Reopening. The test case added in r51119 (specifically, test_1530559() and its infrastructure) doesn't work. The check_float_coerce() function is overwritten by a later assignment, meaning that test_1530559() calls the wrong function. Actually making it call the right check_float_coerce() function results in a NameError ("global name 'func' is not defined").

The reason the test currently passes is because check_float_coerce() is effectively an alias for deprecated_err(). test_1530559() passes deprecated_err() a string as its first argument; when deprecated_err() tries to call the string, a TypeError results. deprecated_err() traps the TypeError and so everything appears from the outside to have gone smoothly.

If the test is tweaked so that struct.pack() is actually invoked with the proper arguments, it fails to raise the expected error on float coercion.