Avoid unnecessary decodes

Author: odersky

compiler/src/dotty/tools/dotc/core/unpickleScala2/Scala2Unpickler.scala

@@ -227,7 +227,7 @@ class Scala2Unpickler(bytes: Array[Byte], classRoot: ClassDenotation, moduleClas
     val major = readNat()
     val minor = readNat()
     if (major != MajorVersion || minor > MinorVersion)
-      throw new IOException("Scala signature " + classRoot.fullName.decode +
+      throw new IOException("Scala signature " + classRoot.fullName +
         " has wrong version\n expected: " +
         MajorVersion + "." + MinorVersion +
         "\n found: " + major + "." + minor +

compiler/src/dotty/tools/dotc/printing/RefinedPrinter.scala

@@ -157,7 +157,7 @@ class RefinedPrinter(_ctx: Context) extends PlainPrinter(_ctx) {
         withoutPos(super.toText(tp))
       case tp: SelectionProto =>
         return "?{ " ~ toText(tp.name) ~
-           (" " provided !tp.name.toSimpleName.decode.last.isLetterOrDigit) ~
+           (" " provided !tp.name.toSimpleName.last.isLetterOrDigit) ~
            ": " ~ toText(tp.memberProto) ~ " }"
       case tp: ViewProto =>
         return toText(tp.argType) ~ " ?=>? " ~ toText(tp.resultType)