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digitalmars.D.bugs - [Issue 6879] New: The difference of between template matching and IsExp

reply d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=6879

           Summary: The difference of between template matching and IsExp
           Product: D
           Version: D2
          Platform: Other
        OS/Version: Windows
            Status: NEW
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: nobody puremagic.com
        ReportedBy: k.hara.pg gmail.com


--- Comment #0 from Kenji Hara <k.hara.pg gmail.com> 2011-11-02 04:57:00 PDT ---
I think following code should compile.

----
private template isStaticArray(T : U[N], U, size_t N)
{
    enum bool isStaticArray = true;
}
private template isStaticArray(T)
{
    enum bool isStaticArray = false;
}

void main()
{
    alias int[3] T;

    enum res1 = isStaticArray!T;

    static if (is(T _ : U[N], U, size_t N))
        enum res2 = true;
    else
        enum res2 = false;

    static assert(res1 == res2);   // fails... Why?
}

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next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=6879



--- Comment #1 from Kenji Hara <k.hara.pg gmail.com> 2011-11-02 06:00:41 PDT ---
When static if condition is same as follows, the judgement succeeds.

    static if (is(T _ : X, X : U[N], U, size_t N))
        ...

This works as expected, but unneeded two symbols require (_ and X).
It seems to me that this syntax has little confusing.

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prev sibling next sibling parent d-bugmail puremagic.com writes:
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Kenji Hara <k.hara.pg gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |rejects-valid


--- Comment #2 from Kenji Hara <k.hara.pg gmail.com> 2011-11-02 07:44:11 PDT ---
I have found the true issue.

alias int[3] T;
static if (is(T _ : U[N], U, int N))      // a: match
static if (is(T _ : U[N], U, uint N))     // b: match
static if (is(T _ : U[N], U, size_t N))   // c: doesn't match

The mismatching of c is 'rejects-valid' issue IMO.

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prev sibling next sibling parent d-bugmail puremagic.com writes:
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Kenji Hara <k.hara.pg gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |patch
           Platform|Other                       |All
         OS/Version|Windows                     |All


--- Comment #3 from Kenji Hara <k.hara.pg gmail.com> 2011-11-02 09:13:04 PDT ---
https://github.com/D-Programming-Language/dmd/pull/489

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prev sibling parent d-bugmail puremagic.com writes:
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Walter Bright <bugzilla digitalmars.com> changed:

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


--- Comment #4 from Walter Bright <bugzilla digitalmars.com> 2011-11-14
22:45:22 PST ---
https://github.com/D-Programming-Language/dmd/commit/4abf4186980b091b450d0a4e3e2cbba29312c87f

https://github.com/D-Programming-Language/dmd/commit/07910aa6400c797cf67b09f0cd8f9754407e59ea

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