http://d.puremagic.com/issues/show_bug.cgi?id=8213

           Summary: Incorrect error message with pointer to ubyte[] and
                    front
           Product: D
           Version: unspecified
          Platform: All
        OS/Version: All
            Status: NEW
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: nobody@puremagic.com
        ReportedBy: jmdavisProg@gmx.com


--- Comment #0 from Jonathan M Davis <jmdavisProg@gmx.com> 2012-06-09 02:21:47 PDT ---
This code

import std.array;

struct S(R)
{
    this(R* range)
    {
        _range = range;
    }

    auto front()
    {
        return _range.front;
    }

    R* _range;
}

void main()
{
    ubyte[] buffer = [42];
    auto s = S!(ubyte[])(&buffer);
    auto f = s.front;
}


results in this error:

q.d(12): Error: no property 'front' for type 'ubyte[]'
q.d(21): Error: template instance q.S!(ubyte[]) error instantiating

I'm tempted to argue that this should just compile, since . automatically dereferences the type that it's on if it's a pointer, and the type in question (ubyte[]) has a front via std.array, but _range itself doesn't match front's parameters, because it's a pointer to a ubyte[] rather than a ubyte[], so I suspect that this _isn't_ supposed to work much as I'd like it to. If it _is_ supposed to work, however, then this obviously shows that it isn't currently and is therefore a bug.

Regardless of the correct behavior, however, the error message is bad. It says that ubyte[] has no property front, which is not only not true, but the type which is failing is ubyte[]*, not ubyte[], so the type in the error message is wrong.

Either this code needs to be fixed so that it compiles and works just fine (automatically dereferencing the pointer and using the type of the dereferenced pointer rather than the pointer itself when lookin for functions to use with UFCS), or the error needs to be fixed so that it gives the correct type.

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Denis Shelomovskij <verylonglogin.reg@gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |verylonglogin.reg@gmail.com


--- Comment #1 from Denis Shelomovskij <verylonglogin.reg@gmail.com> 2013-04-19 12:25:44 MSD ---
See also Issue 8245 (probably, one can say it's a dup).

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--- Comment #2 from Denis Shelomovskij <verylonglogin.reg@gmail.com> 2013-04-23 14:22:59 MSD ---
The error gives the correct type now:
---
main.d(12): Error: template std.array.front does not match any function
template declaration. Candidates are:
<phobos path>\std\array.d(584):        std.array.front(T)(T[] a) if
(!isNarrowString!(T[]) && !is(T[] == void[]))
<phobos path>\std\array.d(605):        std.array.front(T)(T[] a) if
(isNarrowString!(T[]))
<phobos path>\std\array.d(584): Error: template std.array.front cannot deduce
template function from argument types !()(ubyte[]*)
main.d(21): Error: template instance main.S!(ubyte[]) error instantiating
main.d(22): Error: not a property s.front
---

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Kenji Hara <k.hara.pg@gmail.com> changed:

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


--- Comment #3 from Kenji Hara <k.hara.pg@gmail.com> 2013-04-24 00:34:19 PDT ---
(In reply to comment #2)
> The error gives the correct type now:
> ---
> main.d(12): Error: template std.array.front does not match any function
> template declaration. Candidates are:
> <phobos path>\std\array.d(584):        std.array.front(T)(T[] a) if
> (!isNarrowString!(T[]) && !is(T[] == void[]))
> <phobos path>\std\array.d(605):        std.array.front(T)(T[] a) if
> (isNarrowString!(T[]))
> <phobos path>\std\array.d(584): Error: template std.array.front cannot deduce
> template function from argument types !()(ubyte[]*)
> main.d(21): Error: template instance main.S!(ubyte[]) error instantiating
> main.d(22): Error: not a property s.front
> ---

In 2.063a, error message with UFCS issues are got fixed. So I'll close this.

Currently automatic pointer dereference is not supported in UFCS name look up. For the issue, I'll mark issue 8597 as enhancement.

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