Explicit error on declaring a reference type.
Explicit error on declaring a reference type.

This is better than generating invalid code; see #1695.

da-woods/cython,scoder/cython,cython/cython,da-woods/cython,ChristopherHogan/cython,cython/cython,da-woods/cython,cython/cython,scoder/cython,cython/cython,ChristopherHogan/cython,scoder/cython,da-woods/cython,scoder/cython,ChristopherHogan/cython