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#![allow(unused_braces, unused_variables, dead_code)]
#![allow(clippy::collapsible_else_if, clippy::let_unit_value)]
#![warn(clippy::manual_let_else)]
// Ensure that we don't conflict with match -> if let lints
#![warn(clippy::single_match_else, clippy::single_match)]
fn f() -> Result<u32, u32> {
Ok(0)
}
fn g() -> Option<()> {
None
}
fn h() -> (Option<()>, Option<()>) {
(None, None)
}
enum Variant {
Foo,
Bar(u32),
Baz(u32),
}
fn build_enum() -> Variant {
Variant::Foo
}
fn main() {}
fn fire() {
let v = match g() {
Some(v_some) => v_some,
None => return,
};
let v = match g() {
Some(v_some) => v_some,
_ => return,
};
loop {
// More complex pattern for the identity arm and diverging arm
let v = match h() {
(Some(_), Some(_)) | (None, None) => continue,
(Some(v), None) | (None, Some(v)) => v,
};
// Custom enums are supported as long as the "else" arm is a simple _
let v = match build_enum() {
_ => continue,
Variant::Bar(v) | Variant::Baz(v) => v,
};
}
// There is a _ in the diverging arm
// TODO also support unused bindings aka _v
let v = match f() {
Ok(v) => v,
Err(_) => return,
};
// Err(()) is an allowed pattern
let v = match f().map_err(|_| ()) {
Ok(v) => v,
Err(()) => return,
};
let f = Variant::Bar(1);
let _value = match f {
Variant::Bar(_) | Variant::Baz(_) => (),
_ => return,
};
}
fn not_fire() {
// Multiple diverging arms
let v = match h() {
_ => panic!(),
(None, Some(_v)) => return,
(Some(v), None) => v,
};
// Multiple identity arms
let v = match h() {
_ => panic!(),
(None, Some(v)) => v,
(Some(v), None) => v,
};
// No diverging arm at all, only identity arms.
// This is no case for let else, but destructuring assignment.
let v = match f() {
Ok(v) => v,
Err(e) => e,
};
// The identity arm has a guard
let v = match g() {
Some(v) if g().is_none() => v,
_ => return,
};
// The diverging arm has a guard
let v = match f() {
Err(v) if v > 0 => panic!(),
Ok(v) | Err(v) => v,
};
// The diverging arm creates a binding
let v = match f() {
Ok(v) => v,
Err(e) => panic!("error: {e}"),
};
// Custom enum where the diverging arm
// explicitly mentions the variant
let v = match build_enum() {
Variant::Foo => return,
Variant::Bar(v) | Variant::Baz(v) => v,
};
// The custom enum is surrounded by an Err()
let v = match Err(build_enum()) {
Ok(v) | Err(Variant::Bar(v) | Variant::Baz(v)) => v,
Err(Variant::Foo) => return,
};
}
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