Add __annotations__ attribute to functions.

tests/snippets/type_hints.py

@@ -1,7 +1,12 @@
 
 # See also: https://github.com/RustPython/RustPython/issues/587
 
-def curry(foo: int, bla=2) -> float:
+def curry(foo: int, bla: int =2) -> float:
     return foo * 3.1415926 * bla
 
 assert curry(2) > 10
+
+print(curry.__annotations__)
+assert curry.__annotations__['foo'] is int
+assert curry.__annotations__['return'] is float
+assert curry.__annotations__['bla'] is int

vm/src/frame.rs

@@ -453,7 +453,7 @@ impl Frame {
                 let _qualified_name = self.pop_value();
                 let code_obj = self.pop_value();
 
-                let _annotations = if flags.contains(bytecode::FunctionOpArg::HAS_ANNOTATIONS) {
+                let annotations = if flags.contains(bytecode::FunctionOpArg::HAS_ANNOTATIONS) {
                     self.pop_value()
                 } else {
                     vm.new_dict()
@@ -470,13 +470,8 @@ impl Frame {
                 let scope = self.scope.clone();
                 let obj = vm.ctx.new_function(code_obj, scope, defaults);
 
-                let annotation_repr = vm.to_pystr(&_annotations)?;
+                vm.ctx.set_attr(&obj, "__annotations__", annotations);
 
-                warn!(
-                    "Type annotation must be stored in attribute! {:?}",
-                    annotation_repr
-                );
-                // TODO: use annotations with set_attr here!
                 self.push_value(obj);
                 Ok(None)
             }

vm/src/pyobject.rs

@@ -1566,7 +1566,7 @@ impl PyObject {
         PyObject {
             payload,
             typ: Some(typ),
-            dict: None,
+            dict: Some(RefCell::new(PyAttributes::new())),
         }
         .into_ref()
     }