Thread overview
[Issue 11130] New: Regression (2.064 git-head): Enum members hijack module-scoped symbols in initializers
Sep 27, 2013
Andrej Mitrovic
Sep 27, 2013
Walter Bright
[Issue 11130] Enum members are now all in scope when evaluating enum member initializers
Sep 28, 2013
Walter Bright
Sep 28, 2013
Walter Bright
Oct 20, 2013
Andrej Mitrovic
September 27, 2013
http://d.puremagic.com/issues/show_bug.cgi?id=11130

           Summary: Regression (2.064 git-head): Enum members hijack
                    module-scoped symbols in initializers
           Product: D
           Version: D2
          Platform: All
        OS/Version: All
            Status: NEW
          Severity: regression
          Priority: P2
         Component: DMD
        AssignedTo: nobody@puremagic.com
        ReportedBy: andrej.mitrovich@gmail.com


--- Comment #0 from Andrej Mitrovic <andrej.mitrovich@gmail.com> 2013-09-27 06:34:40 PDT ---
This may or may not have been an intended change:

-----
enum A = 1;

enum E
{
    A = A
}

void main()
{
}
-----

$ dmd test.d
test.d(7): Error: enum member test.E.A circular reference to enum member

The workaround is simple for module-scoped enums, use the [dot] expression to look up module-scoped symbols:

-----
enum A = 1;

enum E
{
    A = .A  // works
}

void main()
{
}
-----

However the following code does not have an easy workaround:

-----
void main()
{
    enum A = 1;

    enum E
    {
        // circular reference, cannot use ".A" here
        // because "A" is not in module scope
        A = A
    }
}
-----

Above you would likely have to introduce an alias such as:

-----
void main()
{
    enum A = 1;
    alias thisA = A;
    enum E
    {
        A = thisA  // ok
    }
}
-----

If this regression was intended we're going to have to properly document it, both in the docs and in the upcoming changelog.

The regression was found in DGui, where some enum members have the same name as WinAPI constants, but were purposefully wrapped in the enum to make the constants typed:

enum EdgeType : uint
{
    RAISED_OUTER = BDR_RAISEDOUTER,
    RAISED_INNER = BDR_RAISEDINNER,

    SUNKEN_OUTER = BDR_SUNKENOUTER,
    SUNKEN_INNER = BDR_SUNKENINNER,

    BUMP        = EDGE_BUMP,
    ETCHED      = EDGE_ETCHED,
    EDGE_RAISED = EDGE_RAISED,  // issue here
    SUNKEN      = EDGE_SUNKEN,
}

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September 27, 2013
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Walter Bright <bugzilla@digitalmars.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |spec
                 CC|                            |bugzilla@digitalmars.com
           Severity|regression                  |normal


--- Comment #1 from Walter Bright <bugzilla@digitalmars.com> 2013-09-27 11:56:20 PDT ---
This was an intended change.

Before, an enum member was not inserted into the symbol table until *after* its initialization expression was evaluated. But in order for forward references to work, this is no longer possible, now all the enum member symbols are visible inside the { }.

I am surprised this broke any code, I don't consider it a reasonable practice, but you're right that we need to document this behavior.

I'm going to reset this as a "spec" issue.

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September 28, 2013
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Walter Bright <bugzilla@digitalmars.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|normal                      |enhancement


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--- Comment #2 from Walter Bright <bugzilla@digitalmars.com> 2013-09-28 15:36:09 PDT ---
https://github.com/D-Programming-Language/dlang.org/pull/387

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October 18, 2013
http://d.puremagic.com/issues/show_bug.cgi?id=11130



--- Comment #3 from github-bugzilla@puremagic.com 2013-10-18 14:24:56 PDT ---
Commits pushed to master at https://github.com/D-Programming-Language/dlang.org

https://github.com/D-Programming-Language/dlang.org/commit/9d451c948483ea1425a835841e70bcc20e76c7f6
fix Issue 11130 - Enum members are now all in scope when evaluating enum member
initializers

https://github.com/D-Programming-Language/dlang.org/commit/9ad3961dee2c6ea1710e3a1ba3391b993ab11985 Merge pull request #387 from WalterBright/fix11130

fix Issue 11130 - Enum members are now all in scope when evaluating enum...

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October 20, 2013
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Andrej Mitrovic <andrej.mitrovich@gmail.com> changed:

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


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October 26, 2013
http://d.puremagic.com/issues/show_bug.cgi?id=11130



--- Comment #4 from github-bugzilla@puremagic.com 2013-10-26 08:01:19 PDT ---
Commit pushed to 2.064 at https://github.com/D-Programming-Language/dlang.org

https://github.com/D-Programming-Language/dlang.org/commit/5572a0c432418a36fe3216fd076b84751628c97b Merge pull request #387 from WalterBright/fix11130

fix Issue 11130 - Enum members are now all in scope when evaluating enum...

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