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Report an error if a lang item has the wrong number of generic arguments

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This commit is contained in:
Fabian Wolff 2021-05-15 19:53:16 +02:00
parent b439be03c9
commit 7217d767b2
12 changed files with 212 additions and 7 deletions
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88
compiler/rustc_passes/src/lang_items.rs
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@ -13,12 +13,13 @@ use crate::weak_lang_items;
use rustc_middle::middle::cstore::ExternCrate;
use rustc_middle::ty::TyCtxt;
use rustc_errors::struct_span_err;
use rustc_errors::{pluralize, struct_span_err};
use rustc_hir as hir;
use rustc_hir::def_id::{DefId, LOCAL_CRATE};
use rustc_hir::itemlikevisit::ItemLikeVisitor;
use rustc_hir::lang_items::{extract, ITEM_REFS};
use rustc_hir::{HirId, LangItem, LanguageItems, Target};
use rustc_span::Span;
use rustc_middle::ty::query::Providers;
@ -61,8 +62,7 @@ impl LanguageItemCollector<'tcx> {
match ITEM_REFS.get(&value).cloned() {
// Known lang item with attribute on correct target.
Some((item_index, expected_target)) if actual_target == expected_target => {
let def_id = self.tcx.hir().local_def_id(hir_id);
self.collect_item(item_index, def_id.to_def_id());
self.collect_item_extended(item_index, hir_id, span);
}
// Known lang item with attribute on incorrect target.
Some((_, expected_target)) => {
@ -100,11 +100,12 @@ impl LanguageItemCollector<'tcx> {
}
fn collect_item(&mut self, item_index: usize, item_def_id: DefId) {
let lang_item = LangItem::from_u32(item_index as u32).unwrap();
let name = lang_item.name();
// Check for duplicates.
if let Some(original_def_id) = self.items.items[item_index] {
if original_def_id != item_def_id {
let lang_item = LangItem::from_u32(item_index as u32).unwrap();
let name = lang_item.name();
let mut err = match self.tcx.hir().span_if_local(item_def_id) {
Some(span) => struct_span_err!(
self.tcx.sess,
@ -180,6 +181,83 @@ impl LanguageItemCollector<'tcx> {
self.items.groups[group as usize].push(item_def_id);
}
}
fn collect_item_extended(&mut self, item_index: usize, hir_id: HirId, span: Span) {
let item_def_id = self.tcx.hir().local_def_id(hir_id).to_def_id();
let lang_item = LangItem::from_u32(item_index as u32).unwrap();
let name = lang_item.name();
self.collect_item(item_index, item_def_id);
// Now check whether the lang_item has the expected number of generic
// arguments. Binary and indexing operations have one (for the RHS/index),
// unary operations have no generic arguments.
let expected_num = match lang_item {
LangItem::Add
| LangItem::Sub
| LangItem::Mul
| LangItem::Div
| LangItem::Rem
| LangItem::BitXor
| LangItem::BitAnd
| LangItem::BitOr
| LangItem::Shl
| LangItem::Shr
| LangItem::AddAssign
| LangItem::SubAssign
| LangItem::MulAssign
| LangItem::DivAssign
| LangItem::RemAssign
| LangItem::BitXorAssign
| LangItem::BitAndAssign
| LangItem::BitOrAssign
| LangItem::ShlAssign
| LangItem::ShrAssign
| LangItem::Index
| LangItem::IndexMut => Some(1),
LangItem::Neg | LangItem::Not | LangItem::Deref | LangItem::DerefMut => Some(0),
// FIXME: add more cases?
_ => None,
};
if let Some(expected_num) = expected_num {
let (actual_num, generics_span) = match self.tcx.hir().get(hir_id) {
hir::Node::Item(hir::Item {
kind: hir::ItemKind::Trait(_, _, generics, ..),
..
}) => (generics.params.len(), generics.span),
_ => bug!("op/index/deref lang item target is not a trait: {:?}", lang_item),
};
if expected_num != actual_num {
// We are issuing E0718 "incorrect target" here, because while the
// item kind of the target is correct, the target is still wrong
// because of the wrong number of generic arguments.
struct_span_err!(
self.tcx.sess,
span,
E0718,
"`{}` language item must be applied to a trait with {} generic argument{}",
name,
expected_num,
pluralize!(expected_num)
)
.span_label(
generics_span,
format!(
"this trait has {} generic argument{}, not {}",
actual_num,
pluralize!(actual_num),
expected_num
),
)
.emit();
}
}
}
}
/// Traverses and collects all the lang items in all crates.