Fixed #2000 (segmentation fault of cppcheck with bitfield)

lib/checkclass.cpp

@@ -348,8 +348,10 @@ void CheckClass::createSymbolDatabase()
 
                         // skip over function body
                         tok = next->next();
-                        while (tok->str() != "{")
+                        while (tok && tok->str() != "{")
                             tok = tok->next();
+                        if (!tok)
+                            return;
                         tok = tok->link();
                     }
                 }

test/testclass.cpp

@@ -154,6 +154,7 @@ private:
 
         TEST_CASE(symboldatabase1);
         TEST_CASE(symboldatabase2);
+        TEST_CASE(symboldatabase3); // ticket #2000
     }
 
     // Check the operator Equal
@@ -4278,6 +4279,15 @@ private:
                    "};");
         ASSERT_EQUALS("", errout.str());
     }
+
+    void symboldatabase3()
+    {
+        checkConst("typedef void (func_type)();\n"
+                   "struct A {\n"
+                   "    friend func_type f : 2;\n"
+                   "};\n");
+        ASSERT_EQUALS("", errout.str());
+    }
 };
 
 REGISTER_TEST(TestClass)