From e68dbf6705ea2d69e2d4836ebfdee671b70d79c5 Mon Sep 17 00:00:00 2001
From: Adam Kelly <adam@cthulahoops.org>
Date: Sun, 2 Sep 2018 10:50:03 +0100
Subject: [PATCH 1/4] Ints aren't mutable, change int.__init__ to int.__new__

---
 vm/src/obj/objint.rs | 36 +++++++++++++-----------------------
 1 file changed, 13 insertions(+), 23 deletions(-)

diff --git a/vm/src/obj/objint.rs b/vm/src/obj/objint.rs
index 4b3df926a..92513f485 100644
--- a/vm/src/obj/objint.rs
+++ b/vm/src/obj/objint.rs
@@ -1,6 +1,6 @@
 use super::super::pyobject::{
-    AttributeProtocol, FromPyObjectRef, PyContext, PyFuncArgs, PyObjectKind, PyObjectRef, PyResult,
-    TypeProtocol,
+    AttributeProtocol, FromPyObjectRef, PyContext, PyFuncArgs, PyObject, PyObjectKind, PyObjectRef,
+    PyResult, TypeProtocol,
 };
 use super::super::vm::VirtualMachine;
 use super::objfloat;
@@ -12,22 +12,16 @@ fn str(vm: &mut VirtualMachine, args: PyFuncArgs) -> PyResult {
     Ok(vm.new_str(v.to_string()))
 }
 
-// __init__ (store value into objectkind)
-fn int_init(vm: &mut VirtualMachine, args: PyFuncArgs) -> PyResult {
-    arg_check!(
-        vm,
-        args,
-        required = [(zelf, Some(vm.ctx.int_type())), (arg, None)]
-    );
-
-    // Try to cast to int:
-    let val = match to_int(vm, arg) {
-        Ok(val) => val,
-        Err(err) => return Err(err),
-    };
-
-    set_value(zelf, val);
-    Ok(vm.get_none())
+fn int_new(vm: &mut VirtualMachine, args: PyFuncArgs) -> PyResult {
+    let ref cls = args.args[0];
+    if !objtype::issubclass(cls.clone(), vm.ctx.int_type()) {
+        return Err(vm.new_type_error(format!("{:?} is not a subtype of int", cls)));
+    }
+    let val = to_int(vm, &args.args[1].clone())?;
+    Ok(PyObject::new(
+        PyObjectKind::Integer { value: val },
+        cls.clone(),
+    ))
 }
 
 // Casting function:
@@ -51,10 +45,6 @@ pub fn get_value(obj: &PyObjectRef) -> i32 {
     }
 }
 
-fn set_value(obj: &PyObjectRef, value: i32) {
-    obj.borrow_mut().kind = PyObjectKind::Integer { value };
-}
-
 impl FromPyObjectRef for i32 {
     fn from_pyobj(obj: &PyObjectRef) -> i32 {
         get_value(obj)
@@ -224,7 +214,7 @@ pub fn init(context: &PyContext) {
     int_type.set_attr("__eq__", context.new_rustfunc(int_eq));
     int_type.set_attr("__add__", context.new_rustfunc(int_add));
     int_type.set_attr("__and__", context.new_rustfunc(int_and));
-    int_type.set_attr("__init__", context.new_rustfunc(int_init));
+    int_type.set_attr("__new__", context.new_rustfunc(int_new));
     int_type.set_attr("__mod__", context.new_rustfunc(int_mod));
     int_type.set_attr("__mul__", context.new_rustfunc(int_mul));
     int_type.set_attr("__or__", context.new_rustfunc(int_or));

From e611533d02e06f0e0b1d5161332a36ab9ac26aab Mon Sep 17 00:00:00 2001
From: Adam Kelly <adam@cthulahoops.org>
Date: Sun, 2 Sep 2018 10:51:05 +0100
Subject: [PATCH 2/4] Let getattribute fall through and attribute error on
 types with dicts.

---
 vm/src/pyobject.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/vm/src/pyobject.rs b/vm/src/pyobject.rs
index ca9d0e0c2..0373ca69b 100644
--- a/vm/src/pyobject.rs
+++ b/vm/src/pyobject.rs
@@ -417,7 +417,7 @@ impl AttributeProtocol for PyObjectRef {
                 None
             }
             PyObjectKind::Instance { ref dict } => dict.get_item(attr_name),
-            ref kind => unimplemented!("load_attr unimplemented for: {:?}", kind),
+            _ => None,
         }
     }
 

From 76344e5023368953c605f2ee25fbc2130c202234 Mon Sep 17 00:00:00 2001
From: Adam Kelly <adam@cthulahoops.org>
Date: Sun, 2 Sep 2018 10:57:30 +0100
Subject: [PATCH 3/4] Add object.__init__

---
 vm/src/obj/objobject.rs | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/vm/src/obj/objobject.rs b/vm/src/obj/objobject.rs
index 9206ba266..0df0ba44e 100644
--- a/vm/src/obj/objobject.rs
+++ b/vm/src/obj/objobject.rs
@@ -59,12 +59,17 @@ fn object_str(vm: &mut VirtualMachine, args: PyFuncArgs) -> PyResult {
 pub fn init(context: &PyContext) {
     let ref object = context.object;
     object.set_attr("__new__", context.new_rustfunc(new_instance));
+    object.set_attr("__init__", context.new_rustfunc(object_init));
     object.set_attr("__eq__", context.new_rustfunc(object_eq));
     object.set_attr("__ne__", context.new_rustfunc(object_ne));
     object.set_attr("__dict__", context.new_member_descriptor(object_dict));
     object.set_attr("__str__", context.new_rustfunc(object_str));
 }
 
+fn object_init(vm: &mut VirtualMachine, _args: PyFuncArgs) -> PyResult {
+    Ok(vm.ctx.none())
+}
+
 fn object_dict(vm: &mut VirtualMachine, args: PyFuncArgs) -> PyResult {
     match args.args[0].borrow().kind {
         PyObjectKind::Class { ref dict, .. } => Ok(dict.clone()),

From ec0eb47fc6c63e745ffc964f190cd0a042a56400 Mon Sep 17 00:00:00 2001
From: Adam Kelly <adam@cthulahoops.org>
Date: Sun, 2 Sep 2018 10:59:42 +0100
Subject: [PATCH 4/4] Add snippet to check that int.__init__ doesn't mutate
 int.

---
 tests/snippets/numbers.py | 10 ++++++++++
 1 file changed, 10 insertions(+)
 create mode 100644 tests/snippets/numbers.py

diff --git a/tests/snippets/numbers.py b/tests/snippets/numbers.py
new file mode 100644
index 000000000..eae26b102
--- /dev/null
+++ b/tests/snippets/numbers.py
@@ -0,0 +1,10 @@
+x = 5
+x.__init__(6)
+assert x == 5
+
+class A(int):
+    pass
+
+x = A(7)
+assert x == 7
+assert type(x) is A