Fix #14496 FN variableScope with nullptr (#8221)

Author: chrchr-github

lib/checkother.cpp

@@ -1163,6 +1163,8 @@ static bool isSimpleExpr(const Token* tok, const Variable* var, const Settings&
         return false;
     if (tok->isNumber() || tok->tokType() == Token::eString || tok->tokType() == Token::eChar || tok->isBoolean())
         return true;
+    if (isNullOperand(tok))
+        return true;
     bool needsCheck = tok->varId() > 0;
     if (!needsCheck) {
         if (tok->isArithmeticalOp())

test/testother.cpp

@@ -121,6 +121,7 @@ class TestOther : public TestFixture {
         TEST_CASE(varScope41);      // #11845
         TEST_CASE(varScope42);
         TEST_CASE(varScope43);
+        TEST_CASE(varScope44);
 
         TEST_CASE(oldStylePointerCast);
         TEST_CASE(intToPointerCast);
@@ -1945,6 +1946,32 @@ class TestOther : public TestFixture {
         ASSERT_EQUALS("[test.cpp:3:12]: (style) The scope of the variable 'x' can be reduced. [variableScope]\n", errout_str());
     }
 
+    void varScope44() { // #14496
+        check("char* f() {\n"
+              "    char* p = nullptr;\n"
+              "    {\n"
+              "        p = strdup(\"abc\");\n"
+              "        if (p) {\n"
+              "            return p;\n"
+              "        }\n"
+              "    }\n"
+              "    return nullptr;\n"
+              "}\n"
+              "char* g() {\n"
+              "    char* q = NULL;\n"
+              "    {\n"
+              "        q = strdup(\"abc\");\n"
+              "        if (q) {\n"
+              "            return q;\n"
+              "        }\n"
+              "    }\n"
+              "    return nullptr;\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:2:11]: (style) The scope of the variable 'p' can be reduced. [variableScope]\n"
+                      "[test.cpp:12:11]: (style) The scope of the variable 'q' can be reduced. [variableScope]\n",
+                      errout_str());
+    }
+
 #define checkOldStylePointerCast(...) checkOldStylePointerCast_(__FILE__, __LINE__, __VA_ARGS__)
     template<size_t size>
     void checkOldStylePointerCast_(const char* file, int line, const char (&code)[size], Standards::cppstd_t std = Standards::CPPLatest) {