diff --git a/src/ty-fold.md b/src/ty-fold.md index ecb961cf..da9564d4 100644 --- a/src/ty-fold.md +++ b/src/ty-fold.md @@ -1,7 +1,7 @@ # `TypeFoldable` and `TypeFolder` -In [a previous chapter], we discussed instantiating binders. This must involves looking at everything inside of a `Early/Binder` -to find any usages of the bound vars in order to replace them. Binders can wrap an arbitrary rust type `T` not just a `Ty` so +In [a previous chapter], we discussed instantiating binders. This involves looking at everything inside of a `Early/Binder` +to find any usages of the bound vars in order to replace them. Binders can wrap an arbitrary Rust type `T` not just a `Ty` so how do we implement the `instantiate` methods on the `Early/Binder` types. The answer is a couple of traits: @@ -20,7 +20,7 @@ that takes a type as input and returns a new type as a result. `TypeFoldable` in `TypeFolder` `fold_foo` methods on itself, giving the `TypeFolder` access to its contents (the types, regions, etc that are contained within). -You can think of it with this analogy to the iterator combinators we have come to love in rust: +You can think of it with this analogy to the iterator combinators we have come to love in Rust: ```rust,ignore vec.iter().map(|e1| foo(e2)).collect()