diff --git a/crates/hir-ty/src/diagnostics/expr.rs b/crates/hir-ty/src/diagnostics/expr.rs index b3128712dc..20b0da441d 100644 --- a/crates/hir-ty/src/diagnostics/expr.rs +++ b/crates/hir-ty/src/diagnostics/expr.rs @@ -11,7 +11,6 @@ use hir_def::{ItemContainerId, Lookup}; use hir_expand::name; use itertools::Itertools; use rustc_hash::FxHashSet; -use rustc_pattern_analysis::usefulness::{compute_match_usefulness, PlaceValidity}; use syntax::{ast, AstNode}; use tracing::debug; use triomphe::Arc; @@ -234,13 +233,7 @@ impl ExprValidator { return; } - let report = match compute_match_usefulness( - &cx, - m_arms.as_slice(), - scrut_ty.clone(), - PlaceValidity::ValidOnly, - None, - ) { + let report = match cx.compute_match_usefulness(m_arms.as_slice(), scrut_ty.clone()) { Ok(report) => report, Err(()) => return, }; @@ -282,13 +275,7 @@ impl ExprValidator { continue; } - let report = match compute_match_usefulness( - &cx, - &[match_arm], - ty.clone(), - PlaceValidity::ValidOnly, - None, - ) { + let report = match cx.compute_match_usefulness(&[match_arm], ty.clone()) { Ok(v) => v, Err(e) => { debug!(?e, "match usefulness error"); diff --git a/crates/hir-ty/src/diagnostics/match_check/pat_analysis.rs b/crates/hir-ty/src/diagnostics/match_check/pat_analysis.rs index 81ce51429c..f45beb4c92 100644 --- a/crates/hir-ty/src/diagnostics/match_check/pat_analysis.rs +++ b/crates/hir-ty/src/diagnostics/match_check/pat_analysis.rs @@ -8,6 +8,7 @@ use rustc_hash::FxHashMap; use rustc_pattern_analysis::{ constructor::{Constructor, ConstructorSet, VariantVisibility}, index::IdxContainer, + usefulness::{compute_match_usefulness, PlaceValidity, UsefulnessReport}, Captures, PatCx, PrivateUninhabitedField, }; use smallvec::{smallvec, SmallVec}; @@ -59,6 +60,18 @@ impl<'p> MatchCheckCtx<'p> { Self { module, body, db, exhaustive_patterns, min_exhaustive_patterns } } + pub(crate) fn compute_match_usefulness( + &self, + arms: &[MatchArm<'p>], + scrut_ty: Ty, + ) -> Result, ()> { + // FIXME: Determine place validity correctly. For now, err on the safe side. + let place_validity = PlaceValidity::MaybeInvalid; + // Measured to take ~100ms on modern hardware. + let complexity_limit = Some(500000); + compute_match_usefulness(self, arms, scrut_ty, place_validity, complexity_limit) + } + fn is_uninhabited(&self, ty: &Ty) -> bool { is_ty_uninhabited_from(ty, self.module, self.db) } @@ -465,7 +478,6 @@ impl<'p> PatCx for MatchCheckCtx<'p> { } fn complexity_exceeded(&self) -> Result<(), Self::Error> { - // FIXME(Nadrieril): make use of the complexity counter. Err(()) } } diff --git a/crates/ide-diagnostics/src/handlers/missing_match_arms.rs b/crates/ide-diagnostics/src/handlers/missing_match_arms.rs index 67daa172b2..045154614f 100644 --- a/crates/ide-diagnostics/src/handlers/missing_match_arms.rs +++ b/crates/ide-diagnostics/src/handlers/missing_match_arms.rs @@ -23,6 +23,7 @@ mod tests { }, DiagnosticsConfig, }; + use test_utils::skip_slow_tests; #[track_caller] fn check_diagnostics_no_bails(ra_fixture: &str) { @@ -1004,6 +1005,32 @@ fn f() { ); } + #[test] + fn exponential_match() { + if skip_slow_tests() { + return; + } + // Constructs a match where match checking takes exponential time. Ensures we bail early. + use std::fmt::Write; + let struct_arity = 50; + let mut code = String::new(); + write!(code, "struct BigStruct {{").unwrap(); + for i in 0..struct_arity { + write!(code, " field{i}: bool,").unwrap(); + } + write!(code, "}}").unwrap(); + write!(code, "fn big_match(s: BigStruct) {{").unwrap(); + write!(code, " match s {{").unwrap(); + for i in 0..struct_arity { + write!(code, " BigStruct {{ field{i}: true, ..}} => {{}},").unwrap(); + write!(code, " BigStruct {{ field{i}: false, ..}} => {{}},").unwrap(); + } + write!(code, " _ => {{}},").unwrap(); + write!(code, " }}").unwrap(); + write!(code, "}}").unwrap(); + check_diagnostics_no_bails(&code); + } + mod rust_unstable { use super::*;