[NFC] Mark Result as move-only

This required dropping some superfluous 'const' qualification in the module dependency graph.

Author: CodaFi

include/swift/Driver/Compilation.h

@@ -84,6 +84,12 @@ class Compilation {
     bool hadAbnormalExit;
     int exitCode;
     fine_grained_dependencies::ModuleDepGraph depGraph;
+
+    Result(const Result &) = delete;
+    Result(Result &&) = default;
+
+    Result &operator=(const Result &) = delete;
+    Result &operator=(Result &&) = default;
   };
 
   class IncrementalSchemeComparator {

include/swift/Driver/FineGrainedDependencyDriverGraph.h

@@ -188,8 +188,8 @@ class ModuleDepGraph {
   std::unordered_map<std::string, unsigned> dotFileSequenceNumber;
 
 public:
-  const bool verifyFineGrainedDependencyGraphAfterEveryImport;
-  const bool emitFineGrainedDependencyDotFileAfterEveryImport;
+  bool verifyFineGrainedDependencyGraphAfterEveryImport;
+  bool emitFineGrainedDependencyDotFileAfterEveryImport;
 
 private:
   /// If tracing dependencies, holds a vector used to hold the current path
@@ -203,7 +203,7 @@ class ModuleDepGraph {
       dependencyPathsToJobs;
 
   /// For helping with performance tuning, may be null:
-  UnifiedStatsReporter *const stats;
+  UnifiedStatsReporter *stats;
 
   //==============================================================================
   // MARK: ModuleDepGraph - mutating dependencies