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add links for `Span`, `CodeMap`, and `rustfix` 

It's unfortunate that `code-monospaced` links don't render with link
colors (such that the reader needs to hover over them just to tell that
it is a link), but that's presumably a bug in MdBook, and not something
we need concern ourselves with here.
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Zack M. Davis 2018-06-30 08:34:31 -07:00 committed by Who? Me?!
parent fedeb6a9a0
commit 5774db6f3a
1 changed files with 18 additions and 13 deletions
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@ -5,14 +5,17 @@ This chapter is about how to emit compile errors and lints from the compiler.
## `Span`
`Span` is the primary data structure in `rustc` used to represent a location in
the code being compiled. `Span`s are attached to most constructs in HIR and MIR,
allowing for easier error reporting whenever an error comes up.
[`Span`][span] is the primary data structure in `rustc` used to represent a
location in the code being compiled. `Span`s are attached to most constructs in
HIR and MIR, allowing for easier error reporting whenever an error comes up.
A `Span` can be looked up in a `CodeMap` to get a "snippet" useful for
displaying errors with [`span_to_snippet` and other similar methods][sptosnip]
on the `CodeMap`.
[span]: https://doc.rust-lang.org/nightly/nightly-rustc/syntax/codemap/struct.Span.html
A `Span` can be looked up in a [`CodeMap`][codemap] to get a "snippet" useful
for displaying errors with [`span_to_snippet`][sptosnip] and other similar
methods on the `CodeMap`.
[codemap]: https://doc.rust-lang.org/nightly/nightly-rustc/syntax/codemap/struct.CodeMap.html
[sptosnip]: https://doc.rust-lang.org/nightly/nightly-rustc/syntax/codemap/struct.CodeMap.html#method.span_to_snippet
## Error messages
@ -70,14 +73,16 @@ err.emit();
## Suggestions
We would like to make edition transitions as smooth as possible. To that end,
`rustfix` can use compiler suggestions to automatically fix code. For example,
we could use `rustfix` to mechanically apply the `qux` suggestion from the
previous example. However, not all suggestions are mechanically applicable. We
use the [`span_suggestion_with_applicability`][sswa] method of
`DiagnosticBuilder` to inform the emitter of whether a suggestion is
mechanically applicable or not. This information, in turn, is outputed by
rustc when the error format is `json`, which is used by `rustfix`.
[`rustfix`][rustfix] can use compiler suggestions to automatically fix
code. For example, we could use `rustfix` to mechanically apply the `qux`
suggestion from the previous example. However, not all suggestions are
mechanically applicable. We use the
[`span_suggestion_with_applicability`][sswa] method of `DiagnosticBuilder` to
inform the emitter of whether a suggestion is mechanically applicable or not.
This information, in turn, is outputed by rustc when the error format is
`json`, which is used by `rustfix`.
[rustfix]: https://github.com/rust-lang-nursery/rustfix/
[sswa]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_errors/struct.DiagnosticBuilder.html#method.span_suggestion_with_applicability
For example, to make our `qux` suggestion machine-applicable, we would do: