Lint avoids revisiting Inlined.call (#24277)

Fixes #24266 Restores empty check and "already seen" check for Inlined.call sites.

Author: som-snytt

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

@@ -161,7 +161,10 @@ 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 =
@@ -518,6 +521,7 @@ 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