From 613f8e513cf171a335318221b6050d470a1d765f Mon Sep 17 00:00:00 2001
From: Mark Dickinson <dickinsm@gmail.com>
Date: Sat, 24 Sep 2016 15:26:36 +0100
Subject: [PATCH] Issue #28203: Fix incorrect type in error message from
 complex(1.0, {2:3}). Patch by Soumya Sharma.

---
 Lib/test/test_complex.py |  8 ++++++++
 Misc/ACKS                |  1 +
 Misc/NEWS                |  3 +++
 Objects/complexobject.c  | 23 +++++++++++++++++------
 4 files changed, 29 insertions(+), 6 deletions(-)

diff --git a/Lib/test/test_complex.py b/Lib/test/test_complex.py
index 0ef9a7a1098..403ee3bc580 100644
--- a/Lib/test/test_complex.py
+++ b/Lib/test/test_complex.py
@@ -326,6 +326,14 @@ class ComplexTest(unittest.TestCase):
         self.assertRaises(ValueError, complex, "1e1ej")
         self.assertRaises(ValueError, complex, "1e++1ej")
         self.assertRaises(ValueError, complex, ")1+2j(")
+        self.assertRaisesRegex(
+            TypeError,
+            "first argument must be a string or a number, not 'dict'",
+            complex, {1:2}, 1)
+        self.assertRaisesRegex(
+            TypeError,
+            "second argument must be a number, not 'dict'",
+            complex, 1, {1:2})
         # the following three are accepted by Python 2.6
         self.assertRaises(ValueError, complex, "1..1j")
         self.assertRaises(ValueError, complex, "1.11.1j")
diff --git a/Misc/ACKS b/Misc/ACKS
index f590f6c6a09..ed93e998610 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -1349,6 +1349,7 @@ Daniel Shahaf
 Mark Shannon
 Ha Shao
 Richard Shapiro
+Soumya Sharma
 Varun Sharma
 Daniel Shaulov
 Vlad Shcherbina
diff --git a/Misc/NEWS b/Misc/NEWS
index cf97628edf1..8c9dcc36969 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -10,6 +10,9 @@ Release date: TBA
 Core and Builtins
 -----------------
 
+- Issue #28203: Fix incorrect type in error message from
+  ``complex(1.0, {2:3})``. Patch by Soumya Sharma.
+
 - Issue #27955: Fallback on reading /dev/urandom device when the getrandom()
   syscall fails with EPERM, for example when blocked by SECCOMP.
 
diff --git a/Objects/complexobject.c b/Objects/complexobject.c
index a5bfb667c46..d82c5eb9f1e 100644
--- a/Objects/complexobject.c
+++ b/Objects/complexobject.c
@@ -954,18 +954,29 @@ complex_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
     }
 
     nbr = r->ob_type->tp_as_number;
-    if (i != NULL)
-        nbi = i->ob_type->tp_as_number;
-    if (nbr == NULL || nbr->nb_float == NULL ||
-        ((i != NULL) && (nbi == NULL || nbi->nb_float == NULL))) {
+    if (nbr == NULL || nbr->nb_float == NULL) {
         PyErr_Format(PyExc_TypeError,
-            "complex() argument must be a string or a number, not '%.200s'",
-            Py_TYPE(r)->tp_name);
+                     "complex() first argument must be a string or a number, "
+                     "not '%.200s'",
+                     Py_TYPE(r)->tp_name);
         if (own_r) {
             Py_DECREF(r);
         }
         return NULL;
     }
+    if (i != NULL) {
+        nbi = i->ob_type->tp_as_number;
+        if (nbi == NULL || nbi->nb_float == NULL) {
+            PyErr_Format(PyExc_TypeError,
+                         "complex() second argument must be a number, "
+                         "not '%.200s'",
+                         Py_TYPE(i)->tp_name);
+            if (own_r) {
+                Py_DECREF(r);
+            }
+            return NULL;
+        }
+    }
 
     /* If we get this far, then the "real" and "imag" parts should
        both be treated as numbers, and the constructor should return a