[Issue 493] New: Partial IFTI does not work

[d-bugmail at puremagic.com]

http://d.puremagic.com/issues/show_bug.cgi?id=493

           Summary: Partial IFTI does not work
           Product: D
           Version: 0.173
          Platform: All
        OS/Version: All
            Status: NEW
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: bugzilla at digitalmars.com
        ReportedBy: wbaxter at gmail.com


IFTI should try to deduce the parameter types for any template paramters not
specified (if they don't have defaults).

--------
import std.stdio:writefln;

template foo(T,S)
{
    void foo(T t, S s) {
        writefln("typeof(T)=",typeid(typeof(T)),"
typeof(S)=",typeid(typeof(S)));
    }
}

template bar(T,S)
{
    void bar(S s) {
        writefln("typeof(T)=",typeid(typeof(T)),"
typeof(S)=",typeid(typeof(S)));
    }
}


void main()
{
    // OK -- IFTI works happily
    foo(1.0,33);

    // OK -- Full template parameters specified
    bar!(double,int)(33);

    // error: I gave it T and it should be able to use IFTI to guess S, but it
doesn't
    //bar!(float)(33); 
}
---------------

Not sure if this should be a bug or an enhancement, but anyway, especially with
the new variadic templates I think it will become more common to want to have a
few specified paramters and let IFTI guess the rest.

    templatefunc(T, Var...)(Var v) {
       [...]
    }
    templatefunc!(SomeType)(a,b,c,d,e);

    This basically isn't usable if I have to specify all the types for a,b,c,
and d.


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