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digitalmars.D.bugs - [Issue 12166] New: Template Argument Pattern Matching Fails for Struct With Multiple Nested Template Arguments

reply d-bugmail puremagic.com writes:
https://d.puremagic.com/issues/show_bug.cgi?id=12166

           Summary: Template Argument Pattern Matching Fails for Struct
                    With Multiple Nested Template Arguments
           Product: D
           Version: D2
          Platform: All
        OS/Version: All
            Status: NEW
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: nobody puremagic.com
        ReportedBy: monkeyworks12 hotmail.com



struct Zero    {}
struct Succ(a) {}

struct Nil {}
struct Cons(a, b) {}

alias list1 = Cons!(Three, Cons!(Two, Cons!(Four, Cons!(One, Nil))));

alias numlHead(L: Cons!(a, b), a, b) = a;

alias numlTail(L: Cons!(a, b), a, b) = b;

void main()
{
    //Error: template instance numlHead!(list1) does not 
    //match template declaration numlHead(L : Cons!(a, b), a, b)
    pragma(msg, numlHead!list1);
}

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Feb 14 2014
next sibling parent d-bugmail puremagic.com writes:
https://d.puremagic.com/issues/show_bug.cgi?id=12166




The test case lacks some symbols:

test.d(7): Error: undefined identifier Three
test.d(7): Error: undefined identifier Two
test.d(7): Error: undefined identifier Four
test.d(7): Error: undefined identifier One

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Feb 19 2014
prev sibling next sibling parent d-bugmail puremagic.com writes:
https://d.puremagic.com/issues/show_bug.cgi?id=12166






 The test case lacks some symbols:
 
 test.d(7): Error: undefined identifier Three
 test.d(7): Error: undefined identifier Two
 test.d(7): Error: undefined identifier Four
 test.d(7): Error: undefined identifier One


Sorry, add:

alias One = Succ!Zero;
alias Two = Succ!One;
alias Three = Succ!Two;
alias Four = Succ!Three;

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Feb 19 2014
prev sibling next sibling parent d-bugmail puremagic.com writes:
https://d.puremagic.com/issues/show_bug.cgi?id=12166






 Sorry, add:


[snip]

So, what version do you use? The full test case:

struct Zero    {}
struct Succ(a) {}

alias One   = Succ!Zero;
alias Two   = Succ!One;
alias Three = Succ!Two;
alias Four  = Succ!Three;

struct Nil {}
struct Cons(a, b) {}

alias list1 = Cons!(Three, Cons!(Two, Cons!(Four, Cons!(One, Nil))));

alias numlHead(L: Cons!(a, b), a, b) = a;

alias numlTail(L: Cons!(a, b), a, b) = b;

void main()
{
    pragma(msg, numlHead!list1);
}

compiles with 2.064 (2.063 and earlier does not support new alias syntax). I
cannot see the issue.

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prev sibling next sibling parent d-bugmail puremagic.com writes:
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 Sorry, add:


 [snip]
 
 So, what version do you use? The full test case:
 
 struct Zero    {}
 struct Succ(a) {}
 
 alias One   = Succ!Zero;
 alias Two   = Succ!One;
 alias Three = Succ!Two;
 alias Four  = Succ!Three;
 
 struct Nil {}
 struct Cons(a, b) {}
 
 alias list1 = Cons!(Three, Cons!(Two, Cons!(Four, Cons!(One, Nil))));
 
 alias numlHead(L: Cons!(a, b), a, b) = a;
 
 alias numlTail(L: Cons!(a, b), a, b) = b;
 
 void main()
 {
     pragma(msg, numlHead!list1);
 }
 
 compiles with 2.064 (2.063 and earlier does not support new alias syntax). I
 cannot see the issue.


It seems it was an error on my part. In the full code, I had some testing code
in my main method. I accidentally named a variable list1 as well as having the
list1 alias, so my code broke with this:

void main()
{
    //assert(is(Four == Succ!(Succ!(Succ!(Succ!Zero)))));

    auto list1 = list1(); //Problem

    //assert(is(typeof(three) == Three));
    //assert(numValue!(Number!Zero) == 0);
    assert(numValue!(Number!Four) == 4);
    pragma(msg, numlHead!list1);
    //assert(is(numlHead!list1 == Three));
    //assert(is(typeof(numlTail!list1) == Cons!(Two, Cons!Four, Cons!(One,
Nil))));
}

However, it also seems this is bad behaviour. Should I open a separate report?

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Feb 20 2014
prev sibling next sibling parent d-bugmail puremagic.com writes:
https://d.puremagic.com/issues/show_bug.cgi?id=12166






 However, it also seems this is bad behaviour.


Shadowing *module level* symbols by declared local symbols is legitimate.
Currently there's no plan to disallow it, and I also think it should be
continuously allowed.


 Should I open a separate report?


However of course, it's your free.

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Feb 20 2014
prev sibling parent d-bugmail puremagic.com writes:
https://d.puremagic.com/issues/show_bug.cgi?id=12166


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

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


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