Fix selection on safe value

Author: EnzeXing

compiler/src/dotty/tools/dotc/transform/init/Util.scala

@@ -59,7 +59,7 @@ object Util:
       case TypeApply(fn, targs) =>
         unapply(fn)
 
-      case ref: RefTree if ref.tpe.widenSingleton.isInstanceOf[MethodicType] =>
+      case ref: RefTree if ref.symbol.is(Flags.Method) =>
         Some((ref, Nil))
 
       case _ => None

tests/init-global/pos-tasty/test-safe-value.scala

@@ -0,0 +1,7 @@
+package scala.collection.immutable
+
+object A { // These are a safe values, so no warning should be emitted
+    Node.HashCodeLength
+    Node.BitPartitionSize
+    Node.MaxDepth
+}