anchor.diff:      ;
   
   declarationStart
  -    : declarationKeyword | union '...'? LIDENTIFIER
  +    : declarationKeyword | type '...'? LIDENTIFIER
       ;
   
   declarationKeyword
  
positive.code:     ;
  
  valueFormalParameter
      : '->' union parameterName
      ;
  
  iteratedFormalParameter
      : 'in' union parameterName
      ;
  
  specifiedFormalParameter
      : '=' union parameterName
      ;
  
  specifiedFormalParameterStart
  
negative.code:     ;
  
  typeConstraint
      : 'given' typeName formalParameters? caseTypes? metatypes? satisfiedTypes? abstractedType?
      -> ^(TYPE_CONSTRAINT typeName formalParameters? satisfiedTypes? abstractedType?)
      ;
      
  typeConstraints
      : typeConstraint+
      -> ^(TYPE_CONSTRAINT_LIST typeConstraint+)
      ;
  
  type
  