http://d.puremagic.com/issues/show_bug.cgi?id=7046

           Summary: CTFE: append null does nothing
           Product: D
           Version: D2
          Platform: Other
        OS/Version: Linux
            Status: NEW
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: nobody@puremagic.com
        ReportedBy: destructionator@gmail.com


--- Comment #0 from Adam D. Ruppe <destructionator@gmail.com> 2011-12-01 18:07:38 PST ---
string[] test() {
    string[] ret;

    ret ~= null;
    ret ~= null;

    assert(ret.length == 2); // fails
    return ret;
}

void main() {
    enum ctfe = test();
}

===
test90.d(7): Error: assert(ret.length == 2u) failed
test90.d(12):        called from here: a()

-- 
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
------- You are receiving this mail because: -------

http://d.puremagic.com/issues/show_bug.cgi?id=7046


Don <clugdbug@yahoo.com.au> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |clugdbug@yahoo.com.au


--- Comment #1 from Don <clugdbug@yahoo.com.au> 2011-12-02 02:57:40 PST ---
This works on git HEAD. Probably a duplicate of a recently fixed bug.

-- 
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
------- You are receiving this mail because: -------

http://d.puremagic.com/issues/show_bug.cgi?id=7046


Steven Schveighoffer <schveiguy@yahoo.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |schveiguy@yahoo.com


--- Comment #2 from Steven Schveighoffer <schveiguy@yahoo.com> 2011-12-02 04:30:34 PST ---
Are we sure this isn't expected?  I mean a null could mean a null string[], not a null string.

string[] ret;
string[] a = null;

ret ~= a;
ret ~= a;

neither of these lines should do anything to ret, since they are empty arrays of the same type.

I almost think the code in question should fail to compile for being too ambiguous.

-- 
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
------- You are receiving this mail because: -------

http://d.puremagic.com/issues/show_bug.cgi?id=7046



--- Comment #3 from Don <clugdbug@yahoo.com.au> 2011-12-02 04:44:28 PST ---
See bug 2006.

-- 
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
------- You are receiving this mail because: -------

http://d.puremagic.com/issues/show_bug.cgi?id=7046


bearophile_hugs@eml.cc changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |bearophile_hugs@eml.cc


--- Comment #4 from bearophile_hugs@eml.cc 2011-12-02 04:48:35 PST ---
(In reply to comment #2)

> I almost think the code in question should fail to compile for being too ambiguous.

Right.

-- 
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
------- You are receiving this mail because: -------

http://d.puremagic.com/issues/show_bug.cgi?id=7046



--- Comment #5 from Steven Schveighoffer <schveiguy@yahoo.com> 2011-12-02 04:54:29 PST ---
(In reply to comment #3)
> See bug 2006.

So is this a dupe?  I'm concerned there was a change in git that makes this "work."  Moving from one ambiguous interpretation to another doesn't sound like progress.

Do we have some definitive answer on what *should* happen?

-- 
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
------- You are receiving this mail because: -------

http://d.puremagic.com/issues/show_bug.cgi?id=7046



--- Comment #6 from Adam D. Ruppe <destructionator@gmail.com> 2011-12-02 07:47:17 PST ---
(In reply to comment #2)
> I mean a null could mean a null string[], not a null string.

I oversimplified the test - in the original code it came from, it was more like

string a = null;
ret ~= a;

which gets the same result in 2.056

I haven't tried git though. I'm not sure how to use that yet!

> I almost think the code in question should fail to compile for being too ambiguous.

With null itself... maybe. In the case of string[], ~= null could
have two meanings, but one of them is pretty obviously a no-op, so it's
probably not what you meant.

If a variable happens to be null, maybe doing nothing is what you wanted, but in that case, the variable has an exact type declared so it's not ambiguous anymore.

-- 
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
------- You are receiving this mail because: -------

http://d.puremagic.com/issues/show_bug.cgi?id=7046



--- Comment #7 from Adam D. Ruppe <destructionator@gmail.com> 2011-12-02 07:53:36 PST ---
BTW, I labeled this as CTFE because in 2.056, running the same function at runtime, the assert passes.

I think this worked in CTFE a couple releases ago too, and since it works in the git version again, it was probably just a temporary regression in the interpreter.

-- 
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
------- You are receiving this mail because: -------

http://d.puremagic.com/issues/show_bug.cgi?id=7046


Don <clugdbug@yahoo.com.au> changed:

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


--- Comment #8 from Don <clugdbug@yahoo.com.au> 2011-12-14 08:35:17 PST ---
This compiled on DMD2.053, but generated wrong code. It failed to compile on 2.054 to 2.056. Fixed 2.057 -- dup of bug 6077

*** This issue has been marked as a duplicate of issue 6077 ***

-- 
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
------- You are receiving this mail because: -------