• d-bugmail puremagic.com (37/37) Oct 13 2021 https://issues.dlang.org/show_bug.cgi?id=22384

d-bugmail puremagic.com writes:

https://issues.dlang.org/show_bug.cgi?id=22384

          Issue ID: 22384
           Summary: castSwitch confused by noreturn handlers
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Severity: normal
          Priority: P1
         Component: phobos
          Assignee: nobody puremagic.com
          Reporter: moonlightsentinel disroot.org

castSwitch allows handlers that neither return a value nor throw an exception -
as long as no other handler returns a value. This breaks when passing noreturn
handlers, causing castSwitch to throw an exception for the void handlers that
don't trow an exception and hence being inferred as noreturn.

Example

void main()
{    static void objectSkip(Object) {}
    static void defaultSkip() {}

    static noreturn objectError(Object) { assert(false); }
    static noreturn defaultError() { assert(false); }

    {
        alias test = castSwitch!(objectSkip, defaultError);
        static assert(is(ReturnType!test == void));           // fails,
noreturn
    }{
        alias test = castSwitch!(objectError, defaultSkip);
        static assert(is(ReturnType!test == void));           // fails,
noreturn
    }{
        alias test = castSwitch!(objectError, defaultError);
        static assert(is(ReturnType!test == noreturn));       // valid
    }
}

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