 
     internal var syntaxKindsByLines: [[SyntaxKind]] {
         guard let syntaxKindsByLines = syntaxKindsByLinesCache.get(self) else {
+            if let handler = assertHandler {
+                handler()
+                return []
+            }
             fatalError("Never call this for file that sourcekitd fails.")
         }
         return syntaxKindsByLines

        queueForRebuild = []
        _allDeclarationsByType = [:]
        responseCache.clear()
        structureCache.clear()
        syntaxMapCache.clear()
        syntaxKindsByLinesCache.clear()

})
private var syntaxMapCache = Cache({file in responseCache.get(file).map(SyntaxMap.init)})
private var syntaxKindsByLinesCache = Cache({file in file.syntaxKindsByLine()})

private typealias AssertHandler = () -> ()
private var assertHandlers = [String: AssertHandler?]()

private var _allDeclarationsByType = [String: [String]]()
private var queueForRebuild = [Structure]()
