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Improve the warning messages for the #[diagnostic::on_unimplemented]

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This commit improves warnings emitted for malformed on unimplemented
attributes by:

* Improving the span of the warnings
* Adding a label message to them
* Separating the messages for missing and unexpected options
* Adding a help message that says which options are supported
This commit is contained in:
Georg Semmler 2023-10-19 08:44:15 +02:00
parent 020d00867a
commit 9017b974ee
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GPG key ID: A87BCEE5205CE489
5 changed files with 126 additions and 27 deletions
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57
compiler/rustc_trait_selection/src/traits/error_reporting/on_unimplemented.rs
View file

@ -1,5 +1,8 @@
use super::{ObligationCauseCode, PredicateObligation};
use crate::infer::error_reporting::TypeErrCtxt;
use rustc_ast::AttrArgs;
use rustc_ast::AttrArgsEq;
use rustc_ast::AttrKind;
use rustc_ast::{Attribute, MetaItem, NestedMetaItem};
use rustc_attr as attr;
use rustc_data_structures::fx::FxHashMap;
@ -342,7 +345,22 @@ pub enum AppendConstMessage {
#[derive(LintDiagnostic)]
#[diag(trait_selection_malformed_on_unimplemented_attr)]
pub struct NoValueInOnUnimplementedLint;
#[help]
pub struct MalformedOnUnimplementedAttrLint {
#[label]
pub span: Span,
}
impl MalformedOnUnimplementedAttrLint {
fn new(span: Span) -> Self {
Self { span }
}
}
#[derive(LintDiagnostic)]
#[diag(trait_selection_missing_options_for_on_unimplemented_attr)]
#[help]
pub struct MissingOptionsForOnUnimplementedAttr;
impl<'tcx> OnUnimplementedDirective {
fn parse(
@ -453,7 +471,7 @@ impl<'tcx> OnUnimplementedDirective {
UNKNOWN_OR_MALFORMED_DIAGNOSTIC_ATTRIBUTES,
tcx.hir().local_def_id_to_hir_id(item_def_id.expect_local()),
vec![item.span()],
NoValueInOnUnimplementedLint,
MalformedOnUnimplementedAttrLint::new(item.span()),
);
} else {
// nothing found
@ -530,21 +548,40 @@ impl<'tcx> OnUnimplementedDirective {
append_const_msg: None,
}))
} else {
let item = attr.get_normal_item();
let report_span = match &item.args {
AttrArgs::Empty => item.path.span,
AttrArgs::Delimited(args) => args.dspan.entire(),
AttrArgs::Eq(eq_span, AttrArgsEq::Ast(expr)) => eq_span.to(expr.span),
AttrArgs::Eq(span, AttrArgsEq::Hir(expr)) => span.to(expr.span),
};
tcx.emit_spanned_lint(
UNKNOWN_OR_MALFORMED_DIAGNOSTIC_ATTRIBUTES,
tcx.hir().local_def_id_to_hir_id(item_def_id.expect_local()),
attr.span,
NoValueInOnUnimplementedLint,
report_span,
MalformedOnUnimplementedAttrLint::new(report_span),
);
Ok(None)
}
} else if is_diagnostic_namespace_variant {
tcx.emit_spanned_lint(
UNKNOWN_OR_MALFORMED_DIAGNOSTIC_ATTRIBUTES,
tcx.hir().local_def_id_to_hir_id(item_def_id.expect_local()),
attr.span,
NoValueInOnUnimplementedLint,
);
match &attr.kind {
AttrKind::Normal(p) if !matches!(p.item.args, AttrArgs::Empty) => {
tcx.emit_spanned_lint(
UNKNOWN_OR_MALFORMED_DIAGNOSTIC_ATTRIBUTES,
tcx.hir().local_def_id_to_hir_id(item_def_id.expect_local()),
attr.span,
MalformedOnUnimplementedAttrLint::new(attr.span),
);
}
_ => tcx.emit_spanned_lint(
UNKNOWN_OR_MALFORMED_DIAGNOSTIC_ATTRIBUTES,
tcx.hir().local_def_id_to_hir_id(item_def_id.expect_local()),
attr.span,
MissingOptionsForOnUnimplementedAttr,
),
};
Ok(None)
} else {
let reported =