92 lines
2.3 KiB
Rust
92 lines
2.3 KiB
Rust
#![warn(clippy::collapsible_match)]
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#![allow(
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clippy::needless_return,
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clippy::no_effect,
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clippy::single_match,
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clippy::needless_borrow
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)]
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fn lint_cases(opt_opt: Option<Option<u32>>, res_opt: Result<Option<u32>, String>) {
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// if guards on outer match
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{
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match res_opt {
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Ok(val) if make() => match val {
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//~^ ERROR: this `match` can be collapsed into the outer `match`
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Some(n) => foo(n),
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_ => return,
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},
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_ => return,
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}
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match res_opt {
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Ok(val) => match val {
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//~^ ERROR: this `match` can be collapsed into the outer `match`
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Some(n) => foo(n),
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_ => return,
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},
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_ if make() => return,
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_ => return,
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}
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}
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// macro
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{
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macro_rules! mac {
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($outer:expr => $pat:pat, $e:expr => $inner_pat:pat, $then:expr) => {
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match $outer {
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$pat => match $e {
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$inner_pat => $then,
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_ => return,
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},
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_ => return,
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}
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};
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}
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// Lint this since the patterns are not defined by the macro.
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// Allows the lint to work on if_chain! for example.
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// Fixing the lint requires knowledge of the specific macro, but we optimistically assume that
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// there is still a better way to write this.
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mac!(res_opt => Ok(val), val => Some(n), foo(n));
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}
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// deref reference value
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match Some(&[1]) {
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Some(s) => match *s {
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//~^ ERROR: this `match` can be collapsed into the outer `match`
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[n] => foo(n),
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_ => (),
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},
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_ => (),
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}
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// ref pattern and deref
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match Some(&[1]) {
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Some(ref s) => match s {
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//~^ ERROR: this `match` can be collapsed into the outer `match`
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[n] => foo(n),
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_ => (),
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},
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_ => (),
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}
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}
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fn no_lint() {
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// deref inner value (cannot pattern match with Vec)
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match Some(vec![1]) {
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Some(s) => match *s {
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[n] => foo(n),
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_ => (),
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},
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_ => (),
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}
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}
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fn make<T>() -> T {
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unimplemented!()
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}
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fn foo<T, U>(t: T) -> U {
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unimplemented!()
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}
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fn main() {}
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