mpmath mpc won't coerce to ComplexNumber

[dsm]

Came across this working on #1173:

sage: version()
'Sage Version 4.7.2.alpha3, Release Date: 2011-09-28'
sage: import mpmath
sage: 
sage: z = mpmath.mpf(2)
sage: z
mpf('2.0')
sage: RR(z)
2.00000000000000
sage: CC(z)
2.00000000000000
sage: 
sage: z = mpmath.mpc(2,3)
sage: z
mpc(real='2.0', imag='3.0')
sage: complex(z)
(2+3j)
sage: CC(z)
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
[...]
TypeError: unable to coerce to a ComplexNumber: <type 'sage.libs.mpmath.ext_main.mpc'>

[leif]

A trivial fix would be:

sage/rings/complex_number.pyx

@@ -148 +148 @@
             elif isinstance(real, list) or isinstance(real, tuple):
                 re, imag = real
                 real = re
-            elif isinstance(real, complex):
-                real, imag = real.real, real.imag
             else:
-                imag = 0
+                try:
+                    real, imag = real.real, real.imag
+                except AttributeError:
+                    imag = 0
         try:
             R = parent._real_field()
             rr = R(real)

But perhaps there are better ways.

[jdemeyer]

Milestone sage-4.7.3 deleted