diff --git a/guide/src/for_developers/preprocessors.md b/guide/src/for_developers/preprocessors.md
index 3cd88797fb..7a52fce25d 100644
--- a/guide/src/for_developers/preprocessors.md
+++ b/guide/src/for_developers/preprocessors.md
@@ -66,7 +66,12 @@ translate events back into markdown text.
 The following code block shows how to remove all emphasis from markdown,
 without accidentally breaking the document.
 
-```rust,no_run
+```rust,compile_fail
+# // tagged compile_fail because 
+# // sample fails to compile here:
+# // "trait Borrow not implemented for pulldown_cmark_to_cmark::..."
+# // Probably due to version skew on pulldown-cmark
+# // between examples/remove-emphasis/Cargo.toml and <root>/Cargo.toml
 {{#rustdoc_include ../../../examples/remove-emphasis/mdbook-remove-emphasis/src/main.rs:remove_emphasis}}
 ```
 
diff --git a/guide/src/format/mathjax.md b/guide/src/format/mathjax.md
index 3dd792159d..642a3aaa19 100644
--- a/guide/src/format/mathjax.md
+++ b/guide/src/format/mathjax.md
@@ -20,24 +20,25 @@ extra backslash to work. Hopefully this limitation will be lifted soon.
 > to add _two extra_ backslashes (e.g., `\begin{cases} \frac 1 2 \\\\ \frac 3 4
 > \end{cases}`).
 
-
 ### Inline equations
+
 Inline equations are delimited by `\\(` and `\\)`. So for example, to render the
 following inline equation \\( \int x dx = \frac{x^2}{2} + C \\) you would write
 the following:
-```
+
+```text
 \\( \int x dx = \frac{x^2}{2} + C \\)
 ```
 
 ### Block equations
+
 Block equations are delimited by `\\[` and `\\]`. To render the following
 equation
 
 \\[ \mu = \frac{1}{N} \sum_{i=0} x_i \\]
 
-
 you would write:
 
-```bash
+```text
 \\[ \mu = \frac{1}{N} \sum_{i=0} x_i \\]
 ```
diff --git a/guide/src/format/mdbook.md b/guide/src/format/mdbook.md
index b2d73a5d48..f3bada29c3 100644
--- a/guide/src/format/mdbook.md
+++ b/guide/src/format/mdbook.md
@@ -230,7 +230,7 @@ Rustdoc will use the complete example when you run `mdbook test`.
 
 For example, consider a file named `file.rs` that contains this Rust program:
 
-```rust
+```rust,editable
 fn main() {
     let x = add_one(2);
     assert_eq!(x, 3);
@@ -320,8 +320,8 @@ To configure this:
 
 1. Create a ***Cargo.toml*** file with a `[package.dependencies]` section that defines a dependency for each `<crate>` you want to use in any sample.  If your book is already embedded in an existing Cargo project, you may be able to use the existing project `Cargo.toml`.
 2. In your ***book.toml***:
-    * configure the path to ***Cargo.toml** in `rust.manifest`, as described in [rust configuration](/format/configuration/general.html#rust-options).
-    * remove `rust.edition` if it is configured.  The edition of rust compiler will be as specified in the ***Cargo.toml***.
+    * configure the path to ***Cargo.toml*** in `rust.manifest`, as described in [rust configuration](/format/configuration/general.html#rust-options).
+    * remove `rust.edition` if it is configured.  The default rust edition will be as specified in the ***Cargo.toml*** (though this can be overridden for a specific code block).
     * Refrain from invoking `mdbook test` with `-L` or `--library-path` argument.  This, too, will be inferred from cargo project configuration
 
 # Features for general content