Hint use of use crate:: on invalid mod
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r? @cramertj (rust_highfive has picked a reviewer for you, use r? to override) |
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The job Click to expand the log.I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact |
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The job Click to expand the log.I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact |
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The job Click to expand the log.I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact |
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The job Click to expand the log.I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact |
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I've rebased it. It's ready to merge. |
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r? @dtolnay |
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oops this is compiler.. |
estebank
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| err.help(&format!( | ||
| "if there is `mod {}` elsewhere in the crate already, import it with `use crate::` instead", | ||
| mod_name, | ||
| )); |
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You can do the following instead
err.span_suggestion_verbose(
span,
"if the module exists elsewhere in the crate already, you can import instead",
format!("use crate::{};", mod_name),
Applicability::MaybeIncorrect,
)That being said, it'd be nice to actually check that the module exists in the crate and provide the suggestion with higher certainty. Do not have the time to check what the code would have to be to verify that crate::mod_name exists, but @petrochenkov might know of the top of their head. Otherwise, would you mind exploring how to do that, @kornelski? We want to minimize the cases where we provide incorrect suggestions, as those can be worse than terse ones. If we can make that check, then we can provide the help to create the file exclusively if the mod doesn't exist alredy.
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I'm happy to dig in further, but I'd prefer to land this change in the meantime.
The message starts with a disclaimer, it intentionally only suggests use instead of showing a potentially-incorrect path. So I think risk of confusion is low, and mentioning use is an important improvement.
This check currently happens very early in the parsing, so a naive mod existence checks at this stage would be unreliable and sensitive to order of definitions. A proper fix may be quite involved, e.g. create a "broken mod" AST node for a later pass to pick it up and scan modules after they're all parsed. That might take longer to implement, so the current PR is IMHO good to have in the meantime.
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@estebank you happy with this? |
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Next step in #69492
It's not feasible to know at this stage of parsing what other modules exists, so the help string is speculative unfortunately.
The goal is to help users who assumed
mod foo;works the same way as#include "foo"orrequire("foo"), and should have useduse crate::fooinstead.