Most languages now use "NullReferenceError" in the error message
where they previously used "ValueError". Also exception changes:
Guile: "swig-null-reference-error" instead of "swig-value-error"
MzScheme: "swig-null-reference-error" instead of "swig-value-error"
PHP: zend_ce_type_error instead of zend_ce_value_error
Python: Consistently raises TypeError instead of a mix of ValueError
and TypeError.
Ruby: Consistently raises NullReferenceError instead of a mix of
ArgumentError and NullReferenceErrorError.
The consistent raising of a TypeError instead of ValueError for Python
ensures that incorrectly passing 'None' into a C++ reference argument
will correctly convert the error into a NotImplemented error for
the rich comparisons implementations per PEP 207. Fixes#2987
Note that the li_constraints checking implementation for the NONNULL
typemap for pointers also makes the same error change from
SWIG_ValueError to SWIG_NullReferenceError.
The D typemaps use SWIG_DNullReferenceException instead of
SWIG_DIllegalArgumentException, although this ultimately has no change
as the same D Exception is still thrown.