Fix -Wunused:locals,privates with recursive

Author: PaulCoral

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

@@ -95,15 +95,15 @@ class CheckUnused extends MiniPhase:
   override def prepareForValDef(tree: tpd.ValDef)(using Context): Context =
     _key.unusedDataApply{ud =>
       ud.registerDef(tree)
-      if tree.symbol.is(Flags.Module) then
-        ud.addIgnoredUsage(tree.symbol)
+      ud.addIgnoredUsage(tree.symbol)
     }
 
   override def prepareForDefDef(tree: tpd.DefDef)(using Context): Context =
     _key.unusedDataApply{ ud =>
       import ud.registerTrivial
       tree.registerTrivial
       ud.registerDef(tree)
+      ud.addIgnoredUsage(tree.symbol)
     }
 
   override def prepareForTypeDef(tree: tpd.TypeDef)(using Context): Context =
@@ -121,11 +121,6 @@ class CheckUnused extends MiniPhase:
 
   // ========== MiniPhase Transform ==========
 
-  override def transformValDef(tree: tpd.ValDef)(using Context): tpd.Tree =
-    if tree.symbol.is(Flags.Module) then
-      _key.unusedDataApply(_.removeIgnoredUsage(tree.symbol))
-    tree
-
   override def transformBlock(tree: tpd.Block)(using Context): tpd.Tree =
     popOutBlockTemplatePackageDef()
     tree
@@ -138,6 +133,14 @@ class CheckUnused extends MiniPhase:
     popOutBlockTemplatePackageDef()
     tree
 
+  override def transformValDef(tree: tpd.ValDef)(using Context): tpd.Tree =
+    _key.unusedDataApply(_.removeIgnoredUsage(tree.symbol))
+    tree
+
+  override def transformDefDef(tree: tpd.DefDef)(using Context): tpd.Tree =
+    _key.unusedDataApply(_.removeIgnoredUsage(tree.symbol))
+    tree
+
   override def transformTypeDef(tree: tpd.TypeDef)(using Context): tpd.Tree =
     _key.unusedDataApply(_.removeIgnoredUsage(tree.symbol))
     tree

tests/neg-custom-args/fatal-warnings/i15503c.scala

@@ -12,6 +12,9 @@ class A:
     private[this] val f = e // OK
     private val g = f // OK
 
+    private def fac(x: Int): Int = // error
+      if x == 0 then 1 else x * fac(x - 1)
+
     val x = 1 // OK
     def y = 2 // OK
     def z = g // OK