rust/tests/ui/collapsible_match2.rs

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2020-11-29 18:21:21 -06:00
#![warn(clippy::collapsible_match)]
#![allow(clippy::needless_return, clippy::no_effect, clippy::single_match)]
fn lint_cases(opt_opt: Option<Option<u32>>, res_opt: Result<Option<u32>, String>) {
// if guards on outer match
{
match res_opt {
Ok(val) if make() => match val {
Some(n) => foo(n),
_ => return,
},
_ => return,
}
match res_opt {
Ok(val) => match val {
Some(n) => foo(n),
_ => return,
},
_ if make() => return,
_ => return,
}
}
// macro
{
macro_rules! mac {
($outer:expr => $pat:pat, $e:expr => $inner_pat:pat, $then:expr) => {
match $outer {
$pat => match $e {
$inner_pat => $then,
_ => return,
},
_ => return,
}
};
}
// Lint this since the patterns are not defined by the macro.
// Allows the lint to work on if_chain! for example.
// Fixing the lint requires knowledge of the specific macro, but we optimistically assume that
// there is still a better way to write this.
mac!(res_opt => Ok(val), val => Some(n), foo(n));
}
}
fn make<T>() -> T {
unimplemented!()
}
fn foo<T, U>(t: T) -> U {
unimplemented!()
}
fn main() {}