borisyankov/DefinitelyTyped — pull request #2768 by mhegazy (2014-09-02 21:41:17+00:00)
Title: Fix invalid extend in backgrid tests

Model defines private variables, so for TestCollection to be compatible with Collection it needs to extend Collection to inherit its privates.

This is identified while testing the new version of TypeScript compiler. The new compiler caught this issue that was not detected before.