diff --git a/src/test/ui/const-generics/projection-as-arg-const.rs b/src/test/ui/const-generics/projection-as-arg-const.rs new file mode 100644 index 00000000000..903548c75db --- /dev/null +++ b/src/test/ui/const-generics/projection-as-arg-const.rs @@ -0,0 +1,20 @@ +// This is currently not possible to use projections as const generics. +// More information about this available here: +// https://github.com/rust-lang/rust/pull/104443#discussion_r1029375633 + +pub trait Identity { + type Identity; +} + +impl<T> Identity for T { + type Identity = Self; +} + +pub fn foo<const X: <i32 as Identity>::Identity>() { +//~^ ERROR + assert!(X == 12); +} + +fn main() { + foo::<12>(); +} diff --git a/src/test/ui/const-generics/projection-as-arg-const.stderr b/src/test/ui/const-generics/projection-as-arg-const.stderr new file mode 100644 index 00000000000..803ed9c9597 --- /dev/null +++ b/src/test/ui/const-generics/projection-as-arg-const.stderr @@ -0,0 +1,11 @@ +error: `<i32 as Identity>::Identity` is forbidden as the type of a const generic parameter + --> $DIR/projection-as-arg-const.rs:13:21 + | +LL | pub fn foo<const X: <i32 as Identity>::Identity>() { + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | + = note: the only supported types are integers, `bool` and `char` + = help: more complex types are supported with `#![feature(adt_const_params)]` + +error: aborting due to previous error +