Mark the type of lifted definitions as inferred

Author: noti0na1

compiler/src/dotty/tools/dotc/typer/EtaExpansion.scala

@@ -37,7 +37,9 @@ abstract class Lifter {
   protected def liftedFlags: FlagSet = EmptyFlags
 
   /** The tree of a lifted definition */
-  protected def liftedDef(sym: TermSymbol, rhs: Tree)(using Context): MemberDef = ValDef(sym, rhs)
+  protected def liftedDef(sym: TermSymbol, rhs: Tree)(using Context): MemberDef =
+    // Mark the type of lifted definitions as inferred
+    ValDef(sym, rhs, inferred = true)
 
   private def lift(defs: mutable.ListBuffer[Tree], expr: Tree, prefix: TermName = EmptyTermName)(using Context): Tree =
     if (noLift(expr)) expr

tests/pos-custom-args/captures/i24101/S1.scala

@@ -0,0 +1,4 @@
+import language.experimental.captureChecking
+
+trait MyMap[K, V]:
+  def filterNot(pred: ((K, V)) => Boolean): MyMap[K, V]^{this, pred} = ???

tests/pos-custom-args/captures/i24101/S2.scala

@@ -0,0 +1,14 @@
+trait AttributeValue
+
+case class CompletedSpan(
+  name: String, // remove to make it compile
+  attributes: MyMap[String, AttributeValue],
+){
+  lazy val allAttributes: MyMap[String, AttributeValue] = attributes
+  var allAttributes2: MyMap[String, AttributeValue] = attributes
+}
+
+def Test =
+  val span: CompletedSpan = ???
+  span.copy(attributes = span.allAttributes.filterNot { _ => false })
+  span.copy(attributes = span.allAttributes2.filterNot { _ => false })