http://d.puremagic.com/issues/show_bug.cgi?id=8892

           Summary: Not precise error message with failed fixed size array
                    assign
           Product: D
           Version: D2
          Platform: x86
        OS/Version: Windows
            Status: NEW
          Keywords: diagnostic
          Severity: minor
          Priority: P2
         Component: DMD
        AssignedTo: nobody@puremagic.com
        ReportedBy: bearophile_hugs@eml.cc


--- Comment #0 from bearophile_hugs@eml.cc 2012-10-25 09:57:53 PDT ---
struct Foo {
    char[3] data;
}
int bar(Foo f) {
    return f.data[0];
}
void main() {
    auto f = Foo(['A', 'B']);
}


DMD 2.061alpha:

test.d(8): Error: cannot implicitly convert expression (['A','B']) of type
char[] to char


A better error message is:

test.d(8): Error: cannot implicitly convert expression (['A','B']) of type
char[] to char[4]

Or even something like:

test.d(8): Error: cannot implicitly convert expression (['A','B']) of type
char[] to char[4] ('Foo.data' field)

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Andrej Mitrovic <andrej.mitrovich@gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |andrej.mitrovich@gmail.com


--- Comment #1 from Andrej Mitrovic <andrej.mitrovich@gmail.com> 2012-10-25 10:47:34 PDT ---
(In reply to comment #0)
> A better error message is:
> 
> test.d(8): Error: cannot implicitly convert expression (['A','B']) of type
> char[] to char[4]

Don't you mean char[3]? Also the 'bar' function is not necessary for test-case.

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--- Comment #2 from bearophile_hugs@eml.cc 2012-10-25 11:14:47 PDT ---
(In reply to comment #1)

> Don't you mean char[3]?

Right, sorry (this code comes from Issue 8893 ).


> Also the 'bar' function is not necessary for test-case.

Right, shorter test case:


struct Foo {
    char[2] data;
}
void main() {
    auto f = Foo(['A']);
}

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--- Comment #3 from Andrej Mitrovic <andrej.mitrovich@gmail.com> 2012-11-29 14:49:23 PST ---
*** Issue 8918 has been marked as a duplicate of this issue. ***

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--- Comment #4 from Andrej Mitrovic <andrej.mitrovich@gmail.com> 2013-01-26 14:35:20 PST ---
(In reply to comment #2)
> struct Foo {
>     char[2] data;
> }
> void main() {
>     auto f = Foo(['A']);
> }

What I don't understand is why the above fails at compile-time but the following compiles (it fails at runtime):

char[2] data = ['A'];

$ object.Error: lengths don't match for array copy, 2 = 1

I think this case should also an accepts-invalid, because the compiler can see at compile-time that the lengths don't match.

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Andrej Mitrovic <andrej.mitrovich@gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |pull
           Platform|x86                         |All
         AssignedTo|nobody@puremagic.com        |andrej.mitrovich@gmail.com
            Summary|Not precise error message   |Wrong diagnostic for static
                   |with failed fixed size      |array assignment
                   |array assign                |
         OS/Version|Windows                     |All
           Severity|minor                       |normal


--- Comment #5 from Andrej Mitrovic <andrej.mitrovich@gmail.com> 2013-01-26 14:44:44 PST ---
https://github.com/D-Programming-Language/dmd/pull/1558

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--- Comment #6 from Kenji Hara <k.hara.pg@gmail.com> 2013-01-27 01:16:38 PST ---
(In reply to comment #4)
> What I don't understand is why the above fails at compile-time but the following compiles (it fails at runtime):
> 
> char[2] data = ['A'];
> 
> $ object.Error: lengths don't match for array copy, 2 = 1
> 
> I think this case should also an accepts-invalid, because the compiler can see at compile-time that the lengths don't match.

It is known inconsistency around static array initialization.

int[3] garr = [1,2];
// When creating data section, garr[2] is filled by 0

void main()
{
    int[3] larr = [1,2];
    // This is translated to runtime element-wise blit assign:
    // larr[0..3] = [1,2]
    // and fails at runtime.
}

When we based on the issue, following code still have similar issue.

struct Foo {
    char[2] data;
}
void main() {
    auto f = Foo(['A']);
    // 1. should be compile time error, array length mismatch, or
    // 2. the initializer should be translated to Foo(['A', char.init]) ?
}

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--- Comment #7 from github-bugzilla@puremagic.com 2013-01-27 01:32:19 PST ---
Commits pushed to master at https://github.com/D-Programming-Language/dmd

https://github.com/D-Programming-Language/dmd/commit/646ce34fae3a1e12032bb7a2343e54daf0074db0 Fixes Issue 8892 - Better diagnostic for static array assignment.

https://github.com/D-Programming-Language/dmd/commit/c316e2e6d059b7e6fdc6ae8616e72dfda9dfa8f6 Merge pull request #1558 from AndrejMitrovic/Fix8892

Issue 8892 - Better diagnostic for static array assignment

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Kenji Hara <k.hara.pg@gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED


--- Comment #8 from Kenji Hara <k.hara.pg@gmail.com> 2013-01-27 07:01:24 PST ---
Error message is now improved.

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--- Comment #9 from github-bugzilla@puremagic.com 2013-02-11 12:20:20 PST ---
Commits pushed to staging at https://github.com/D-Programming-Language/dmd

https://github.com/D-Programming-Language/dmd/commit/646ce34fae3a1e12032bb7a2343e54daf0074db0 Fixes Issue 8892 - Better diagnostic for static array assignment.

https://github.com/D-Programming-Language/dmd/commit/c316e2e6d059b7e6fdc6ae8616e72dfda9dfa8f6 Merge pull request #1558 from AndrejMitrovic/Fix8892

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