Rollup of 7 pull requests

src/doc/rustc/src/command-line-arguments.md

@@ -42,11 +42,11 @@ This flag prints out various information about the compiler.
 
 ## `-g`: include debug information
 
-A synonym for `-C debug-level=2`.
+A synonym for `-C debuginfo=2`, for more see [here](codegen-options/index.html#debuginfo).
 
 ## `-O`: optimize your code
 
-A synonym for `-C opt-level=2`.
+A synonym for `-C opt-level=2`, for more see [here](codegen-options/index.html#opt-level).
 
 ## `-o`: filename of the output
 

src/doc/rustc/src/lints/levels.md

@@ -90,7 +90,9 @@ This lint level gives you that.
 'forbid' is a special lint level that's stronger than 'deny'. It's the same
 as 'deny' in that a lint at this level will produce an error, but unlike the
 'deny' level, the 'forbid' level can not be overridden to be anything lower
-than an error.
+than an error.  However, lint levels may still be capped with `--cap-lints`
+(see below) so `rustc --cap-lints warn` will make lints set to 'forbid' just
+warn.
 
 ## Configuring warning levels
 

src/doc/rustdoc/src/documentation-tests.md

@@ -236,6 +236,23 @@ appears to the reader as the initial idea but works with doc tests:
 /// ```
 ```
 
+As of version 1.34.0, one can also omit the `fn main()`, but you will have to
+disambiguate the error type:
+
+```ignore
+/// ```
+/// use std::io;
+/// let mut input = String::new();
+/// io::stdin().read_line(&mut input)?;
+/// # Ok::<(), io:Error>(())
+/// ```
+```
+
+This is an unfortunate consequence of the `?` operator adding an implicit
+conversion, so type inference fails because the type is not unique. Please note
+that you must write the `(())` in one sequence without intermediate whitespace
+so that rustdoc understands you want an implicit `Result`-returning function.
+
 ## Documenting macros
 
 Here’s an example of documenting a macro: