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This commit is contained in:
Nathaniel Hamovitz 2021-10-18 16:53:05 -07:00
parent d8bacf078a
commit 18c863dd0e
1 changed files with 26 additions and 61 deletions
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87
clippy_lints/src/trailing_zero_sized_array_without_repr.rs
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@ -2,12 +2,10 @@
diagnostics::{span_lint_and_help, span_lint_and_sugg, span_lint_and_then},
source::{indent_of, snippet},
};
use rustc_ast::Attribute;
use rustc_errors::Applicability;
use rustc_hir::{HirId, Item, ItemKind};
use rustc_lint::{LateContext, LateLintPass};
use rustc_middle::dep_graph::DepContext;
use rustc_middle::ty::{self as ty_mod, Const, ReprFlags};
use rustc_middle::ty::{Const, TyS};
use rustc_session::{declare_lint_pass, declare_tool_lint};
use rustc_span::sym;
@ -43,18 +41,28 @@
impl<'tcx> LateLintPass<'tcx> for TrailingZeroSizedArrayWithoutRepr {
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_attr(cx, item) {
eprintln!("consider yourself linted 😎");
// span_lint_and_help(
// cx,
// TRAILING_ZERO_SIZED_ARRAY_WITHOUT_REPR,
// item.span,
// "trailing zero-sized array in a struct which is not marked with a `repr`
// attribute",
// None,
// "consider annotating the struct definition with `#[repr(C)]` or another
// `repr` attribute",
// );
if is_struct_with_trailing_zero_sized_array(cx, item) && !has_repr_attr(cx, item.hir_id()) {
let help_msg = format!(
"consider annotating {} with `#[repr(C)]` or another `repr` attribute",
cx.tcx
.type_of(item.def_id)
.ty_adt_def()
.map(|adt_def| cx.tcx.def_path_str(adt_def.did))
.unwrap_or_else(
// I don't think this will ever be the case, since we made it through
// `is_struct_with_trailing_zero_sized_array`, but I don't feel comfortable putting an `unwrap`
|| "the struct definition".to_string()
)
);
span_lint_and_help(
cx,
TRAILING_ZERO_SIZED_ARRAY_WITHOUT_REPR,
item.span,
"trailing zero-sized array in a struct which is not marked with a `repr` attribute",
None,
&help_msg,
);
}
}
}
@ -83,52 +91,9 @@ fn is_struct_with_trailing_zero_sized_array(cx: &LateContext<'tcx>, item: &'tcx
}
}
fn has_repr_attr(cx: &LateContext<'tcx>, item: &'tcx Item<'tcx>) -> bool {
fn has_repr_attr(cx: &LateContext<'tcx>, hir_id: HirId) -> bool {
// NOTE: there's at least four other ways to do this but I liked this one the best. (All five agreed
// on all testcases (when i wrote this comment. I added a few since then).) Happy to use another;
// on all testcases.) Happy to use another;
// they're in the commit history if you want to look (or I can go find them).
let attrs1 = cx.tcx.hir().attrs(item.hir_id());
let attrs2 = cx.tcx.get_attrs(item.def_id.to_def_id());
let res11 = {
let sess = cx.tcx.sess(); // are captured values in closures evaluated once or every time?
attrs1
.iter()
.any(|attr| !rustc_attr::find_repr_attrs(sess, attr).is_empty())
};
let res12 = { attrs1.iter().any(|attr| attr.has_name(sym::repr)) };
let res21 = {
let sess = cx.tcx.sess(); // are captured values in closures evaluated once or every time?
attrs2
.iter()
.any(|attr| !rustc_attr::find_repr_attrs(sess, attr).is_empty())
};
let res22 = { attrs2.iter().any(|attr| attr.has_name(sym::repr)) };
let res_adt = {
let ty = cx.tcx.type_of(item.def_id.to_def_id());
if let ty_mod::Adt(adt, _) = ty.kind() {
if adt.is_struct() {
let repr = adt.repr;
let repr_attr = ReprFlags::IS_C | ReprFlags::IS_TRANSPARENT | ReprFlags::IS_SIMD | ReprFlags::IS_LINEAR;
repr.int.is_some() || repr.align.is_some() || repr.pack.is_some() || repr.flags.intersects(repr_attr)
} else {
false
}
} else {
false
}
};
let all_same = (res11 && res12 && res21 && res22 && res_adt) || (!res11 && !res12 && !res21 && !res22 && !res_adt);
dbg!((
(res11, res12, res21, res22, res_adt),
all_same,
));
res12
cx.tcx.hir().attrs(hir_id).iter().any(|attr| attr.has_name(sym::repr))
}