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digitalmars.D.learn - AliasSeq in UDA

reply 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
Mar 10
parent reply 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.
Mar 10
next sibling parent 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...
Mar 10
prev sibling parent reply 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
Mar 10
parent reply 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.
Mar 10
parent reply 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.
Mar 10
parent 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.
Mar 10