Rename type variables to improve readability

Addresses #4 (comment)

src/HasReader.hs

@@ -75,15 +75,15 @@ instance
   -- The constraint raises @-Wsimplifiable-class-constraints@.
   -- This could be avoided by instead placing @HasField'@s constraints here.
   -- Unfortunately, it uses non-exported symbols from @generic-lens@.
-  ( Generic r', Generic.HasField' field r' r, HasReader tag r' m )
-  => HasReader tag r (Field field m)
+  ( Generic record, Generic.HasField' field record v, HasReader tag record m )
+  => HasReader tag v (Field field m)
   where
-    ask_ _ = coerce @(m r) $
+    ask_ _ = coerce @(m v) $
       asks @tag $ view (Generic.field' @field)
     local_
-      :: forall a. Proxy# tag -> (r -> r) -> Field field m a -> Field field m a
-    local_ tag = coerce @((r -> r) -> m a -> m a) $
+      :: forall a. Proxy# tag -> (v -> v) -> Field field m a -> Field field m a
+    local_ tag = coerce @((v -> v) -> m a -> m a) $
       local_ tag . over (Generic.field' @field)
-    reader_ :: forall a. Proxy# tag -> (r -> a) -> Field field m a
+    reader_ :: forall a. Proxy# tag -> (v -> a) -> Field field m a
     reader_ tag f = coerce @(m a) $
       reader_ tag $ f . view (Generic.field' @field)

src/HasState.hs

@@ -88,15 +88,15 @@ instance
   -- The constraint raises @-Wsimplifiable-class-constraints@.
   -- This could be avoided by instead placing @HasField'@s constraints here.
   -- Unfortunately, it uses non-exported symbols from @generic-lens@.
-  ( Generic s', Generic.HasField' field s' s, HasState tag s' m )
-  => HasState tag s (Field field m)
+  ( Generic record, Generic.HasField' field record v, HasState tag record m )
+  => HasState tag v (Field field m)
   where
-    get_ _ = coerce @(m s) $
+    get_ _ = coerce @(m v) $
       gets @tag $ view (Generic.field' @field)
-    put_ _ = coerce @(s -> m ()) $
-      modify @tag . set (Generic.field' @field @s')
-    state_ :: forall a. Proxy# tag -> (s -> (a, s)) -> Field field m a
-    state_ _ = coerce @((s -> (a, s)) -> m a) $
+    put_ _ = coerce @(v -> m ()) $
+      modify @tag . set (Generic.field' @field @record)
+    state_ :: forall a. Proxy# tag -> (v -> (a, v)) -> Field field m a
+    state_ _ = coerce @((v -> (a, v)) -> m a) $
       state @tag . Generic.field' @field @_ @_ @((,) a)