Code using ConstraintKinds needs explicit kind signature with GHC 8.2.1

The attached module compiles without errors with GHC 8.0.1 but needs an explicit kind signature with GHC 8.2.1-rc2.

Mentioned in this ghc-dev thread.

Compiling the attached file fails gives the error:

[[1 of 1] Compiling CKBug            ( CKBug.hs, interpreted )

CKBug.hs:33:4: error:
    • Expected a type, but
      ‘(PropagIOConstraint l a,
        Missing (PropagIOVector l) (PropagIONullable l a),
        Elem (PropagIONullable l a) ~ a)’ has kind
      ‘Constraint’
    • In the type ‘((PropagIOConstraint l a,
                     Missing (PropagIOVector l) (PropagIONullable l a),
                     Elem (PropagIONullable l a) ~ a))’
      In the type declaration for ‘CanSerialize’
   |
33 |   (( PropagIOConstraint l a
   |    ^^^^^^^^^^^^^^^^^^^^^^^^...

CKBug.hs:42:4: error:
    • Expected a constraint,
        but ‘(CanSerialize l Double, CanSerialize l Int)’ has kind ‘*’
    • In the type ‘(CanSerialize l Double, CanSerialize l Int)’
      In the type declaration for ‘CanSerializePropagTypes’
   |
42 |    ( CanSerialize l Double
   |    ^^^^^^^^^^^^^^^^^^^^^^^...