---
description: "Learn more about: Warning C26478: Don't use std::move on constant variables. (es.56)"
title: Warning C26478
ms.date: 07/15/2019
f1_keywords: ["C26478", "NO_MOVE_OP_ON_CONST"]
helpviewer_keywords: ["C26478"]
---
# Warning C26478

> Don't use `std::move` on constant variables. (es.56)

## Remarks

This warning is to indicate that the use of `std::move` not consistent with how `std::move` is intended to be used.

When called on a `const` object, `std::move` returns a copy of the object, which is likely not the developer's intent.

Code analysis name: `NO_MOVE_OP_ON_CONST`

## Example 1

```cpp
struct node
{
    node* next;
    int id;
};

void foo(const node& n)
{
    const node local = std::move(n); // C26478 reported here
    // ...
}
```

An assignment operator or using the passed in parameter will prevent this warning from being issued and will adequately serve the developer's use case.

## Example 2

```cpp
struct s;

template <typename T>
void bar(T t){};

void foo()
{
    const s s1;
    bar(std::move(s1)); // C26478 reported here
}
```

## See also

[ES.56 - Write std::move() only when you need to explicitly move an object to another scope](https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#es56-write-stdmove-only-when-you-need-to-explicitly-move-an-object-to-another-scope)