A first very incomplete implementation of named expression support

jedi/evaluate/syntax_tree.py

@@ -142,6 +142,8 @@ def eval_node(context, element):
 
         # Generator.send() is not implemented.
         return NO_CONTEXTS
+    elif typ == 'namedexpr_test':
+        return eval_node(context, element.children[2])
     else:
         return eval_or_test(context, element)
 

test/completion/named_expression.py

@@ -0,0 +1,13 @@
+# python >= 3.8
+b = (a:=1, a)
+
+#? int()
+b[0]
+#?
+b[1]
+
+# Should not fail
+b = ('':=1,)
+
+#? int()
+b[0]