Audit code blocks.

Author: ehuss

src/abi.md

@@ -68,7 +68,8 @@ The *`link_section` attribute* specifies the section of the object file that a
 [function] or [static]'s content will be placed into. It uses the
 [_MetaNameValueStr_] syntax to specify the section name.
 
-```rust,ignore
+<!-- no_run: don't link. The format of the section name is platform-specific. -->
+```rust,no_run
 #[no_mangle]
 #[link_section = ".example_section"]
 pub static VAR1: u32 = 1;
@@ -80,7 +81,7 @@ The *`export_name` attribute* specifies the name of the symbol that will be
 exported on a [function] or [static]. It uses the [_MetaNameValueStr_] syntax
 to specify the symbol name.
 
-```rust,ignore
+```rust
 #[export_name = "exported_symbol_name"]
 pub fn name_in_rust() { }
 ```

src/attributes/codegen.md

@@ -49,7 +49,8 @@ enable code generation of that function for specific platform architecture
 features. It uses the [_MetaListNameValueStr_] syntax with a single key of
 `enable` whose value is a string of comma-separated feature names to enable.
 
-```rust,ignore
+```rust
+# #[cfg(target_feature = "avx2")]
 #[target_feature(enable = "avx2")]
 unsafe fn foo_avx2() {}
 ```

src/attributes/type_system.md

@@ -66,7 +66,8 @@ Non-exhaustive types cannot be constructed outside of the defining crate:
   with a [_StructExpression_] \(including with [functional update syntax]).
 - [`enum`][enum] instances can be constructed in an [_EnumerationVariantExpression_].
 
-```rust,ignore (requires multiple crates)
+<!-- ignore: requires external crates -->
+```rust,ignore
 // `Config`, `Error`, and `Message` are types defined in an upstream crate that have been
 // annotated as `#[non_exhaustive]`.
 use upstream::{Config, Error, Message};
@@ -99,7 +100,8 @@ There are limitations when matching on non-exhaustive types outside of the defin
 - When pattern matching on a non-exhaustive [`enum`][enum], matching on a variant does not
   contribute towards the exhaustiveness of the arms.
 
-```rust, ignore (requires multiple crates)
+<!-- ignore: requires external crates -->
+```rust, ignore
 // `Config`, `Error`, and `Message` are types defined in an upstream crate that have been
 // annotated as `#[non_exhaustive]`.
 use upstream::{Config, Error, Message};

src/conditional-compilation.md

@@ -264,6 +264,7 @@ When the configuration predicate is true, this attribute expands out to the
 attributes listed after the predicate. For example, the following module will
 either be found at `linux.rs` or `windows.rs` based on the target.
 
+<!-- ignore: `mod` needs multiple files -->
 ```rust,ignore
 #[cfg_attr(linux, path = "linux.rs")]
 #[cfg_attr(windows, path = "windows.rs")]
@@ -273,6 +274,7 @@ mod os;
 Zero, one, or more attributes may be listed. Multiple attributes will each be
 expanded into separate attributes. For example:
 
+<!-- ignore: fake attributes -->
 ```rust,ignore
 #[cfg_attr(feature = "magic", sparkles, crackles)]
 fn bewitched() {}

src/crates-and-source-files.md

@@ -53,7 +53,7 @@ that apply to the containing module, most of which influence the behavior of
 the compiler. The anonymous crate module can have additional attributes that
 apply to the crate as a whole.
 
-```rust,no_run
+```rust
 // Specify the crate name.
 #![crate_name = "projx"]
 
@@ -75,7 +75,8 @@ essentially to treat the source file as an executable script. The shebang
 can only occur at the beginning of the file (but after the optional
 _UTF8BOM_). It is ignored by the compiler. For example:
 
-```text,ignore
+<!-- ignore: tests don't like shebang -->
+```rust,ignore
 #!/usr/bin/env rustx
 
 fn main() {
@@ -136,7 +137,7 @@ other object being linked to defines `main`.
 The *`crate_name` [attribute]* may be applied at the crate level to specify the
 name of the crate with the [_MetaNameValueStr_] syntax.
 
-```rust,ignore
+```rust
 #![crate_name = "mycrate"]
 ```
 

src/expressions/await-expr.md

@@ -51,6 +51,7 @@ context, there must be some task context available.
 Effectively, an `<expr>.await` expression is roughly
 equivalent to the following (this desugaring is not normative):
 
+<!-- ignore: example expansion -->
 ```rust,ignore
 match /* <expr> */ {
     mut pinned => loop {

src/expressions/field-expr.md

@@ -10,6 +10,7 @@ A _field expression_ consists of an expression followed by a single dot and an
 field of a [struct] or [union]. To call a function stored in a struct,
 parentheses are needed around the field expression.
 
+<!-- ignore: needs lots of support code -->
 ```rust,ignore
 mystruct.myfield;
 foo().x;

src/expressions/if-expr.md

@@ -97,6 +97,7 @@ assert_eq!(a, 3);
 
 An `if let` expression is equivalent to a [`match` expression] as follows:
 
+<!-- ignore: expansion example -->
 ```rust,ignore
 if let PATS = EXPR {
     /* body */
@@ -107,6 +108,7 @@ if let PATS = EXPR {
 
 is equivalent to
 
+<!-- ignore: expansion example -->
 ```rust,ignore
 match EXPR {
     PATS => { /* body */ },
@@ -135,6 +137,7 @@ of the language (the implementation of if-let chains - see [eRFC 2947][_eRFCIfLe
 When lazy boolean operator expression is desired, this can be achieved
 by using parenthesis as below:
 
+<!-- ignore: psuedo code -->
 ```rust,ignore
 // Before...
 if let PAT = EXPR && EXPR { .. }

src/expressions/loop-expr.md

@@ -93,6 +93,7 @@ while let _ = 5 {
 A `while let` loop is equivalent to a `loop` expression containing a [`match`
 expression] as follows.
 
+<!-- ignore: expansion example -->
 ```rust,ignore
 'label: while let PATS = EXPR {
     /* loop body */
@@ -101,6 +102,7 @@ expression] as follows.
 
 is equivalent to
 
+<!-- ignore: expansion example -->
 ```rust,ignore
 'label: loop {
     match EXPR {
@@ -156,6 +158,7 @@ assert_eq!(sum, 55);
 
 A for loop is equivalent to the following block expression.
 
+<!-- ignore: expansion example -->
 ```rust,ignore
 'label: for PATTERN in iter_expr {
     /* loop body */
@@ -164,6 +167,7 @@ A for loop is equivalent to the following block expression.
 
 is equivalent to
 
+<!-- ignore: expansion example -->
 ```rust,ignore
 {
     let result = match IntoIterator::into_iter(iter_expr) {

src/expressions/operator-expr.md

@@ -260,7 +260,9 @@ functions and macros in the standard library can then use that assumption
 above, these operators implicitly take shared borrows of their operands,
 evaluating them in [place expression context][place expression]:
 
-```rust,ignore
+```rust
+# let a = 1;
+# let b = 1;
 a == b;
 // is equivalent to
 ::std::cmp::PartialEq::eq(&a, &b);