Avoiding an idiom which is not supported by dotty.

Normally, Predef.identity cannot be used as an expression with unknown expected type. You need a trailing `_`.
But when used as a default argument, Scala 2x allows it. I am not sure why it is allowed. In dotty it's disallowed everywhere, hence the fix.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/dotty/tools/dotc/ast/tpd.scala b/src/dotty/tools/dotc/ast/tpd.scala
index 70016c0a6..2e6604bc2 100644
--- a/src/dotty/tools/dotc/ast/tpd.scala
+++ b/src/dotty/tools/dotc/ast/tpd.scala
@@ -429,7 +429,7 @@ object tpd extends Trees.Instance[Type] with TypedTreeInfo {
     def tpes: List[Type] = xs map (_.tpe)
   }
 
-  class TreeMapper(val typeMap: TypeMap = IdentityTypeMap, val ownerMap: Symbol => Symbol = identity)(implicit ctx: Context) extends TreeTransformer {
+  class TreeMapper(val typeMap: TypeMap = IdentityTypeMap, val ownerMap: Symbol => Symbol = identity _)(implicit ctx: Context) extends TreeTransformer {
     override def transform(tree: tpd.Tree)(implicit ctx: Context): tpd.Tree = super.transform {
       tree.withType(typeMap(tree.tpe)) match {
         case bind: tpd.Bind =>