Fix star_expr unpacking issues. For now star_expr is not supported

jedi/evaluate/base_context.py

@@ -247,18 +247,30 @@ class ContextualizedName(ContextualizedNode):
             x, (y, z) = 2, ''
 
         would result in ``[(1, xyz_node), (0, yz_node)]``.
+
+        When searching for b in the case ``a, *b, c = [...]`` it will return::
+
+            [(slice(1, -1), abc_node)]
         """
         indexes = []
+        is_star_expr = False
         node = self.node.parent
         compare = self.node
         while node is not None:
             if node.type in ('testlist', 'testlist_comp', 'testlist_star_expr', 'exprlist'):
                 for i, child in enumerate(node.children):
                     if child == compare:
-                        indexes.insert(0, (int(i / 2), node))
+                        index = int(i / 2)
+                        if is_star_expr:
+                            from_end = int((len(node.children) - i) / 2)
+                            index = slice(index, -from_end)
+                        indexes.insert(0, (index, node))
                         break
                 else:
                     raise LookupError("Couldn't find the assignment.")
+                is_star_expr = False
+            elif node.type == 'star_expr':
+                is_star_expr = True
             elif isinstance(node, (ExprStmt, CompFor)):
                 break
 

jedi/evaluate/syntax_tree.py

@@ -636,6 +636,9 @@ def check_tuple_assignments(evaluator, contextualized_name, context_set):
     for index, node in contextualized_name.assignment_indexes():
         cn = ContextualizedNode(contextualized_name.context, node)
         iterated = context_set.iterate(cn)
+        if isinstance(index, slice):
+            # For no star unpacking is not possible.
+            return NO_CONTEXTS
         for _ in range(index + 1):
             try:
                 lazy_context = next(iterated)

test/completion/arrays.py

@@ -448,7 +448,7 @@ tuple({1})[0]
 a, *b, c = [1, 'b', list, dict]
 #? int()
 a
-#? str()
+#?
 b
 #? list
 c
@@ -457,12 +457,14 @@ c
 a, *b, *c = [1, 'd', list]
 #? int()
 a
-#? str()
+#?
 b
-#? list
+#?
 c
 
 lc = [x for a, *x in [(1, '', 1.0)]]
 
 #?
 lc[0][0]
+#?
+lc[0][1]