Fix mdbook; remove FIXMEs

Author: gnzlbg

reference/src/SUMMARY.md

@@ -4,9 +4,11 @@
 
 - [Data layout](./layout.md)
   - [Structs and tuples](./layout/structs-and-tuples.md)
-  - [Integers and Floating Points](./layout/integers-floatingpoint.md)
+  - [Scalar types](./layout/scalar.md)
   - [Enums](./layout/enums.md)
   - [Unions](./layout/unions.md)
+  - [Pointers](./layout/pointers.md)
+  - [Function pointers](./layout/function-pointers.md)
   - [Arrays and Slices](./layout/arrays-and-slices.md)
   - [Packed SIMD vectors](./layout/packed-simd-vectors.md)
 - [Optimizations](./optimizations.md)

reference/src/layout/function-pointers.md

@@ -81,6 +81,11 @@ bool for_all(struct Cons const *self, bool (*func)(int, void *), void *thunk);
 ```
 
 ```rust
+# use std::{
+#    ffi::c_void,
+#    os::raw::c_int,
+# };
+#
 pub struct Cons {
   data: c_int,
   next: Option<Box<Cons>>,
@@ -117,9 +122,6 @@ pub extern "C" fn for_all(
     }
     it = node.next.as_ref().map(|x| &**x);
   }
+  true
 }
 ```
-
-### Unresolved Questions
-
-- dunno

reference/src/layout/pointers.md

@@ -36,7 +36,7 @@ multi-trait objects `&(dyn T + U)` or references to other dynamically sized type
 other than that they are at least word-aligned, and have size at least one word.
 
 The layout of `&dyn T` when `T` is a trait is the same as that of:
-```rust
+```rust,ignore
 #[repr(C)]
 struct DynObject {
   data: *u8,
@@ -45,7 +45,7 @@ struct DynObject {
 ```
 
 The layout of `&[T]` is the same as that of:
-```rust
+```rust,ignore
 #[repr(C)]
 struct Slice<T> {
   ptr: *T,

reference/src/layout/integers-floatingpoint.md renamed to reference/src/layout/scalar.md

@@ -1,8 +1,7 @@
-# Layout of Boolean, Floating Point, and Integral Types
+# Layout of scalar types
 
 This chapter represents the consensus from issue [#9]. It documents the memory
-layout and considerations for `bool`, floating point types (`f{32, 64}`), and
-integral types (`{i,u}{8,16,32,64,128,size}`).
+layout and considerations for `bool`, `char`, floating point types (`f{32, 64}`), and integral types (`{i,u}{8,16,32,64,128,size}`).
 
 These types are all scalar types, representing a single value, and have no
 layout `#[repr()]` flags.
@@ -48,22 +47,10 @@ The layout of `usize` determines the following:
 - the maximum number of elements in an array (`[T; N: usize]`),
 - how much a pointer of a certain type can be offseted (limited by `usize::max_value()`).
 
-> **FIXME**: Pointer `add` operates on `usize`, but pointer `offset` operates on
-> `isize`, so unless by "offseted" we mean something different from `ptr.offset`
-> above, `usize::max_value()` does not determine how much a pointer can be
-> "offseted". We should probably be more specific here and call out `ptr.add`
-> and `ptr.offset` explicitly.
-
 The maximum size of any single value must fit within `usize` to [ensure that
 pointer diff is
 representable](https://github.com/rust-rfcs/unsafe-code-guidelines/pull/5#discussion_r212703192).
 
-> **FIXME**: This does not make sense. We state that the layout of `usize`
-> determines the maximum size of an object, and then argue that this is to
-> ensure that pointer diff is representable, which won't be the case if the size
-> of an object is `usize::max_val()`. The link cited actually states that, right
-> now, the largest size of a Rust object is limited by `isize::max_value()`.
-
 [pointer types]: ./pointers.md
 
 ## Fixed-width integer types