Fix #11007 FP nullPointerRedundantCheck with static function pointer (#4051)

lib/checknullpointer.cpp

@@ -182,8 +182,13 @@ bool CheckNullPointer::isPointerDeRef(const Token *tok, bool &unknown, const Set
         return false;
 
     // Dereferencing pointer..
-    if (parent->isUnaryOp("*") && !addressOf)
-        return true;
+    if (parent->isUnaryOp("*")) {
+        // declaration of function pointer
+        if (tok->variable() && tok->variable()->nameToken() == tok)
+            return false;
+        if (!addressOf)
+            return true;
+    }
 
     // array access
     if (firstOperand && parent->str() == "[" && !addressOf)

test/testnullpointer.cpp

@@ -1137,6 +1137,15 @@ private:
               "}");
         ASSERT_EQUALS("[test.cpp:5]: (error) Null pointer dereference: f\n", errout.str());
 
+        check("int* g();\n" // #11007
+              "int* f() {\n"
+              "    static int* (*fun)() = 0;\n"
+              "    if (!fun)\n"
+              "        fun = g;\n"
+              "    return fun();\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+
         // loops..
         check("void f() {\n"
               "    int *p = 0;\n"