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Ran dev bless!

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This commit is contained in:
Nathaniel Hamovitz
2021-10-16 02:26:08 -07:00
parent 4b4db59772
commit b9948c4be6
3 changed files with 147 additions and 41 deletions
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58
clippy_lints/src/trailing_zero_sized_array_without_repr_c.rs
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@@ -26,7 +26,7 @@ declare_clippy_lint! {
/// Use instead:
/// ```rust
/// #[repr(C)]
/// struct MakesSense {
/// struct MoreOftenUseful {
/// some_field: usize,
/// last: [SomeType; 0],
/// }
@@ -45,15 +45,13 @@ declare_lint_pass!(TrailingZeroSizedArrayWithoutReprC => [TRAILING_ZERO_SIZED_AR
impl<'tcx> LateLintPass<'tcx> for TrailingZeroSizedArrayWithoutReprC {
fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx Item<'tcx>) {
dbg!(item.ident);
if is_struct_with_trailing_zero_sized_array(cx, item) && !has_repr_c(cx, item.def_id) {
span_lint_and_sugg(
cx,
TRAILING_ZERO_SIZED_ARRAY_WITHOUT_REPR_C,
item.span,
"trailing zero-sized array in a struct which is not marked `#[repr(C)]`",
"try",
"try annotating the struct definition with `#[repr(C)]` (or another `repr` attribute):",
format!("#[repr(C)]\n{}", snippet(cx, item.span, "..")),
Applicability::MaybeIncorrect,
);
@@ -62,46 +60,40 @@ impl<'tcx> LateLintPass<'tcx> for TrailingZeroSizedArrayWithoutReprC {
}
fn is_struct_with_trailing_zero_sized_array(cx: &LateContext<'tcx>, item: &'tcx Item<'tcx>) -> bool {
if let ItemKind::Struct(data, _generics) = &item.kind {
if let VariantData::Struct(field_defs, _) = data {
if let Some(last_field) = field_defs.last() {
if let TyKind::Array(_, aconst) = last_field.ty.kind {
let aconst_def_id = cx.tcx.hir().body_owner_def_id(aconst.body).to_def_id();
let ty = cx.tcx.type_of(aconst_def_id);
let constant = cx
.tcx
// NOTE: maybe const_eval_resolve? seems especially cursed to be using a const expr which
// resolves to 0 to create a zero-sized array, tho
.const_eval_poly(aconst_def_id)
.ok()
.map(|val| rustc_middle::ty::Const::from_value(cx.tcx, val, ty));
if let Some(Constant::Int(val)) = constant.and_then(miri_to_const) {
if val == 0 {
// eprintln!("trailing: true");
return true;
}
}
}
}
if_chain! {
if let ItemKind::Struct(data, _generics) = &item.kind;
if let VariantData::Struct(field_defs, _) = data;
if let Some(last_field) = field_defs.last();
if let TyKind::Array(_, aconst) = last_field.ty.kind;
let aconst_def_id = cx.tcx.hir().body_owner_def_id(aconst.body).to_def_id();
let ty = cx.tcx.type_of(aconst_def_id);
let constant = cx
.tcx
// NOTE: maybe const_eval_resolve?
.const_eval_poly(aconst_def_id)
.ok()
.map(|val| rustc_middle::ty::Const::from_value(cx.tcx, val, ty));
if let Some(Constant::Int(val)) = constant.and_then(miri_to_const);
if val == 0;
then {
true
} else {
false
}
}
// dbg!(aconst);
// eprintln!("trailing: false");
false
}
fn has_repr_c(cx: &LateContext<'tcx>, def_id: LocalDefId) -> bool {
let hir_id = cx.tcx.hir().local_def_id_to_hir_id(def_id);
let attrs = cx.tcx.hir().attrs(hir_id);
let hir_map = cx.tcx.hir();
let hir_id = hir_map.local_def_id_to_hir_id(def_id);
let attrs = hir_map.attrs(hir_id);
// NOTE: Can there ever be more than one `repr` attribute?
// other `repr` syms: repr, repr128, repr_align, repr_align_enum, repr_no_niche, repr_packed,
// repr_simd, repr_transparent
if let Some(_repr_attr) = attrs.iter().find(|attr| attr.has_name(sym::repr)) {
// eprintln!("repr: true");
if let Some(_attr) = attrs.iter().find(|attr| attr.has_name(sym::repr)) {
true
} else {
// eprintln!("repr: false");
false
}
}