One of Perl’s design principles was the Robustness principle, though it probably wasn’t known by that name at the time. (The name came about around the same time Perl was becoming a thing, something something zeitgeist something.)

Perl can be locked down and made to complain (with at least a couple of levels of pedantry) when things are wrong, but unlike most other languages, it doesn’t do so by default.

probably TECO, too