Backport "Lint avoids revisiting Inlined.call" to 3.3 LTS

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

@@ -166,7 +166,10 @@ class CheckUnused private (phaseMode: PhaseMode, suffix: String) extends MiniPha
       tree.expansion.putAttachment(InlinedParameter, ())
     ctx
   override def transformInlined(tree: Inlined)(using Context): tree.type =
-    transformAllDeep(tree.call)
+    if !tree.call.isEmpty then
+      if !refInfos.calls.containsKey(tree.call) then
+        refInfos.calls.put(tree.call, ())
+        transformAllDeep(tree.call)
     tree
 
   override def prepareForBind(tree: Bind)(using Context): Context =
@@ -491,6 +494,7 @@ object CheckUnused:
     val asss = mutable.Set.empty[Symbol]              // targets of assignment
     val skip = mutable.Set.empty[Symbol]              // methods to skip (don't warn about their params)
     val nowarn = mutable.Set.empty[Symbol]            // marked @nowarn
+    val calls = new IdentityHashMap[Tree, Unit]          // inlined call already seen
     val imps = new IdentityHashMap[Import, Unit]         // imports
     val sels = new IdentityHashMap[ImportSelector, Unit] // matched selectors
     def register(tree: Tree)(using Context): Unit = if tree.srcPos.isUserCode then

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

@@ -369,10 +369,7 @@ class PostTyper extends MacroTransform with IdentityDenotTransformer { thisPhase
         case UnApply(fun, implicits, patterns) =>
           // Reverse transform order for the same reason as in `app1` above.
           val patterns1 = transform(patterns)
-          val tree1 = cpy.UnApply(tree)(transform(fun), transform(implicits), patterns1)
-          // The pickling of UnApply trees uses the tpe of the tree,
-          // so we need to clean retains from it here
-          tree1.withType(transformAnnotsIn(CleanupRetains()(tree1.tpe)))
+          cpy.UnApply(tree)(transform(fun), transform(implicits), patterns1)
         case tree: TypeApply =>
           if tree.symbol == defn.QuotedTypeModule_of then
             ctx.compilationUnit.needsStaging = true