• Sebastiaan Koppe (14/14) Mar 10 2019 The compiler complains about `cannot form tuple of tuples`
• Basile B. (8/22) Mar 10 2019 It looks like a bug, a "reject-valid" one.
• Basile B. (2/34) Mar 10 2019 It was 19605. But the relationship is not so obvious...
• Sebastiaan Koppe (15/21) Mar 10 2019 Thanks. The example I posted was a reduced case, but I can still
• Basile B. (3/26) Mar 10 2019 Yes I see. I've refined a bit the test case and maybe I'll took a
• Sebastiaan Koppe (4/6) Mar 10 2019 Cool. Is it normal to create a testcase that doesn't depend on
• Basile B. (2/8) Mar 10 2019 Yes.

Sebastiaan Koppe <mail skoppe.eu> writes:

The compiler complains about `cannot form tuple of tuples` 
whenever I try to put an AliasSeq in a UDA and try to use it.

You would expect the compiler to expand it. Is this a bug?

---

import std.meta;

enum A; enum B;

 AliasSeq!(A,B) // <-- Error: cannot form tuple of tuples
struct Foo {}

pragma(msg, __traits(getAttributes, Foo)); // <- must be present 
(error happens only when queried)

void main() {}

---

link to run.dlang.io: 
https://run.dlang.io/gist/cd5cd94d8ce5327e8a7d5ad77f1d15b8

Basile B. <b2.temp gmx.com> writes:

On Sunday, 10 March 2019 at 13:20:12 UTC, Sebastiaan Koppe wrote:
 The compiler complains about `cannot form tuple of tuples` 
 whenever I try to put an AliasSeq in a UDA and try to use it.

 You would expect the compiler to expand it. Is this a bug?

 ---

 import std.meta;

 enum A; enum B;

  AliasSeq!(A,B) // <-- Error: cannot form tuple of tuples
 struct Foo {}

 pragma(msg, __traits(getAttributes, Foo)); // <- must be 
 present (error happens only when queried)

 void main() {}

 ---

 link to run.dlang.io: 
 https://run.dlang.io/gist/cd5cd94d8ce5327e8a7d5ad77f1d15b8

It looks like a bug, a "reject-valid" one.
Try the same code with

     enum A = 0;

and it work, despite of B being still opaque. The problem may be 
related to the fact the enum A in the orginal code is opaque and 
has not type.

I've seen a related issue lately.

Basile B. <b2.temp gmx.com> writes:

On Sunday, 10 March 2019 at 13:41:32 UTC, Basile B. wrote:
 On Sunday, 10 March 2019 at 13:20:12 UTC, Sebastiaan Koppe 
 wrote:
 The compiler complains about `cannot form tuple of tuples` 
 whenever I try to put an AliasSeq in a UDA and try to use it.

 You would expect the compiler to expand it. Is this a bug?

 ---

 import std.meta;

 enum A; enum B;

  AliasSeq!(A,B) // <-- Error: cannot form tuple of tuples
 struct Foo {}

 pragma(msg, __traits(getAttributes, Foo)); // <- must be 
 present (error happens only when queried)

 void main() {}

 ---

 link to run.dlang.io: 
 https://run.dlang.io/gist/cd5cd94d8ce5327e8a7d5ad77f1d15b8

 It looks like a bug, a "reject-valid" one.
 Try the same code with

     enum A = 0;

 and it work, despite of B being still opaque. The problem may 
 be related to the fact the enum A in the orginal code is opaque 
 and has not type.

 I've seen a related issue lately.

It was 19605. But the relationship is not so obvious...

Sebastiaan Koppe <mail skoppe.eu> writes:

On Sunday, 10 March 2019 at 13:41:32 UTC, Basile B. wrote:
 It looks like a bug, a "reject-valid" one.
 Try the same code with

     enum A = 0;

 and it work, despite of B being still opaque. The problem may 
 be related to the fact the enum A in the orginal code is opaque 
 and has not type.

Thanks. The example I posted was a reduced case, but I can still 
use your trick to fool the compiler.

The following is more real:

---

import std.meta;

enum A; enum B; enum Dummy = 0; // <- Dummy needs to be 0

struct Param(alias T) {}

 AliasSeq!(Dummy,Param!A,Param!B) // <- Here Dummy is needed
struct Foo {}

pragma(msg, __traits(getAttributes, Foo));

void main() {}

---

I have created an issue: 
https://issues.dlang.org/show_bug.cgi?id=19728

Basile B. <b2.temp gmx.com> writes:

On Sunday, 10 March 2019 at 16:05:19 UTC, Sebastiaan Koppe wrote:
 On Sunday, 10 March 2019 at 13:41:32 UTC, Basile B. wrote:
 It looks like a bug, a "reject-valid" one.
 Try the same code with

     enum A = 0;

 and it work, despite of B being still opaque. The problem may 
 be related to the fact the enum A in the orginal code is 
 opaque and has not type.

 Thanks. The example I posted was a reduced case, but I can 
 still use your trick to fool the compiler.

 The following is more real:

 ---

 import std.meta;

 enum A; enum B; enum Dummy = 0; // <- Dummy needs to be 0

 struct Param(alias T) {}

  AliasSeq!(Dummy,Param!A,Param!B) // <- Here Dummy is needed
 struct Foo {}

 pragma(msg, __traits(getAttributes, Foo));

 void main() {}

 ---

 I have created an issue: 
 https://issues.dlang.org/show_bug.cgi?id=19728

Yes I see. I've refined a bit the test case and maybe I'll took a 
look this week.

Sebastiaan Koppe <mail skoppe.eu> writes:

On Sunday, 10 March 2019 at 16:46:43 UTC, Basile B. wrote:
 Yes I see. I've refined a bit the test case and maybe I'll took 
 a look this week.

Cool. Is it normal to create a testcase that doesn't depend on 
phobos? I suppose it is needed for it to be included in dmd's 
testcases.

Basile B. <b2.temp gmx.com> writes:

On Sunday, 10 March 2019 at 17:04:20 UTC, Sebastiaan Koppe wrote:
 On Sunday, 10 March 2019 at 16:46:43 UTC, Basile B. wrote:
 Yes I see. I've refined a bit the test case and maybe I'll 
 took a look this week.

 Cool. Is it normal to create a testcase that doesn't depend on 
 phobos? I suppose it is needed for it to be included in dmd's 
 testcases.

Yes.