http://d.puremagic.com/issues/show_bug.cgi?id=5606

           Summary: [CTFE] filter(iota) minus enforce
           Product: D
           Version: D2
          Platform: x86
        OS/Version: Windows
            Status: NEW
          Keywords: rejects-valid
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: nobody@puremagic.com
        ReportedBy: bearophile_hugs@eml.cc


--- Comment #0 from bearophile_hugs@eml.cc 2011-02-17 14:48:06 PST ---
In attach there is a CTFE bug I don't understand, dmd 2.052beta. I have reduced
it from Phobos filter() and iota() code, but it's about one hundred lines
still.

This main doesn't compile:

void main() {
    auto odds = filter!isOdd(iota(0, 10, 1));
    auto b1 = foo!isOdd(iota(0, 10, 1)); // OK
    enum b2 = foo!isOdd(iota(0, 10, 1)); // Error
}


This compiles:

void main() {
    auto b1 = foo!isOdd(iota(0, 10, 1));
    enum b2 = foo!isOdd(iota(0, 10, 1));
}


This too:

void main() {
    auto b1 = foo!isOdd(iota(0, 10, 1));
    enum b2 = foo!isOdd(iota(0, 10, 1));
    auto odds = filter!isOdd(iota(0, 10, 1));
}


This too:

void main() {
    auto odds = filter!isOdd(iota(0, 10, 1));
    auto b1 = foo!isOdd(iota(0, 10, 1));
}


In a bit more longer version of the code, removing this produced a stack overflow (not anymore), so the cause may be isInfinite or isInputRange:

static if (isInfinite!Range) {


(Beside killing inlining, reducing performance, and not allowing the nothrow
tag, the enforce() also makes a function not fit for CTFE. Here I have
commented out the enforce()).

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--- Comment #1 from bearophile_hugs@eml.cc 2011-02-17 14:49:08 PST ---
Created an attachment (id=914)
filter(iota) minus enforce, reduced in many ways

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
                 CC|                            |clugdbug@yahoo.com.au
         Resolution|                            |DUPLICATE


--- Comment #2 from Don <clugdbug@yahoo.com.au> 2011-06-07 01:23:06 PDT ---
Reduced test case:
-------------
struct Bug5606 {
    bool empty(){ return true; }
}
static assert(!is(char[1 + Bug5606.empty]));
static assert(Bug5606().empty());

It's a dup of bug 4910 which is fixed in git.

*** This issue has been marked as a duplicate of issue 4910 ***

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