Assertions

^Syntax
Assertion :
      PointsToAssertion
   | PredicateAssertion
   | TypePredicateAssertion
   | BooleanAssertion
   | PatternMatchingEqualityAssertion
   | ConditionalAssertion
   | MatchAssertion
   | Assertion &*& Assertion

PointsToAssertion : ( [ VFPattern ] )^? Expression ( |-> | |-?-> ) VFPattern

VFPattern : _ | ? ( IDENTIFIER | _ ) | Expression

PredicateAssertion : ( [ VFPattern ] )^? Expression VFPatternList ^? VFPatternList

VFPatternList : ( (( VFPattern , )^* VFPattern )^? )

TypePredicateAssertion : < Type > . IDENTIFIER VFPatternList

BooleanAssertion : Expression

PatternMatchingEqualityAssertion : Expression == VFPattern

ConditionalAssertion : if Expression { Assertion } else { Assertion }

MatchAssertion : match Scrutinee { ( MatchAssertionArm ,^? )^* }

MatchAssertionArm : Pattern => Assertion