rust/compiler/rustc_pattern_analysis/tests/exhaustiveness.rs
2024-03-19 02:22:43 +01:00

78 lines
1.8 KiB
Rust

//! Test exhaustiveness checking.
use common::*;
use rustc_pattern_analysis::{
pat::{DeconstructedPat, WitnessPat},
usefulness::PlaceValidity,
MatchArm,
};
#[macro_use]
mod common;
/// Analyze a match made of these patterns.
fn check(patterns: Vec<DeconstructedPat<Cx>>) -> Vec<WitnessPat<Cx>> {
let ty = *patterns[0].ty();
let arms: Vec<_> =
patterns.iter().map(|pat| MatchArm { pat, has_guard: false, arm_data: () }).collect();
let report =
compute_match_usefulness(arms.as_slice(), ty, PlaceValidity::ValidOnly, None).unwrap();
report.non_exhaustiveness_witnesses
}
#[track_caller]
fn assert_exhaustive(patterns: Vec<DeconstructedPat<Cx>>) {
let witnesses = check(patterns);
if !witnesses.is_empty() {
panic!("non-exaustive match: missing {witnesses:?}");
}
}
#[track_caller]
fn assert_non_exhaustive(patterns: Vec<DeconstructedPat<Cx>>) {
let witnesses = check(patterns);
assert!(!witnesses.is_empty())
}
#[test]
fn test_int_ranges() {
let ty = Ty::U8;
assert_exhaustive(pats!(ty;
0..=255,
));
assert_exhaustive(pats!(ty;
0..,
));
assert_non_exhaustive(pats!(ty;
0..255,
));
assert_exhaustive(pats!(ty;
0..255,
255,
));
assert_exhaustive(pats!(ty;
..10,
10..
));
}
#[test]
fn test_nested() {
let ty = Ty::BigStruct { arity: 2, ty: &Ty::BigEnum { arity: 2, ty: &Ty::Bool } };
assert_non_exhaustive(pats!(ty;
Struct(Variant.0, _),
));
assert_exhaustive(pats!(ty;
Struct(Variant.0, _),
Struct(Variant.1, _),
));
assert_non_exhaustive(pats!(ty;
Struct(Variant.0, _),
Struct(_, Variant.0),
));
assert_exhaustive(pats!(ty;
Struct(Variant.0, _),
Struct(_, Variant.0),
Struct(Variant.1, Variant.1),
));
}