I wish more languages would lean into having a really permissive compiler that emits a lot of warnings. I have CI so I'm never going to actually merge anything that makes warnings. But when testing, just let me do whatever I want!
GHC has an -fdefer-type-errors option that lets you compile and run this code:
a :: Int
a = 'a'
main = print "b"
Which obviously doesn't typecheck since 'a' is not an Int, but will run just fine since the value of `a` is not observed by this program. (If it were observed, -fdefer-type-errors guarantees that you get a runtime panic when it happens.) This basically gives you the no-types Python experience when iterating, then you clean it all up when you're done.
This would be even better in cases where it can be automatically fixed. Just like how `cargo clippy --fix` will automatically fix lint errors whenever it can, there's no reason it couldn't also add explicit coercions of numeric types for you.
GHC has an -fdefer-type-errors option that lets you compile and run this code:
Which obviously doesn't typecheck since 'a' is not an Int, but will run just fine since the value of `a` is not observed by this program. (If it were observed, -fdefer-type-errors guarantees that you get a runtime panic when it happens.) This basically gives you the no-types Python experience when iterating, then you clean it all up when you're done.This would be even better in cases where it can be automatically fixed. Just like how `cargo clippy --fix` will automatically fix lint errors whenever it can, there's no reason it couldn't also add explicit coercions of numeric types for you.