I'm submitting a ...

• bug report
• feature request
• other

Current behavior:
When redefine module, orgin module lost.

Expected / new behavior:
Override a module, or do something whether the modele is defined or not.

Minimal reproduction of the problem with instructions:
none

AngularJS version: 1.x.y
all

Browser: [all]

Anything else:
before the code:

      if (requires && modules.hasOwnProperty(name)) {
        modules[name] = null;
      }

add:

      if(isBoolean(requires)){
        return modules.hasOwnProperty(name);
      }

then I can user like this:

      if(angular.module('my-module', true)){
        // codes
      }
      else{
        // codes if not exit module 'my-module'
      }