diff options
Diffstat (limited to 'tests/ui/consts/const_in_pattern/warn_corner_cases.rs')
-rw-r--r-- | tests/ui/consts/const_in_pattern/warn_corner_cases.rs | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/tests/ui/consts/const_in_pattern/warn_corner_cases.rs b/tests/ui/consts/const_in_pattern/warn_corner_cases.rs new file mode 100644 index 000000000..15cf3c84d --- /dev/null +++ b/tests/ui/consts/const_in_pattern/warn_corner_cases.rs @@ -0,0 +1,41 @@ +// run-pass + +// This test is checking our logic for structural match checking by enumerating +// the different kinds of const expressions. This test is collecting cases where +// we have accepted the const expression as a pattern in the past but we want +// to begin warning the user that a future version of Rust may start rejecting +// such const expressions. + +// The specific corner cases we are exploring here are instances where the +// const-evaluator computes a value that *does* meet the conditions for +// structural-match, but the const expression itself has abstractions (like +// calls to const functions) that may fit better with a type-based analysis +// rather than a commitment to a specific value. + +#![warn(indirect_structural_match)] + +#[derive(Copy, Clone, Debug)] +struct NoDerive(#[allow(unused_tuple_struct_fields)] u32); + +// This impl makes `NoDerive` irreflexive. +impl PartialEq for NoDerive { fn eq(&self, _: &Self) -> bool { false } } +impl Eq for NoDerive { } + +fn main() { + const INDEX: Option<NoDerive> = [None, Some(NoDerive(10))][0]; + match None { Some(_) => panic!("whoops"), INDEX => dbg!(INDEX), }; + //~^ WARN must be annotated with `#[derive(PartialEq, Eq)]` + //~| WARN this was previously accepted + + const fn build() -> Option<NoDerive> { None } + const CALL: Option<NoDerive> = build(); + match None { Some(_) => panic!("whoops"), CALL => dbg!(CALL), }; + //~^ WARN must be annotated with `#[derive(PartialEq, Eq)]` + //~| WARN this was previously accepted + + impl NoDerive { const fn none() -> Option<NoDerive> { None } } + const METHOD_CALL: Option<NoDerive> = NoDerive::none(); + match None { Some(_) => panic!("whoops"), METHOD_CALL => dbg!(METHOD_CALL), }; + //~^ WARN must be annotated with `#[derive(PartialEq, Eq)]` + //~| WARN this was previously accepted +} |