py: Properly implement deletion of locals and derefs, and detect errors.

Needed to reinstate 2 delete opcodes, to specifically check that a local
is not deleted twice.

2 files changed, 47 insertions, 0 deletions

diff --git a/tests/basics/del-deref.py b/tests/basics/del-deref.py
new file mode 100644
index 000000000..1e7c0e41f
--- /dev/null
+++ b/tests/basics/del-deref.py
@@ -0,0 +1,22 @@
+def f():
+    x = 1
+    y = 2
+    def g():
+        nonlocal x
+        print(y)
+        try:
+            print(x)
+        except NameError:
+            print("NameError")
+    def h():
+        nonlocal x
+        print(y)
+        try:
+            del x
+        except NameError:
+            print("NameError")
+    print(x, y)
+    del x
+    g()
+    h()
+f()
diff --git a/tests/basics/del-local.py b/tests/basics/del-local.py
new file mode 100644
index 000000000..05aa98b42
--- /dev/null
+++ b/tests/basics/del-local.py
@@ -0,0 +1,25 @@
+# delete local then try to reference it
+def f():
+    x = 1
+    y = 2
+    print(x, y)
+    del x
+    print(y)
+    try:
+        print(x)
+    except NameError:
+        print("NameError");
+f()
+
+# delete local then try to delete it again
+def g():
+    x = 3
+    y = 4
+    print(x, y)
+    del x
+    print(y)
+    try:
+        del x
+    except NameError:
+        print("NameError");
+g()