diff --git a/jedi/parsing_representation.py b/jedi/parsing_representation.py
index 4d2e091c..3bffa084 100644
--- a/jedi/parsing_representation.py
+++ b/jedi/parsing_representation.py
@@ -794,7 +794,10 @@ class Statement(Simple):
         """
 
         if not set_vars:
-            return set_vars
+            return []
+
+        if _assignment_details():
+            s
         result = set(set_vars)
         last = None
         in_lookup = 0
@@ -805,14 +808,16 @@ class Statement(Simple):
                     result.discard(tok)
             elif isinstance(tok, tuple):
                 tok = tok[1]
-            if in_lookup == 0 and tok == '(':
-                is_execution = True
-                for t in self.token_list[:i]:
-                    result.discard(t)
-            if tok == '[' and isinstance(last, Name):
-                in_lookup += 1
-            elif tok == ']' and in_lookup > 0:
-                in_lookup -= 1
+                if in_lookup == 0 and tok == '(':
+                    is_execution = True
+                    for t in self.token_list[:i]:
+                       result.discard(t)
+                if tok in '[(' and isinstance(last, Name):
+                    in_lookup += 1
+                elif tok in ')]' and in_lookup > 0:
+                    in_lookup -= 1
+                elif '=' in tok and in_lookup == 0:
+                    break
             last = tok
         return list(result)
 
@@ -842,6 +847,15 @@ class Statement(Simple):
 
     @property
     def assignment_details(self):
+        """
+        Returns an array of tuples of the elements before the assignment.
+
+        For example the following code::
+
+            x = (y, z) = 2, ''
+
+        would result in ``[(Name(x), '='), (Array([Name(y), Name(z)]), '=')]``.
+        """
         # parse statement which creates the assignment details.
         self.get_commands()
         return self._assignment_details