Missing stripMethodPrefix in FullParameterization.

Author: gsps

compiler/src/dotty/tools/dotc/transform/FullParameterization.scala

@@ -234,7 +234,7 @@ trait FullParameterization {
     else {
       // this type could have changed on forwarding. Need to insert a cast.
       originalDef.vparamss.foldLeft(fun)((acc, vparams) => {
-        val meth = acc.tpe.asInstanceOf[MethodType]
+        val meth = acc.tpe.stripMethodPrefix.asInstanceOf[MethodType]
         val paramTypes = meth.instantiateParamInfos(vparams.map(_.tpe))
         acc.appliedToArgs(
           (vparams, paramTypes).zipped.map((vparam, paramType) => {