http://d.puremagic.com/issues/show_bug.cgi?id=2257

           Summary: Template value parameters behave like alias parameters
           Product: D
           Version: 2.017
          Platform: PC
        OS/Version: Windows
            Status: NEW
          Keywords: accepts-invalid
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: bugzilla@digitalmars.com
        ReportedBy: samukha@voliacable.com


import std.stdio;

template Foo(string s)
{
  enum Foo = s; // changing enum to invariant fixes the issue.
}

void main()
{
  string a = "str";
  alias Foo!(a) b; // b is now an alias of a. Should be a compiler error
}


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http://d.puremagic.com/issues/show_bug.cgi?id=2257





------- Comment #1 from samukha@voliacable.com  2008-10-13 00:32 -------
"compiler error" in the example was meant to be "compile error"


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http://d.puremagic.com/issues/show_bug.cgi?id=2257


Rob Jacques <sandford@jhu.edu> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |sandford@jhu.edu


--- Comment #2 from Rob Jacques <sandford@jhu.edu> 2009-10-13 10:21:10 PDT ---
This issue causes major issues with Nd-array and Small Vector implementations, as the incorrect type signatures play havoc with other templated functions. Here is another test case illustrating the problem:

import std.stdio;
struct Matrix(T,size_t D) {
    Matrix!(U,D) foo(U)(U v) { return Matrix!(U,D)(); }
}

void main() {
    real r;
    size_t d = 2;
    Matrix!(float,2) m;
    writeln(typeof( m.foo(r) ).stringof);            //writes Matrix(float,D)
    Matrix!(float,d) n;
    writeln(typeof( n ).stringof);                   //writes Matrix(float,d)
}

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--- Comment #3 from Rob Jacques <sandford@jhu.edu> 2009-11-06 22:23:35 PST ---
(In reply to comment #2)
> This issue causes major issues with Nd-array and Small Vector implementations, as the incorrect type signatures play havoc with other templated functions. Here is another test case illustrating the problem:
> 
> import std.stdio;
> struct Matrix(T,size_t D) {
>     Matrix!(U,D) foo(U)(U v) { return Matrix!(U,D)(); }
> }
> 
> void main() {
>     real r;
>     size_t d = 2;
>     Matrix!(float,2) m;
>     writeln(typeof( m.foo(r) ).stringof);            //writes Matrix(float,D)
>     Matrix!(float,d) n;
>     writeln(typeof( n ).stringof);                   //writes Matrix(float,d)
> }

A Mitigation for the above example:
Matrix!(U,D+0) foo(U)(U v) { return Matrix!(U,D)(); }
changes "Matrix(float,D)" to "writes Matrix(float,2u)"
However, the original template type is still distinct: Matrix(float,2)

Also, it appears that even though D is unsigned, the template type is signed.

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

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


--- Comment #4 from Don <clugdbug@yahoo.com.au> 2010-12-01 02:29:17 PST ---
*** Issue 4289 has been marked as a duplicate of this issue. ***

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

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


--- Comment #5 from Don <clugdbug@yahoo.com.au> 2010-12-01 02:29:56 PST ---
Bug 2550 has the same root cause, I think.

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--- Comment #6 from yebblies <yebblies@gmail.com> 2012-01-30 17:25:10 EST ---
*** Issue 2733 has been marked as a duplicate of this issue. ***

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Stewart Gordon <smjg@iname.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |smjg@iname.com


--- Comment #7 from Stewart Gordon <smjg@iname.com> 2012-02-05 14:56:56 PST ---
This might be related:
----------
struct DimensionedValue(Val, int Dim) {
    Val value;

    auto opMul(T)(T v) {
        return DimensionedValue!(typeof(value * T.init), Dim)(value * v);
    }
}

template isDimensionedValue(T : DimensionedValue!(V, D), V, int D) {
    enum bool isDimensionedValue = true;
}
template isDimensionedValue(T) {
    enum bool isDimensionedValue = false;
}

DimensionedValue!(int, 1) x;
//DimensionedValue!(double, 1) y;
pragma(msg, typeof(x * 2));
pragma(msg, isDimensionedValue!(typeof(x * 2)));
pragma(msg, typeof(x * 2.5));
pragma(msg, isDimensionedValue!(typeof(x * 2.5)));
----------
DimensionedValue!(int,1)
true
DimensionedValue!(double,Dim)
false
----------

Reinstating the declaration of y suppresses the bug.  As does using Dim + 0 in opMul.

Is this another manifestation of the same bug, or does it warrant a separate bug report?

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Andrej Mitrovic <andrej.mitrovich@gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
                 CC|                            |andrej.mitrovich@gmail.com
           Platform|x86                         |All
         Resolution|                            |WORKSFORME
         OS/Version|Windows                     |All


--- Comment #8 from Andrej Mitrovic <andrej.mitrovich@gmail.com> 2013-02-04 17:55:12 PST ---
Fixed since a long time ago, tested as far back as 2.053.

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