Still reproducible (2017.11, HEAD(5929887)), but with a slightly different error:
===SORRY!=== Error while compiling -e Cannot import the following symbols from X, because they already exist in this lexical scope: B, A at -e:1 ------> use X⏏; use Y On 2015-01-11 05:44:26, masak wrote: > <masak> here: https://gist.github.com/masak/406d687c3e4e0684c013 > > Inlined here for your benefit: > > $ cat X.pm > enum X is export <A B>; > $ cat Y.pm > enum Y is export <B W>; > $ perl6 -I. -e 'use X; use Y' > ===SORRY!=== > Merging GLOBAL symbols failed: duplicate definition of symbol B > > <masak> by my reading of S12, this should work, but then you're not > allowed to refer to just `B`; you have to say `X::B` or `Y::B`. > <masak> (and if you also import a `sub B { ... }` from somewhere, it > takes precedence and "un-poisons" the slot for itself) > <moritz> that takes slot &B > <masak> no doubt -- but I'm talking about what happens when you write > `B` in code after that. > <masak> if the sub has been imported, that's a call to `&B`. > <moritz> that should resolve to &B, yes > * moritz skims S12 > <masak> but if it hasn't, then it's still a compile-time error, > because it's not clear if you're referring to `X::B` or `Y::B`. > <moritz> Since there is an enum C<OK>, the function C<OK> may only be > <moritz> called using parentheses, never in list operator form. > <moritz> so you'd be able to call B() when the B slot is poisoned, but > not just 'B args', iiuc > <moritz> ah yes > <moritz> "If there is > <moritz> a collision on two enum values that cancels them both, the function > <moritz> still may only be called with parentheses, since the enum key > <moritz> is "poisoned"." > <masak> right. > <masak> that's the only reference to the concept of poisoning I've found. > <masak> it mentions the effect in passing, but it's pretty clear about it. > * masak submits rakudobug > <moritz> masak: S12 doesn't talk about in which circumstances > poisoning, so I'd assume it happens everywhere > <moritz> so, also in importation/exportation > <masak> moritz: ah, you mean between any two imported symbols? > <masak> moritz: that's very possible. > <moritz> masak: no > <masak> moritz: but enum values are a bit special in that they're > essentially short-form aliases for their real unambiguous names. > <masak> moritz: like, `True` is short for `Bool::True`. > <moritz> yes > <moritz> masak: I mean between two imported enum items vs. two > declared-here enum items > <masak> moritz: oh, that's entirely possible, yes. > <masak> moritz: though I could equally well argue that the > declared-here enum value takes precedence... > <moritz> with "everywhere" I meant "at declaration and at {ex,im}portation" > <masak> declaring something feels like much more of a "conscious act" > than importation. > <masak> like, you might not know you're importing a `B`, but you > definitely know you're declaring one! > > To summarize: the error message "Merging GLOBAL symbols failed: > duplicate definition of symbol B" on importing Y.pm is wrong. That > should work without an error. Referring to `B` after that in code > should be a (compile-time) error, though. This is the "poisoning" > effect referred to by S12. > > The rest of the discussion is pertinent, but doesn't figure in the > closability of this ticket.
