[mypyc] Fix generated __ne__ to work if __eq__ returns NotImplemented

mypyc/genops.py

@@ -84,7 +84,7 @@ def f(x: int) -> int:
     check_stop_op, send_op, yield_from_except_op, coro_op,
     py_getattr_op, py_setattr_op, py_delattr_op, py_hasattr_op,
     py_call_op, py_call_with_kwargs_op, py_method_call_op,
-    fast_isinstance_op, bool_op, new_slice_op,
+    fast_isinstance_op, bool_op, new_slice_op, not_implemented_op,
     type_op, pytype_from_template_op, import_op, get_module_dict_op,
     ellipsis_op, method_new_op, type_is_op, type_object_op, py_calc_meta_op,
     dataclass_sleight_of_hand,
@@ -1794,12 +1794,24 @@ def gen_glue_ne_method(self, cls: ClassIR, line: int) -> FuncIR:
         fake_vars = [(Var(arg.name), arg.type) for arg in rt_args]
         args = [self.read(self.environment.add_local_reg(var, type, is_arg=True), line)
                 for var, type in fake_vars]  # type: List[Value]
-        self.ret_types[-1] = bool_rprimitive
-
-        retval = self.add(MethodCall(args[0], '__eq__', [args[1]], line))
-        retval = self.unary_op(retval, 'not', line)
+        self.ret_types[-1] = object_rprimitive
+
+        not_implemented_block, regular_block = BasicBlock(), BasicBlock()
+        eqval = self.add(MethodCall(args[0], '__eq__', [args[1]], line))
+        not_implemented = self.primitive_op(not_implemented_op, [], line)
+        self.add(Branch(
+            self.binary_op(eqval, not_implemented, 'is', line),
+            not_implemented_block,
+            regular_block,
+            Branch.BOOL_EXPR))
+
+        self.activate_block(regular_block)
+        retval = self.coerce(self.unary_op(eqval, 'not', line), object_rprimitive, line)
         self.add(Return(retval))
 
+        self.activate_block(not_implemented_block)
+        self.add(Return(not_implemented))
+
         blocks, env, ret_type, _ = self.leave()
         return FuncIR(
             FuncDecl('__ne__', cls.name, self.module_name,

mypyc/ops_misc.py

@@ -42,11 +42,11 @@
                         emit=name_emit('Py_Ellipsis'),
                         is_borrowed=True)
 
-name_ref_op(name='builtins.NotImplemented',
-            result_type=object_rprimitive,
-            error_kind=ERR_NEVER,
-            emit=name_emit('Py_NotImplemented'),
-            is_borrowed=True)
+not_implemented_op = name_ref_op(name='builtins.NotImplemented',
+                                 result_type=object_rprimitive,
+                                 error_kind=ERR_NEVER,
+                                 emit=name_emit('Py_NotImplemented'),
+                                 is_borrowed=True)
 
 func_op(name='builtins.id',
         arg_types=[object_rprimitive],

mypyc/test-data/run.test

@@ -3300,6 +3300,10 @@ class BoxedThing:
 class Subclass2(BoxedThing):
     pass
 
+class UsesNotImplemented:
+    def __eq__(self, b: object) -> bool:
+        return NotImplemented
+
 def index_into(x : Any, y : Any) -> Any:
     return x[y]
 
@@ -3345,6 +3349,8 @@ assert is_truthy(Item('a'))
 assert not is_truthy(Subclass1(''))
 assert is_truthy(Subclass1('a'))
 
+assert UsesNotImplemented() != object()
+
 internal_index_into()
 [out]
 7 7