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

70 lines
1.7 KiB
Rust

//! Test the computation of arm intersections.
use common::*;
use rustc_pattern_analysis::{pat::DeconstructedPat, usefulness::PlaceValidity, MatchArm};
#[macro_use]
mod common;
/// Analyze a match made of these patterns and returns the computed arm intersections.
fn check(patterns: Vec<DeconstructedPat<Cx>>) -> Vec<Vec<usize>> {
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.arm_intersections.into_iter().map(|bitset| bitset.iter().collect()).collect()
}
#[track_caller]
fn assert_intersects(patterns: Vec<DeconstructedPat<Cx>>, intersects: &[&[usize]]) {
let computed_intersects = check(patterns);
assert_eq!(computed_intersects, intersects);
}
#[test]
fn test_int_ranges() {
let ty = Ty::U8;
assert_intersects(
pats!(ty;
0..=100,
100..,
),
&[&[], &[0]],
);
assert_intersects(
pats!(ty;
0..=101,
100..,
),
&[&[], &[0]],
);
assert_intersects(
pats!(ty;
0..100,
100..,
),
&[&[], &[]],
);
}
#[test]
fn test_nested() {
let ty = Ty::Tuple(&[Ty::Bool; 2]);
assert_intersects(
pats!(ty;
(true, true),
(true, _),
(_, true),
),
&[&[], &[0], &[0, 1]],
);
// Here we shortcut because `(true, true)` is irrelevant, so we fail to detect the intersection.
assert_intersects(
pats!(ty;
(true, _),
(_, true),
),
&[&[], &[]],
);
}