removal of fail keyword Issue #4524

[nickdesaulniers]

Removed fail keyword. 2 of the 3 steps here. The followup pull request will be replacing die! with fail! after a new snapshot is created. The first commit removes almost all invocations of fail with die!, the rest are caught in the second after fail is removed from the lexer & parser. Tests are green after applying the first or both patches. I'd like to separate these from the final commit that involves a new snapshot. Heads up @bstrie & @brson.

[bstrie]

Unrelated observation here, but I wonder how hard it would be to make die! act like debug! et al with respect to having an implicit fmt! inside of it.

[nickdesaulniers]

Referencing Issue #4524

[bstrie]

Heh, I've never before seen a patch so long that Github refuses to show its complete diff. Looks good, though I'm not qualified to comment on the part about ripping out the fail keyword itself.

[nickdesaulniers]

Awesome! Thanks for taking the time to review it for me @bstrie! I appreciate it!

[brson]

There were some big merge conflicts (there have been a lot of wide-reaching changes going in lately), so I've pushed just the first commit converting to die!(), minus all the conflicting bits. That's the bulk of your work merged.

The next step is to rebase your branch onto mozilla/incoming and fix all the merge conflicts ... and everything will be a conflict :-D. @nickdesaulniers would you mind trying to do that? It's not going to be pleasant, and I'm sorry about that, but it's the nature of these big syntax changes.

[nickdesaulniers]

That's ok, I need some experience with merge conflict resolution. So I think I've done it right. Either 100% correct or 100% wrong. Building now. Seeing warnings when building src/libcore/private/finally.rs L35 warning: argument 1 uses by-copy mode. Not sure that I caused that. Will have an incoming pull request shortly, hopefully!

[brson]

@nickdesaulniers The warning is unrelated. Before we do a snapshot you will need to create a duplicate definition of die! called fail!. Once the snapshot compiler knows how to interpret fail! you can start using it.