// Check that safe fns are not a subtype of unsafe fns. trait Foo { unsafe fn len(&self) -> u32; } impl Foo for u32 { fn len(&self) -> u32 { *self } //~^ ERROR method `len` has an incompatible type for trait //~| expected signature `unsafe fn(&_) -> _` //~| found signature `fn(&_) -> _` } fn main() { }