lift lifetimes

src/ch04/s00-concerns.md

@@ -3,13 +3,13 @@
 ## There exist alternative `Functor` implementations
 See the [relevant subchapter](./s01-alternatives.md)
 
-## It might be better to have a per-lifetime trait for `Functor`s
+## ~~It might be better to have a per-lifetime trait for `Functor`s~~ done
 See the [relevant subchapter](./s02-lifetimes.md)
 
 ## `Stackless` is kind of bad
 See the [relevant subchapter](./s03-stackless.md)
 
-## `WeakFunctor::F<'a, A>` is not (yet) covariant over the lifetime `'a`
+## `WeakFunctor<'a>` is not (yet) covariant over the lifetime `'a`
 See the [relevant subchapter](./s04-covariance.md)
 
 ## `Fail`/`FailMonad`/etc. have unclear semantics

src/ch04/s01-alternatives.md

@@ -6,10 +6,8 @@ Copied for reference. All following examples are in the same `Functor`-`Applicat
 without extra (sub)traits like `WeakFunctor`, `Pure`, `ApplicativeLA2`, etc. .
 
 ```rust
-trait Functor {
+trait Functor<'a>: 'a {
-    type F<'a, A: 'a>: 'a
+    type F<A: 'a>: 'a;
-    where
-        Self: 'a;
 
     fn fmap<'a, A: 'a, B: 'a>(
         f: impl 'a + FnOnce(A) -> B, fa: Self::F<'a, A>,

src/ch04/s02-lifetimes.md

@@ -2,17 +2,13 @@
 
 Current:
 ```rust
+pub trait WeakFunctorA<'a>: 'a {
+    type F<A: 'a>: 'a;
+}
+
 pub trait WeakFunctor {
     type F<'a, A: 'a>: 'a
     where
         Self: 'a;
 }
 ```
-
-Proposed:
-```rust
-pub trait WeakFunctor<'a>: 'a {
-    type F<A: 'a>: 'a;
-}
-```
-

src/ch04/s04-covariance.md

@@ -1,4 +1,4 @@
-## `CovariantFunctor` not (yet) included in `Monad`
+**`CovariantFunctor` was deleted.**
 
 ## Specific case: `Stackless<'a>` isn't covariant