dotty.tools.dotc.parsing

Performs the following context-free rewritings:

• Places all pattern variables in Bind nodes. In a pattern, for identifiers x:

               x  => x @ _
             x:T  => x @ (_ : T)

• Removes pattern definitions (PatDef's) as follows: If pattern is a simple (typed) identifier:

      val x = e     ==>  val x = e
      val x: T = e  ==>  val x: T = e

if there are no variables in pattern

      val p = e  ==>  e match (case p => ())

if there is exactly one variable in pattern

      val x_1 = e match (case p => (x_1))

if there is more than one variable in pattern

      val p = e  ==>  private synthetic val t$ = e match (case p => (x_1, ..., x_N))
                      val x_1 = t$._1
                      ...
                      val x_N = t$._N

• Removes function types as follows:

      (argtpes) => restpe   ==>   scala.Function_n[argtpes, restpe]

• Wraps naked case definitions in a match as follows:

      { cases }   ==>   (x => x.match {cases}), except when already argument to match

Compute the precedence of infix operator operator according to the SLS § 6.12.3. We implement SIP-33 and give type operators the same precedence as term operators.