bjoernager/rust
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Handle several #[diagnostic::on_unimplemented] attributes correctly

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This PR fixes an issues where rustc would ignore subsequent
`#[diagnostic::on_unimplemented]` attributes. The [corresponding
RFC](https://rust-lang.github.io/rfcs/3368-diagnostic-attribute-namespace.html)
specifies that the first matching instance of each option is used.
Invalid attributes are linted and otherwise ignored.
This commit is contained in:
Georg Semmler 2023-10-11 21:57:53 +02:00
parent 71704c4f84
commit 232aaeba7c
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GPG key ID: A87BCEE5205CE489
3 changed files with 108 additions and 12 deletions
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46
compiler/rustc_trait_selection/src/traits/error_reporting/on_unimplemented.rs
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@ -1,6 +1,6 @@
use super::{ObligationCauseCode, PredicateObligation};
use crate::infer::error_reporting::TypeErrCtxt;
use rustc_ast::{MetaItem, NestedMetaItem};
use rustc_ast::{Attribute, MetaItem, NestedMetaItem};
use rustc_attr as attr;
use rustc_data_structures::fx::FxHashMap;
use rustc_errors::{struct_span_err, ErrorGuaranteed};
@ -474,18 +474,40 @@ impl<'tcx> OnUnimplementedDirective {
}
pub fn of_item(tcx: TyCtxt<'tcx>, item_def_id: DefId) -> Result<Option<Self>, ErrorGuaranteed> {
let mut is_diagnostic_namespace_variant = false;
let Some(attr) = tcx.get_attr(item_def_id, sym::rustc_on_unimplemented).or_else(|| {
if tcx.features().diagnostic_namespace {
is_diagnostic_namespace_variant = true;
tcx.get_attrs_by_path(item_def_id, &[sym::diagnostic, sym::on_unimplemented]).next()
} else {
None
}
}) else {
return Ok(None);
};
if let Some(attr) = tcx.get_attr(item_def_id, sym::rustc_on_unimplemented) {
return Self::parse_attribute(attr, false, tcx, item_def_id);
} else if tcx.features().diagnostic_namespace {
tcx.get_attrs_by_path(item_def_id, &[sym::diagnostic, sym::on_unimplemented])
.filter_map(|attr| Self::parse_attribute(attr, true, tcx, item_def_id).transpose())
.try_fold(None, |aggr: Option<Self>, directive| {
let directive = directive?;
if let Some(aggr) = aggr {
let mut subcommands = aggr.subcommands;
subcommands.extend(directive.subcommands);
Ok(Some(Self {
condition: aggr.condition.or(directive.condition),
subcommands,
message: aggr.message.or(directive.message),
label: aggr.label.or(directive.label),
note: aggr.note.or(directive.note),
parent_label: aggr.parent_label.or(directive.parent_label),
append_const_msg: aggr.append_const_msg.or(directive.append_const_msg),
}))
} else {
Ok(Some(directive))
}
})
} else {
Ok(None)
}
}
fn parse_attribute(
attr: &Attribute,
is_diagnostic_namespace_variant: bool,
tcx: TyCtxt<'tcx>,
item_def_id: DefId,
) -> Result<Option<Self>, ErrorGuaranteed> {
let result = if let Some(items) = attr.meta_item_list() {
Self::parse(tcx, item_def_id, &items, attr.span, true, is_diagnostic_namespace_variant)
} else if let Some(value) = attr.value_str() {