IL2049: Unrecognized internal attribute

Cause

An internal attribute name specified in a custom attribute annotations file is not supported by the trimmer.

Example

<!-- IL2049: Unrecognized internal attribute 'InvalidInternalAttributeName' -->
<linker>
  <assembly fullname="MyAssembly">
    <type fullname="MyType">
      <method name="MyMethod">
        <attribute internal="InvalidInternalAttributeName" />
      </method>
    </type>
  </assembly>
</linker>