warning: this function depends on never type fallback being `()` --> $DIR/never-type-fallback-breaking.rs:18:1 | LL | fn m() { | ^^^^^^ | = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions! = note: for more information, see = help: specify the types explicitly note: in edition 2024, the requirement `!: Default` will fail --> $DIR/never-type-fallback-breaking.rs:22:17 | LL | true => Default::default(), | ^^^^^^^^^^^^^^^^^^ = note: `#[warn(dependency_on_unit_never_type_fallback)]` (part of `#[warn(rust_2024_compatibility)]`) on by default help: use `()` annotations to avoid fallback changes | LL | let x: () = match true { | ++++ warning: this function depends on never type fallback being `()` --> $DIR/never-type-fallback-breaking.rs:30:1 | LL | fn q() -> Option<()> { | ^^^^^^^^^^^^^^^^^^^^ | = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions! = note: for more information, see = help: specify the types explicitly note: in edition 2024, the requirement `!: Default` will fail --> $DIR/never-type-fallback-breaking.rs:37:5 | LL | deserialize()?; | ^^^^^^^^^^^^^ help: use `()` annotations to avoid fallback changes | LL | deserialize::<()>()?; | ++++++ warning: this function depends on never type fallback being `()` --> $DIR/never-type-fallback-breaking.rs:47:1 | LL | fn meow() -> Result<(), ()> { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ | = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions! = note: for more information, see = help: specify the types explicitly note: in edition 2024, the requirement `(): From` will fail --> $DIR/never-type-fallback-breaking.rs:50:5 | LL | help(1)?; | ^^^^^^^ help: use `()` annotations to avoid fallback changes | LL | help::<(), _>(1)?; | +++++++++ warning: this function depends on never type fallback being `()` --> $DIR/never-type-fallback-breaking.rs:59:1 | LL | pub fn fallback_return() -> Result<(), ()> { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions! = note: for more information, see = help: specify the types explicitly note: in edition 2024, the requirement `!: Default` will fail --> $DIR/never-type-fallback-breaking.rs:62:19 | LL | takes_apit(|| Default::default())?; | ^^^^^^^^^^^^^^^^^^ help: use `()` annotations to avoid fallback changes | LL | takes_apit::<()>(|| Default::default())?; | ++++++ warning: this function depends on never type fallback being `()` --> $DIR/never-type-fallback-breaking.rs:73:1 | LL | fn fully_apit() -> Result<(), ()> { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions! = note: for more information, see = help: specify the types explicitly note: in edition 2024, the requirement `!: Default` will fail --> $DIR/never-type-fallback-breaking.rs:76:17 | LL | takes_apit2(mk()?); | ^^^^^ help: use `()` annotations to avoid fallback changes | LL | takes_apit2(mk::<()>()?); | ++++++ warning: 5 warnings emitted Future incompatibility report: Future breakage diagnostic: warning: this function depends on never type fallback being `()` --> $DIR/never-type-fallback-breaking.rs:18:1 | LL | fn m() { | ^^^^^^ | = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions! = note: for more information, see = help: specify the types explicitly note: in edition 2024, the requirement `!: Default` will fail --> $DIR/never-type-fallback-breaking.rs:22:17 | LL | true => Default::default(), | ^^^^^^^^^^^^^^^^^^ = note: `#[warn(dependency_on_unit_never_type_fallback)]` (part of `#[warn(rust_2024_compatibility)]`) on by default help: use `()` annotations to avoid fallback changes | LL | let x: () = match true { | ++++ Future breakage diagnostic: warning: this function depends on never type fallback being `()` --> $DIR/never-type-fallback-breaking.rs:30:1 | LL | fn q() -> Option<()> { | ^^^^^^^^^^^^^^^^^^^^ | = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions! = note: for more information, see = help: specify the types explicitly note: in edition 2024, the requirement `!: Default` will fail --> $DIR/never-type-fallback-breaking.rs:37:5 | LL | deserialize()?; | ^^^^^^^^^^^^^ = note: `#[warn(dependency_on_unit_never_type_fallback)]` (part of `#[warn(rust_2024_compatibility)]`) on by default help: use `()` annotations to avoid fallback changes | LL | deserialize::<()>()?; | ++++++ Future breakage diagnostic: warning: this function depends on never type fallback being `()` --> $DIR/never-type-fallback-breaking.rs:47:1 | LL | fn meow() -> Result<(), ()> { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ | = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions! = note: for more information, see = help: specify the types explicitly note: in edition 2024, the requirement `(): From` will fail --> $DIR/never-type-fallback-breaking.rs:50:5 | LL | help(1)?; | ^^^^^^^ = note: `#[warn(dependency_on_unit_never_type_fallback)]` (part of `#[warn(rust_2024_compatibility)]`) on by default help: use `()` annotations to avoid fallback changes | LL | help::<(), _>(1)?; | +++++++++ Future breakage diagnostic: warning: this function depends on never type fallback being `()` --> $DIR/never-type-fallback-breaking.rs:59:1 | LL | pub fn fallback_return() -> Result<(), ()> { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions! = note: for more information, see = help: specify the types explicitly note: in edition 2024, the requirement `!: Default` will fail --> $DIR/never-type-fallback-breaking.rs:62:19 | LL | takes_apit(|| Default::default())?; | ^^^^^^^^^^^^^^^^^^ = note: `#[warn(dependency_on_unit_never_type_fallback)]` (part of `#[warn(rust_2024_compatibility)]`) on by default help: use `()` annotations to avoid fallback changes | LL | takes_apit::<()>(|| Default::default())?; | ++++++ Future breakage diagnostic: warning: this function depends on never type fallback being `()` --> $DIR/never-type-fallback-breaking.rs:73:1 | LL | fn fully_apit() -> Result<(), ()> { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions! = note: for more information, see = help: specify the types explicitly note: in edition 2024, the requirement `!: Default` will fail --> $DIR/never-type-fallback-breaking.rs:76:17 | LL | takes_apit2(mk()?); | ^^^^^ = note: `#[warn(dependency_on_unit_never_type_fallback)]` (part of `#[warn(rust_2024_compatibility)]`) on by default help: use `()` annotations to avoid fallback changes | LL | takes_apit2(mk::<()>()?); | ++++++