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digitalmars.D.bugs - [Issue 7358] New: `final switch` over enum should add throwing default in debug mode at least

reply d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=7358

           Summary: `final switch` over enum should add throwing default
                    in debug mode at least
           Product: D
           Version: D2
          Platform: All
        OS/Version: All
            Status: NEW
          Keywords: wrong-code
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: nobody puremagic.com
        ReportedBy: verylonglogin.reg gmail.com


--- Comment #0 from Denis <verylonglogin.reg gmail.com> 2012-01-24 14:52:00 MSK
---
Inspired by bug 5713, comment 5

Even if every enum member is present a default statement should be added at
least in debug mode to catch such situation if enum members doesn't cover every
possible value:
---
enum E { a = 1, b }
void f(E e) {
    final switch (e) {
        case E.a:
        case E.b:
    }
}
void g() {
    f(E.a | E.b); // like `f(cast(E)3);`, should throw
}
---

As was written in bug 5713 description:

The purpose of "final switch" is to increase code safety compared to normal
switches on enums.


So it's really bad that it works silently incorrect. Personally I have used
`final switch` carefully and thought about it's behavior in such situation
since it has been introduced because it is undocumented. So the documentation
should be fixed too.

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Jan 24 2012
next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=7358


yebblies <yebblies gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |patch
                 CC|                            |yebblies gmail.com
         AssignedTo|nobody puremagic.com        |yebblies gmail.com


--- Comment #1 from yebblies <yebblies gmail.com> 2012-02-01 16:09:02 EST ---
https://github.com/D-Programming-Language/dmd/pull/673

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prev sibling next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=7358


bearophile_hugs eml.cc changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |bearophile_hugs eml.cc


--- Comment #2 from bearophile_hugs eml.cc 2012-02-05 06:14:36 PST ---
(In reply to comment #1)

 https://github.com/D-Programming-Language/dmd/pull/673


I don't like it. There are better solutions, like:
is(typeof(E.a | E.b) == int)

This means f(E.a | E.b) becomes a compile-time error, a type mismatch.

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prev sibling next sibling parent d-bugmail puremagic.com writes:
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--- Comment #4 from github-bugzilla puremagic.com 2012-10-30 07:42:24 PDT ---
Commits pushed to master at https://github.com/D-Programming-Language/dmd

https://github.com/D-Programming-Language/dmd/commit/b9ad0b8517c23fa4deca3ddb433dfbb0fab8fb65
Issue 7358 - final switch over enum should add throwing default in debug mode
at least

Add a throwing default case when compiled with asserts on.

https://github.com/D-Programming-Language/dmd/commit/638d81d792d5f12c887de3da6ab00c07d9f227b2
Merge pull request #673 from yebblies/issue7358

Issue 7358 - final switch over enum should add throwing default in debug mode

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prev sibling parent d-bugmail puremagic.com writes:
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yebblies <yebblies gmail.com> changed:

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


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