[Clang] Fix Static Code Analysis Concerns with copy without assign

This patch adds missing assignment operator to the class which has user-defined copy constructor.

Reviewed By: tahonermann, aaronpuchert

Differential Revision: https://reviews.llvm.org/D150931

clang/include/clang/Analysis/Analyses/ThreadSafetyTIL.h

@@ -319,6 +319,7 @@ class SExpr {
 protected:
   SExpr(TIL_Opcode Op) : Opcode(Op) {}
   SExpr(const SExpr &E) : Opcode(E.Opcode), Flags(E.Flags) {}
+  SExpr &operator=(const SExpr &) = delete;
 
   const TIL_Opcode Opcode;
   unsigned char Reserved = 0;

clang/include/clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h

@@ -84,6 +84,10 @@ class CallEventRef : public IntrusiveRefCntPtr<const T> {
   CallEventRef(const T *Call) : IntrusiveRefCntPtr<const T>(Call) {}
   CallEventRef(const CallEventRef &Orig) : IntrusiveRefCntPtr<const T>(Orig) {}
 
+  // The copy assignment operator is defined as deleted pending further
+  // motivation.
+  CallEventRef &operator=(const CallEventRef &) = delete;
+
   CallEventRef<T> cloneWithState(ProgramStateRef State) const {
     return this->get()->template cloneWithState<T>(State);
   }