Handling casting from a non-nullable wildcard capture to a type varia…

…ble.

src/main/java/com/google/jspecify/nullness/NullSpecVisitor.java

@@ -119,6 +119,22 @@ private void ensureNonNull(Tree tree, String messageKey) {
     }
   }
 
+  @Override
+  protected boolean isTypeCastSafe(AnnotatedTypeMirror castType, AnnotatedTypeMirror exprType) {
+    /*
+     * TODO(cpovirk): I probably need to completely revisit this method to understand what it does
+     * and what the Right Way is to reconcile it with our non-standard treatment of wildcards and
+     * type variables.
+     *
+     * For now, the supermethod reports errors for some problematic casts (like from Object to int)
+     * but also reports errors for some safe casts (like from ? to T when the wildcard's
+     * corresponding type parameter doesn't permit null values). As an expedient measure, we
+     * short-circuit the check in the second case.
+     */
+    return atypeFactory.isNullExclusiveUnderEveryParameterization(exprType)
+        || super.isTypeCastSafe(castType, exprType);
+  }
+
   @Override
   protected String extraArgForReturnTypeError(Tree tree) {
     /*