diff --git a/compiler/src/dotty/tools/dotc/ast/Desugar.scala b/compiler/src/dotty/tools/dotc/ast/Desugar.scala
index 541fd9ecfc3a..6521deaa1f70 100644
--- a/compiler/src/dotty/tools/dotc/ast/Desugar.scala
+++ b/compiler/src/dotty/tools/dotc/ast/Desugar.scala
@@ -1017,7 +1017,7 @@ object desugar {
       var tested: MemberDef = tree
       def fail(msg: String) = ctx.error(msg, tree.sourcePos)
       def checkApplicable(flag: FlagSet, test: MemberDefTest): Unit =
-        if (tested.mods.is(flag) && !test.applyOrElse(tree, _ => false)) {
+        if (tested.mods.is(flag) && !test.applyOrElse(tree, (md: MemberDef) => false)) {
           fail(i"modifier `$flag` is not allowed for this definition")
           tested = tested.withMods(tested.mods.withoutFlags(flag))
         }
diff --git a/compiler/src/dotty/tools/dotc/core/Annotations.scala b/compiler/src/dotty/tools/dotc/core/Annotations.scala
index b74603d8bd44..c21dadf3ed05 100644
--- a/compiler/src/dotty/tools/dotc/core/Annotations.scala
+++ b/compiler/src/dotty/tools/dotc/core/Annotations.scala
@@ -181,6 +181,7 @@ object Annotations {
     object WithBounds {
       def unapply(ann: Annotation)(implicit ctx: Context): Option[TypeBounds] =
         if (ann.symbol == defn.WithBoundsAnnot) {
+          import ast.Trees._
           // We need to extract the type of the type tree in the New itself.
           // The annotation's type has been simplified as the type of an expression,
           // which means that `&` or `|` might have been lost.
diff --git a/compiler/src/dotty/tools/dotc/core/CheckRealizable.scala b/compiler/src/dotty/tools/dotc/core/CheckRealizable.scala
index 0102cc0471d1..e4849bdf1c25 100644
--- a/compiler/src/dotty/tools/dotc/core/CheckRealizable.scala
+++ b/compiler/src/dotty/tools/dotc/core/CheckRealizable.scala
@@ -146,16 +146,18 @@ class CheckRealizable(implicit ctx: Context) {
   private def boundsRealizability(tp: Type) = {
 
     val memberProblems =
-      for mbr <- tp.nonClassTypeMembers if !(mbr.info.loBound <:< mbr.info.hiBound)
-      yield new HasProblemBounds(mbr.name, mbr.info)
+      for {
+        mbr <- tp.nonClassTypeMembers
+        if !(mbr.info.loBound <:< mbr.info.hiBound)
+      } yield new HasProblemBounds(mbr.name, mbr.info)
 
     val refinementProblems =
-      for
+      for {
         name <- refinedNames(tp)
         if (name.isTypeName)
         mbr <- tp.member(name).alternatives
         if !(mbr.info.loBound <:< mbr.info.hiBound)
-      yield new HasProblemBounds(name, mbr.info)
+      } yield new HasProblemBounds(name, mbr.info)
 
     def baseTypeProblems(base: Type) = base match {
       case AndType(base1, base2) =>
diff --git a/library/src/scala/annotation/internal/WithBounds.scala b/library/src-3.x/scala/internal/WithBounds.scala
similarity index 100%
rename from library/src/scala/annotation/internal/WithBounds.scala
rename to library/src-3.x/scala/internal/WithBounds.scala