Fix #4491 FN redundantAssignment: assigning same value twice (#7955)

Author: chrchr-github

lib/checkother.cpp

@@ -681,7 +681,7 @@ void CheckOther::checkRedundantAssignment()
                 // Is there a redundant assignment?
                 const Token *start;
                 if (tok->isAssignmentOp())
-                    start = tok->next();
+                    start = tok->astOperand2();
                 else
                     start = tok->findExpressionStartEndTokens().second->next();
 

test/testother.cpp

@@ -11032,6 +11032,15 @@ class TestOther : public TestFixture {
               "    a = x;\n"
               "}\n");
         ASSERT_EQUALS("", errout_str());
+
+        check("int f(int a, int b, int c) {\n" // #4491
+              "    int x = a + b;\n"
+              "    if (c)\n"
+              "        x = a + b;\n"
+              "    return x;\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:2:11] -> [test.cpp:4:9]: (style) Variable 'x' is assigned an expression that holds the same value. [redundantAssignment]\n",
+                      errout_str());
     }
 
     void varFuncNullUB() { // #4482