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Prefer expr_or_init over manual init detection

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This commit is contained in:
Urgau 2023-09-17 16:24:22 +02:00
parent 1f2bacf677
commit e577dcdd4d
4 changed files with 74 additions and 49 deletions
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2
compiler/rustc_lint/src/lib.rs
View file

@ -200,7 +200,7 @@ late_lint_methods!(
BoxPointers: BoxPointers, BoxPointers: BoxPointers,
PathStatements: PathStatements, PathStatements: PathStatements,
LetUnderscore: LetUnderscore, LetUnderscore: LetUnderscore,
InvalidReferenceCasting: InvalidReferenceCasting::default(), InvalidReferenceCasting: InvalidReferenceCasting,
// Depends on referenced function signatures in expressions // Depends on referenced function signatures in expressions
UnusedResults: UnusedResults, UnusedResults: UnusedResults,
NonUpperCaseGlobals: NonUpperCaseGlobals, NonUpperCaseGlobals: NonUpperCaseGlobals,

35
compiler/rustc_lint/src/reference_casting.rs
View file

@ -1,8 +1,7 @@
use rustc_ast::Mutability; use rustc_ast::Mutability;
use rustc_data_structures::fx::FxHashMap; use rustc_hir::{Expr, ExprKind, UnOp};
use rustc_hir::{def::Res, Expr, ExprKind, HirId, Local, QPath, StmtKind, UnOp};
use rustc_middle::ty::{self, TypeAndMut}; use rustc_middle::ty::{self, TypeAndMut};
use rustc_span::{sym, Span}; use rustc_span::sym;
use crate::{lints::InvalidReferenceCastingDiag, LateContext, LateLintPass, LintContext}; use crate::{lints::InvalidReferenceCastingDiag, LateContext, LateLintPass, LintContext};
@ -34,38 +33,18 @@ declare_lint! {
"casts of `&T` to `&mut T` without interior mutability" "casts of `&T` to `&mut T` without interior mutability"
} }
#[derive(Default)] declare_lint_pass!(InvalidReferenceCasting => [INVALID_REFERENCE_CASTING]);
pub struct InvalidReferenceCasting {
casted: FxHashMap<HirId, Span>,
}
impl_lint_pass!(InvalidReferenceCasting => [INVALID_REFERENCE_CASTING]);
impl<'tcx> LateLintPass<'tcx> for InvalidReferenceCasting { impl<'tcx> LateLintPass<'tcx> for InvalidReferenceCasting {
fn check_stmt(&mut self, cx: &LateContext<'tcx>, stmt: &'tcx rustc_hir::Stmt<'tcx>) {
let StmtKind::Local(local) = stmt.kind else {
return;
};
let Local { init: Some(init), els: None, .. } = local else {
return;
};
if is_cast_from_const_to_mut(cx, init) {
self.casted.insert(local.pat.hir_id, init.span);
}
}
fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) { fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) {
let Some((is_assignment, e)) = is_operation_we_care_about(cx, expr) else { let Some((is_assignment, e)) = is_operation_we_care_about(cx, expr) else {
return; return;
}; };
let orig_cast = if is_cast_from_const_to_mut(cx, e) { let init = cx.expr_or_init(e);
None
} else if let ExprKind::Path(QPath::Resolved(_, path)) = e.kind let orig_cast = if is_cast_from_const_to_mut(cx, init) {
&& let Res::Local(hir_id) = &path.res if init.span != e.span { Some(init.span) } else { None }
&& let Some(orig_cast) = self.casted.get(hir_id) {
Some(*orig_cast)
} else { } else {
return; return;
}; };

13
tests/ui/lint/reference_casting.rs
View file

@ -47,9 +47,19 @@ unsafe fn ref_to_mut() {
let deferred = (std::ptr::from_ref(num) as *const i32 as *const i32).cast_mut() as *mut i32; let deferred = (std::ptr::from_ref(num) as *const i32 as *const i32).cast_mut() as *mut i32;
let _num = &mut *deferred; let _num = &mut *deferred;
//~^ ERROR casting `&T` to `&mut T` is undefined behavior //~^ ERROR casting `&T` to `&mut T` is undefined behavior
let deferred_rebind = deferred;
let _num = &mut *deferred_rebind;
//~^ ERROR casting `&T` to `&mut T` is undefined behavior
let _num = &mut *(num as *const _ as usize as *mut i32); let _num = &mut *(num as *const _ as usize as *mut i32);
//~^ ERROR casting `&T` to `&mut T` is undefined behavior //~^ ERROR casting `&T` to `&mut T` is undefined behavior
static NUM: &'static i32 = &2;
let num = NUM as *const i32 as *mut i32;
let num = num;
let num = num;
let _num = &mut *num;
//~^ ERROR casting `&T` to `&mut T` is undefined behavior
unsafe fn generic_ref_cast_mut<T>(this: &T) -> &mut T { unsafe fn generic_ref_cast_mut<T>(this: &T) -> &mut T {
&mut *((this as *const _) as *mut _) &mut *((this as *const _) as *mut _)
//~^ ERROR casting `&T` to `&mut T` is undefined behavior //~^ ERROR casting `&T` to `&mut T` is undefined behavior
@ -94,6 +104,9 @@ unsafe fn assign_to_ref() {
let value = num as *const i32 as *mut i32; let value = num as *const i32 as *mut i32;
*value = 1; *value = 1;
//~^ ERROR assigning to `&T` is undefined behavior //~^ ERROR assigning to `&T` is undefined behavior
let value_rebind = value;
*value_rebind = 1;
//~^ ERROR assigning to `&T` is undefined behavior
*(num as *const i32).cast::<i32>().cast_mut() = 2; *(num as *const i32).cast::<i32>().cast_mut() = 2;
//~^ ERROR assigning to `&T` is undefined behavior //~^ ERROR assigning to `&T` is undefined behavior
*(num as *const _ as usize as *mut i32) = 2; *(num as *const _ as usize as *mut i32) = 2;

73
tests/ui/lint/reference_casting.stderr
View file

@ -112,7 +112,18 @@ LL | let _num = &mut *deferred;
= note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html> = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>
error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell` error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell`
--> $DIR/reference_casting.rs:50:16 --> $DIR/reference_casting.rs:51:16
|
LL | let deferred = (std::ptr::from_ref(num) as *const i32 as *const i32).cast_mut() as *mut i32;
| ---------------------------------------------------------------------------- casting happend here
...
LL | let _num = &mut *deferred_rebind;
| ^^^^^^^^^^^^^^^^^^^^^
|
= note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>
error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell`
--> $DIR/reference_casting.rs:53:16
| |
LL | let _num = &mut *(num as *const _ as usize as *mut i32); LL | let _num = &mut *(num as *const _ as usize as *mut i32);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -120,7 +131,18 @@ LL | let _num = &mut *(num as *const _ as usize as *mut i32);
= note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html> = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>
error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell` error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell`
--> $DIR/reference_casting.rs:54:9 --> $DIR/reference_casting.rs:60:16
|
LL | let num = NUM as *const i32 as *mut i32;
| ----------------------------- casting happend here
...
LL | let _num = &mut *num;
| ^^^^^^^^^
|
= note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>
error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell`
--> $DIR/reference_casting.rs:64:9
| |
LL | &mut *((this as *const _) as *mut _) LL | &mut *((this as *const _) as *mut _)
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -128,7 +150,7 @@ LL | &mut *((this as *const _) as *mut _)
= note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html> = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>
error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell` error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell`
--> $DIR/reference_casting.rs:59:18 --> $DIR/reference_casting.rs:69:18
| |
LL | unsafe { &mut *std::cell::UnsafeCell::raw_get(x as *const _ as *const _) } LL | unsafe { &mut *std::cell::UnsafeCell::raw_get(x as *const _ as *const _) }
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -136,7 +158,7 @@ LL | unsafe { &mut *std::cell::UnsafeCell::raw_get(x as *const _ as *con
= note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html> = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>
error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell` error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell`
--> $DIR/reference_casting.rs:64:18 --> $DIR/reference_casting.rs:74:18
| |
LL | unsafe { &mut *std::cell::UnsafeCell::raw_get(x as *const _ as *const _) } LL | unsafe { &mut *std::cell::UnsafeCell::raw_get(x as *const _ as *const _) }
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -144,7 +166,7 @@ LL | unsafe { &mut *std::cell::UnsafeCell::raw_get(x as *const _ as *con
= note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html> = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>
error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell` error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell`
--> $DIR/reference_casting.rs:74:5 --> $DIR/reference_casting.rs:84:5
| |
LL | *(a as *const _ as *mut _) = String::from("Replaced"); LL | *(a as *const _ as *mut _) = String::from("Replaced");
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -152,7 +174,7 @@ LL | *(a as *const _ as *mut _) = String::from("Replaced");
= note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html> = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>
error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell` error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell`
--> $DIR/reference_casting.rs:76:5 --> $DIR/reference_casting.rs:86:5
| |
LL | *(a as *const _ as *mut String) += " world"; LL | *(a as *const _ as *mut String) += " world";
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -160,7 +182,7 @@ LL | *(a as *const _ as *mut String) += " world";
= note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html> = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>
error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell` error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell`
--> $DIR/reference_casting.rs:78:5 --> $DIR/reference_casting.rs:88:5
| |
LL | *std::ptr::from_ref(num).cast_mut() += 1; LL | *std::ptr::from_ref(num).cast_mut() += 1;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -168,7 +190,7 @@ LL | *std::ptr::from_ref(num).cast_mut() += 1;
= note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html> = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>
error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell` error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell`
--> $DIR/reference_casting.rs:80:5 --> $DIR/reference_casting.rs:90:5
| |
LL | *std::ptr::from_ref({ num }).cast_mut() += 1; LL | *std::ptr::from_ref({ num }).cast_mut() += 1;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -176,7 +198,7 @@ LL | *std::ptr::from_ref({ num }).cast_mut() += 1;
= note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html> = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>
error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell` error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell`
--> $DIR/reference_casting.rs:82:5 --> $DIR/reference_casting.rs:92:5
| |
LL | *{ std::ptr::from_ref(num) }.cast_mut() += 1; LL | *{ std::ptr::from_ref(num) }.cast_mut() += 1;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -184,7 +206,7 @@ LL | *{ std::ptr::from_ref(num) }.cast_mut() += 1;
= note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html> = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>
error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell` error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell`
--> $DIR/reference_casting.rs:84:5 --> $DIR/reference_casting.rs:94:5
| |
LL | *(std::ptr::from_ref({ num }) as *mut i32) += 1; LL | *(std::ptr::from_ref({ num }) as *mut i32) += 1;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -192,7 +214,7 @@ LL | *(std::ptr::from_ref({ num }) as *mut i32) += 1;
= note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html> = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>
error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell` error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell`
--> $DIR/reference_casting.rs:86:5 --> $DIR/reference_casting.rs:96:5
| |
LL | *std::mem::transmute::<_, *mut i32>(num) += 1; LL | *std::mem::transmute::<_, *mut i32>(num) += 1;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -200,7 +222,7 @@ LL | *std::mem::transmute::<_, *mut i32>(num) += 1;
= note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html> = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>
error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell` error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell`
--> $DIR/reference_casting.rs:88:5 --> $DIR/reference_casting.rs:98:5
| |
LL | / std::ptr::write( LL | / std::ptr::write(
LL | | LL | |
@ -212,7 +234,7 @@ LL | | );
= note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html> = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>
error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell` error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell`
--> $DIR/reference_casting.rs:95:5 --> $DIR/reference_casting.rs:105:5
| |
LL | let value = num as *const i32 as *mut i32; LL | let value = num as *const i32 as *mut i32;
| ----------------------------- casting happend here | ----------------------------- casting happend here
@ -222,7 +244,18 @@ LL | *value = 1;
= note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html> = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>
error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell` error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell`
--> $DIR/reference_casting.rs:97:5 --> $DIR/reference_casting.rs:108:5
|
LL | let value = num as *const i32 as *mut i32;
| ----------------------------- casting happend here
...
LL | *value_rebind = 1;
| ^^^^^^^^^^^^^^^^^
|
= note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>
error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell`
--> $DIR/reference_casting.rs:110:5
| |
LL | *(num as *const i32).cast::<i32>().cast_mut() = 2; LL | *(num as *const i32).cast::<i32>().cast_mut() = 2;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -230,7 +263,7 @@ LL | *(num as *const i32).cast::<i32>().cast_mut() = 2;
= note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html> = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>
error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell` error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell`
--> $DIR/reference_casting.rs:99:5 --> $DIR/reference_casting.rs:112:5
| |
LL | *(num as *const _ as usize as *mut i32) = 2; LL | *(num as *const _ as usize as *mut i32) = 2;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -238,7 +271,7 @@ LL | *(num as *const _ as usize as *mut i32) = 2;
= note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html> = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>
error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell` error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell`
--> $DIR/reference_casting.rs:101:5 --> $DIR/reference_casting.rs:114:5
| |
LL | let value = num as *const i32 as *mut i32; LL | let value = num as *const i32 as *mut i32;
| ----------------------------- casting happend here | ----------------------------- casting happend here
@ -249,7 +282,7 @@ LL | std::ptr::write(value, 2);
= note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html> = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>
error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell` error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell`
--> $DIR/reference_casting.rs:103:5 --> $DIR/reference_casting.rs:116:5
| |
LL | let value = num as *const i32 as *mut i32; LL | let value = num as *const i32 as *mut i32;
| ----------------------------- casting happend here | ----------------------------- casting happend here
@ -260,7 +293,7 @@ LL | std::ptr::write_unaligned(value, 2);
= note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html> = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>
error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell` error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell`
--> $DIR/reference_casting.rs:105:5 --> $DIR/reference_casting.rs:118:5
| |
LL | let value = num as *const i32 as *mut i32; LL | let value = num as *const i32 as *mut i32;
| ----------------------------- casting happend here | ----------------------------- casting happend here
@ -271,12 +304,12 @@ LL | std::ptr::write_volatile(value, 2);
= note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html> = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>
error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell` error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell`
--> $DIR/reference_casting.rs:109:9 --> $DIR/reference_casting.rs:122:9
| |
LL | *(this as *const _ as *mut _) = a; LL | *(this as *const _ as *mut _) = a;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
| |
= note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html> = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>
error: aborting due to 32 previous errors error: aborting due to 35 previous errors