Re: alias this and shadowing

[Adam D. Ruppe via Digitalmars-d]

On Thursday, 15 June 2017 at 15:01:27 UTC, Jonathan Shamir wrote:
To quote Andrei, if it looks like it should work, it should. 
(Also something about turtles).


Hmm, interestingly, even if you explicitly merge the overloads 
with `alias foo  s.foo;` (which is required btw, see: 
http://dlang.org/hijack.html )


but even doing that here gives

Error: this for foo needs to be type S1 not type S2

and I actually would expect alias this to be invoked there to 
make it work.

alias this and shadowing

[Jonathan Shamir via Digitalmars-d]

I think the following example is legitimate code that should work:

struct S1 {
void foo() {
writeln("S1.foo()");
}
void foo(ulong x) {
writefln("S1.foo(%d)", x);
}
}

struct S2 {
S1 s;
alias s this;

void foo(string str) {
writeln("S2.foo(%s)", str);
}
}

void main() {
S2 s;

s.foo("hahaha");
s.foo(100);  // XXX this doesn't compile, since there's no 
S2.foo that accepts an int

}


To quote Andrei, if it looks like it should work, it should. 
(Also something about turtles).


My original code did something a bit different, just to show 
another example of why this behavior looks fundamentally broken 
to me:


struct S2 {
S1 s;
alias s this;
@disable void foo(ulong); // calling foo(ulong) doesn't make 
sense in the context of S2

}

Now, calling S2.foo() won't compile, since S2 only knows one 
prototype for foo which accepts a ulong.