Erase constant type

Author: som-snytt

src/compiler/scala/tools/nsc/transform/Constructors.scala

@@ -607,7 +607,7 @@ abstract class Constructors extends Statics with Transform with TypingTransforme
 
       private def triage() = {
         // Constant typed vals are not memoized.
-        def memoizeValue(sym: Symbol) = !sym.info.resultType.isInstanceOf[FoldableConstantType]
+        def memoizeValue(sym: Symbol) = enteringErasure(!sym.info.resultType.isInstanceOf[FoldableConstantType])
 
         // The early initialized field definitions of the class (these are the class members)
         val presupers = treeInfo.preSuperFields(stats)

src/reflect/scala/reflect/internal/transform/Erasure.scala

@@ -135,7 +135,7 @@ trait Erasure {
       case FoldableConstantType(ct) =>
         // erase classOf[List[_]] to classOf[List]. special case for classOf[Unit], avoid erasing to classOf[BoxedUnit].
         if (ct.tag == ClazzTag && ct.typeValue.typeSymbol != UnitClass) ConstantType(Constant(apply(ct.typeValue)))
-        else tp
+        else ct.tpe
       case st: ThisType if st.sym.isPackageClass =>
         tp
       case st: SubType =>

test/files/run/patmat-seq.check

@@ -264,7 +264,7 @@ package <empty> {
       ()
     };
     def t(): Object = {
-      case <synthetic> val x1: Int(2) = 2;
+      case <synthetic> val x1: Int = 2;
       case16(){
         <synthetic> val o18: scala.collection.SeqOps = A.unapplySeq(x1);
         if (scala.collection.SeqFactory.UnapplySeqWrapper.isEmpty$extension(o18).unary_!())