There's no occurrence of Object.assign() in code in the Elm platform packages or code generated directly by Elm. The closest thing I could find that might be introducing this is https://github.com/fluxxu/elm-hot-loader/blob/master/hmr.js#L182
This is the same function mentioned in https://groups.google.com/forum/#!searchin/elm-discuss/Object.assign%7Csort:relevance/elm-discuss/wtG5LXxBP2g/R71aLRQHAwAJ Elm programs *should* be compatible through at least IE9. Rex, you should file an issue with elm-hot-loader about their use of Object.assign() -- You received this message because you are subscribed to the Google Groups "Elm Discuss" group. To unsubscribe from this group and stop receiving emails from it, send an email to elm-discuss+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.