error: using `#![feature(effects)]` without enabling next trait solver globally | = note: the next trait solver must be enabled globally for the effects feature to work correctly = help: use `-Znext-solver` to enable warning: this function depends on never type fallback being `()` --> $DIR/unsupported.rs:20:9 | LL | fn opaque_ret() -> impl Trait { unimplemented!() } | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release! = note: for more information, see issue #123748 = help: specify the types explicitly note: in edition 2024, the requirement `!: opaque::Trait` will fail --> $DIR/unsupported.rs:20:28 | LL | fn opaque_ret() -> impl Trait { unimplemented!() } | ^^^^^^^^^^ = note: `#[warn(dependency_on_unit_never_type_fallback)]` on by default error[E0391]: cycle detected when computing type of `opaque::::{synthetic#0}` --> $DIR/unsupported.rs:27:25 | LL | reuse to_reuse::opaque_ret; | ^^^^^^^^^^ | note: ...which requires comparing an impl and trait method signature, inferring any hidden `impl Trait` types in the process... --> $DIR/unsupported.rs:27:25 | LL | reuse to_reuse::opaque_ret; | ^^^^^^^^^^ = note: ...which again requires computing type of `opaque::::{synthetic#0}`, completing the cycle note: cycle used when checking that `opaque::` is well-formed --> $DIR/unsupported.rs:26:5 | LL | impl ToReuse for u8 { | ^^^^^^^^^^^^^^^^^^^ = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information warning: this function depends on never type fallback being `()` --> $DIR/unsupported.rs:14:9 | LL | pub fn opaque_ret() -> impl Trait { unimplemented!() } | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release! = note: for more information, see issue #123748 = help: specify the types explicitly note: in edition 2024, the requirement `!: opaque::Trait` will fail --> $DIR/unsupported.rs:14:32 | LL | pub fn opaque_ret() -> impl Trait { unimplemented!() } | ^^^^^^^^^^ error[E0391]: cycle detected when computing type of `opaque::::{synthetic#0}` --> $DIR/unsupported.rs:30:24 | LL | reuse ToReuse::opaque_ret; | ^^^^^^^^^^ | note: ...which requires comparing an impl and trait method signature, inferring any hidden `impl Trait` types in the process... --> $DIR/unsupported.rs:30:24 | LL | reuse ToReuse::opaque_ret; | ^^^^^^^^^^ = note: ...which again requires computing type of `opaque::::{synthetic#0}`, completing the cycle note: cycle used when checking that `opaque::` is well-formed --> $DIR/unsupported.rs:29:5 | LL | impl ToReuse for u16 { | ^^^^^^^^^^^^^^^^^^^^ = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information error: recursive delegation is not supported yet --> $DIR/unsupported.rs:43:22 | LL | pub reuse to_reuse2::foo; | --- callee defined here ... LL | reuse to_reuse1::foo; | ^^^ error: delegation to a function with effect parameter is not supported yet --> $DIR/unsupported.rs:53:18 | LL | fn foo(); | --------- callee defined here ... LL | reuse Trait::foo; | ^^^ error: aborting due to 5 previous errors; 2 warnings emitted For more information about this error, try `rustc --explain E0391`.