Why is this an issue?

To avoid confusion, even in different scopes, there should not be multiple interfaces with the same name.

How to fix it

Code examples

Noncompliant code example

File 1:
interface fly;
  ...
endinterface

File 2:
interface dream;
  interface fly;
    ...
  endinterface
  ...
endinterface

Compliant solution

File 1:
interface fly;
  ...
endinterface

File 2:
interface dream;
  interface sleep;
    ...
  endinterface
  ...
endinterface