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digitalmars.D - Potential bug in __traits(parent).

reply "Mike" <none none.com> writes:
Consider the following code:

/*********** mmio.d ************/
module mmio;

mixin template HasValue(uint value) {
     static uint getValue() {
         return value;
     }
}

mixin template Parent() {
     final abstract class Child(uint value) {
         mixin HasValue!(value);
     }
}

/*********** test.d ************/
module test;
import mmio;

mixin Parent;

alias Two = Child!(2);

/*********** main.d ************/
import std.stdio;
import test;

void main()
{
     writeln(__traits(parent, test.Two).stringof);
     writeln(__traits(parent, __traits(parent, 
test.Two)).stringof);

     readln();
}

DMD 2.065 Output:
Child!(2)
Child!(2)

GDC 4.8.2 20130725 Output:
Child
Child

LDC 0.12.1 Output:
Child
Chlld

All of these seem wrong to me.  What I expect for output is:
module test
{the second `writeln` shouldn't compile since `test` has no 
parent}

A couple of observations:
1. `Child` is not the parent of `test.Two`, `test` is the parent 
of `test.Two`.
2. If you believe `__traits(parent, test.Two)` is `Child`, 
`Child` should not be its own parent.

Incidentally, if I remove the template parameter on `Child`, I 
get the results I expect.

Could someone please confirm if this is a bug or not?

Thanks for the help,
Mike
Mar 28 2014
parent "Mike" <none none.com> writes:
On Saturday, 29 March 2014 at 03:00:30 UTC, Mike wrote:
 Consider the following code:

 /*********** mmio.d ************/
 module mmio;

 mixin template HasValue(uint value) {
     static uint getValue() {
         return value;
     }
 }

 mixin template Parent() {
     final abstract class Child(uint value) {
         mixin HasValue!(value);
     }
 }

 /*********** test.d ************/
 module test;
 import mmio;

 mixin Parent;

 alias Two = Child!(2);

 /*********** main.d ************/
 import std.stdio;
 import test;

 void main()
 {
     writeln(__traits(parent, test.Two).stringof);
     writeln(__traits(parent, __traits(parent, 
 test.Two)).stringof);

     readln();
 }

 DMD 2.065 Output:
 Child!(2)
 Child!(2)

 GDC 4.8.2 20130725 Output:
 Child
 Child

 LDC 0.12.1 Output:
 Child
 Chlld

 All of these seem wrong to me.  What I expect for output is:
 module test
 {the second `writeln` shouldn't compile since `test` has no 
 parent}

 A couple of observations:
 1. `Child` is not the parent of `test.Two`, `test` is the 
 parent of `test.Two`.
 2. If you believe `__traits(parent, test.Two)` is `Child`, 
 `Child` should not be its own parent.

 Incidentally, if I remove the template parameter on `Child`, I 
 get the results I expect.

 Could someone please confirm if this is a bug or not?

 Thanks for the help,
 Mike

https://d.puremagic.com/issues/show_bug.cgi?id=12496
Mar 30 2014