From ee3f35c608d4ab9ef09203ac875720dc7dfa71de Mon Sep 17 00:00:00 2001
From: whitequark <whitequark@whitequark.org>
Date: Sat, 8 Aug 2015 21:06:13 +0300
Subject: [PATCH] Improve error message on passing an argument twice.

---
 artiq/compiler/transforms/inferencer.py | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/artiq/compiler/transforms/inferencer.py b/artiq/compiler/transforms/inferencer.py
index 6df5d3eec..47145b9a9 100644
--- a/artiq/compiler/transforms/inferencer.py
+++ b/artiq/compiler/transforms/inferencer.py
@@ -696,7 +696,7 @@ class Inferencer(algorithm.Visitor):
             return
 
         typ = node.func.type.find()
-        passed_args = set()
+        passed_args = dict()
 
         if len(node.args) > typ.arity():
             note = diagnostic.Diagnostic("note",
@@ -714,14 +714,14 @@ class Inferencer(algorithm.Visitor):
                 zip(node.args, list(typ.args.items()) + list(typ.optargs.items())):
             self._unify(actualarg.type, formaltyp,
                         actualarg.loc, None)
-            passed_args.add(formalname)
+            passed_args[formalname] = actualarg.loc
 
         for keyword in node.keywords:
             if keyword.arg in passed_args:
                 diag = diagnostic.Diagnostic("error",
-                    "the argument '{name}' is already passed",
+                    "the argument '{name}' has been passed earlier as positional",
                     {"name": keyword.arg},
-                    keyword.arg_loc)
+                    keyword.arg_loc, [passed_args[keyword.arg]])
                 self.engine.process(diag)
                 return