// revisions: no_flag with_flag // [no_flag] check-pass // [with_flag] compile-flags: -Zextra-const-ub-checks #![feature(const_ptr_read)] use std::mem::transmute; const INVALID_BOOL: () = unsafe { let _x: bool = transmute(3u8); //[with_flag]~^ ERROR: evaluation of constant value failed //[with_flag]~| invalid value }; const INVALID_PTR_IN_INT: () = unsafe { let _x: usize = transmute(&3u8); //[with_flag]~^ ERROR: evaluation of constant value failed }; const INVALID_SLICE_TO_USIZE_TRANSMUTE: () = unsafe { let x: &[u8] = &[0; 32]; let _x: (usize, usize) = transmute(x); //[with_flag]~^ ERROR: evaluation of constant value failed }; const UNALIGNED_PTR: () = unsafe { let _x: &u32 = transmute(&[0u8; 4]); //[with_flag]~^ ERROR: evaluation of constant value failed //[with_flag]~| invalid value }; const UNALIGNED_READ: () = { INNER; //[with_flag]~ERROR evaluation of constant value failed // There is an error here but its span is in the standard library so we cannot match it... // so we have this in a *nested* const, such that the *outer* const fails to use it. const INNER: () = unsafe { let x = &[0u8; 4]; let ptr = x.as_ptr().cast::(); ptr.read(); }; }; fn main() {}