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Auto merge of #10564 - asquared31415:cast_doesnt_wrap, r=giraffate

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make cast_possible_wrap work correctly for 16 bit {u,i}size

These changes make `cast_possible_wrap` aware of the different pointer widths and fixes the implementation to print the correct pointer widths.

Fixes #9337

changelog: `cast_possible_wrap` does not lint on `u8 as isize` or `usize as i8`, since these can never wrap.
`cast_possible_wrap` now properly considers 16 bit pointer size and prints the correct bit widths.
This commit is contained in:
bors 2023-06-06 23:54:27 +00:00
commit c8a056547b
4 changed files with 187 additions and 40 deletions
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8
tests/ui/cast.rs
View file

@ -41,6 +41,14 @@ fn main() {
1u32 as i32;
1u64 as i64;
1usize as isize;
1usize as i8; // should not wrap, usize is never 8 bits
1usize as i16; // wraps on 16 bit ptr size
1usize as i32; // wraps on 32 bit ptr size
1usize as i64; // wraps on 64 bit ptr size
1u8 as isize; // should not wrap, isize is never 8 bits
1u16 as isize; // wraps on 16 bit ptr size
1u32 as isize; // wraps on 32 bit ptr size
1u64 as isize; // wraps on 64 bit ptr size
// Test clippy::cast_sign_loss
1i32 as u32;
-1i32 as u32;

118
tests/ui/cast.stderr
View file

@ -215,20 +215,110 @@ error: casting `usize` to `isize` may wrap around the value
LL | 1usize as isize;
| ^^^^^^^^^^^^^^^
error: casting `i32` to `u32` may lose the sign of the value
error: casting `usize` to `i8` may truncate the value
--> $DIR/cast.rs:44:5
|
LL | 1usize as i8; // should not wrap, usize is never 8 bits
| ^^^^^^^^^^^^
|
= help: if this is intentional allow the lint with `#[allow(clippy::cast_possible_truncation)]` ...
help: ... or use `try_from` and handle the error accordingly
|
LL | i8::try_from(1usize); // should not wrap, usize is never 8 bits
| ~~~~~~~~~~~~~~~~~~~~
error: casting `usize` to `i16` may truncate the value
--> $DIR/cast.rs:45:5
|
LL | 1usize as i16; // wraps on 16 bit ptr size
| ^^^^^^^^^^^^^
|
= help: if this is intentional allow the lint with `#[allow(clippy::cast_possible_truncation)]` ...
help: ... or use `try_from` and handle the error accordingly
|
LL | i16::try_from(1usize); // wraps on 16 bit ptr size
| ~~~~~~~~~~~~~~~~~~~~~
error: casting `usize` to `i16` may wrap around the value on targets with 16-bit wide pointers
--> $DIR/cast.rs:45:5
|
LL | 1usize as i16; // wraps on 16 bit ptr size
| ^^^^^^^^^^^^^
|
= note: `usize` and `isize` may be as small as 16 bits on some platforms
= note: for more information see https://doc.rust-lang.org/reference/types/numeric.html#machine-dependent-integer-types
error: casting `usize` to `i32` may truncate the value on targets with 64-bit wide pointers
--> $DIR/cast.rs:46:5
|
LL | 1usize as i32; // wraps on 32 bit ptr size
| ^^^^^^^^^^^^^
|
= help: if this is intentional allow the lint with `#[allow(clippy::cast_possible_truncation)]` ...
help: ... or use `try_from` and handle the error accordingly
|
LL | i32::try_from(1usize); // wraps on 32 bit ptr size
| ~~~~~~~~~~~~~~~~~~~~~
error: casting `usize` to `i32` may wrap around the value on targets with 32-bit wide pointers
--> $DIR/cast.rs:46:5
|
LL | 1usize as i32; // wraps on 32 bit ptr size
| ^^^^^^^^^^^^^
error: casting `usize` to `i64` may wrap around the value on targets with 64-bit wide pointers
--> $DIR/cast.rs:47:5
|
LL | 1usize as i64; // wraps on 64 bit ptr size
| ^^^^^^^^^^^^^
error: casting `u16` to `isize` may wrap around the value on targets with 16-bit wide pointers
--> $DIR/cast.rs:49:5
|
LL | 1u16 as isize; // wraps on 16 bit ptr size
| ^^^^^^^^^^^^^
|
= note: `usize` and `isize` may be as small as 16 bits on some platforms
= note: for more information see https://doc.rust-lang.org/reference/types/numeric.html#machine-dependent-integer-types
error: casting `u32` to `isize` may wrap around the value on targets with 32-bit wide pointers
--> $DIR/cast.rs:50:5
|
LL | 1u32 as isize; // wraps on 32 bit ptr size
| ^^^^^^^^^^^^^
error: casting `u64` to `isize` may truncate the value on targets with 32-bit wide pointers
--> $DIR/cast.rs:51:5
|
LL | 1u64 as isize; // wraps on 64 bit ptr size
| ^^^^^^^^^^^^^
|
= help: if this is intentional allow the lint with `#[allow(clippy::cast_possible_truncation)]` ...
help: ... or use `try_from` and handle the error accordingly
|
LL | isize::try_from(1u64); // wraps on 64 bit ptr size
| ~~~~~~~~~~~~~~~~~~~~~
error: casting `u64` to `isize` may wrap around the value on targets with 64-bit wide pointers
--> $DIR/cast.rs:51:5
|
LL | 1u64 as isize; // wraps on 64 bit ptr size
| ^^^^^^^^^^^^^
error: casting `i32` to `u32` may lose the sign of the value
--> $DIR/cast.rs:54:5
|
LL | -1i32 as u32;
| ^^^^^^^^^^^^
error: casting `isize` to `usize` may lose the sign of the value
--> $DIR/cast.rs:48:5
--> $DIR/cast.rs:56:5
|
LL | -1isize as usize;
| ^^^^^^^^^^^^^^^^
error: casting `i64` to `i8` may truncate the value
--> $DIR/cast.rs:115:5
--> $DIR/cast.rs:123:5
|
LL | (-99999999999i64).min(1) as i8; // should be linted because signed
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -240,7 +330,7 @@ LL | i8::try_from((-99999999999i64).min(1)); // should be linted because sig
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
error: casting `u64` to `u8` may truncate the value
--> $DIR/cast.rs:127:5
--> $DIR/cast.rs:135:5
|
LL | 999999u64.clamp(0, 256) as u8; // should still be linted
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -252,7 +342,7 @@ LL | u8::try_from(999999u64.clamp(0, 256)); // should still be linted
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
error: casting `main::E2` to `u8` may truncate the value
--> $DIR/cast.rs:148:21
--> $DIR/cast.rs:156:21
|
LL | let _ = self as u8;
| ^^^^^^^^^^
@ -264,7 +354,7 @@ LL | let _ = u8::try_from(self);
| ~~~~~~~~~~~~~~~~~~
error: casting `main::E2::B` to `u8` will truncate the value
--> $DIR/cast.rs:149:21
--> $DIR/cast.rs:157:21
|
LL | let _ = Self::B as u8;
| ^^^^^^^^^^^^^
@ -272,7 +362,7 @@ LL | let _ = Self::B as u8;
= note: `-D clippy::cast-enum-truncation` implied by `-D warnings`
error: casting `main::E5` to `i8` may truncate the value
--> $DIR/cast.rs:185:21
--> $DIR/cast.rs:193:21
|
LL | let _ = self as i8;
| ^^^^^^^^^^
@ -284,13 +374,13 @@ LL | let _ = i8::try_from(self);
| ~~~~~~~~~~~~~~~~~~
error: casting `main::E5::A` to `i8` will truncate the value
--> $DIR/cast.rs:186:21
--> $DIR/cast.rs:194:21
|
LL | let _ = Self::A as i8;
| ^^^^^^^^^^^^^
error: casting `main::E6` to `i16` may truncate the value
--> $DIR/cast.rs:200:21
--> $DIR/cast.rs:208:21
|
LL | let _ = self as i16;
| ^^^^^^^^^^^
@ -302,7 +392,7 @@ LL | let _ = i16::try_from(self);
| ~~~~~~~~~~~~~~~~~~~
error: casting `main::E7` to `usize` may truncate the value on targets with 32-bit wide pointers
--> $DIR/cast.rs:215:21
--> $DIR/cast.rs:223:21
|
LL | let _ = self as usize;
| ^^^^^^^^^^^^^
@ -314,7 +404,7 @@ LL | let _ = usize::try_from(self);
| ~~~~~~~~~~~~~~~~~~~~~
error: casting `main::E10` to `u16` may truncate the value
--> $DIR/cast.rs:256:21
--> $DIR/cast.rs:264:21
|
LL | let _ = self as u16;
| ^^^^^^^^^^^
@ -326,7 +416,7 @@ LL | let _ = u16::try_from(self);
| ~~~~~~~~~~~~~~~~~~~
error: casting `u32` to `u8` may truncate the value
--> $DIR/cast.rs:264:13
--> $DIR/cast.rs:272:13
|
LL | let c = (q >> 16) as u8;
| ^^^^^^^^^^^^^^^
@ -338,7 +428,7 @@ LL | let c = u8::try_from(q >> 16);
| ~~~~~~~~~~~~~~~~~~~~~
error: casting `u32` to `u8` may truncate the value
--> $DIR/cast.rs:267:13
--> $DIR/cast.rs:275:13
|
LL | let c = (q / 1000) as u8;
| ^^^^^^^^^^^^^^^^
@ -349,5 +439,5 @@ help: ... or use `try_from` and handle the error accordingly
LL | let c = u8::try_from(q / 1000);
| ~~~~~~~~~~~~~~~~~~~~~~
error: aborting due to 41 previous errors
error: aborting due to 51 previous errors