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All five has_repr_attr agree + are correct

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Nathaniel Hamovitz 2021-10-18 15:33:11 -07:00
parent 3a41f226c5
commit d8bacf078a
1 changed files with 65 additions and 50 deletions
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115
clippy_lints/src/trailing_zero_sized_array_without_repr.rs
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@ -1,11 +1,15 @@
use clippy_utils::{diagnostics::{span_lint_and_help, span_lint_and_then, span_lint_and_sugg}, source::{indent_of, snippet}};
use clippy_utils::{
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::{Item, ItemKind};
use rustc_hir::{HirId, Item, ItemKind};
use rustc_lint::{LateContext, LateLintPass};
use rustc_middle::dep_graph::DepContext;
use rustc_middle::ty::Const;
use rustc_middle::ty::{self as ty_mod, Const, ReprFlags};
use rustc_session::{declare_lint_pass, declare_tool_lint};
use rustc_span::sym;
declare_clippy_lint! {
/// ### What it does
@ -38,48 +42,19 @@ declare_lint_pass!(TrailingZeroSizedArrayWithoutRepr => [TRAILING_ZERO_SIZED_ARR
impl<'tcx> LateLintPass<'tcx> for TrailingZeroSizedArrayWithoutRepr {
fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx Item<'tcx>) {
if is_struct_with_trailing_zero_sized_array(cx, item) {
// NOTE: This is to include attributes on the definition when we print the lint. If the convention
// is to not do that with struct definitions (I'm not sure), then this isn't necessary. (note: if
// you don't get rid of this, change `has_repr_attr` to `includes_repr_attr`).
let attrs = cx.tcx.get_attrs(item.def_id.to_def_id());
let first_attr = attrs.iter().min_by_key(|attr| attr.span.lo());
let lint_span = if let Some(first_attr) = first_attr {
first_attr.span.to(item.span)
} else {
item.span
};
if !has_repr_attr(cx, attrs) {
let suggestion_span = item.span.shrink_to_lo();
let indent = " ".repeat(indent_of(cx, item.span).unwrap_or(0));
span_lint_and_sugg(cx, TRAILING_ZERO_SIZED_ARRAY_WITHOUT_REPR, item.span, "trailing zero-sized array in a struct which is not marked with a `repr` attribute", "consider adding `#[repr(C)]` or another `repr` attribute", format!("#[repr(C)]\n{}", snippet(cx, item.span.shrink_to_lo().to(item.ident.span), "..")), Applicability::MaybeIncorrect);
// span_lint_and_then(
// cx,
// TRAILING_ZERO_SIZED_ARRAY_WITHOUT_REPR,
// item.span,
// "trailing zero-sized array in a struct which is not marked with a `repr` attribute",
// |diag| {
// let sugg = format!("#[repr(C)]\n{}", indent);
// let sugg2 = format!("#[repr(C)]\n{}", item.ident.span);
// diag.span_suggestion(item.span,
// "consider adding `#[repr(C)]` or another `repr` attribute",
// sugg2,
// Applicability::MaybeIncorrect);
// }
// );
// span_lint_and_help(
// cx,
// TRAILING_ZERO_SIZED_ARRAY_WITHOUT_REPR,
// lint_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",
// );
}
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",
// );
}
}
}
@ -108,12 +83,52 @@ fn is_struct_with_trailing_zero_sized_array(cx: &LateContext<'tcx>, item: &'tcx
}
}
fn has_repr_attr(cx: &LateContext<'tcx>, attrs: &[Attribute]) -> bool {
fn has_repr_attr(cx: &LateContext<'tcx>, item: &'tcx Item<'tcx>) -> 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;
// they're in the commit history if you want to look (or I can go find them).
let sess = cx.tcx.sess(); // are captured values in closures evaluated once or every time?
attrs
.iter()
.any(|attr| !rustc_attr::find_repr_attrs(sess, attr).is_empty())
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
}