http://d.puremagic.com/issues/show_bug.cgi?id=3735

           Summary: op=
           Product: D
           Version: 2.038
          Platform: Other
        OS/Version: Linux
            Status: NEW
          Severity: normal
          Priority: P2
         Component: www.digitalmars.com
        AssignedTo: nobody@puremagic.com
        ReportedBy: ellery-newcomer@utulsa.edu


--- Comment #0 from Ellery Newcomer <ellery-newcomer@utulsa.edu> 2010-01-23 08:46:43 PST ---
Spec says a op= b is semantically equivalent to a = a op b.

Spec lies, or at least is at odds with DMD.

-- 
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=3735


Stewart Gordon <smjg@iname.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |rejects-valid
                URL|                            |http://www.digitalmars.com/
                   |                            |d/1.0/expression.html
                 CC|                            |smjg@iname.com
           Platform|Other                       |All
            Version|2.038                       |D1 & D2
         OS/Version|Linux                       |All


--- Comment #1 from Stewart Gordon <smjg@iname.com> 2010-09-23 06:16:30 PDT ---
I assume you're talking about the fact that code like this fails:
----------
class Qwert {
    Qwert opAdd(Qwert yuiop) { return this; }
}

void main() {
    Qwert asfdg = new Qwert;
    asdfg += asdfg;
}
----------
I entirely agree that this code should work, on the bases both of common sense and of this spec.

-- 
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=3735



--- Comment #2 from Don <clugdbug@yahoo.com.au> 2012-01-18 12:06:10 PST ---
Apart from Stewart's comment, there's also the case of >>>.

a >>>= b is different to a = a >>> b, if a is short or byte.

(The first does an unsigned shift, the second does a signed shift).

-- 
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=3735


timon.gehr@gmx.ch changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |timon.gehr@gmx.ch


--- Comment #3 from timon.gehr@gmx.ch 2012-01-18 12:18:44 PST ---
The same halds for other binary operators. The sentence should probably just be removed from the spec.

-- 
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=3735



--- Comment #4 from Stewart Gordon <smjg@iname.com> 2012-01-18 16:31:48 PST ---
(In reply to comment #2)
> Apart from Stewart's comment, there's also the case of >>>.
> 
> a >>>= b is different to a = a >>> b, if a is short or byte.
> 
> (The first does an unsigned shift, the second does a signed shift).

Oh yes, that crazy abomination that is promotion.  Suppose you have

byte a = cast(byte) 0b11110000;  // why does it insist on a cast?
a = a >>> 3;

then what actually happens is

0b11110000 >> 3
promote to int
0b1111111111110000 >> 3
apply shift
0b0001111111111110
convert back to a byte
0b11111110

If you shift by 25 or more (17 or more for short), you'll start to see the zero
bits come through.

-- 
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=3735



--- Comment #5 from timon.gehr@gmx.ch 2012-01-18 16:36:54 PST ---
(In reply to comment #4)
> byte a = cast(byte) 0b11110000;  // why does it insist on a cast?

Because 240 does not fit inside the range -128 to 127.
static assert(0b11110000 != cast(byte)0b11110000);

-- 
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=3735



--- Comment #6 from github-bugzilla@puremagic.com 2012-01-23 14:15:24 PST ---
Commit pushed to https://github.com/D-Programming-Language/d-programming-language.org

https://github.com/D-Programming-Language/d-programming-language.org/commit/2b757bdcc82c69ff4021361acd93f8a0b26df65c fix Issue 3735 - op=

-- 
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=3735


Walter Bright <bugzilla@digitalmars.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
                 CC|                            |bugzilla@digitalmars.com
         Resolution|                            |FIXED


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