// run-pass #![feature(arbitrary_self_types)] use std::ptr; trait Foo { fn foo(self: *const Self) -> &'static str; unsafe fn bar(self: *const Self) -> i64; unsafe fn complicated(self: *const *const Self) -> i64 where Self: Sized { (*self).bar() } } impl Foo for i32 { fn foo(self: *const Self) -> &'static str { "I'm an i32!" } unsafe fn bar(self: *const Self) -> i64 { *self as i64 } } impl Foo for u32 { fn foo(self: *const Self) -> &'static str { "I'm a u32!" } unsafe fn bar(self: *const Self) -> i64 { *self as i64 } } fn main() { let null_i32 = ptr::null::() as *const dyn Foo; let null_u32 = ptr::null::() as *const dyn Foo; assert_eq!("I'm an i32!", null_i32.foo()); assert_eq!("I'm a u32!", null_u32.foo()); let valid_i32 = 5i32; let valid_i32_thin = &valid_i32 as *const i32; assert_eq!("I'm an i32!", valid_i32_thin.foo()); assert_eq!(5, unsafe { valid_i32_thin.bar() }); assert_eq!(5, unsafe { (&valid_i32_thin as *const *const i32).complicated() }); let valid_i32_fat = valid_i32_thin as *const dyn Foo; assert_eq!("I'm an i32!", valid_i32_fat.foo()); assert_eq!(5, unsafe { valid_i32_fat.bar() }); let valid_u32 = 18u32; let valid_u32_thin = &valid_u32 as *const u32; assert_eq!("I'm a u32!", valid_u32_thin.foo()); assert_eq!(18, unsafe { valid_u32_thin.bar() }); assert_eq!(18, unsafe { (&valid_u32_thin as *const *const u32).complicated() }); let valid_u32_fat = valid_u32_thin as *const dyn Foo; assert_eq!("I'm a u32!", valid_u32_fat.foo()); assert_eq!(18, unsafe { valid_u32_fat.bar() }); }