error[E0800]: cannot find type or const parameter `T` in this scope --> $DIR/bad-params.rs:1:34 | LL | fn missing() -> impl Sized + use {} | ^ not found in this scope | help: you might be missing a type parameter | LL | fn missing() -> impl Sized + use {} | +++ error[E0411]: cannot find type or const parameter `Self` in this scope --> $DIR/bad-params.rs:4:39 | LL | fn missing_self() -> impl Sized + use {} | ------------ ^^^^ `Self` is only available in impls, traits, and type definitions | | | `Self` not allowed in a function error[E0799]: expected type or const parameter, found function `hello` --> $DIR/bad-params.rs:13:32 | LL | fn hello() -> impl Sized + use {} | ^^^^^ not a type or const parameter error[E0799]: expected type or const parameter, found local variable `x` --> $DIR/bad-params.rs:16:35 | LL | fn arg(x: ()) -> impl Sized + use {} | ^ not a type or const parameter error[E0799]: `Self` can't be captured in `use<...>` precise captures list, since it is an alias --> $DIR/bad-params.rs:9:48 | LL | impl MyType { | ----------- `Self` is not a generic argument, but an alias to the type of the implementation LL | fn self_is_not_param() -> impl Sized + use {} | ^^^^ error: aborting due to 5 previous errors Some errors have detailed explanations: E0411, E0799, E0800. For more information about an error, try `rustc --explain E0411`.