Basic implementation support for namedexpr, fixes #1647

CHANGELOG.rst

@@ -16,6 +16,7 @@ Unreleased
 - Functions with ``@property`` now return ``property`` instead of ``function``
   in ``Name().type``
 - Started using annotations
+- Better support for the walrus operator
 - Project attributes are now read accessible
 
 This is likely going to be the last minor release before 1.0.

jedi/inference/__init__.py

@@ -170,6 +170,8 @@ class InferenceState:
                 return tree_name_to_values(self, context, name)
             elif type_ == 'param':
                 return context.py__getattribute__(name.value, position=name.end_pos)
+            elif type_ == 'namedexpr_test':
+                return context.infer_node(def_)
         else:
             result = follow_error_node_imports_if_possible(context, name)
             if result is not None:

jedi/inference/syntax_tree.py

@@ -753,6 +753,8 @@ def tree_name_to_values(inference_state, context, tree_name):
         types = NO_VALUES
     elif typ == 'del_stmt':
         types = NO_VALUES
+    elif typ == 'namedexpr_test':
+        types = infer_node(context, node)
     else:
         raise ValueError("Should not happen. type: %s" % typ)
     return types

jedi/parser_utils.py

@@ -90,7 +90,7 @@ def get_flow_branch_keyword(flow_node, node):
         first_leaf = child.get_first_leaf()
         if first_leaf in _FLOW_KEYWORDS:
             keyword = first_leaf
-    return 0
+    return None
 
 
 def clean_scope_docstring(scope_node):
@@ -239,7 +239,7 @@ def get_parent_scope(node, include_flows=False):
         return None  # It's a module already.
 
     while True:
-        if is_scope(scope) or include_flows and isinstance(scope, tree.Flow):
+        if is_scope(scope):
             if scope.type in ('classdef', 'funcdef', 'lambdef'):
                 index = scope.children.index(':')
                 if scope.children[index].start_pos >= node.start_pos:
@@ -251,6 +251,14 @@ def get_parent_scope(node, include_flows=False):
                         scope = scope.parent
                         continue
             return scope
+        elif include_flows and isinstance(scope, tree.Flow):
+            # The cursor might be on `if foo`, so the parent scope will not be
+            # the if, but the parent of the if.
+            if not (scope.type == 'if_stmt'
+                    and any(n.start_pos <= node.start_pos < n.end_pos
+                            for n in scope.get_test_nodes())):
+                return scope
+
         scope = scope.parent
 
 

test/completion/flow_analysis.py

@@ -5,7 +5,7 @@
 x = 3
 if NOT_DEFINED:
     x = ''
-#? 6 int()
+#? 6 int() str()
 elif x:
     pass
 else:

test/completion/named_expression.py

@@ -1,3 +1,6 @@
+# For assignment expressions / named expressions / walrus operators / whatever
+# they are called.
+
 # python >= 3.8
 b = (a:=1, a)
 
@@ -11,3 +14,39 @@ b = ('':=1,)
 
 #? int()
 b[0]
+
+def test_assignments():
+    match = ''
+    #? str()
+    match
+    #? 8 int()
+    if match := 1:
+        #? int()
+        match
+    #? int()
+    match
+
+def test_assignments2():
+    class Foo:
+        match = ''
+    #? str()
+    Foo.match
+    #? 13 int()
+    if Foo.match := 1:
+        #? str()
+        Foo.match
+    #? str()
+    Foo.match
+
+    #?
+    y
+    #? 16 str()
+    if y := Foo.match:
+        #? str()
+        y
+    #? str()
+    y
+
+    #? 8 str()
+    if z := Foo.match:
+        pass