catch two more exhaustive issue in compiler

Author: liufengyun

compiler/src/dotty/tools/dotc/core/SymDenotations.scala

@@ -1678,7 +1678,7 @@ object SymDenotations {
           case tp @ AppliedType(tycon, args) =>
             val subsym = tycon.typeSymbol
             if (subsym eq symbol) tp
-            else tycon.typeParams match {
+            else (tycon.typeParams: @unchecked) match {
               case LambdaParam(_, _) :: _ =>
                 baseTypeOf(tp.superType)
               case tparams: List[Symbol @unchecked] =>

compiler/src/dotty/tools/dotc/core/Types.scala

@@ -2674,7 +2674,7 @@ object Types {
      *  either a list of type parameter symbols or a list of lambda parameters
      */
     def integrate(tparams: List[ParamInfo], tp: Type)(implicit ctx: Context): Type =
-      tparams match {
+      (tparams: @unchecked) match {
         case LambdaParam(lam, _) :: _ => tp.subst(lam, this)
         case params: List[Symbol @unchecked] => tp.subst(params, paramRefs)
       }