abstract type pattern is unchecked since it is eliminated by erasure

Question

julien-truffaut opened this issue 8 years ago · comments

I got the following error in scala 2.10 once I upgraded from 1.1.0 to 1.1.1

Miles Sabin · Answer 1 · Thu Oct 20 2016 17:15:09 GMT+0800 (China Standard Time)

Can you point me at the corresponding source?

Julien Truffaut · Answer 2 · Thu Oct 20 2016 17:29:00 GMT+0800 (China Standard Time)

Julien Truffaut · Answer 3 · Thu Oct 20 2016 19:55:37 GMT+0800 (China Standard Time)

Thanks @milessabin, you're fixed worked :)

Miles Sabin · Answer 4 · Thu Oct 20 2016 19:58:02 GMT+0800 (China Standard Time)

For the record the fix (I think it is a fix rather than a workaround) is to use patterns of the form,

case n: TermName => ...
case n: TypeName => ...

rather than,

case n@TermName(_) => ...
case n@TypeName(_) => ...

Dale Wijnand · Answer 5 · Thu Oct 20 2016 20:00:22 GMT+0800 (China Standard Time)

@milessabin Can you explain why the latter doesn't work in 2.10?

Miles Sabin · Answer 6 · Thu Oct 20 2016 20:02:04 GMT+0800 (China Standard Time)

It seems that the extractors are being viewed as non-stable.

Dale Wijnand · Answer 7 · Thu Oct 20 2016 20:09:41 GMT+0800 (China Standard Time)

Personally I would qualify that as an issue with macro-compat that requires a workaround in user-land.

I wonder what project required support for them in macro-compat in the first place: 83ceac1