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One more test + final tidying

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This commit is contained in:
Nathaniel Hamovitz 2021-10-18 17:41:27 -07:00
parent 6303d2d075
commit c654cc56da
3 changed files with 53 additions and 54 deletions
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55
clippy_lints/src/trailing_zero_sized_array_without_repr.rs
View file

@ -1,11 +1,7 @@
use clippy_utils::{
diagnostics::{span_lint_and_help, span_lint_and_sugg, span_lint_and_then},
source::{indent_of, snippet},
};
use rustc_errors::Applicability;
use clippy_utils::diagnostics::span_lint_and_help;
use rustc_hir::{HirId, Item, ItemKind};
use rustc_lint::{LateContext, LateLintPass};
use rustc_middle::ty::{Const, TyS};
use rustc_middle::ty::Const;
use rustc_session::{declare_lint_pass, declare_tool_lint};
use rustc_span::sym;
@ -40,54 +36,39 @@ 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>) {
dbg!(item.ident);
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,
&format!(
"consider annotating `{}` with `#[repr(C)]` or another `repr` attribute",
cx.tcx.def_path_str(item.def_id.to_def_id())
),
);
}
}
}
fn is_struct_with_trailing_zero_sized_array(cx: &LateContext<'tcx>, item: &'tcx Item<'tcx>) -> bool {
// TODO: when finalized, replace with an `if_chain`. I have it like this because my rust-analyzer
// doesn't work when it's an `if_chain`.
if_chain! {
// First check if last field is an array
if let ItemKind::Struct(data, _) = &item.kind;
if let Some(last_field) = data.fields().last();
if let rustc_hir::TyKind::Array(_, length) = last_field.ty.kind;
// First check if last field is an array
if let ItemKind::Struct(data, _) = &item.kind {
if let Some(last_field) = data.fields().last() {
if let rustc_hir::TyKind::Array(_, length) = last_field.ty.kind {
// Then check if that that array zero-sized
let length_ldid = cx.tcx.hir().local_def_id(length.hir_id);
let length = Const::from_anon_const(cx.tcx, length_ldid);
let length = length.try_eval_usize(cx.tcx, cx.param_env);
length == Some(0)
} else {
false
}
// Then check if that that array zero-sized
let length_ldid = cx.tcx.hir().local_def_id(length.hir_id);
let length = Const::from_anon_const(cx.tcx, length_ldid);
let length = length.try_eval_usize(cx.tcx, cx.param_env);
if let Some(length) = length;
then {
length == 0
} else {
false
}
} else {
false
}
}

8
tests/ui/trailing_zero_sized_array_without_repr.rs
View file

@ -46,6 +46,14 @@ struct ZeroSizedWithConstFunction {
last: [usize; compute_zero()],
}
const fn compute_zero_from_arg(x: usize) -> usize {
x - 1
}
struct ZeroSizedWithConstFunction2 {
field: i32,
last: [usize; compute_zero_from_arg(1)],
}
struct ZeroSizedArrayWrapper([usize; 0]);
struct TupleStruct(i32, [usize; 0]);

44
tests/ui/trailing_zero_sized_array_without_repr.stderr
View file

@ -8,7 +8,7 @@ LL | | }
| |_^
|
= note: `-D clippy::trailing-zero-sized-array-without-repr` implied by `-D warnings`
= help: consider annotating the struct definition with `#[repr(C)]` or another `repr` attribute
= help: consider annotating `RarelyUseful` with `#[repr(C)]` or another `repr` attribute
error: trailing zero-sized array in a struct which is not marked with a `repr` attribute
--> $DIR/trailing_zero_sized_array_without_repr.rs:11:1
@ -18,7 +18,7 @@ LL | | first_and_last: [usize; 0],
LL | | }
| |_^
|
= help: consider annotating the struct definition with `#[repr(C)]` or another `repr` attribute
= help: consider annotating `OnlyField` with `#[repr(C)]` or another `repr` attribute
error: trailing zero-sized array in a struct which is not marked with a `repr` attribute
--> $DIR/trailing_zero_sized_array_without_repr.rs:15:1
@ -29,19 +29,18 @@ LL | | last: [T; 0],
LL | | }
| |_^
|
= help: consider annotating the struct definition with `#[repr(C)]` or another `repr` attribute
= help: consider annotating `GenericArrayType` with `#[repr(C)]` or another `repr` attribute
error: trailing zero-sized array in a struct which is not marked with a `repr` attribute
--> $DIR/trailing_zero_sized_array_without_repr.rs:20:1
--> $DIR/trailing_zero_sized_array_without_repr.rs:21:1
|
LL | / #[must_use]
LL | | struct OnlyAnotherAttribute {
LL | / struct OnlyAnotherAttribute {
LL | | field: i32,
LL | | last: [usize; 0],
LL | | }
| |_^
|
= help: consider annotating the struct definition with `#[repr(C)]` or another `repr` attribute
= help: consider annotating `OnlyAnotherAttribute` with `#[repr(C)]` or another `repr` attribute
error: trailing zero-sized array in a struct which is not marked with a `repr` attribute
--> $DIR/trailing_zero_sized_array_without_repr.rs:29:1
@ -52,7 +51,7 @@ LL | | last: [usize; 0],
LL | | }
| |_^
|
= help: consider annotating the struct definition with `#[repr(C)]` or another `repr` attribute
= help: consider annotating `OnlyADeriveAttribute` with `#[repr(C)]` or another `repr` attribute
error: trailing zero-sized array in a struct which is not marked with a `repr` attribute
--> $DIR/trailing_zero_sized_array_without_repr.rs:35:1
@ -63,7 +62,7 @@ LL | | last: [usize; ZERO],
LL | | }
| |_^
|
= help: consider annotating the struct definition with `#[repr(C)]` or another `repr` attribute
= help: consider annotating `ZeroSizedWithConst` with `#[repr(C)]` or another `repr` attribute
error: trailing zero-sized array in a struct which is not marked with a `repr` attribute
--> $DIR/trailing_zero_sized_array_without_repr.rs:44:1
@ -74,26 +73,37 @@ LL | | last: [usize; compute_zero()],
LL | | }
| |_^
|
= help: consider annotating the struct definition with `#[repr(C)]` or another `repr` attribute
= help: consider annotating `ZeroSizedWithConstFunction` with `#[repr(C)]` or another `repr` attribute
error: trailing zero-sized array in a struct which is not marked with a `repr` attribute
--> $DIR/trailing_zero_sized_array_without_repr.rs:49:1
--> $DIR/trailing_zero_sized_array_without_repr.rs:52:1
|
LL | / struct ZeroSizedWithConstFunction2 {
LL | | field: i32,
LL | | last: [usize; compute_zero_from_arg(1)],
LL | | }
| |_^
|
= help: consider annotating `ZeroSizedWithConstFunction2` with `#[repr(C)]` or another `repr` attribute
error: trailing zero-sized array in a struct which is not marked with a `repr` attribute
--> $DIR/trailing_zero_sized_array_without_repr.rs:57:1
|
LL | struct ZeroSizedArrayWrapper([usize; 0]);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= help: consider annotating the struct definition with `#[repr(C)]` or another `repr` attribute
= help: consider annotating `ZeroSizedArrayWrapper` with `#[repr(C)]` or another `repr` attribute
error: trailing zero-sized array in a struct which is not marked with a `repr` attribute
--> $DIR/trailing_zero_sized_array_without_repr.rs:51:1
--> $DIR/trailing_zero_sized_array_without_repr.rs:59:1
|
LL | struct TupleStruct(i32, [usize; 0]);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= help: consider annotating the struct definition with `#[repr(C)]` or another `repr` attribute
= help: consider annotating `TupleStruct` with `#[repr(C)]` or another `repr` attribute
error: trailing zero-sized array in a struct which is not marked with a `repr` attribute
--> $DIR/trailing_zero_sized_array_without_repr.rs:53:1
--> $DIR/trailing_zero_sized_array_without_repr.rs:61:1
|
LL | / struct LotsOfFields {
LL | | f1: u32,
@ -104,7 +114,7 @@ LL | | last: [usize; 0],
LL | | }
| |_^
|
= help: consider annotating the struct definition with `#[repr(C)]` or another `repr` attribute
= help: consider annotating `LotsOfFields` with `#[repr(C)]` or another `repr` attribute
error: aborting due to 10 previous errors
error: aborting due to 11 previous errors