http://d.puremagic.com/issues/show_bug.cgi?id=5073

           Summary: wrong file name in error message for "voids have no
                    value" inside alias templates (affects
                    std.algorithm.map)
           Product: D
           Version: D2
          Platform: Other
        OS/Version: Windows
            Status: NEW
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: nobody@puremagic.com
        ReportedBy: sandford@jhu.edu


--- Comment #0 from Rob Jacques <sandford@jhu.edu> 2010-10-18 17:28:42 PDT ---
There seems to be an issue with the reported filename for alias templates that create a variable of type void. Here is a test case:

using DMD 2.049:

import std.algorithm;
void main(string[] args) {
    auto foobar  = map!( (int i){} )([0]); // using a named delegate also
errors
}

results in the error message

hello.d, Line 119
Error: variable hello.main.Map!(__dgliteral1,int[]).Map._cache voids have no
value

Line 119 of std.algorithm (part of the Map struct):
Unqual!ElementType _cache;

This may be related to issue 2180.

Here is a reduced test case that gives a slightly better set of error messages than the std.algorithm example:

hello.d:
import std.stdio: writeln;
import goodbye;

void main(string[] args) {
    auto foobar  = map!( (int i){} )(5);
    return;
}

goodbye.d:
module goodbye;







// line 9
template map(fun...)            //
{
    auto map(Range)(Range r)
    {
        return Map!(fun)(r);    // line 14, must instantiate with fun or r not
Range
    }
}

struct Map(alias fun) {         // Must be an alias template
    void _cache;                // line 19
}


Error messages produced:

hello.d Line 19
Error: variable hello.main.Map!(delegate void(int i)
hello.d Line 14
Error: template instance hello.main.Map!(delegate void(int i)
hello.d Line 5
instantiated from here: map!(int)

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Rob Jacques <sandford@jhu.edu> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |patch, wrong-code
           Severity|normal                      |regression


--- Comment #1 from Rob Jacques <sandford@jhu.edu> 2011-01-05 13:14:37 PST ---
In DMD 2.051, this error message has ceased to be generated for certain inputs and instead a runtime access violation is generated. Here is a reduced test case:

struct Bar(T) {
    T x;
    Bar dot(Bar b) { return Bar(x+b.x); }
}

void main(string[] args) {
    Bar!real   b;
    Bar!real[] data = new Bar!real[5];
    auto foobar  = map!((a){return a.dot(b); })(data);
    return;
}

Here is a modified to std.algorithm.map that works arounds this specific bug:

template map(fun...) {
    auto map(Range)(Range r) {
        static if (fun.length > 1) {
            return Map!( unaryFun!( adjoin!(staticMap!(unaryFun, fun)) ), Range
)(r);
        } else {
            static if( is(typeof(fun[0]) == delegate) ) {
                return Map!(fun, Range)(fun[0],r);
            } else {
                return Map!(unaryFun!fun, Range)(r);
            }
        }
    }
}

struct Map(alias fun, Range) if (isInputRange!(Range))
{
    Unqual!Range _input;
    static if( is(typeof(fun) == delegate) ) {
        typeof(fun) _fun;
        this(typeof(fun) dg, Range input) { _fun = dg;  _input = input; }
    } else {
        alias fun _fun;
        this(Range input) { _input = input; }
    }


    alias typeof({ return _fun(.ElementType!(Range).init); }()) ElementType;

    static if (isBidirectionalRange!(Range)) {
        @property ElementType back()    { return  _fun(_input.back); }
                  void        popBack() {         _input.popBack;    }
    }

    // Propagate infinite-ness.
    static if (isInfinite!Range)  {
        enum bool empty = false;
    } else {
        @property bool empty() { return _input.empty; }
    }

    void popFront() { _input.popFront; }

    @property ElementType front() { return _fun(_input.front); }

    static if (isRandomAccessRange!Range)
    {
        ElementType opIndex(size_t index)
        {
            return _fun(_input[index]);
        }
    }

    // hasLength is busted, Bug 2873
    static if (is(typeof(_input.length) : size_t)
        || is(typeof(_input.length()) : size_t))
    {
        @property size_t length()
        {
            return _input.length;
        }
    }

    static if (hasSlicing!(Range)) {
        typeof(this) opSlice(size_t lowerBound, size_t upperBound) {
            auto result = this;
            result._input = result._input[lowerBound..upperBound];
            return result;
        }
    }

    static if (isForwardRange!Range)
    @property Map save()
    {
        auto result = this;
        result._input = result._input.save;
        return result;
    }
}

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Andrei Alexandrescu <andrei@metalanguage.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
                 CC|                            |andrei@metalanguage.com
         AssignedTo|nobody@puremagic.com        |andrei@metalanguage.com


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--- Comment #2 from Andrei Alexandrescu <andrei@metalanguage.com> 2011-01-16 14:18:23 PST ---
(In reply to comment #1)
> In DMD 2.051, this error message has ceased to be generated for certain inputs and instead a runtime access violation is generated. Here is a reduced test case:
> 
> struct Bar(T) {
>     T x;
>     Bar dot(Bar b) { return Bar(x+b.x); }
> }
> 
> void main(string[] args) {
>     Bar!real   b;
>     Bar!real[] data = new Bar!real[5];
>     auto foobar  = map!((a){return a.dot(b); })(data);
>     return;
> }

I just tried the example above with 2.051. It compiles and runs. Could you please provide a different example? Thanks!

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--- Comment #3 from Rob Jacques <sandford@jhu.edu> 2011-01-20 09:33:15 PST ---
(In reply to comment #2)
> (In reply to comment #1)
> > In DMD 2.051, this error message has ceased to be generated for certain inputs and instead a runtime access violation is generated. Here is a reduced test case:
> > 
> > struct Bar(T) {
> >     T x;
> >     Bar dot(Bar b) { return Bar(x+b.x); }
> > }
> > 
> > void main(string[] args) {
> >     Bar!real   b;
> >     Bar!real[] data = new Bar!real[5];
> >     auto foobar  = map!((a){return a.dot(b); })(data);
> >     return;
> > }
> 
> I just tried the example above with 2.051. It compiles and runs. Could you please provide a different example? Thanks!

While it does compile on my system, when it runs it causes an "object.Error: Access Violation". I'm on an Intel Core-i7 920 (Quad core) running Windows 7 64-bit. Just to double check, here is a more extensive version of the same test which verifies the map is run correctly.

void main(string[] args) {
    Bar!real   b = Bar!real(5);
    Bar!real[] data = new Bar!real[5];
    foreach(i,ref d;data)
        d.x = i;
    Bar!real[] expected = new Bar!real[5];
    foreach(i,ref e;expected)
        e = data[i].dot(b);
    auto foobar  = map!((a){return a.dot(b); })(data);
    foreach(z;zip(foobar,expected))
        assert(z[0].x == z[1].x);
    return;
}

Also, does the example from my first post compile & run for you?

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--- Comment #4 from Rob Jacques <sandford@jhu.edu> 2011-05-19 17:22:16 PDT ---
Minor update to handle fixed sized arrays properly.

template map(fun...) {
    auto map(Range)(Range r) {
        static if (fun.length > 1) {
            return Map!(unaryFun!(adjoin!(staticMap!(unaryFun,fun))),Range)(r);
        } else {
            static if( is(typeof(fun[0]) == delegate) ) {
                return Map!(fun, Range)(fun[0],r);
            } static if( is(Range E:E[]) ) {
                return Map!(unaryFun!fun, E[])(r[]);
            } else {
                return Map!(unaryFun!fun, Range)(r);
            }
        }
    }
}

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--- Comment #5 from Rob Jacques <sandford@jhu.edu> 2011-05-19 17:36:31 PDT ---
*oops* forgot the else statements

template map(fun...) {
    auto map(Range)(Range r) {
        static if (fun.length > 1) {
            return Map!(unaryFun!(adjoin!(staticMap!(unaryFun,fun))),Range)(r);
        } else {
            static if( is(typeof(fun[0]) == delegate) ) {
                return Map!(fun, Range)(fun[0],r);
            } else static if( is(typeof(unaryFun!fun) == delegate) ) {
                return Map!(unaryFun!fun, Range)(unaryFun!fun,r);
            } else static if( is(Range E:E[]) ) {
                return Map!(unaryFun!fun, E[])(r[]);
            } else {
                return Map!(unaryFun!fun, Range)(r);
            }
        }
    }
}

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yebblies <yebblies@gmail.com> changed:

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


--- Comment #6 from yebblies <yebblies@gmail.com> 2011-07-04 02:57:48 EST ---
None of these examples fail for me with dmd 2.054 head on win32.  Can anybody reproduce this with a current dmd?

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--- Comment #7 from Rob Jacques <sandford@jhu.edu> 2011-07-03 17:58:29 PDT ---
I've had trouble with map in DMD 2.053 and fixed it with this patch. I've even updated the patch to the new internal struct style being used in std.algorithm. (not-yet posted). But this has been due to map not handling fixed sized arrays:

    ubyte[12] datum;
    map!"a"(datum);

Which as of this evening's SVN, is still true. I don't know about the original code which spawned this bug report, but once fixed-sized arrays work, I can re-test it.

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bearophile_hugs@eml.cc changed:

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


--- Comment #8 from bearophile_hugs@eml.cc 2011-07-03 18:28:49 PDT ---
(In reply to comment #7)
> I've had trouble with map in DMD 2.053 and fixed it with this patch. I've even updated the patch to the new internal struct style being used in std.algorithm. (not-yet posted). But this has been due to map not handling fixed sized arrays:
> 
>     ubyte[12] datum;
>     map!"a"(datum);
> 
> Which as of this evening's SVN, is still true. I don't know about the original code which spawned this bug report, but once fixed-sized arrays work, I can re-test it.

I'd like map to work on fixed-size arrays too, but I think Andrei doesn't want this to be fixed.

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