py/objset: Check that RHS of a binary op is a set/frozenset.

CPython docs explicitly state that the RHS of a set/frozenset binary op
must be a set to prevent user errors.  It also preserves commutativity of
the ops, eg: "abc" & set() is a TypeError, and so should be set() & "abc".

This change actually decreases unix (x64) code by 160 bytes; it increases
stm32 by 4 bytes and esp8266 by 28 bytes (but previous patch already
introduced a much large saving).

1 files changed, 12 insertions, 0 deletions

diff --git a/tests/basics/set_binop.py b/tests/basics/set_binop.py
index 7848920b6..bc76533b1 100644
--- a/tests/basics/set_binop.py
+++ b/tests/basics/set_binop.py
@@ -47,6 +47,18 @@ s1 = s2 = set('abc')
 s1 -= set('ad')
 print(s1 is s2, len(s1))
 
+# RHS must be a set
+try:
+    print(set('12') >= '1')
+except TypeError:
+    print('TypeError')
+
+# RHS must be a set
+try:
+    print(set('12') <= '123')
+except TypeError:
+    print('TypeError')
+
 # unsupported operator
 try:
     set('abc') * 2