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Rollup merge of #127283 - dingxiangfei2009:check-repr-transparent, r=davidtwco

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Reject SmartPointer constructions not serving the purpose

Tracking issue: #123430

With this PR we will reject a row of malformed `SmartPointer` implementor candidates.

cc `@Darksonn` `@davidtwco` for context.
This commit is contained in:
Matthias Krüger 2024-07-04 18:16:23 +02:00 • committed by GitHub
commit d27136fb29
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6 changed files with 159 additions and 4 deletions
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39
compiler/rustc_builtin_macros/src/deriving/smart_ptr.rs
View file

@ -3,8 +3,9 @@ use std::mem::swap;
use ast::HasAttrs;
use rustc_ast::{
self as ast, GenericArg, GenericBound, GenericParamKind, ItemKind, MetaItem,
TraitBoundModifiers,
TraitBoundModifiers, VariantData,
};
use rustc_attr as attr;
use rustc_expand::base::{Annotatable, ExtCtxt};
use rustc_span::symbol::{sym, Ident};
use rustc_span::Span;
@ -24,11 +25,43 @@ pub fn expand_deriving_smart_ptr(
_is_const: bool,
) {
let (name_ident, generics) = if let Annotatable::Item(aitem) = item
&& let ItemKind::Struct(_, g) = &aitem.kind
&& let ItemKind::Struct(struct_data, g) = &aitem.kind
{
let is_transparent = aitem.attrs.iter().any(|attr| {
attr::find_repr_attrs(cx.sess, attr)
.into_iter()
.any(|r| matches!(r, attr::ReprTransparent))
});
if !is_transparent {
cx.dcx()
.struct_span_err(
span,
"`SmartPointer` can only be derived on `struct`s with `#[repr(transparent)]`",
)
.emit();
return;
}
if !matches!(
struct_data,
VariantData::Struct { fields, recovered: _ } | VariantData::Tuple(fields, _)
if !fields.is_empty())
{
cx.dcx()
.struct_span_err(
span,
"`SmartPointer` can only be derived on `struct`s with at least one field",
)
.emit();
return;
}
(aitem.ident, g)
} else {
cx.dcx().struct_span_err(span, "`SmartPointer` can only be derived on `struct`s").emit();
cx.dcx()
.struct_span_err(
span,
"`SmartPointer` can only be derived on `struct`s with `#[repr(transparent)]`",
)
.emit();
return;
};