We realised last time that our type checker needs to move on from just saying "yes" or "no" for whether our program is OK: we need to keep hold of the… ...more

The type checker is passing our unit tests, but it's stopping our language from actually working. Time to fill in the gaps. You can find the source c… ...more

We have a plan for what error message we should get when we try to write code like let x: i32 = 3.0;. Let's try to make it a reality! You can find th… ...more

This is it: we're going to do some actual type-checking. We want to be able to identify that let x: i32 = 3.0; is wrong, but for now we're going to ch… ...more

We're still on a mission to do some type-checking, and our plan is to allow writing let x: i32 = 3.0;, then produce a type error because 3.0 is not an… ...more