Add info about emitting lints and errors #139
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src/diag.md
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| [errors]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_errors/index.html | ||
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| Most "session"-like types in the compiler (e.g. [`Session`][session]) have |
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I think it's fine to just say Session and ParseSess here.
src/diag.md
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| For example, to add a help message to an error, one might do: | ||
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| ```rust,ignore | ||
| let snip = sess.codemap().span_to_snippet(sp); |
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Needs an unwrap_or, span_to_snippet returns an Option
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I would prefer to show the more common code of:
let mut err = sess.struct_span_err(sp, "oh no! this is an error!");
// add code to verify that `sp` is not a macro if this is a consideration <...expand explanation of this later...>
if let Some(snippet) = sess.codemap().span_to_snippet(sp) {
err.span_suggestion(suggestion_sp, "try using a qux here", format!("qux {}", snip));
} else { // in practice this is unlikely to be reached <...add explanation of this later...>
err.span_help(suggestion_sp, "you could use a qux here instead");
}
err.emit();
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// add code to verify that
spis not a macro if this is a consideration <...expand explanation of this later...>
@estebank I didn't quite understand what you meant by this.
I think will just create a new section for suggestions since they will play a big role in the edition.
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No problem, you can forego that comment. It is a caveat that we'll need to add at some point, as suggestions that do not verify wether the current context is mixing macros can lead to very incorrect suggestions (like in #39450). This is not a problem under normal circumstances, but adding a check for this in the documentation could go a long way. Don't need to add it now though.
src/diag.md
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| } | ||
| ``` | ||
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| ### Edition Lints |
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"Edition-gated lints", there are more kinds of edition lints.
src/diag.md
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| .span_suggestion(other_sp, "try using a qux here", format!("qux {}", snip)) | ||
| .emit(); | ||
| ``` | ||
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Could you also include some stuff on suggestion applicabilities here?
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I don't want to block too much on this, once this PR is merged it can be expanded more iteratively.
| error: aborting due to previous error | ||
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| For more information about this error, try `rustc --explain E0999`. | ||
| ``` |
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Add explanation:
In some cases, like when the suggestion spans multiple lines or when there are multiple suggestions, the suggestions are displayed on its own:
error[E0999]: oh no! this is an error!
--> mycode.rs:3:5
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3 | sad()
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help: try using a qux here:
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3 | qux sad()
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error: aborting due to previous error
For more information about this error, try `rustc --explain E0999`.
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@Manishearth @estebank Thanks for the feedback! I think I addressed all the comments. |
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@bors r+ |
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rust-lang/rust#48309 merged |
Since I was just working on this, I thought I would write something up.
We should wait to merge this until rust-lang/rust#48309 merges.
r? @estebank @Manishearth
cc #14 #50