#### Note: this error code is no longer emitted by the compiler.

`#[cmse_nonsecure_entry]` is only valid for targets with the TrustZone-M
extension.

Erroneous code example:

```ignore (no longer emitted)
#![feature(cmse_nonsecure_entry)]

pub extern "cmse-nonsecure-entry" fn entry_function() {}
```

To fix this error, compile your code for a Rust target that supports the
TrustZone-M extension. The current possible targets are:
* `thumbv8m.main-none-eabi`
* `thumbv8m.main-none-eabihf`
* `thumbv8m.base-none-eabi`