On 5/23/2013 7:38 PM, Steven Schveighoffer wrote:
On Thu, 23 May 2013 21:56:47 -0400, Walter Bright <[email protected]>
wrote:
On 5/23/2013 5:56 PM, Walter Bright wrote:
On 5/23/2013 5:35 PM, Steven Schveighoffer wrote:
What about making it an error UNLESS you pass a compiler flag. The user
will be
informed, and the new behavior (which I find useful) is possible.
While that idea has significant merit, I oppose it on the following grounds:
1. It forces a very abrupt change. We've followed a policy of gradual change,
giving people plenty of time to adapt their codebase. This does not.
What we need is a message that says "what you are doing is wrong, you need to
put static in front of it." Since the new behavior never before existed, all
existing code will be identical if they put static before the declaration.
There is no real time needed to adapt their codebase, except for the time it
takes to find the errors, open a file, type "static " and save it. No thinking
is involved. The error message can say as much.
2. Having optional errors like that leads to unfortunate problems inside generic
code that tests whether some constructs compile or not.
I just realized that there is a large problem with my proposed solution. Let's
say one library writer has not updated his code to work with the latest
compiler. Another library writer starts using the new feature.
Compile them together, and now you have a mish-mash of valid and invalid code
that either all fails or all compiles based on a switch.
Yeah, that is a problem I hadn't thought of.
I think the only good solution is to use an error.
Yes, and the error has to be there for long enough to get all the existing code
in use to be corrected before the new behavior is enabled.
A warning is not good
enough/strong enough.
For now, it is the proper path. The warning is that "change is coming, but you
have time to fix it."
This is one change where ALL code broken by this change
is fixable with a simple solution, and at some point, people will have to deal
with this.
Yes, but it is not so urgent as RIGHT NOW YOU MUST FIX IT. Hence, the warning.
