• d-bugmail puremagic.com (55/55) Feb 11 2020 https://issues.dlang.org/show_bug.cgi?id=20575

d-bugmail puremagic.com writes:

https://issues.dlang.org/show_bug.cgi?id=20575

          Issue ID: 20575
           Summary: Version'ed cases in
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Severity: normal
          Priority: P1
         Component: dmd
          Assignee: nobody puremagic.com
          Reporter: moonlightsentinel disroot.org

Consider the following example:

void main()
{
    import std.stdio;

    foreach (i; 1 .. 4)
    {
        write(i, ": ");
        switch (i)
        {
            version (A) case 1:
            version (B) case 2:
                write("Case");
                break;

            case 3:

            default:
                write("Default");
        }
        writeln();
    }
}

Executing this example with different versions yields strange results:

[ ]: // OK
1: Default
2: Default
3: Default

[A]: // Strange
1:
2: Default
3: Default

[B]: // Maybe?
1: Default
2: Default
3: Default

[A, B]: // OK
1: Case
2: Case
3: Default

[B] suggests that the missing A discards both case statements (which form a
CaseRangeStatement) and hence executes the default.

But [A] seems to discard "case 2: writeln(...);" without implicit fallthough /
compiler warning.

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