• Brian Schott (9/9) Nov 09 2015 Given the following code:
• Marc =?UTF-8?B?U2Now7x0eg==?= (8/17) Nov 10 2015 This fails, too:
• Brian Schott (2/9) Nov 10 2015 You're talking about Tuple. I'm talking about AliasSeq.
• Marc =?UTF-8?B?U2Now7x0eg==?= (6/17) Nov 10 2015 A Tuple is just a struct with an AliasSeq member. Or seen from a
• Alex Parrill (5/14) Nov 10 2015 `:` in `is` is for testing whether the left type is implicitly

Brian Schott <briancschott gmail.com> writes:

Given the following code:
```
import std.meta;

static assert(is(char : dchar));
static assert(is(AliasSeq!(int, char) : AliasSeq!(int, char)));
static assert(is(AliasSeq!(int, char) : AliasSeq!(int, dchar)));
```

The third static assert fails. Should it, given that the first 
and second pass?

Marc =?UTF-8?B?U2Now7x0eg==?= <schuetzm gmx.net> writes:

On Monday, 9 November 2015 at 22:41:50 UTC, Brian Schott wrote:
 Given the following code:
 ```
 import std.meta;

 static assert(is(char : dchar));
 static assert(is(AliasSeq!(int, char) : AliasSeq!(int, char)));
 static assert(is(AliasSeq!(int, char) : AliasSeq!(int, dchar)));
 ```

 The third static assert fails. Should it, given that the first 
 and second pass?

This fails, too:
static assert(is(AliasSeq!(char) : AliasSeq!(dchar)));

Which makes sense IMO, because it can be thought of as an unnamed 
struct, cp. the following:

struct A { char c; }
struct B { dchar c; }
static assert(is(A : B)); // fails, as expected

Brian Schott <briancschott gmail.com> writes:

On Tuesday, 10 November 2015 at 10:28:45 UTC, Marc Schütz wrote:
 This fails, too:
 static assert(is(AliasSeq!(char) : AliasSeq!(dchar)));

 Which makes sense IMO, because it can be thought of as an 
 unnamed struct, cp. the following:

 struct A { char c; }
 struct B { dchar c; }
 static assert(is(A : B)); // fails, as expected

You're talking about Tuple. I'm talking about AliasSeq.

Marc =?UTF-8?B?U2Now7x0eg==?= <schuetzm gmx.net> writes:

On Tuesday, 10 November 2015 at 13:47:23 UTC, Brian Schott wrote:
 On Tuesday, 10 November 2015 at 10:28:45 UTC, Marc Schütz wrote:
 This fails, too:
 static assert(is(AliasSeq!(char) : AliasSeq!(dchar)));

 Which makes sense IMO, because it can be thought of as an 
 unnamed struct, cp. the following:

 struct A { char c; }
 struct B { dchar c; }
 static assert(is(A : B)); // fails, as expected

 You're talking about Tuple. I'm talking about AliasSeq.

A Tuple is just a struct with an AliasSeq member. Or seen from a 
different POV, an AliasSeq can be interpreted as the "innards" of 
the struct. IMO it therefore makes sense to expect an AliasSeq to 
behave analogously to a struct. The only exception to that is 
that AliasSeq auto-expands, of course.

Alex Parrill <initrd.gz gmail.com> writes:

On Monday, 9 November 2015 at 22:41:50 UTC, Brian Schott wrote:
 Given the following code:
 ```
 import std.meta;

 static assert(is(char : dchar));
 static assert(is(AliasSeq!(int, char) : AliasSeq!(int, char)));
 static assert(is(AliasSeq!(int, char) : AliasSeq!(int, dchar)));
 ```

 The third static assert fails. Should it, given that the first 
 and second pass?

`:` in `is` is for testing whether the left type is implicitly 
convertible to the right type. `char` is implicitly convertible 
to `dchar` by promoting it. But `AliasSeq`s are collections; 
they're only implicitly convertible to themselves.