synchronizes pendingVolatiles

Called from isVolatile, which is called from isStable, which is a part
of the public reflection API.

2 files changed, 2 insertions, 4 deletions

diff --git a/src/reflect/scala/reflect/internal/Types.scala b/src/reflect/scala/reflect/internal/Types.scala
index 0afbdc56c8..6d91948d66 100644
--- a/src/reflect/scala/reflect/internal/Types.scala
+++ b/src/reflect/scala/reflect/internal/Types.scala
@@ -2066,10 +2066,6 @@ trait Types extends api.Types { self: SymbolTable =>
     def apply(value: Constant) = unique(new UniqueConstantType(value))
   }
 
-  /* Syncnote: The `volatile` var and `pendingVolatiles` mutable set need not be protected
-   * with synchronized, because they are accessed only from isVolatile, which is called only from
-   * Typer.
-   */
   private var volatileRecursions: Int = 0
   private val pendingVolatiles = new mutable.HashSet[Symbol]
 
diff --git a/src/reflect/scala/reflect/runtime/SynchronizedSymbols.scala b/src/reflect/scala/reflect/runtime/SynchronizedSymbols.scala
index 85bd9ff8b6..5a0ac01ac4 100644
--- a/src/reflect/scala/reflect/runtime/SynchronizedSymbols.scala
+++ b/src/reflect/scala/reflect/runtime/SynchronizedSymbols.scala
@@ -61,6 +61,8 @@ private[reflect] trait SynchronizedSymbols extends internal.Symbols { self: Symb
       }
     }
 
+    override def isStable: Boolean = gilSynchronized { super.isStable }
+
 // ------ creators -------------------------------------------------------------------
 
     override protected def createAbstractTypeSymbol(name: TypeName, pos: Position, newFlags: Long): AbstractTypeSymbol =