http://d.puremagic.com/issues/show_bug.cgi?id=6511

           Summary: [CTFE] Array op gives wrong result
           Product: D
           Version: D2
          Platform: x86
        OS/Version: Windows
            Status: NEW
          Keywords: wrong-code
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: nobody@puremagic.com
        ReportedBy: bearophile_hugs@eml.cc


--- Comment #0 from bearophile_hugs@eml.cc 2011-08-16 13:49:05 PDT ---
T foo(T)() {
    T[1] a = [1];
    a[] += a[];
    return a[0];
}
static assert(foo!ulong() == 2); // error
static assert(foo!long() == 2); // error
void main() {
    assert(foo!ulong() == 2); // OK
    assert(foo!long() == 2); // OK
}


DMD gives:

test.d(6): Error: static assert  (1LU == 2LU) is false

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Walter Bright <bugzilla@digitalmars.com> changed:

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


--- Comment #1 from Walter Bright <bugzilla@digitalmars.com> 2011-08-22 22:47:12 PDT ---
https://github.com/D-Programming-Language/dmd/commit/563a291a5c7757fca87685909afa37100e3b44f6

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--- Comment #2 from bearophile_hugs@eml.cc 2011-08-22 23:21:42 PDT ---
The given code example now works. But this:


T foo(T)() {
    T[1] a = [1];
    a[] += a[];
    return a[0];
}
static assert(foo!long() == 2); // OK
static assert(foo!int() == 2); // error
void main() {}


Gives:

test.d(3): Error: _arraySliceSliceAddass_i cannot be interpreted at compile
time, because it has no available source code
test.d(7): Error: cannot evaluate foo() at compile time
test.d(7): Error: static assert  (foo() == 2) is not evaluatable at compile
time

This behaviour difference between long and int is not good. Do you prefer me to reopen this bug or to open a new one?

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

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


--- Comment #3 from Don <clugdbug@yahoo.com.au> 2011-08-23 01:29:13 PDT ---
(In reply to comment #2)
> The given code example now works. But this:
> 
> 
> T foo(T)() {
>     T[1] a = [1];
>     a[] += a[];
>     return a[0];
> }
> static assert(foo!long() == 2); // OK
> static assert(foo!int() == 2); // error
> void main() {}
> 
> 
> Gives:
> 
> test.d(3): Error: _arraySliceSliceAddass_i cannot be interpreted at compile
> time, because it has no available source code
> test.d(7): Error: cannot evaluate foo() at compile time
> test.d(7): Error: static assert  (foo() == 2) is not evaluatable at compile
> time
> 
> This behaviour difference between long and int is not good. Do you prefer me to reopen this bug or to open a new one?

A new one. Surprisingly, it actually has *nothing* in common with this bug.
This bug was actually a problem with array slicing, and didn't require array
operations.
The new case is that the array operations which are special-cased in the
runtime don't have special case treatment in the CTFE engine, since CTFE
doesn't have access to the source code of druntime. The array ops which aren't
special-cased don't use druntime code, so they should all work.

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--- Comment #4 from bearophile_hugs@eml.cc 2011-08-23 02:10:18 PDT ---
(In reply to comment #3)

> A new one.

OK. It is bug 6545

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