On 04/19/2012 11:28 AM, Jens Mueller wrote:
Hi,

using UFCS with alias this behaves strange.
Consider

struct Foo
{
     int _member;
     alias _member this;
}

int foo(Foo f) { return f._member; }
int foo(int i) { return i; }

unittest
{
     Foo f;
     f.foo(); // which function will be called? Isn't it ambiguous?
}

Due to the alias this the function foo(int i) will be called. Is this
the indented behavior? Practically, I want UFCS to just perform a
syntactic rewrite from f.foo() to foo(f).
When using alias this you have to define the second function. Providing
only the first one results in a compile error. If you remove the alias
this things work as expected (first one needs to be defined).

I stumbled upon this problem when trying to define additional functions
for a Tuple. Tuple has "alias field this" for falling back on
TypeTuple's opIndex. Unfortunately,

alias Tuple!(int) Bar;
int bar(typeof(Bar.field) b) { return 1; }

unittest
{
     Bar b;
     b.bar();
}

does not work.

Jens

This is a bug. You can report it to:
http://d.puremagic.com/issues/

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