derivative-1.0.0 beta regression

[est31]

derivative version 1.0.0 regressed from stable to beta (full log):

error[E0277]: the trait bound `[u8]: std::marker::Sized` is not satisfied in `Row<u8>`
  --> tests/rustc-issue-25394.rs:18:24
   |
18 | fn use_row(_: Row<u8>) {}
   |                        ^ `[u8]` does not have a constant size known at compile-time
   |
   = help: within `Row<u8>`, the trait `std::marker::Sized` is not implemented for `[u8]`
   = note: required because it appears within the type `Row<u8>`

cc @mcarton

[arielb1]

• rustc_typeck: enforce argument type is sized #42642: argument types are now required to be sized, even if they are not used. That is a bug-fix and it found a bug on derivative's end.

[alexcrichton]

There's a PR at mcarton/rust-derivative#13 to fix this, but it hasn't been merged yet

[nikomatsakis]

Closing as expected fallout from #42642.