src/test/ui/fn/fn-item-type.rs

   1 // Test that the types of distinct fn items are not compatible by
   2 // default. See also `run-pass/fn-item-type-*.rs`.
   3
   4 fn foo<T>(x: isize) -> isize { x * 2 }
   5 fn bar<T>(x: isize) -> isize { x * 4 }
   6
   7 fn eq<T>(x: T, y: T) { }
   8
   9 trait Foo { fn foo() { /* this is a default fn */ } }
  10 impl<T> Foo for T { /* `foo` is still default here */ }
  11
  12 fn main() {
  13     eq(foo::<u8>, bar::<u8>);
  14     //~^ ERROR mismatched types
  15     //~| expected fn item `fn(_) -> _ {foo::<u8>}`
  16     //~| found fn item `fn(_) -> _ {bar::<u8>}`
  17     //~| expected fn item, found a different fn item
  18     //~| different `fn` items always have unique types, even if their signatures are the same
  19     //~| change the expected type to be function pointer
  20     //~| if the expected type is due to type inference, cast the expected `fn` to a function pointer
  21
  22     eq(foo::<u8>, foo::<i8>);
  23     //~^ ERROR mismatched types
  24     //~| expected `u8`, found `i8`
  25     //~| different `fn` items always have unique types, even if their signatures are the same
  26     //~| change the expected type to be function pointer
  27     //~| if the expected type is due to type inference, cast the expected `fn` to a function pointer
  28
  29     eq(bar::<String>, bar::<Vec<u8>>);
  30     //~^ ERROR mismatched types
  31     //~| expected fn item `fn(_) -> _ {bar::<String>}`
  32     //~| found fn item `fn(_) -> _ {bar::<Vec<u8>>}`
  33     //~| expected struct `String`, found struct `Vec`
  34     //~| different `fn` items always have unique types, even if their signatures are the same
  35     //~| change the expected type to be function pointer
  36     //~| if the expected type is due to type inference, cast the expected `fn` to a function pointer
  37
  38     // Make sure we distinguish between trait methods correctly.
  39     eq(<u8 as Foo>::foo, <u16 as Foo>::foo);
  40     //~^ ERROR mismatched types
  41     //~| expected `u8`, found `u16`
  42     //~| different `fn` items always have unique types, even if their signatures are the same
  43     //~| change the expected type to be function pointer
  44     //~| if the expected type is due to type inference, cast the expected `fn` to a function pointer
  45
  46     eq(foo::<u8>, bar::<u8> as fn(isize) -> isize);
  47     //~^ ERROR mismatched types
  48     //~| expected fn item `fn(_) -> _ {foo::<u8>}`
  49     //~| found fn pointer `fn(_) -> _`
  50     //~| expected fn item, found fn pointer
  51     //~| change the expected type to be function pointer
  52     //~| if the expected type is due to type inference, cast the expected `fn` to a function pointer
  53
  54     eq(foo::<u8> as fn(isize) -> isize, bar::<u8>); // ok!
  55 }