Mutable field in an object? I don't think so.

This is a dirty quick fix for now until we rewrite the FunctionClosure
phase.

src/main/scala/leon/Main.scala

@@ -17,7 +17,7 @@ object Main {
       xlang.ImperativeCodeElimination,
       xlang.FixReportLabels,
       xlang.XLangDesugaringPhase,
-      purescala.FunctionClosure,
+      new purescala.FunctionClosure,
       synthesis.SynthesisPhase,
       termination.TerminationPhase,
       verification.AnalysisPhase,
@@ -190,12 +190,12 @@ object Main {
         else if (synthesisF) SynthesisPhase
         else if (repairF) RepairPhase
         else if (analysisF) Pipeline.both(
-          FunctionClosure andThen analysis,
+          (new FunctionClosure) andThen analysis,
           TerminationPhase
         )
         else if (terminationF) TerminationPhase
         else if (evalF) EvaluationPhase
-        else FunctionClosure andThen analysis
+        else (new FunctionClosure) andThen analysis
       }
 
       pipeBegin andThen

src/main/scala/leon/purescala/FunctionClosure.scala

@@ -10,7 +10,7 @@ import Extractors._
 import ExprOps._
 import Constructors._
 
-object FunctionClosure extends TransformationPhase {
+class FunctionClosure extends TransformationPhase {
 
   val name = "Function Closure"
   val description = "Closing function with its scoping variables"
@@ -175,5 +175,4 @@ object FunctionClosure extends TransformationPhase {
     } while(newVars != Set())
     (filteredConstraints, allVars)
   }
-
 }

src/main/scala/leon/xlang/XLangDesugaringPhase.scala

@@ -16,7 +16,7 @@ object XLangDesugaringPhase extends TransformationPhase {
       ArrayTransformation andThen
       EpsilonElimination andThen
       ImperativeCodeElimination andThen
-      FunctionClosure
+      (new FunctionClosure)
     phases.run(ctx)(pgm)
   }
 

src/test/scala/leon/regression/synthesis/StablePrintingSuite.scala

@@ -33,7 +33,7 @@ class StablePrintingSuite extends LeonRegressionSuite {
       val pipeline = leon.utils.TemporaryInputPhase andThen 
                      frontends.scalac.ExtractionPhase andThen
                      leon.utils.PreprocessingPhase andThen
-                     purescala.FunctionClosure
+                     (new purescala.FunctionClosure)
 
       val program = pipeline.run(ctx)((List(content), Nil))