Add `pattern_complexity_limit` to `Limits`.

It's similar to the other limits, e.g. obtained via `get_limit`. So it
makes sense to handle it consistently with the other limits. We now use
`Limit`/`usize` in most places instead of `Option<usize>`, so we use
`Limit::new(usize::MAX)`/`usize::MAX` to emulate how `None` used to work.

The commit also adds `Limit::unlimited`.

4 files changed, 6 insertions, 4 deletions

diff --git a/compiler/rustc_pattern_analysis/tests/common/mod.rs b/compiler/rustc_pattern_analysis/tests/common/mod.rs
index cd697632d1b..23560ad6419 100644
--- a/compiler/rustc_pattern_analysis/tests/common/mod.rs
+++ b/compiler/rustc_pattern_analysis/tests/common/mod.rs
@@ -124,7 +124,7 @@ pub fn compute_match_usefulness<'p>(
     arms: &[MatchArm<'p, Cx>],
     ty: Ty,
     scrut_validity: PlaceValidity,
-    complexity_limit: Option<usize>,
+    complexity_limit: usize,
 ) -> Result<UsefulnessReport<'p, Cx>, ()> {
     init_tracing();
     rustc_pattern_analysis::usefulness::compute_match_usefulness(
diff --git a/compiler/rustc_pattern_analysis/tests/complexity.rs b/compiler/rustc_pattern_analysis/tests/complexity.rs
index 43b585bc533..abd1ec24d93 100644
--- a/compiler/rustc_pattern_analysis/tests/complexity.rs
+++ b/compiler/rustc_pattern_analysis/tests/complexity.rs
@@ -14,7 +14,7 @@ fn check(patterns: &[DeconstructedPat<Cx>], complexity_limit: usize) -> Result<(
     let ty = *patterns[0].ty();
     let arms: Vec<_> =
         patterns.iter().map(|pat| MatchArm { pat, has_guard: false, arm_data: () }).collect();
-    compute_match_usefulness(arms.as_slice(), ty, PlaceValidity::ValidOnly, Some(complexity_limit))
+    compute_match_usefulness(arms.as_slice(), ty, PlaceValidity::ValidOnly, complexity_limit)
         .map(|_report| ())
 }
 
diff --git a/compiler/rustc_pattern_analysis/tests/exhaustiveness.rs b/compiler/rustc_pattern_analysis/tests/exhaustiveness.rs
index 0d80042a850..61ce0fd11e7 100644
--- a/compiler/rustc_pattern_analysis/tests/exhaustiveness.rs
+++ b/compiler/rustc_pattern_analysis/tests/exhaustiveness.rs
@@ -14,7 +14,8 @@ fn check(patterns: Vec<DeconstructedPat<Cx>>) -> Vec<WitnessPat<Cx>> {
     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();
+        compute_match_usefulness(arms.as_slice(), ty, PlaceValidity::ValidOnly, usize::MAX)
+            .unwrap();
     report.non_exhaustiveness_witnesses
 }
 
diff --git a/compiler/rustc_pattern_analysis/tests/intersection.rs b/compiler/rustc_pattern_analysis/tests/intersection.rs
index a852056b6a6..45674338efd 100644
--- a/compiler/rustc_pattern_analysis/tests/intersection.rs
+++ b/compiler/rustc_pattern_analysis/tests/intersection.rs
@@ -14,7 +14,8 @@ fn check(patterns: Vec<DeconstructedPat<Cx>>) -> Vec<Vec<usize>> {
     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();
+        compute_match_usefulness(arms.as_slice(), ty, PlaceValidity::ValidOnly, usize::MAX)
+            .unwrap();
     report.arm_intersections.into_iter().map(|bitset| bitset.iter().collect()).collect()
 }