Synthesis should be a UnitPhase

src/main/scala/leon/LeonPhase.scala

@@ -28,7 +28,7 @@ abstract class UnitPhase[T] extends LeonPhase[T, T] {
   def apply(ctx: LeonContext, p: T): Unit
 
   override def run(ctx: LeonContext, p: T) = {
-    ctx.reporter.debug("Running unit phase phase: " + name)(utils.DebugSectionLeon)
+    ctx.reporter.debug("Running unit phase: " + name)(utils.DebugSectionLeon)
     apply(ctx, p)
     (ctx, p)
   }

src/main/scala/leon/synthesis/SynthesisPhase.scala

@@ -10,7 +10,7 @@ import purescala.Definitions.{Program, FunDef}
 import leon.utils._
 import graph._
 
-object SynthesisPhase extends TransformationPhase {
+object SynthesisPhase extends UnitPhase[Program] {
   val name        = "Synthesis"
   val description = "Partial synthesis of \"choose\" constructs. Also used by repair during the synthesis stage."
 
@@ -65,7 +65,7 @@ object SynthesisPhase extends TransformationPhase {
     )
   }
 
-  def apply(ctx: LeonContext, program: Program): Program = {
+  def apply(ctx: LeonContext, program: Program): Unit = {
     val options = processOptions(ctx)
 
     val chooses = SourceInfo.extractFromProgram(ctx, program)
@@ -106,7 +106,6 @@ object SynthesisPhase extends TransformationPhase {
       ctx.reporter.info("")
     }
 
-    program
   }
 
 }