[Issue 11986] New: IFTI type deduction / implicit conversion does not work for null literal

[d-bugmail at puremagic.com]

https://d.puremagic.com/issues/show_bug.cgi?id=11986

           Summary: IFTI type deduction / implicit conversion does not
                    work for null literal
           Product: D
           Version: D2
          Platform: All
        OS/Version: All
            Status: NEW
          Keywords: rejects-valid
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: nobody at puremagic.com
        ReportedBy: andrej.mitrovich at gmail.com


--- Comment #0 from Andrej Mitrovic <andrej.mitrovich at gmail.com> 2014-01-24 12:35:52 PST ---
-----
class C(T) { }

void foo(T)(C!T a, C!T b) { }

void main()
{
    C!int c;
    foo(c, null);
}
-----

test.d(10): Error: template test.foo cannot deduce function from argument types
!()(C!int, typeof(null)), candidates are:
test.d(5):        test.foo(T)(C!T a, C!T b)

null should be implicitly convertible to C!T since it's a reference type. Note
that the programmer can't simply introduce another templated type parameter
since the parameter might end up being typed as typeof(null), which is
problematic. For example:

-----
class C(T) { void bar() { } }

void foo(T, T2)(C!T a, T2 b) if (is(T2 : C!T))
{
    b.bar();  // Error: no property 'bar' for type 'typeof(null)'
}

void main()
{
    C!int c;
    foo(c, null);
}
-----

So I think the OP case is rejects-valid.

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