Sparse Decoration

Sparse decoration of the base object is prohibited.

Incorrect:

[] > decorates-five
  five > @

Correct:

[] > decorates-application
  if > @
    true
    5
    five

[free] > decorates-with-free-args
  five > @

Also, it is possible to have sparse decoration in tests:

# This is my unit test.
[] > runs-analysis
  assert > @
    foo.eq 42