Changed isHidden condition back to isSynthetic.

Since we were blessed with spurious warnings.

With this commit I have eliminated every warning in trunk
except for deprecation, feature, and inliner warnings, plus
one due to SI-6146.  I'm not going to count "pattern matcher
performance warnings" which are presently preventing me from
turning on -unchecked even though there are no genuine
-unchecked warnings remaining.  Hey, get your own option!

Conflicts:
	src/compiler/scala/tools/nsc/transform/SpecializeTypes.scala

1 files changed, 4 insertions, 0 deletions

diff --git a/src/compiler/scala/tools/nsc/transform/SpecializeTypes.scala b/src/compiler/scala/tools/nsc/transform/SpecializeTypes.scala
index ffcb682cf7..63f93aa000 100644
--- a/src/compiler/scala/tools/nsc/transform/SpecializeTypes.scala
+++ b/src/compiler/scala/tools/nsc/transform/SpecializeTypes.scala
@@ -798,6 +798,10 @@ abstract class SpecializeTypes extends InfoTransform with TypingTransformers {
         var specializingOn = specializedParams(sym)
         val unusedStvars   = specializingOn filterNot specializedTypeVars(sym.info)
 
+        // I think the last condition should be !sym.isHidden, but that made the
+        // compiler start warning about Tuple1.scala and Tuple2.scala claiming
+        // their type parameters are used in non-specializable positions.  Why is
+        // unusedStvars.nonEmpty for these classes???
         if (unusedStvars.nonEmpty && currentRun.compiles(sym) && !sym.isSynthetic) {
           reporter.warning(sym.pos,
             "%s %s unused or used in non-specializable positions.".format(