[Issue 24857] Unknown error while instantiating: __traits(compiles) hides the real issue

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=24857

Nick Treleaven <nick at geany.org> changed:

           What    |Removed                     |Added
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                 CC|                            |nick at geany.org

--- Comment #1 from Nick Treleaven <nick at geany.org> ---
I couldn't reduce it any more than this:

```
template AllMembersInModule(alias Module) {
    import std.meta : Filter;
    alias all_members = __traits(allMembers, Module);

    template CanAccess(string member) {
        enum CanAccess = __traits(compiles, __traits(getMember, Module,
member));
    }
    alias x = Filter!(CanAccess, all_members);

    alias AllMembersInModule = y;
}

alias AllMembers = AllMembersInModule!(__traits(parent, {}));
pragma(msg, AllMembers); // added
```

Error: unknown, please file report on issues.dlang.org
aliastypo.d(15):        while evaluating `pragma(msg, AllMembers)`

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