Hi all,
I recently ran into the issue that some error messages in Guile are not
formatted properly.
As a simple reproducer, fire up a REPL and do

,option on-error 'foo

Which will yield

"While executing meta-command:
Bad on-error value ~a; expected one of ~a foo (debug backtrace report pass)"

The reason is that format strings occurring in the message are
escaped, see `module/ice-9/boot-9.scm`  and
`module/language/tree-il/primitives.scm`.

So a call of

`(error "Wrong argument: ~a" 42)`

is rendered as

"Wrong argument: ~a 42"
Some callers did not take this behavior into account.

Patch attached.

Michael