Nits fixed

Author: David Ungar

Sources/SwiftDriver/IncrementalCompilation/ModuleDependencyGraph.swift

@@ -449,8 +449,8 @@ extension ModuleDependencyGraph {
     options: IncrementalCompilationState.Options
   ) throws -> ModuleDependencyGraph? {
     guard try fileSystem.exists(path) else {
-         return nil
-       }
+      return nil
+    }
     let data = try fileSystem.readFileContents(path)
 
     struct Visitor: BitstreamVisitor {
@@ -935,7 +935,7 @@ extension ModuleDependencyGraph {
             $0.append(RecordID.mapNode)
             $0.append(serializer.lookupIdentifierCode(for: input.file.name))
             $0.append(serializer.lookupIdentifierCode(for: dependencySource.file.name))
-         }
+          }
         }
 
         for fingerprintedExternalDependency in graph.fingerprintedExternalDependencies {

Tests/SwiftDriverTests/DependencyGraphSerializationTests.swift

@@ -21,11 +21,12 @@ class DependencyGraphSerializationTests: XCTestCase {
     let fs = InMemoryFileSystem()
     graph.write(to: mockPath, on: fs, compilerVersion: "Swift 99")
 
-    let deserializedGraph = try ModuleDependencyGraph.read(from: mockPath,
-                                                           on: fs,
-                                                           diagnosticEngine: de,
-                                                           reporter: nil,
-                                                           options: [])!
+    let deserializedGraph = try XCTUnwrap(
+      try ModuleDependencyGraph.read(from: mockPath,
+                                     on: fs,
+                                     diagnosticEngine: de,
+                                     reporter: nil,
+                                     options: []))
     var originalNodes = Set<ModuleDependencyGraph.Node>()
     graph.nodeFinder.forEachNode {
       originalNodes.insert($0)