Fix cpp exception catching.

Cython/Compiler/Nodes.py

@@ -547,14 +547,20 @@ class CFuncDeclaratorNode(CDeclaratorNode):
             if self.exception_value:
                 self.exception_value.analyse_const_expression(env)
                 if self.exception_check == '+':
+                    self.exception_value.analyse_types(env)
                     exc_val_type = self.exception_value.type
                     if not exc_val_type.is_error and \
                           not exc_val_type.is_pyobject and \
                           not (exc_val_type.is_cfunction and not exc_val_type.return_type.is_pyobject and len(exc_val_type.args)==0):
                         error(self.exception_value.pos,
                             "Exception value must be a Python exception or cdef function with no arguments.")
+                    exc_val = self.exception_value
                 else:
+                    if self.exception_value.analyse_const_expression(env):
                         exc_val = self.exception_value.get_constant_c_result_code()
+                        if exc_val is None:
+                            raise InternalError("get_constant_c_result_code not implemented for %s" %
+                                self.exception_value.__class__.__name__)
                         if not return_type.assignable_from(self.exception_value.type):
                             error(self.exception_value.pos,
                                   "Exception value incompatible with function return type")