Channels
#stdlib
- y
yole
04/18/2016, 1:39 PMyes, but this is inferred by the JVM bytecode verifier - y
yole
04/18/2016, 1:39 PMthere is a local variable table, but it’s optional debug information - k
kirillrakhman
04/18/2016, 1:39 PMvia
?ALOAD - y
yole
04/18/2016, 1:39 PMyep - k
kirillrakhman
04/18/2016, 1:39 PMmind blown - y
yole
04/18/2016, 1:39 PMI’m not sure whether the verifier would actually be happy with an intersection type - k
kirillrakhman
04/18/2016, 1:40 PMit's inferred from what, though? - k
kirillrakhman
04/18/2016, 1:42 PMfrom what was in the register before
?ASTORE - k
kmruiz
04/18/2016, 1:42 PMAFAIK all the types used in compiletime are in the constant pool - k
kmruiz
04/18/2016, 1:43 PMfor invokeinterface we need to say the interface and the method we are going to use, if I remember fine - k
kirillrakhman
04/18/2016, 1:43 PMbtw, the error message for
is not very helpfulfun <T, R> mutableRandomAccess(): T where T : MutableList<R>, T : RandomAccess = ArrayList<R>() - k
kirillrakhman
04/18/2016, 1:44 PMError:(137, 82) Type mismatch: inferred type is ArrayList<R> but T was expected - k
kmruiz
04/18/2016, 1:44 PMawesome - k
kmruiz
04/18/2016, 1:45 PMhmm it has sense, because ArrayList implements RandomAccess, but does not implement MutableList AFAIK - k
kirillrakhman
04/18/2016, 1:46 PMsure it does - k
kirillrakhman
04/18/2016, 1:46 PMvia compiler ✨ - k
kmruiz
04/18/2016, 1:46 PMoh - k
kirillrakhman
04/18/2016, 1:48 PM
will compile thoughfun <T, R> mutableRandomAccess(item : R): T where T : MutableList<R>, T : RandomAccess = null!! - k
kirillrakhman
04/18/2016, 1:49 PMhowever now the return type is completely unclear, you can't really use.
doesn't compilemutableRandomAccess("") - k
kmruiz
04/18/2016, 1:49 PMlooks like a dark corner in the compiler - k
kirillrakhman
04/18/2016, 1:49 PMError:(140, 5) Type inference failed: Cannot infer type parameter T in fun <T : MutableList<R>, R> mutableRandomAccess(item: R): T where T : RandomAccess None of the following substitutions (String) (String) can be applied to (String) - k
kirillrakhman
04/18/2016, 1:50 PMoh okay, it makes sense - k
kirillrakhman
04/18/2016, 1:51 PMif you somehow manage to call it,
is substituted by the actual type, e.g.TArrayList<String> - k
kirillrakhman
04/18/2016, 1:51 PMCopy codefun <T, R> mutableRandomAccess(list: T, item : R): T where T : MutableList<R>, T : RandomAccess = list fun foo() { val list: ArrayList<String> = mutableRandomAccess(ArrayList<String>(), "") } - k
kirillrakhman
04/18/2016, 1:51 PMit only goes to show that you can't have intersection types as return type - k
kmruiz
04/18/2016, 1:56 PMyep looks like it's not implemented - k
kmruiz
04/18/2016, 1:58 PM-.kt - k
kmruiz
04/18/2016, 1:58 PMif you typecast arr as T, it works, but you ignore the compiler - k
kmruiz
04/18/2016, 1:59 PMalso, as you said, you need to put all the type parameters because the compiler does not infer anything - k
kmruiz
04/18/2016, 1:59 PMhowever the JVM doesn't blame and seems to work