diff options
| -rw-r--r-- | tests/ui/fn/fn_def_opaque_coercion_to_fn_ptr.rs | 57 | ||||
| -rw-r--r-- | tests/ui/fn/fn_def_opaque_coercion_to_fn_ptr.stderr | 77 |
2 files changed, 134 insertions, 0 deletions
diff --git a/tests/ui/fn/fn_def_opaque_coercion_to_fn_ptr.rs b/tests/ui/fn/fn_def_opaque_coercion_to_fn_ptr.rs new file mode 100644 index 00000000000..4f7be6811eb --- /dev/null +++ b/tests/ui/fn/fn_def_opaque_coercion_to_fn_ptr.rs @@ -0,0 +1,57 @@ +//! Test that coercing between function items of different functions works, +//! as long as their signatures match. The resulting value is a function pointer. + +#![feature(type_alias_impl_trait)] + +fn foo<T>(t: T) -> T { + t +} + +fn bar<T>(t: T) -> T { + t +} + +type F = impl Sized; + +fn f(a: F) { + let mut x = bar::<F>; + x = foo::<()>; //~ ERROR: mismatched types + x(a); + x(()); +} + +type I = impl Sized; + +fn i(a: I) { + let mut x = bar::<()>; + x = foo::<I>; //~ ERROR: mismatched types + x(a); + x(()); +} + +type J = impl Sized; + +fn j(a: J) { + let x = match true { + true => bar::<J>, + false => foo::<()>, //~ ERROR: incompatible types + }; + x(a); + x(()); +} + +fn k() -> impl Sized { + fn bind<T, F: FnOnce(T) -> T>(_: T, f: F) -> F { + f + } + let x = match true { + true => { + let f = foo; + bind(k(), f) + } + false => bar::<()>, //~ ERROR: incompatible types + }; + todo!() +} + +fn main() {} diff --git a/tests/ui/fn/fn_def_opaque_coercion_to_fn_ptr.stderr b/tests/ui/fn/fn_def_opaque_coercion_to_fn_ptr.stderr new file mode 100644 index 00000000000..ca01376ee49 --- /dev/null +++ b/tests/ui/fn/fn_def_opaque_coercion_to_fn_ptr.stderr @@ -0,0 +1,77 @@ +error[E0308]: mismatched types + --> $DIR/fn_def_opaque_coercion_to_fn_ptr.rs:18:9 + | +LL | type F = impl Sized; + | ---------- the expected opaque type +... +LL | let mut x = bar::<F>; + | -------- expected due to this value +LL | x = foo::<()>; + | ^^^^^^^^^ expected fn item, found a different fn item + | + = note: expected fn item `fn(F) -> F {bar::<F>}` + found fn item `fn(()) {foo::<()>}` + +error[E0308]: mismatched types + --> $DIR/fn_def_opaque_coercion_to_fn_ptr.rs:27:9 + | +LL | fn foo<T>(t: T) -> T { + | -------------------- function `foo` defined here +... +LL | type I = impl Sized; + | ---------- the found opaque type +... +LL | let mut x = bar::<()>; + | --------- expected due to this value +LL | x = foo::<I>; + | ^^^^^^^^ expected fn item, found a different fn item + | + = note: expected fn item `fn(()) {bar::<()>}` + found fn item `fn(I) -> I {foo::<I>}` +help: use parentheses to call this function + | +LL | x = foo::<I>(/* I */); + | +++++++++ + +error[E0308]: `match` arms have incompatible types + --> $DIR/fn_def_opaque_coercion_to_fn_ptr.rs:37:18 + | +LL | type J = impl Sized; + | ---------- the expected opaque type +... +LL | let x = match true { + | _____________- +LL | | true => bar::<J>, + | | -------- this is found to be of type `fn(J) -> J {bar::<J>}` +LL | | false => foo::<()>, + | | ^^^^^^^^^ expected opaque type, found `()` +LL | | }; + | |_____- `match` arms have incompatible types + | + = note: expected fn item `fn(J) -> J {bar::<J>}` + found fn item `fn(()) {foo::<()>}` + +error[E0308]: `match` arms have incompatible types + --> $DIR/fn_def_opaque_coercion_to_fn_ptr.rs:52:18 + | +LL | fn k() -> impl Sized { + | ---------- the expected opaque type +... +LL | let x = match true { + | _____________- +LL | | true => { +LL | | let f = foo; +LL | | bind(k(), f) + | | ------------ this is found to be of type `fn(impl Sized) -> impl Sized {foo::<impl Sized>}` +LL | | } +LL | | false => bar::<()>, + | | ^^^^^^^^^ expected opaque type, found `()` +LL | | }; + | |_____- `match` arms have incompatible types + | + = note: expected fn item `fn(impl Sized) -> impl Sized {foo::<impl Sized>}` + found fn item `fn(()) {bar::<()>}` + +error: aborting due to 4 previous errors + +For more information about this error, try `rustc --explain E0308`. |