Issue4435-1.agda:6,1-25
The following names are declared but not accompanied by a
definition: Foo
Issue4435-1.agda:10,6-17
Multiple definitions of Foo. Previous definition at
Issue4435-1.agda:6,6-9
Perhaps you meant to write 
  'data Foo a where'
at Issue4435-1.agda:10,6-17?
In data definitions separate from data declaration, the ':' and type must be omitted.
when scope checking the declaration
  data Foo a : Set
