCTAssertEqual(settings?.compilerArguments, ["-a", "-b"])
+    XCTAssertEqual(settings?.workingDirectory, fileURL.deletingLastPathComponent().path)
+
+    // test error
+    let missingFileURL = URL(fileURLWithPath: "/path/to/some/missingfile.missing")
+    XCTAssertNil(buildSystem._settings(for: DocumentURI(missingFileURL)))
+  }
+
   func testFileRegistration() throws {
     let buildSystem = try BuildServerBuildSystem(projectRoot: root, buildFolder: buildFolder)
 
diff --git a/Tests/SKCoreTests/BuildSystemManagerTests.swift b/Tests/SKCoreTests/BuildSystemManagerTests.swift
index 99724f25..837133b4 100644
--- a/Tests/SKCoreTests/BuildSystemManagerTests.swift
+++ b/Tests/SKCoreTests/BuildSystemManagerTests.swift
@@ -149,7 +149,7 @@ final class BuildSystemManagerTests: XCTestCase {
       mainFilesProvider: mainFiles)
     defer { withExtendedLifetime(bsm) {} } // Keep BSM alive for callbacks.
     let del = BSMDelegate(bsm)
-    let fallbackSettings = fallback.buildSettings(for: a, language: .swift)
+    let fallbackSettings = fallback.settings(for: a, .swift)
     let initial = expectation(description: "initial fallback settings")
     del.expected = [(a, fallbackSettings, initial, #file, #line)]
     bsm.registerForChangeNotifications(for: a, language: .swift)
@@ -475,12 +475,12 @@ class ManualBuildSystem: BuildSystem {
 
   var delegate: BuildSystemDelegate? = nil
 
-  func buildSettings(for uri: DocumentURI, language: Language) -> FileBuildSettings? {
+  func settings(for uri: DocumentURI, _ language: Language) -> FileBuildSettings? {
     return map[uri]
   }
 
   func registerForChangeNotifications(for uri: DocumentURI, language: Language) {
-    let settings = self.buildSettings(for: uri, language: language)
+    let settings = self.settings(for: uri, language)
     self.delegate?.fileBuildSettingsChanged([uri: FileBuildSettingsChange(settings)])
   }
 
diff --git a/Tests/SKCoreTests/FallbackBuildSystemTests.swift b/Tests/SKCoreTests/FallbackBuildSystemTests.swift
index 6d103a3b..68b54ef1 100644
--- a/Tests/SKCoreTests/FallbackBuildSystemTests.swift
+++ b/Tests/SKCoreTests/FallbackBuildSystemTests.swift
@@ -29,7 +29,7 @@ final class FallbackBuildSystemTests: XCTestCase {
     XCTAssertNil(bs.indexStorePath)
     XCTAssertNil(bs.indexDatabasePath)
 
-    let settings = bs.buildSettings(for: source.asURI, language: .swift)!
+    let settings = bs.settings(for: source.asURI, .swift)!
     XCTAssertNil(settings.workingDirectory)
 
     let args = settings.compilerArguments
@@ -41,7 +41,7 @@ final class FallbackBuildSystemTests: XCTestCase {
 
     bs.sdkpath = nil
 
-    XCTAssertEqual(bs.buildSettings(for: source.asURI, language: .swift)?.compilerArguments, [
+    XCTAssertEqual(bs.settings(for: source.asURI, .swift)?.compilerArguments, [
       source.pathString,
     ])
   }
@@ -57,7 +57,7 @@ final class FallbackBuildSystemTests: XCTestCase {
     let bs = FallbackBuildSystem(buildSetup: buildSetup)
     bs.sdkpath = sdk
 
-    let args = bs.buildSettings(for: source.asURI, language: .swift)?.compilerArguments
+    let args = bs.settings(for: source.asURI, .swift)?.compilerArguments
     XCTAssertEqual(args, [
       "-Xfrontend",
       "-debug-constraints",
@@ -68,7 +68,7 @@ final class FallbackBuildSystemTests: XCTestCase {
 
     bs.sdkpath = nil
 
-    XCTAssertEqual(bs.buildSettings(for: source.asURI, language: .swift)?.compilerArguments, [
+    XCTAssertEqual(bs.settings(for: source.asURI, .swift)?.compilerArguments, [
       "-Xfrontend",
       "-debug-constraints",
       source.pathString,
@@ -88,7 +88,7 @@ final class FallbackBuildSystemTests: XCTestCase {
     let bs = FallbackBuildSystem(buildSetup: buildSetup)
     bs.sdkpath = sdk
 
-    XCTAssertEqual(bs.buildSettings(for: source.asURI, language: .swift)!.compilerArguments, [
+    XCTAssertEqual(bs.settings(for: source.asURI, .swift)!.compilerArguments, [
       "-sdk",
       "/some/custom/sdk",
       "-Xfrontend",
@@ -98,7 +98,7 @@ final class FallbackBuildSystemTests: XCTestCase {
 
     bs.sdkpath = nil
 
-    XCTAssertEqual(bs.buildSettings(for: source.asURI, language: .swift)!.compilerArguments, [
+    XCTAssertEqual(bs.settings(for: source.asURI, .swift)!.compilerArguments, [
       "-sdk",
       "/some/custom/sdk",
       "-Xfrontend",
@@ -114,7 +114,7 @@ final class FallbackBuildSystemTests: XCTestCase {
     let bs = FallbackBuildSystem(buildSetup: .default)
     bs.sdkpath = sdk
 
-    let settings = bs.buildSettings(for: source.asURI, language: .cpp)!
+    let settings = bs.settings(for: source.asURI, .cpp)!
     XCTAssertNil(settings.workingDirectory)
 
     let args = settings.compilerArguments
@@ -126,7 +126,7 @@ final class FallbackBuildSystemTests: XCTestCase {
 
     bs.sdkpath = nil
 
-    XCTAssertEqual(bs.buildSettings(for: source.asURI, language: .cpp)?.compilerArguments, [
+    XCTAssertEqual(bs.settings(for: source.asURI, .cpp)?.compilerArguments, [
       source.pathString,
     ])
   }
@@ -141,7 +141,7 @@ final class FallbackBuildSystemTests: XCTestCase {
     let bs = FallbackBuildSystem(buildSetup: buildSetup)
     bs.sdkpath = sdk
 
-    XCTAssertEqual(bs.buildSettings(for: source.asURI, language: .cpp)?.compilerArguments, [
+    XCTAssertEqual(bs.settings(for: source.asURI, .cpp)?.compilerArguments, [
       "-v",
       "-isysroot",
       sdk.pathString,
@@ -150,7 +150,7 @@ final class FallbackBuildSystemTests: XCTestCase {
 
     bs.sdkpath = nil
 
-    XCTAssertEqual(bs.buildSettings(for: source.asURI, language: .cpp)?.compilerArguments, [
+    XCTAssertEqual(bs.settings(for: source.asURI, .cpp)?.compilerArguments, [
       "-v",
       source.pathString,
     ])
@@ -168,7 +168,7 @@ final class FallbackBuildSystemTests: XCTestCase {
     let bs = FallbackBuildSystem(buildSetup: buildSetup)
     bs.sdkpath = sdk
 
-    XCTAssertEqual(bs.buildSettings(for: source.asURI, language: .cpp)?.compilerArguments, [
+    XCTAssertEqual(bs.settings(for: source.asURI, .cpp)?.compilerArguments, [
       "-isysroot",
       "/my/custom/sdk",
       "-v",
@@ -177,7 +177,7 @@ final class FallbackBuildSystemTests: XCTestCase {
 
     bs.sdkpath = nil
 
-    XCTAssertEqual(bs.buildSettings(for: source.asURI, language: .cpp)?.compilerArguments, [
+    XCTAssertEqual(bs.settings(for: source.asURI, .cpp)?.compilerArguments, [
       "-isysroot",
       "/my/custom/sdk",
       "-v",
@@ -189,7 +189,7 @@ final class FallbackBuildSystemTests: XCTestCase {
     let source = try AbsolutePath(validating: "/my/source.c")
     let bs = FallbackBuildSystem(buildSetup: .default)
     bs.sdkpath = nil
-    XCTAssertEqual(bs.buildSettings(for: source.asURI, language: .c)?.compilerArguments, [
+    XCTAssertEqual(bs.settings(for: source.asURI, .c)?.compilerArguments, [
       source.pathString,
     ])
   }
@@ -202,7 +202,7 @@ final class FallbackBuildSystemTests: XCTestCase {
     ]))
     let bs = FallbackBuildSystem(buildSetup: buildSetup)
     bs.sdkpath = nil
-    XCTAssertEqual(bs.buildSettings(for: source.asURI, language: .c)?.compilerArguments, [
+    XCTAssertEqual(bs.settings(for: source.asURI, .c)?.compilerArguments, [
       "-v",
       source.pathString,
     ])
@@ -212,7 +212,7 @@ final class FallbackBuildSystemTests: XCTestCase {
     let source = try AbsolutePath(validating: "/my/source.m")
     let bs = FallbackBuildSystem(buildSetup: .default)
     bs.sdkpath = nil
-    XCTAssertEqual(bs.buildSettings(for: source.asURI, language: .objective_c)?.compilerArguments, [
+    XCTAssertEqual(bs.settings(for: source.asURI, .objective_c)?.compilerArguments, [
       source.pathString,
     ])
   }
@@ -221,7 +221,7 @@ final class FallbackBuildSystemTests: XCTestCase {
     let source = try AbsolutePath(validating: "/my/source.mm")
     let bs = FallbackBuildSystem(buildSetup: .default)
     bs.sdkpath = nil
-    XCTAssertEqual(bs.buildSettings(for: source.asURI, language: .objective_cpp)?.compilerArguments, [
+    XCTAssertEqual(bs.settings(for: source.asURI, .objective_cpp)?.compilerArguments, [
       source.pathString,
     ])
   }
@@ -229,6 +229,6 @@ final class FallbackBuildSystemTests: XCTestCase {
   func testUnknown() throws {
     let source = try AbsolutePath(validating: "/my/source.mm")
     let bs = FallbackBuildSystem(buildSetup: .default)
-    XCTAssertNil(bs.buildSettings(for: source.asURI, language: Language(rawValue: "unknown")))
+    XCTAssertNil(bs.settings(for: source.asURI, Language(rawValue: "unknown")))
   }
 }
diff --git a/Tests/SourceKitLSPTests/BuildSystemTests.swift b/Tests/SourceKitLSPTests/BuildSystemTests.swift
index 95f1aa4a..ac05bedd 100644
--- a/Tests/SourceKitLSPTests/BuildSystemTests.swift
+++ b/Tests/SourceKitLSPTests/BuildSystemTests.swift
@@ -43,10 +43,6 @@ final class TestBuildSystem: BuildSystem {
   /// Files currently being watched by our delegate.
   var watchedFiles: Set<DocumentURI> = []
 
-  func buildSettings(for document: DocumentURI, language: Language) async throws -> FileBuildSettings? {
-    return buildSettingsByFile[document]
-  }
-
   func registerForChangeNotifications(for uri: DocumentURI, language: Language) {
     watchedFiles.insert(uri)
 
@@ -200,7 +196,7 @@ final class BuildSystemTests: XCTestCase {
   func testSwiftDocumentUpdatedBuildSettings() async throws {
     let url = URL(fileURLWithPath: "/\(UUID())/a.swift")
     let doc = DocumentURI(url)
-    let args = FallbackBuildSystem(buildSetup: .default).buildSettings(for: doc, language: .swift)!.compilerArguments
+    let args = FallbackBuildSystem(buildSetup: .default).settings(for: doc, .swift)!.compilerArguments
 
     buildSystem.buildSettingsByFile[doc] = FileBuildSettings(compilerArguments: args)
 
@@ -310,7 +306,7 @@ final class BuildSystemTests: XCTestCase {
     let doc = DocumentURI(url)
 
     // Primary settings must be different than the fallback settings.
-    var primarySettings = FallbackBuildSystem(buildSetup: .default).buildSettings(for: doc, language: .swift)!
+    var primarySettings = FallbackBuildSystem(buildSetup: .default).settings(for: doc, .swift)!
     primarySettings.compilerArguments.append("-DPRIMARY")
 
     let text = """