There's currently a function in the lexer that rejects a line comment that is all slashes from being a doc comment. I think the intention was that you could draw boxes,
/////////////
// like so //
/////////////
Since a line doc comment split up over multiple paragraphs will have a "blank" line that is just /// between the paragraphs, that would get mistaken for a box segment, lexed as a regular comment, and go missing from the sequence of doc comment attributes before they were reassembled by rustdoc into markdown input.
I figure the best plan here is to just declare that a comment that is exactly `///` is a doc comment after all, and to only omit comments with four slashes or more, which is what this commit implements. Can't really draw boxes that narrow, anyway.
Fixes https://github.com/mozilla/rust/issues/6578 by merging the 3 different ways to build an AST into a single `AstBuilder` trait, creating a more uniform and briefer interface.
Also, converts the `ext_ctxt` trait-object to be a plain struct, as well as renaming it to `ExtCtxt`.
Seems to make expansion slightly faster for the normal case (e.g. `libcore` and `libstd`), but slower for `librustc` (slightly) and `libsyntax` (0.3s -> 0.8s! I'm investigating this, but I'd prefer this patch to land relatively quickly.).
`git blame` suggests maybe @graydon or @erickt are familiar with this area of the code. r?
Replace all instances of #[auto_*code] with the appropriate #[deriving] attribute
and remove the majority of the actual auto_* code, leaving stubs to refer the user to
the new syntax.
Also, moves the useful contents of auto_encode.rs to more appropriate spots: tests and comments to deriving/encodable.rs, and the ExtCtxtMethods trait to build.rs (unused so far, but the method syntax might be nicer than using the mk_* fns in many instances).
Replace all instances of #[auto_*code] with the appropriate #[deriving] attribute
and remove the majority of the actual code, leaving stubs to refer the user to
the new syntax.