Utility method for phase replacement

Allows to replace existing phase by sequence of new
phases.

1 files changed, 7 insertions, 0 deletions

diff --git a/src/dotty/tools/dotc/core/Phases.scala b/src/dotty/tools/dotc/core/Phases.scala
index 970a9297a..83ac64d53 100644
--- a/src/dotty/tools/dotc/core/Phases.scala
+++ b/src/dotty/tools/dotc/core/Phases.scala
@@ -347,6 +347,13 @@ object Phases {
     override def toString = phaseName
   }
 
+  /** Replace all instances of `oldPhaseClass` in `current` phases
+   *  by the result of `newPhases` applied to the old phase.
+   */
+  def replace(oldPhaseClass: Class[_ <: Phase], newPhases: Phase => List[Phase], current: List[List[Phase]]): List[List[Phase]] =
+    current.map(_.flatMap(phase =>
+      if (oldPhaseClass.isInstance(phase)) newPhases(phase) else phase :: Nil))
+
   /** Dotty deviation: getClass yields Class[_], instead of [Class <: <type of receiver>].
    *  We can get back the old behavior using this decorator. We should also use the same
    *  trick for standard getClass.