From 5439c4c9aa9ef03c061fa9c2c4689a722729b8f9 Mon Sep 17 00:00:00 2001 From: Den Shabalin Date: Thu, 8 Aug 2013 18:53:42 +0200 Subject: SI-7731 make CannotHaveAttrs more consistent Previously setPos, pos_=, setType, tpe_= all behaved inconsistently between each other even though they all represent similar attributes that cannot be changed on CannotHaveAttrs trees. In order to simplify handling of such trees in compiler code each of these fields now supports assignment to its current default value: NoType for tpe and NoPosition for pos. Such assignments don't mutate underlying trees. --- src/reflect/scala/reflect/internal/Trees.scala | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) (limited to 'src/reflect') diff --git a/src/reflect/scala/reflect/internal/Trees.scala b/src/reflect/scala/reflect/internal/Trees.scala index df1ba1e2ea..02bee5e369 100644 --- a/src/reflect/scala/reflect/internal/Trees.scala +++ b/src/reflect/scala/reflect/internal/Trees.scala @@ -1017,14 +1017,16 @@ trait Trees extends api.Trees { self: SymbolTable => trait CannotHaveAttrs extends Tree { override def canHaveAttrs = false - private def unsupported(what: String, args: Any*) = - throw new UnsupportedOperationException(s"$what($args) inapplicable for "+self.toString) + private def requireLegal(value: Any, allowed: Any, what: String) = + require(value == allowed, s"can't set $what for $self to value other than $allowed") super.setPos(NoPosition) - override def setPos(pos: Position) = unsupported("setPos", pos) + override def setPos(pos: Position) = { requireLegal(pos, NoPosition, "pos"); this } + override def pos_=(pos: Position) = setPos(pos) super.setType(NoType) - override def tpe_=(t: Type) = if (t != NoType) unsupported("tpe_=", t) + override def setType(t: Type) = { requireLegal(t, NoType, "tpe"); this } + override def tpe_=(t: Type) = setType(t) } case object EmptyTree extends TermTree with CannotHaveAttrs { override def isEmpty = true; val asList = List(this) } -- cgit v1.2.3