Removed as many "```ignore" as possible.

Replaced by adding extra imports, adding hidden code (`# ...`), modifying
examples to be runnable (sorry Homura), specifying non-Rust code, and
converting to should_panic, no_run, or compile_fail.

Remaining "```ignore"s received an explanation why they are being ignored.

4 files changed, 10 insertions, 8 deletions

diff --git a/src/libsyntax/ast.rs b/src/libsyntax/ast.rs
index 2eb39bc26b5..8bd58ec7a52 100644
--- a/src/libsyntax/ast.rs
+++ b/src/libsyntax/ast.rs
@@ -775,10 +775,10 @@ pub struct Local {
 ///
 /// E.g. `0...10 => { println!("match!") }` as in
 ///
-/// ```rust,ignore
-/// match n {
+/// ```
+/// match 123 {
 ///     0...10 => { println!("match!") },
-///     // ..
+///     _ => { println!("no match!") },
 /// }
 /// ```
 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
@@ -977,7 +977,7 @@ pub enum ExprKind {
 /// separately. `position` represents the index of the associated
 /// item qualified with this Self type.
 ///
-/// ```rust,ignore
+/// ```ignore (only-for-syntax-highlight)
 /// <Vec<T> as a::b::Trait>::AssociatedItem
 ///  ^~~~~     ~~~~~~~~~~~~~~^
 ///  ty        position = 3
diff --git a/src/libsyntax/diagnostic_list.rs b/src/libsyntax/diagnostic_list.rs
index 01d1277ea62..508feca9731 100644
--- a/src/libsyntax/diagnostic_list.rs
+++ b/src/libsyntax/diagnostic_list.rs
@@ -51,12 +51,14 @@ fn main() {}
 
 The parenthesized `inline` attribute requires the parameter to be specified:
 
-```ignore
+```
 #[inline(always)]
 fn something() {}
+```
 
-// or:
+or:
 
+```
 #[inline(never)]
 fn something() {}
 ```
diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index 0b145c54f61..851a638e148 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -4436,7 +4436,7 @@ impl<'a> Parser<'a> {
 
     /// Parses an optional `where` clause and places it in `generics`.
     ///
-    /// ```ignore
+    /// ```ignore (only-for-syntax-highlight)
     /// where T : Trait<U, V> + 'b, 'a : 'b
     /// ```
     pub fn parse_where_clause(&mut self) -> PResult<'a, WhereClause> {
diff --git a/src/libsyntax/print/pp.rs b/src/libsyntax/print/pp.rs
index e893c859247..82b5d7e284b 100644
--- a/src/libsyntax/print/pp.rs
+++ b/src/libsyntax/print/pp.rs
@@ -11,7 +11,7 @@
 //! This pretty-printer is a direct reimplementation of Philip Karlton's
 //! Mesa pretty-printer, as described in appendix A of
 //!
-//! ````ignore
+//! ````text
 //! STAN-CS-79-770: "Pretty Printing", by Derek C. Oppen.
 //! Stanford Department of Computer Science, 1979.
 //! ````