Now that object has __doc__, fix others

Otherwise they would inherit object's __doc__

src/runtime/objmodel.cpp

@@ -636,6 +636,10 @@ void BoxedClass::freeze() {
     assert(!is_constant);
     assert(tp_name); // otherwise debugging will be very hard
 
+    auto doc_str = getStaticString("__doc__");
+    if (!hasattr(doc_str))
+        giveAttr(incref(doc_str), boxString(tp_name));
+
     fixup_slot_dispatchers(this);
 
     if (instancesHaveDictAttrs() || instancesHaveHCAttrs()) {

src/runtime/types.cpp

@@ -1791,6 +1791,17 @@ static Box* functionNonzero(BoxedFunction* self) {
     Py_RETURN_TRUE;
 }
 
+static Box* im_doc(Box* b, void*) noexcept {
+    RELEASE_ASSERT(b->cls == instancemethod_cls, "");
+    auto doc_str = getStaticString("__doc__");
+    try {
+        return getattr(static_cast<BoxedInstanceMethod*>(b)->func, doc_str);
+    } catch (ExcInfo e) {
+        setCAPIException(e);
+        return NULL;
+    }
+}
+
 extern "C" {
 Box* Py_None = NULL;
 Box* NotImplemented = NULL;
@@ -4234,7 +4245,10 @@ void setupRuntime() {
     none_cls->giveAttr("__base__", object_cls);
     Py_INCREF(Py_None);
     object_cls->giveAttr("__base__", Py_None);
+
     object_cls->giveAttr("__doc__", boxString("The most base type"));
+    type_cls->giveAttr("__doc__",
+                       boxString("type(object) -> the object's type\ntype(name, bases, dict) -> a new type"));
 
     // Not sure why CPython defines sizeof(PyTupleObject) to include one element,
     // but we copy that, which means we have to subtract that extra pointer to get the tp_basicsize:
@@ -4574,10 +4588,14 @@ void setupRuntime() {
     instancemethod_cls->giveAttrBorrowed("__func__", instancemethod_cls->getattr(getStaticString("im_func")));
     instancemethod_cls->giveAttrMember("im_self", T_OBJECT, offsetof(BoxedInstanceMethod, obj));
     instancemethod_cls->giveAttrBorrowed("__self__", instancemethod_cls->getattr(getStaticString("im_self")));
-    instancemethod_cls->freeze();
 
     instancemethod_cls->giveAttrMember("im_class", T_OBJECT, offsetof(BoxedInstanceMethod, im_class), true);
 
+    // TODO: this should be handled via a getattro instead (which proxies to the function):
+    instancemethod_cls->giveAttrDescriptor("__doc__", im_doc, NULL);
+
+    instancemethod_cls->freeze();
+
     slice_cls->giveAttr("__new__",
                         new BoxedFunction(BoxedCode::create((void*)sliceNew, UNKNOWN, 4, false, false, "slice.__new__"),
                                           { NULL, Py_None }));