Fix issues with yield.

test/completion/generators.py

@@ -179,6 +179,25 @@ gen().send()
 #? 
 gen()()
 
+# -----------------
+# empty yield
+# -----------------
+
+def x():
+    yield
+
+#? None
+next(x())
+#? gen()
+x()
+
+def x():
+    for i in range(3):
+        yield
+
+#? None
+next(x())
+
 # -----------------
 # yield in expression
 # -----------------