diff --git a/jedi/evaluate.py b/jedi/evaluate.py
index 9f1cfebf..c7b794ad 100644
--- a/jedi/evaluate.py
+++ b/jedi/evaluate.py
@@ -1125,6 +1125,8 @@ def get_scopes_for_name(scope, name_str, position=None, search_global=False,
         result = []
         # compare func uses the tuple of line/indent = line/column
         comparison_func = lambda name: (name.start_pos)
+        check_for_param = lambda p: isinstance(p, parsing.Param) \
+                                                    and not p.is_generated
         for nscope, name_list in scope_generator:
             break_scopes = []
             # here is the position stuff happening (sorting of variables)
@@ -1150,13 +1152,17 @@ def get_scopes_for_name(scope, name_str, position=None, search_global=False,
                         if not name.parent() or p == s:
                             break
                         break_scopes.append(p)
-            # if there are results, ignore the other scopes
-            if result:
+            # if there are results, ignore the other scopes, if params are in
+            # there, we still need to check flows, if they contain information.
+            if result and not [r for r in result if check_for_param(r)]:
                 break
 
             while flow_scope:
-                result = dynamic.check_flow_information(flow_scope, name_str,
+                n = dynamic.check_flow_information(flow_scope, name_str,
                                                                     position)
+                if n and result:
+                    result = n + [p for p in result if not check_for_param(r)]
+
                 if result:
                     break
                 if flow_scope == nscope:
diff --git a/test/completion/isinstance.py b/test/completion/isinstance.py
index 01d1f7a5..07618edd 100644
--- a/test/completion/isinstance.py
+++ b/test/completion/isinstance.py
@@ -28,3 +28,13 @@ assert not isinstance(ass, int):
 if 2:
     #? str()
     ass
+
+# -----------------
+# in functions
+# -----------------
+
+import datetime
+def fooooo(obj):
+    if isinstance(obj, datetime.datetime):
+        #? datetime.datetime
+        obj