testing exceptions + bug?

[thi]

hello,

first off, many thanks go to the current maintainers for allowing me
write privs to the repo.  v.cool...

my first commit is test-suite/tests/exceptions.test, which was inspired
by the (cond (1 => (lambda (x y) y))) problem reported earlier this
week.  that case is now working, but in writing other tests, i think
i've found at least one other bug.  the failing tests are marked "no
exception" in the code, and are revealed when doing a "make check".

briefly, they are:
FAIL: exceptions.test: syntax: let: `bad-bindings' expected but not thrown: 
(let ((x 1) (x 2)) x)
FAIL: exceptions.test: bindings: `bad-var' expected but not thrown: 
(string-set! (symbol->string (quote abc)) 1 #\space)
FAIL: exceptions.test: bindings: `bad-var' expected but not thrown: 
(string-set! "abc" 1 #\space)
FAIL: exceptions.test: lambda: `bad-formals' expected but not thrown: (lambda 
(x x) 1)
FAIL: exceptions.test: lambda: `bad-formals' expected but not thrown: (lambda 
(x x x) 1)

please let me know if i've misunderstood something, or if it's better to
not commit tests that cause "make check" to fail, etc.  (i usually frown
on nightly-build breakage, like this.)

anyway, exceptions.test is by no means complete; the process of grepping
r5rs for "error" and writing more tests continues.

thi