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src/tools/clippy/tests/ui/transmutes_expressible_as_ptr_casts.fixed
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// run-rustfix | ||
#![warn(clippy::transmutes_expressible_as_ptr_casts)] | ||
// These two warnings currrently cover the cases transmutes_expressible_as_ptr_casts | ||
// would otherwise be responsible for | ||
#![warn(clippy::useless_transmute)] | ||
#![warn(clippy::transmute_ptr_to_ptr)] | ||
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use std::mem::transmute; | ||
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// rustc_typeck::check::cast contains documentation about when a cast `e as U` is | ||
// valid, which we quote from below. | ||
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fn main() { | ||
// We should see an error message for each transmute, and no error messages for | ||
// the casts, since the casts are the recommended fixes. | ||
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// e is an integer and U is *U_0, while U_0: Sized; addr-ptr-cast | ||
let ptr_i32_transmute = unsafe { | ||
-1 as *const i32 | ||
}; | ||
let ptr_i32 = -1isize as *const i32; | ||
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// e has type *T, U is *U_0, and either U_0: Sized ... | ||
let ptr_i8_transmute = unsafe { | ||
ptr_i32 as *const i8 | ||
}; | ||
let ptr_i8 = ptr_i32 as *const i8; | ||
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let slice_ptr = &[0,1,2,3] as *const [i32]; | ||
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// ... or pointer_kind(T) = pointer_kind(U_0); ptr-ptr-cast | ||
let ptr_to_unsized_transmute = unsafe { | ||
slice_ptr as *const [u16] | ||
}; | ||
let ptr_to_unsized = slice_ptr as *const [u16]; | ||
// TODO: We could try testing vtable casts here too, but maybe | ||
// we should wait until std::raw::TraitObject is stabilized? | ||
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// e has type *T and U is a numeric type, while T: Sized; ptr-addr-cast | ||
let usize_from_int_ptr_transmute = unsafe { | ||
ptr_i32 as usize | ||
}; | ||
let usize_from_int_ptr = ptr_i32 as usize; | ||
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let array_ref: &[i32; 4] = &[1,2,3,4]; | ||
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// e has type &[T; n] and U is *const T; array-ptr-cast | ||
let array_ptr_transmute = unsafe { | ||
array_ref as *const [i32; 4] | ||
}; | ||
let array_ptr = array_ref as *const [i32; 4]; | ||
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fn foo(_: usize) -> u8 { 42 } | ||
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// e is a function pointer type and U has type *T, while T: Sized; fptr-ptr-cast | ||
let usize_ptr_transmute = unsafe { | ||
foo as *const usize | ||
}; | ||
let usize_ptr_transmute = foo as *const usize; | ||
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// e is a function pointer type and U is an integer; fptr-addr-cast | ||
let usize_from_fn_ptr_transmute = unsafe { | ||
foo as usize | ||
}; | ||
let usize_from_fn_ptr = foo as *const usize; | ||
} | ||
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// If a ref-to-ptr cast of this form where the pointer type points to a type other | ||
// than the referenced type, calling `CastCheck::do_check` has been observed to | ||
// cause an ICE error message. `do_check` is currently called inside the | ||
// `transmutes_expressible_as_ptr_casts` check, but other, more specific lints | ||
// currently prevent it from being called in these cases. This test is meant to | ||
// fail if the ordering of the checks ever changes enough to cause these cases to | ||
// fall through into `do_check`. | ||
fn trigger_do_check_to_emit_error(in_param: &[i32; 1]) -> *const u8 { | ||
unsafe { in_param as *const [i32; 1] as *const u8 } | ||
} |