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Also lint on cast/cast_mut and ptr::from_mut/ptr::from_ref

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This commit is contained in:
Urgau 2023-07-13 14:13:08 +02:00
parent 0b9529cca3
commit 4b3dadbe5a
4 changed files with 122 additions and 37 deletions
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54
compiler/rustc_lint/src/ptr_nulls.rs
View File

@ -31,25 +31,45 @@
declare_lint_pass!(PtrNullChecks => [USELESS_PTR_NULL_CHECKS]);
fn incorrect_check<'a>(cx: &LateContext<'a>, expr: &Expr<'_>) -> Option<PtrNullChecksDiag<'a>> {
let mut expr = expr.peel_blocks();
/// This function detects and returns the original expression from a series of consecutive casts,
/// ie. `(my_fn as *const _ as *mut _).cast_mut()` would return the expression for `my_fn`.
fn ptr_cast_chain<'a>(cx: &'a LateContext<'_>, mut e: &'a Expr<'a>) -> Option<&'a Expr<'a>> {
let mut had_at_least_one_cast = false;
while let ExprKind::Cast(cast_expr, cast_ty) = expr.kind
&& let TyKind::Ptr(_) = cast_ty.kind {
expr = cast_expr.peel_blocks();
had_at_least_one_cast = true;
}
if !had_at_least_one_cast {
None
} else {
let orig_ty = cx.typeck_results().expr_ty(expr);
if orig_ty.is_fn() {
Some(PtrNullChecksDiag::FnPtr)
} else if orig_ty.is_ref() {
Some(PtrNullChecksDiag::Ref { orig_ty, label: expr.span })
loop {
e = e.peel_blocks();
e = if let ExprKind::Cast(expr, t) = e.kind
&& let TyKind::Ptr(_) = t.kind {
had_at_least_one_cast = true;
expr
} else if let ExprKind::MethodCall(_, expr, [], _) = e.kind
&& let Some(def_id) = cx.typeck_results().type_dependent_def_id(e.hir_id)
&& matches!(cx.tcx.get_diagnostic_name(def_id), Some(sym::ptr_cast | sym::ptr_cast_mut)) {
had_at_least_one_cast = true;
expr
} else if let ExprKind::Call(path, [arg]) = e.kind
&& let ExprKind::Path(ref qpath) = path.kind
&& let Some(def_id) = cx.qpath_res(qpath, path.hir_id).opt_def_id()
&& matches!(cx.tcx.get_diagnostic_name(def_id), Some(sym::ptr_from_ref | sym::ptr_from_mut)) {
had_at_least_one_cast = true;
arg
} else if had_at_least_one_cast {
return Some(e);
} else {
None
}
return None;
};
}
}
fn incorrect_check<'a>(cx: &LateContext<'a>, expr: &Expr<'_>) -> Option<PtrNullChecksDiag<'a>> {
let expr = ptr_cast_chain(cx, expr)?;
let orig_ty = cx.typeck_results().expr_ty(expr);
if orig_ty.is_fn() {
Some(PtrNullChecksDiag::FnPtr)
} else if orig_ty.is_ref() {
Some(PtrNullChecksDiag::Ref { orig_ty, label: expr.span })
} else {
None
}
}

1
tests/ui/consts/ptr_is_null.rs
View File

@ -2,6 +2,7 @@
// check-pass
#![feature(const_ptr_is_null)]
#![allow(useless_ptr_null_checks)]
const FOO: &usize = &42;

16
tests/ui/lint/ptr_null_checks.rs
View File

@ -1,5 +1,9 @@
// check-pass
#![feature(ptr_from_ref)]
use std::ptr;
extern "C" fn c_fn() {}
fn static_i32() -> &'static i32 { &1 }
@ -21,6 +25,10 @@ fn main() {
//~^ WARN function pointers are not nullable
if (fn_ptr as *mut fn() as *const fn() as *const ()).is_null() {}
//~^ WARN function pointers are not nullable
if (fn_ptr as *mut fn() as *const fn()).cast_mut().is_null() {}
//~^ WARN function pointers are not nullable
if ((fn_ptr as *mut fn()).cast() as *const fn()).cast_mut().is_null() {}
//~^ WARN function pointers are not nullable
if (fn_ptr as fn() as *const ()).is_null() {}
//~^ WARN function pointers are not nullable
if (c_fn as *const fn()).is_null() {}
@ -29,8 +37,16 @@ fn main() {
// ---------------- References ------------------
if (&mut 8 as *mut i32).is_null() {}
//~^ WARN references are not nullable
if ptr::from_mut(&mut 8).is_null() {}
//~^ WARN references are not nullable
if (&8 as *const i32).is_null() {}
//~^ WARN references are not nullable
if ptr::from_ref(&8).is_null() {}
//~^ WARN references are not nullable
if ptr::from_ref(&8).cast_mut().is_null() {}
//~^ WARN references are not nullable
if (ptr::from_ref(&8).cast_mut() as *mut i32).is_null() {}
//~^ WARN references are not nullable
if (&8 as *const i32) == std::ptr::null() {}
//~^ WARN references are not nullable
let ref_num = &8;

88
tests/ui/lint/ptr_null_checks.stderr
View File

@ -1,5 +1,5 @@
warning: function pointers are not nullable, so checking them for null will always return false
--> $DIR/ptr_null_checks.rs:10:8
--> $DIR/ptr_null_checks.rs:14:8
|
LL | if (fn_ptr as *mut ()).is_null() {}
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -8,7 +8,7 @@ LL | if (fn_ptr as *mut ()).is_null() {}
= note: `#[warn(useless_ptr_null_checks)]` on by default
warning: function pointers are not nullable, so checking them for null will always return false
--> $DIR/ptr_null_checks.rs:12:8
--> $DIR/ptr_null_checks.rs:16:8
|
LL | if (fn_ptr as *const u8).is_null() {}
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -16,7 +16,7 @@ LL | if (fn_ptr as *const u8).is_null() {}
= help: wrap the function pointer inside an `Option` and use `Option::is_none` to check for null pointer value
warning: function pointers are not nullable, so checking them for null will always return false
--> $DIR/ptr_null_checks.rs:14:8
--> $DIR/ptr_null_checks.rs:18:8
|
LL | if (fn_ptr as *const ()) == std::ptr::null() {}
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -24,7 +24,7 @@ LL | if (fn_ptr as *const ()) == std::ptr::null() {}
= help: wrap the function pointer inside an `Option` and use `Option::is_none` to check for null pointer value
warning: function pointers are not nullable, so checking them for null will always return false
--> $DIR/ptr_null_checks.rs:16:8
--> $DIR/ptr_null_checks.rs:20:8
|
LL | if (fn_ptr as *mut ()) == std::ptr::null_mut() {}
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -32,7 +32,7 @@ LL | if (fn_ptr as *mut ()) == std::ptr::null_mut() {}
= help: wrap the function pointer inside an `Option` and use `Option::is_none` to check for null pointer value
warning: function pointers are not nullable, so checking them for null will always return false
--> $DIR/ptr_null_checks.rs:18:8
--> $DIR/ptr_null_checks.rs:22:8
|
LL | if (fn_ptr as *const ()) == (0 as *const ()) {}
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -40,7 +40,7 @@ LL | if (fn_ptr as *const ()) == (0 as *const ()) {}
= help: wrap the function pointer inside an `Option` and use `Option::is_none` to check for null pointer value
warning: function pointers are not nullable, so checking them for null will always return false
--> $DIR/ptr_null_checks.rs:20:8
--> $DIR/ptr_null_checks.rs:24:8
|
LL | if <*const _>::is_null(fn_ptr as *const ()) {}
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -48,7 +48,7 @@ LL | if <*const _>::is_null(fn_ptr as *const ()) {}
= help: wrap the function pointer inside an `Option` and use `Option::is_none` to check for null pointer value
warning: function pointers are not nullable, so checking them for null will always return false
--> $DIR/ptr_null_checks.rs:22:8
--> $DIR/ptr_null_checks.rs:26:8
|
LL | if (fn_ptr as *mut fn() as *const fn() as *const ()).is_null() {}
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -56,7 +56,23 @@ LL | if (fn_ptr as *mut fn() as *const fn() as *const ()).is_null() {}
= help: wrap the function pointer inside an `Option` and use `Option::is_none` to check for null pointer value
warning: function pointers are not nullable, so checking them for null will always return false
--> $DIR/ptr_null_checks.rs:24:8
--> $DIR/ptr_null_checks.rs:28:8
|
LL | if (fn_ptr as *mut fn() as *const fn()).cast_mut().is_null() {}
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= help: wrap the function pointer inside an `Option` and use `Option::is_none` to check for null pointer value
warning: function pointers are not nullable, so checking them for null will always return false
--> $DIR/ptr_null_checks.rs:30:8
|
LL | if ((fn_ptr as *mut fn()).cast() as *const fn()).cast_mut().is_null() {}
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= help: wrap the function pointer inside an `Option` and use `Option::is_none` to check for null pointer value
warning: function pointers are not nullable, so checking them for null will always return false
--> $DIR/ptr_null_checks.rs:32:8
|
LL | if (fn_ptr as fn() as *const ()).is_null() {}
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -64,7 +80,7 @@ LL | if (fn_ptr as fn() as *const ()).is_null() {}
= help: wrap the function pointer inside an `Option` and use `Option::is_none` to check for null pointer value
warning: function pointers are not nullable, so checking them for null will always return false
--> $DIR/ptr_null_checks.rs:26:8
--> $DIR/ptr_null_checks.rs:34:8
|
LL | if (c_fn as *const fn()).is_null() {}
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -72,7 +88,7 @@ LL | if (c_fn as *const fn()).is_null() {}
= help: wrap the function pointer inside an `Option` and use `Option::is_none` to check for null pointer value
warning: references are not nullable, so checking them for null will always return false
--> $DIR/ptr_null_checks.rs:30:8
--> $DIR/ptr_null_checks.rs:38:8
|
LL | if (&mut 8 as *mut i32).is_null() {}
| ^------^^^^^^^^^^^^^^^^^^^^^^^
@ -80,7 +96,15 @@ LL | if (&mut 8 as *mut i32).is_null() {}
| expression has type `&mut i32`
warning: references are not nullable, so checking them for null will always return false
--> $DIR/ptr_null_checks.rs:32:8
--> $DIR/ptr_null_checks.rs:40:8
|
LL | if ptr::from_mut(&mut 8).is_null() {}
| ^^^^^^^^^^^^^^------^^^^^^^^^^^
| |
| expression has type `&mut i32`
warning: references are not nullable, so checking them for null will always return false
--> $DIR/ptr_null_checks.rs:42:8
|
LL | if (&8 as *const i32).is_null() {}
| ^--^^^^^^^^^^^^^^^^^^^^^^^^^
@ -88,7 +112,31 @@ LL | if (&8 as *const i32).is_null() {}
| expression has type `&i32`
warning: references are not nullable, so checking them for null will always return false
--> $DIR/ptr_null_checks.rs:34:8
--> $DIR/ptr_null_checks.rs:44:8
|
LL | if ptr::from_ref(&8).is_null() {}
| ^^^^^^^^^^^^^^--^^^^^^^^^^^
| |
| expression has type `&i32`
warning: references are not nullable, so checking them for null will always return false
--> $DIR/ptr_null_checks.rs:46:8
|
LL | if ptr::from_ref(&8).cast_mut().is_null() {}
| ^^^^^^^^^^^^^^--^^^^^^^^^^^^^^^^^^^^^^
| |
| expression has type `&i32`
warning: references are not nullable, so checking them for null will always return false
--> $DIR/ptr_null_checks.rs:48:8
|
LL | if (ptr::from_ref(&8).cast_mut() as *mut i32).is_null() {}
| ^^^^^^^^^^^^^^^--^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
| |
| expression has type `&i32`
warning: references are not nullable, so checking them for null will always return false
--> $DIR/ptr_null_checks.rs:50:8
|
LL | if (&8 as *const i32) == std::ptr::null() {}
| ^--^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -96,7 +144,7 @@ LL | if (&8 as *const i32) == std::ptr::null() {}
| expression has type `&i32`
warning: references are not nullable, so checking them for null will always return false
--> $DIR/ptr_null_checks.rs:37:8
--> $DIR/ptr_null_checks.rs:53:8
|
LL | if (ref_num as *const i32) == std::ptr::null() {}
| ^-------^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -104,7 +152,7 @@ LL | if (ref_num as *const i32) == std::ptr::null() {}
| expression has type `&i32`
warning: references are not nullable, so checking them for null will always return false
--> $DIR/ptr_null_checks.rs:39:8
--> $DIR/ptr_null_checks.rs:55:8
|
LL | if (b"\0" as *const u8).is_null() {}
| ^-----^^^^^^^^^^^^^^^^^^^^^^^^
@ -112,7 +160,7 @@ LL | if (b"\0" as *const u8).is_null() {}
| expression has type `&[u8; 1]`
warning: references are not nullable, so checking them for null will always return false
--> $DIR/ptr_null_checks.rs:41:8
--> $DIR/ptr_null_checks.rs:57:8
|
LL | if ("aa" as *const str).is_null() {}
| ^----^^^^^^^^^^^^^^^^^^^^^^^^^
@ -120,7 +168,7 @@ LL | if ("aa" as *const str).is_null() {}
| expression has type `&str`
warning: references are not nullable, so checking them for null will always return false
--> $DIR/ptr_null_checks.rs:43:8
--> $DIR/ptr_null_checks.rs:59:8
|
LL | if (&[1, 2] as *const i32).is_null() {}
| ^-------^^^^^^^^^^^^^^^^^^^^^^^^^
@ -128,7 +176,7 @@ LL | if (&[1, 2] as *const i32).is_null() {}
| expression has type `&[i32; 2]`
warning: references are not nullable, so checking them for null will always return false
--> $DIR/ptr_null_checks.rs:45:8
--> $DIR/ptr_null_checks.rs:61:8
|
LL | if (&mut [1, 2] as *mut i32) == std::ptr::null_mut() {}
| ^-----------^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -136,7 +184,7 @@ LL | if (&mut [1, 2] as *mut i32) == std::ptr::null_mut() {}
| expression has type `&mut [i32; 2]`
warning: references are not nullable, so checking them for null will always return false
--> $DIR/ptr_null_checks.rs:47:8
--> $DIR/ptr_null_checks.rs:63:8
|
LL | if (static_i32() as *const i32).is_null() {}
| ^------------^^^^^^^^^^^^^^^^^^^^^^^^^
@ -144,12 +192,12 @@ LL | if (static_i32() as *const i32).is_null() {}
| expression has type `&i32`
warning: references are not nullable, so checking them for null will always return false
--> $DIR/ptr_null_checks.rs:49:8
--> $DIR/ptr_null_checks.rs:65:8
|
LL | if (&*{ static_i32() } as *const i32).is_null() {}
| ^------------------^^^^^^^^^^^^^^^^^^^^^^^^^
| |
| expression has type `&i32`
warning: 19 warnings emitted
warning: 25 warnings emitted