This track from "Roger Rabbit" was a duet and shouldn't be credited to Mel Blanc alone. The whole point was to have Warner & Disney toons appear together in that movie. Mickey Mouse & Bugs Bunny appear together in a later scene just in case the point wasn't driven home the first time.

This was done right. Both names are in the members box, so the pages are linked. Linking = good, merging, not so much.