# CMP0010

Bad variable reference syntax is an error.

In CMake 2.6.2 and below, incorrect variable reference syntax such as a missing close-brace (`${FOO`) was reported but did not stop processing of CMake code. This policy determines whether a bad variable reference is an error. The `OLD` behavior for this policy is to warn about the error, leave the string untouched, and continue. The `NEW` behavior for this policy is to report an error.

If `CMP0053` is set to `NEW`, this policy has no effect and is treated as always being `NEW`.

This policy was introduced in CMake version 2.6.3. CMake version 3.18.0-rc4 warns when the policy is not set and uses `OLD` behavior. Use the `cmake_policy()` command to set it to `OLD` or `NEW` explicitly.

Note

The `OLD` behavior of a policy is `deprecated by definition` and may be removed in a future version of CMake.