Move foreachSubTreeOf of to tpd.

Reason: The tree traverser created by it only handles the cases for typed tree nodes.
Also add convenience existsSubTreeOf combinator.

2 files changed, 16 insertions, 9 deletions

diff --git a/src/dotty/tools/dotc/ast/Trees.scala b/src/dotty/tools/dotc/ast/Trees.scala
index 9803f8ac1..8d243a0cb 100644
--- a/src/dotty/tools/dotc/ast/Trees.scala
+++ b/src/dotty/tools/dotc/ast/Trees.scala
@@ -925,15 +925,6 @@ object Trees {
       case ys => Thicket(ys)
     }
 
-    // ----- Position handling -----------------------------------------
-
-    def foreachSubTreeOf(tree: Tree)(f: Tree => Unit): Unit = {
-      val traverser = new TreeTraverser {
-        def traverse(tree: Tree) = foldOver(f(tree), tree)
-      }
-      traverser.traverse(tree)
-    }
-
     // ----- Helper classes for copying, transforming, accumulating -----------------
 
     val cpy: TreeCopier
diff --git a/src/dotty/tools/dotc/ast/tpd.scala b/src/dotty/tools/dotc/ast/tpd.scala
index 7cdd8b7ac..5a9198adc 100644
--- a/src/dotty/tools/dotc/ast/tpd.scala
+++ b/src/dotty/tools/dotc/ast/tpd.scala
@@ -331,6 +331,22 @@ object tpd extends Trees.Instance[Type] with TypedTreeInfo {
       } else foldOver(sym, tree)
   }
 
+  // --- Higher order traversal methods -------------------------------
+
+  def foreachSubTreeOf(tree: Tree)(f: Tree => Unit): Unit = { //TODO should go in tpd.
+    val traverser = new TreeTraverser {
+      def traverse(tree: Tree) = foldOver(f(tree), tree)
+    }
+    traverser.traverse(tree)
+  }
+
+  def existsSubTreeOf(tree: Tree)(p: Tree => Boolean): Boolean = {
+    val acc = new TreeAccumulator[Boolean] {
+      def apply(x: Boolean, t: Tree) = x || p(t) || foldOver(x, t)
+    }
+    acc(false, tree)
+  }
+
   override val cpy = new TypedTreeCopier
 
   class TypedTreeCopier extends TreeCopier {