Issue 7444 - Require [] for array copies too

[9rnsr]

http://d.puremagic.com/issues/show_bug.cgi?id=7444

Deprecate ambiguity between slice assignment and element-wise one.
See test/runnable/assignable.d

Requires: dlang/druntime#314 (merged)
Requires: dlang/phobos#960

[andralex]

This looks good, and I like how you handled the covariance a lot. Kudos to @9rnsr! Now I know you'll hate this, but we can't pull this in without adequate documentation. Could you please find the time to write a draft?

[yebblies]

Fails to compile druntime

[9rnsr]

I've posted a pull request which fixes druntime code based on this enhancement.
See dlang/druntime#314 .

[WalterBright]

As I wrote on the bugzilla entry, I'm not sure this is worth code breakage.

[WalterBright]

Maybe do it as a warning?

[9rnsr]

OK. I changed deprecation errors to warning.
And I posted an additional Phobos pull #960 (I've completely forgotten to post it).

[9rnsr]

Comemnt to re-run auto tester.

[ghost]

Can we improve the error message here? Saying one syntax is better than the other without a reason in the error message has no meaning.

Also the message itself is unpleasant:

void main()
{
    int[] a;
    int[] b;
    a[] = b;
}

test.d(18): Warning: explicit element-wise assignment a[] = (b)[] is better than a[] = b

What's with the parenthesized b?

Another one:

void main()
{
    char[3] dst;
    char[3] src = [1, 2, 3];
    char* ptr = &dst[0];
    ptr[0 .. 3] = src;
}

Warning: explicit element-wise assignment ptr[cast(uint)0..cast(uint)3] = (src)[] is better than ptr[cast(uint)0..cast(uint)3] = src

This is an extremely ugly diagnostic, it needs to improve.