Merge pull request RustPython#789 from skinny121/dict_literal_order

Fix order of dict literal

Author: windelbouwman

Cargo.lock

@@ -80,3 +80,9 @@ def __eq__(self, other):
 x[Hashable(19,8)] = 1
 assert x[Hashable(8)] == 1
 assert len(x) == 2
+
+assert list({'a': 2, 'b': 10}) == ['a', 'b']
+x = {}
+x['a'] = 2
+x['b'] = 10
+assert list(x) == ['a', 'b']

tests/snippets/dict.py

@@ -26,3 +26,4 @@ caseless = "0.2.1"
 unicode-segmentation = "1.2.1"
 lazy_static = "^1.0.1"
 lexical = "2.0.0"
+itertools = "^0.8.0"

vm/Cargo.toml

@@ -25,6 +25,7 @@ use crate::pyobject::{
     TryFromObject, TypeProtocol,
 };
 use crate::vm::VirtualMachine;
+use itertools::Itertools;
 
 /*
  * So a scope is a linked list of scopes.
@@ -386,21 +387,22 @@ impl Frame {
             }
             bytecode::Instruction::BuildMap { size, unpack } => {
                 let map_obj = vm.ctx.new_dict();
-                for _x in 0..*size {
-                    let obj = self.pop_value();
-                    if *unpack {
+                if *unpack {
+                    for obj in self.pop_multiple(*size) {
                         // Take all key-value pairs from the dict:
                         let dict: PyDictRef =
                             obj.downcast().expect("Need a dictionary to build a map.");
                         let dict_elements = dict.get_key_value_pairs();
                         for (key, value) in dict_elements.iter() {
                             map_obj.set_item(key.clone(), value.clone(), vm);
                         }
-                    } else {
-                        let key = self.pop_value();
-                        map_obj.set_item(key, obj, vm)
+                    }
+                } else {
+                    for (key, value) in self.pop_multiple(2 * size).into_iter().tuples() {
+                        map_obj.set_item(key, value, vm)
                     }
                 }
+
                 self.push_value(map_obj.into_object());
                 Ok(None)
             }