Same expression: don't warn for same expressions when there is assignment

lib/checkother.cpp

@@ -114,7 +114,7 @@ bool isSameExpression(const Token *tok1, const Token *tok2, const std::set<std::
         if (t1 != end1 || t2 != end2)
             return false;
     }
-    if (Token::Match(tok1, "++|--"))
+    if (Token::Match(tok1, "++|--") || tok1->isAssignmentOp())
         return false;
     if (tok1->str() == "(" && tok1->previous() && !tok1->previous()->isName()) { // cast => assert that the casts are equal
         const Token *t1 = tok1->next();

test/testother.cpp

@@ -4974,6 +4974,12 @@ private:
               "    if (*a-- != b || *a-- != b) {}\n"
               "}");
         ASSERT_EQUALS("", errout.str());
+
+        // assignment
+        check("void f() {\n"
+              "  while (*(a+=2)==*(b+=2) && *(a+=2)==*(b+=2)) {}\n"
+              "}");
+        ASSERT_EQUALS("", errout.str());
     }
 
     void duplicateExpression5() {  // #3749 - macros with same values