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add lint deref_nullptr detecting when a null ptr is dereferenced #83948

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Merged
merged 7 commits into from
Apr 14, 2021
Merged

add lint deref_nullptr detecting when a null ptr is dereferenced #83948

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3891009
add lint deref_nullptr
ABouttefeux Apr 6, 2021
c7bc41f
add test
ABouttefeux Apr 7, 2021
3d215bd
change documentation of lint
ABouttefeux Apr 7, 2021
0531ed0
fix lint doc
ABouttefeux Apr 8, 2021
79666c8
changes based on review
ABouttefeux Apr 9, 2021
c288414
add test offset of a field
ABouttefeux Apr 10, 2021
7f0f83a
remove redundant test
ABouttefeux Apr 10, 2021
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26 changes: 17 additions & 9 deletions src/test/ui/lint/lint-deref-nullptr.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -2,29 +2,37 @@

#![deny(deref_nullptr)]

use std::ptr;

struct Struct {
field: u8,
}

fn f() {
unsafe {
let a = 1;
let ub = *(a as *const i32);
let ub = *(0 as *const i32);
//~^ ERROR dereferencing a null pointer
let ub = *core::ptr::null::<i32>();
let ub = *ptr::null::<i32>();
//~^ ERROR dereferencing a null pointer
let ub = *ptr::null_mut::<i32>();
//~^ ERROR dereferencing a null pointer
let ub = *core::ptr::null_mut::<i32>();
let ub = *(ptr::null::<i16>() as *const i32);
//~^ ERROR dereferencing a null pointer
let ub = *(core::ptr::null::<i16>() as *const i32);
let ub = *(ptr::null::<i16>() as *mut i32 as *mut usize as *const u8);
//~^ ERROR dereferencing a null pointer
let ub = *(core::ptr::null::<i16>() as *mut i32 as *mut usize as *const u8);
let ub = &*ptr::null::<i32>();
//~^ ERROR dereferencing a null pointer
let ub = &*core::ptr::null::<i32>();
ptr::addr_of!(*ptr::null::<i32>());
//~^ ERROR dereferencing a null pointer
core::ptr::addr_of!(*core::ptr::null::<i32>());
ptr::addr_of_mut!(*ptr::null_mut::<i32>());
//~^ ERROR dereferencing a null pointer
std::ptr::addr_of_mut!(*core::ptr::null_mut::<i32>());
let ub = *ptr::null::<i32>();
//~^ ERROR dereferencing a null pointer
let ub = *std::ptr::null::<i32>();
let ub = *ptr::null_mut::<i32>();
//~^ ERROR dereferencing a null pointer
let ub = *std::ptr::null_mut::<i32>();
let offset = ptr::addr_of!((*ptr::null::<Struct>()).field);
//~^ ERROR dereferencing a null pointer
}
}
Expand Down
64 changes: 35 additions & 29 deletions src/test/ui/lint/lint-deref-nullptr.stderr
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Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
error: dereferencing a null pointer
--> $DIR/lint-deref-nullptr.rs:9:18
--> $DIR/lint-deref-nullptr.rs:15:18
|
LL | let ub = *(0 as *const i32);
| ^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed
Expand All @@ -11,58 +11,64 @@ LL | #![deny(deref_nullptr)]
| ^^^^^^^^^^^^^

error: dereferencing a null pointer
--> $DIR/lint-deref-nullptr.rs:11:18
--> $DIR/lint-deref-nullptr.rs:17:18
|
LL | let ub = *core::ptr::null::<i32>();
| ^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed
LL | let ub = *ptr::null::<i32>();
| ^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

error: dereferencing a null pointer
--> $DIR/lint-deref-nullptr.rs:13:18
--> $DIR/lint-deref-nullptr.rs:19:18
|
LL | let ub = *core::ptr::null_mut::<i32>();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed
LL | let ub = *ptr::null_mut::<i32>();
| ^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

error: dereferencing a null pointer
--> $DIR/lint-deref-nullptr.rs:15:18
--> $DIR/lint-deref-nullptr.rs:21:18
|
LL | let ub = *(core::ptr::null::<i16>() as *const i32);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed
LL | let ub = *(ptr::null::<i16>() as *const i32);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

error: dereferencing a null pointer
--> $DIR/lint-deref-nullptr.rs:17:18
--> $DIR/lint-deref-nullptr.rs:23:18
|
LL | let ub = *(ptr::null::<i16>() as *mut i32 as *mut usize as *const u8);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

error: dereferencing a null pointer
--> $DIR/lint-deref-nullptr.rs:25:19
|
LL | let ub = *(core::ptr::null::<i16>() as *mut i32 as *mut usize as *const u8);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed
LL | let ub = &*ptr::null::<i32>();
| ^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

error: dereferencing a null pointer
--> $DIR/lint-deref-nullptr.rs:19:19
--> $DIR/lint-deref-nullptr.rs:27:23
|
LL | let ub = &*core::ptr::null::<i32>();
| ^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed
LL | ptr::addr_of!(*ptr::null::<i32>());
| ^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

error: dereferencing a null pointer
--> $DIR/lint-deref-nullptr.rs:21:29
--> $DIR/lint-deref-nullptr.rs:29:27
|
LL | core::ptr::addr_of!(*core::ptr::null::<i32>());
| ^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed
LL | ptr::addr_of_mut!(*ptr::null_mut::<i32>());
| ^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

error: dereferencing a null pointer
--> $DIR/lint-deref-nullptr.rs:23:32
--> $DIR/lint-deref-nullptr.rs:31:18
|
LL | std::ptr::addr_of_mut!(*core::ptr::null_mut::<i32>());
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed
LL | let ub = *ptr::null::<i32>();
| ^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

error: dereferencing a null pointer
--> $DIR/lint-deref-nullptr.rs:25:18
--> $DIR/lint-deref-nullptr.rs:33:18
|
LL | let ub = *std::ptr::null::<i32>();
| ^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed
LL | let ub = *ptr::null_mut::<i32>();
| ^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

error: dereferencing a null pointer
--> $DIR/lint-deref-nullptr.rs:27:18
--> $DIR/lint-deref-nullptr.rs:35:36
|
LL | let ub = *std::ptr::null_mut::<i32>();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed
LL | let offset = ptr::addr_of!((*ptr::null::<Struct>()).field);
| ^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

error: aborting due to 10 previous errors
error: aborting due to 11 previous errors