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digitalmars.D.bugs - [Issue 6235] New: Regression(DMD 2.053) ICE on typeof(Range.init[0..$]) inside a templated struct/class

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http://d.puremagic.com/issues/show_bug.cgi?id=6235

           Summary: Regression(DMD 2.053) ICE on typeof(Range.init[0..$])
                    inside a templated struct/class
           Product: D
           Version: D2
          Platform: Other
        OS/Version: Windows
            Status: NEW
          Keywords: ice-on-valid-code
          Severity: regression
          Priority: P2
         Component: DMD
        AssignedTo: nobody puremagic.com
        ReportedBy: sandford jhu.edu


--- Comment #0 from Rob Jacques <sandford jhu.edu> 2011-07-01 13:51:56 PDT ---
This is a regression between DMD 2.052 and DMD 2.053. Here is a very reduced
test case:

struct Bug(Range) { pragma(msg, typeof(Range.init[0..$]) ); }

void main(string[] args) {
    Bug!(ubyte[]) bug;
}

The issue also effect classes and is statements, i.e.

    enum useSlicing = is(typeof(Range.init[0..$]) : const ubyte[] );

This problem seems to be limited to the use of a template parameter inside a
struct/class defined outside of the current scope. All of the following
compile:

void main(string[] args) {
    pragma(msg, typeof((ubyte[]).init[0..$]) );

    alias ubyte[] Range;
    pragma(msg, typeof(Range.init[0..$]) );

    struct NotBug(Range2) { pragma(msg, typeof(Range2.init[0..$]) ); }
    NotBug!(ubyte[]) notBug; 
}     

This bug can be worked around by placing the statement inside its own
sub-template. I.e:

struct Bug(Range) {
    template UseSlicing(__Range) {
        enum UseSlicing = is(typeof(__Range.init[0..$]) : const ubyte[] );
    }
    pragma(msg, UseSlicing!Range);
}

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Don <clugdbug yahoo.com.au> changed:

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


--- Comment #1 from Don <clugdbug yahoo.com.au> 2011-07-01 14:36:38 PDT ---
It's crashing in VoidInitializer::toDt(). Seems that 'type' hasn't been set.

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yebblies <yebblies gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |yebblies gmail.com


--- Comment #2 from yebblies <yebblies gmail.com> 2011-07-02 15:16:36 EST ---
Using $ seems to be adding the declaration to the struct as a field.
Is there any reason $ is always a variable, not just re-written as
exp[... $ ... ] => exp[... exp.length ...] ?

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--- Comment #3 from Don <clugdbug yahoo.com.au> 2011-07-03 13:41:49 PDT ---
(In reply to comment #2)

 Using $ seems to be adding the declaration to the struct as a field.
 Is there any reason $ is always a variable, not just re-written as
 exp[... $ ... ] => exp[... exp.length ...] ?


I think it's because exp may have side effects, so it should only be evaluated
once.

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--- Comment #4 from yebblies <yebblies gmail.com> 2011-07-04 18:05:23 EST ---
(In reply to comment #3)

 exp[... $ ... ] => exp[... exp.length ...] ?


 
 I think it's because exp may have side effects, so it should only be evaluated
 once.


Ah, of course.
Can you see anything wrong with rewriting it as:
(auto __tmp = exp, __tmp[... __tmp.length ...])
I'll have to dig into it to be sure, but I think something like this would
solve a lot of the problems caused by __dollar.

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--- Comment #5 from Don <clugdbug yahoo.com.au> 2011-07-04 06:00:57 PDT ---
(In reply to comment #4)

 (In reply to comment #3)

 exp[... $ ... ] => exp[... exp.length ...] ?


 
 I think it's because exp may have side effects, so it should only be evaluated
 once.


 
 Ah, of course.
 Can you see anything wrong with rewriting it as:
 (auto __tmp = exp, __tmp[... __tmp.length ...])


Not sure. There might be problem if exp defines postblit.


 I'll have to dig into it to be sure, but I think something like this would
 solve a lot of the problems caused by __dollar.


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--- Comment #6 from Don <clugdbug yahoo.com.au> 2011-10-24 00:35:48 PDT ---
Regression introduced by me:

https://github.com/D-Programming-Language/dmd/commit/03e022f8cbfed660d31ebe6217f3faab01ca7472

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prev sibling parent d-bugmail puremagic.com writes:
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Don <clugdbug yahoo.com.au> changed:

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


--- Comment #7 from Don <clugdbug yahoo.com.au> 2011-11-03 23:56:14 PDT ---
https://github.com/D-Programming-Language/dmd/commit/56d4a1bc4781837823665ef7423aa7e2b2df1083

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