bjoernager/rust
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A custom error message for lending iterators

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This commit is contained in:
Michael Baikov 2024-05-22 09:26:02 -04:00
parent 464987730a
commit d6e4fe569c
5 changed files with 74 additions and 5 deletions
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9
compiler/rustc_resolve/src/errors.rs
View file

@ -882,6 +882,15 @@ pub(crate) struct ElidedAnonymousLivetimeReportError {
pub(crate) suggestion: Option<ElidedAnonymousLivetimeReportErrorSuggestion>,
}
#[derive(Diagnostic)]
#[diag(resolve_lending_iterator_report_error)]
pub(crate) struct LendingIteratorReportError {
#[primary_span]
pub(crate) lifetime: Span,
#[note]
pub(crate) ty: Span,
}
#[derive(Subdiagnostic)]
#[multipart_suggestion(
resolve_elided_anonymous_lifetime_report_error_suggestion,

40
compiler/rustc_resolve/src/late.rs
View file

@ -9,7 +9,7 @@
use crate::{errors, path_names_to_string, rustdoc, BindingError, Finalize, LexicalScopeBinding};
use crate::{BindingKey, Used};
use crate::{Module, ModuleOrUniformRoot, NameBinding, ParentScope, PathResult};
use crate::{ResolutionError, Resolver, Segment, UseError};
use crate::{ResolutionError, Resolver, Segment, TyCtxt, UseError};
use rustc_ast::ptr::P;
use rustc_ast::visit::{visit_opt, walk_list, AssocCtxt, BoundKind, FnCtxt, FnKind, Visitor};
@ -1703,10 +1703,28 @@ impl<'a: 'ast, 'b, 'ast, 'tcx> LateResolutionVisitor<'a, 'b, 'ast, 'tcx> {
break;
}
}
self.r.dcx().emit_err(errors::ElidedAnonymousLivetimeReportError {
span: lifetime.ident.span,
suggestion,
});
// Is it caused by user trying to implement a lending iterator?
if !self.in_func_body
&& let Some((module, _)) = &self.current_trait_ref
&& let Some(ty) = &self.diag_metadata.current_self_type
&& let crate::ModuleKind::Def(DefKind::Trait, trait_id, _) = module.kind
&& def_id_matches_path(
self.r.tcx,
trait_id,
&["core", "iter", "traits", "iterator", "Iterator"],
)
{
self.r.dcx().emit_err(errors::LendingIteratorReportError {
lifetime: lifetime.ident.span,
ty: ty.span(),
});
} else {
self.r.dcx().emit_err(errors::ElidedAnonymousLivetimeReportError {
span: lifetime.ident.span,
suggestion,
});
}
} else {
self.r.dcx().emit_err(errors::ExplicitAnonymousLivetimeReportError {
span: lifetime.ident.span,
@ -4824,3 +4842,15 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
}
}
}
/// Check if definition matches a path
fn def_id_matches_path(tcx: TyCtxt<'_>, mut def_id: DefId, expected_path: &[&str]) -> bool {
let mut path = expected_path.iter().rev();
while let (Some(parent), Some(next_step)) = (tcx.opt_parent(def_id), path.next()) {
if !tcx.opt_item_name(def_id).map_or(false, |n| n.as_str() == *next_step) {
return false;
}
def_id = parent;
}
return true;
}