---
description: "Learn more about: Warning C26473 NO_IDENTITY_CAST"
title: Warning C26473
ms.date: 11/15/2017
f1_keywords: ["C26473", "NO_IDENTITY_CAST"]
helpviewer_keywords: ["C26473"]
ms.assetid: d88aaa57-0003-421f-8377-4e6a5c27f2df
---
# Warning C26473

> Don't cast between pointer types where the source type and the target type are the same.

**C++ Core Guidelines**:
[Type.1](https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#prosafety-type-safety-profile): Avoid casts

This rule helps to remove unnecessary or suspicious casts. Obviously, when a type is converted to itself, such a conversion is ineffective. Yet the fact that the cast is used may indicate a subtle design issue or a potential for regression if types change in future. It's always safer to use as few casts as possible.

## Remarks

- This rule is implemented for static casts and reinterpret casts, and checks only pointer types.

## Example

dangerously generic lookup

```cpp
gsl::span<server> servers_;

template<class T>
server* resolve_server(T tag) noexcept {
    auto p = reinterpret_cast<server*>(tag); // C26473, also 26490 NO_REINTERPRET_CAST
    return p >= &(*servers_.begin()) && p < &(*servers_.end()) ? p : nullptr;
}

void promote(server *s, int index) noexcept {
    auto s0 = resolve_server(s);
    auto s1 = resolve_server(index);
   if (s0 && s1)
        std::swap(s0, s1);
}
```

dangerously generic lookup - reworked

```cpp
// ...
server* resolve_server(server *p) noexcept {
    return p >= &(*servers_.begin()) && p < &(*servers_.end()) ? p : nullptr;
}

server* resolve_server(ptrdiff_t i) noexcept {
    return !servers_.empty() && i >= 0 && i < servers_.size() ? &servers_[i] : nullptr;
}
// ...
```