Thread overview
[Issue 10555] New: enumerator can no longer increment beyond maximum of initializer
Jul 06, 2013
Rainer Schuetze
Jul 10, 2013
Andrej Mitrovic
Aug 31, 2013
Henning Pohl
Aug 31, 2013
Henning Pohl
Oct 02, 2013
Kenji Hara
July 06, 2013
http://d.puremagic.com/issues/show_bug.cgi?id=10555

           Summary: enumerator can no longer increment beyond maximum of
                    initializer
           Product: D
           Version: D2
          Platform: All
        OS/Version: All
            Status: NEW
          Severity: regression
          Priority: P2
         Component: DMD
        AssignedTo: nobody@puremagic.com
        ReportedBy: r.sagitario@gmx.de


--- Comment #0 from Rainer Schuetze <r.sagitario@gmx.de> 2013-07-06 06:03:46 PDT ---
I'm not sure if the new behaviour in git HEAD is desired or not, but this code used to compile until one or two weeks ago:

enum A
{
    A0
}
enum B
{
    B0 = A.A0,
    B1
}

Now it errors out with

Error: enum test.B overflow of enum value cast(B)cast(A)0

because dmd does not want to increment A0.

More strange things:

////////////////////////
enum A
{
    A0
}
enum B
{
    B0 = A.A0,
    B1 = A.A0 + 1
}
Error: cannot implicitly convert expression (1) of type int to A

though this works

enum A
{
    A0
}
enum B
{
    B0 = A.A0 + 0,
    B1
}

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July 10, 2013
http://d.puremagic.com/issues/show_bug.cgi?id=10555


Andrej Mitrovic <andrej.mitrovich@gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |andrej.mitrovich@gmail.com


--- Comment #1 from Andrej Mitrovic <andrej.mitrovich@gmail.com> 2013-07-10 08:16:59 PDT ---
Well if anything, the recent enum fixes and subsequent regressions exposed that we have a really poor enum test-suite.

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August 30, 2013
http://d.puremagic.com/issues/show_bug.cgi?id=10555


hsteoh@quickfur.ath.cx changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |hsteoh@quickfur.ath.cx


--- Comment #2 from hsteoh@quickfur.ath.cx 2013-08-30 11:02:19 PDT ---
git bisect shows that the offending commit was 88ebe192d605bd8d4b5768e8a2500f54d73fb5fd - fix issue 3096 - EnumBaseType

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August 31, 2013
http://d.puremagic.com/issues/show_bug.cgi?id=10555


Henning Pohl <henning@still-hidden.de> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |henning@still-hidden.de


--- Comment #3 from Henning Pohl <henning@still-hidden.de> 2013-08-31 04:16:03 PDT ---
I think this behaviour is correct:

Spec:
----
If the EnumBaseType is not explicitly set, and the first EnumMember has an initializer, it is set to the type of that initializer. Otherwise, it defaults to type int.

Named enum members may not have individual Types.

A named enum member can be implicitly cast to its EnumBaseType, but EnumBaseType types cannot be implicitly cast to an enum type.
----

The behaviour before issue 3096 always used int as EnumBaseType even though there is a first initializer.

enum A // int
{
    A0
}
enum B // A
{
    B0 = A.A0,
    B1
}

In this case the base type of B is A and A does not have a member whith a value of 1.

enum A // int
{
    A0
}
enum B // A
{
    B0 = A.A0,
    B1 = A.A0 + 1
}

This is basically the same case as above.

enum A // int
{
    A0
}

enum B // int
{
    B0 = A.A0 + 0,
    B1
}

This works because the type of the first initializer is int. So the base type of B becomes int and ints can be incremented easily.

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--- Comment #4 from Henning Pohl <henning@still-hidden.de> 2013-08-31 04:23:52 PDT ---
Keep in mind that you can always cast to the base type:

enum A // int
{
    A0
}

template BaseType(E)
{
    static if (is(E e == enum))
    {
        alias BaseType = e;
    }
    else
    {
        static assert("not an enum");
    }
}

enum B // int
{
    B0 = cast(BaseType!A)A.A0,
    B1
}

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October 02, 2013
http://d.puremagic.com/issues/show_bug.cgi?id=10555


Kenji Hara <k.hara.pg@gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |INVALID


--- Comment #5 from Kenji Hara <k.hara.pg@gmail.com> 2013-10-01 23:13:04 PDT ---
I agree with Henning Pohl. The behavior in 2.063/earlier was an accepts-invalid bug, and it has been correctly fixed in git-head.

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