Support multiple implicitly typed local variables in a single declaration.

[CyrusNajmabadi]

Fixes: #4294

[gafter]

I'm not sure I understand why this is viewed as an improvement to the language.

[CyrusNajmabadi]

@gafter We can talk about it at today's LDM.

[CyrusNajmabadi]

@gafter Hey Neal... why was this closed? Thanks!

[gafter]

@CyrusNajmabadi Based on LDM "never".

[CyrusNajmabadi]

Really? That seems rather unfortunate. My proposal provided a way to allow this functionality in a way that simply allowed more scenarios when there was no chance of confusion or other problems. From the last LDM where I remember talking about this, the options were:

1. Don't do anything.
2. Allow multi-var, if all the types were the same.
3. Allow multi-var, the type of all the locals is the 'best common type'.
4. Allow multi-var, each local gets its own inferred type.

There were problems with both 3 and 4. Namely that there was a split (both in the LDM and the community) as to which was better. However, there was no problem with '2' afaik. Indeed, '2' had the benefit that it didn't exclude us from doing '3' or '4' in the future if we wanted to. So '2' was a strictly positive step forward for where we are now, with no downsides (that I can remember). It does not disallow anything allowed today, and it at least allows multi-var in some common cases where the user does want to use the same type for each var.

What's the reason we think 'never' is appropriate here? Thanks!

[gafter]

@CyrusNajmabadi Excellent question to raise at the LDM.