From 2bb00741d463143a10e632bb118d4ed336dbb75f Mon Sep 17 00:00:00 2001 From: Nadrieril Date: Sat, 19 Jul 2025 11:28:31 +0200 Subject: pattern_analysis: add option to get a full set of witnesses --- compiler/rustc_pattern_analysis/src/constructor.rs | 4 +--- compiler/rustc_pattern_analysis/src/lib.rs | 7 +++++++ compiler/rustc_pattern_analysis/src/usefulness.rs | 4 +++- 3 files changed, 11 insertions(+), 4 deletions(-) (limited to 'compiler/rustc_pattern_analysis/src') diff --git a/compiler/rustc_pattern_analysis/src/constructor.rs b/compiler/rustc_pattern_analysis/src/constructor.rs index 09685640e50..9a9e0db964c 100644 --- a/compiler/rustc_pattern_analysis/src/constructor.rs +++ b/compiler/rustc_pattern_analysis/src/constructor.rs @@ -950,9 +950,7 @@ impl Constructor { } } Never => write!(f, "!")?, - Wildcard | Missing | NonExhaustive | Hidden | PrivateUninhabited => { - write!(f, "_ : {:?}", ty)? - } + Wildcard | Missing | NonExhaustive | Hidden | PrivateUninhabited => write!(f, "_")?, } Ok(()) } diff --git a/compiler/rustc_pattern_analysis/src/lib.rs b/compiler/rustc_pattern_analysis/src/lib.rs index 66df35f9ee4..d9bb93a829b 100644 --- a/compiler/rustc_pattern_analysis/src/lib.rs +++ b/compiler/rustc_pattern_analysis/src/lib.rs @@ -57,6 +57,13 @@ pub trait PatCx: Sized + fmt::Debug { fn is_exhaustive_patterns_feature_on(&self) -> bool; + /// Whether to ensure the non-exhaustiveness witnesses we report for a complete set. This is + /// `false` by default to avoid some exponential blowup cases such as + /// . + fn exhaustive_witnesses(&self) -> bool { + false + } + /// The number of fields for this constructor. fn ctor_arity(&self, ctor: &Constructor, ty: &Self::Ty) -> usize; diff --git a/compiler/rustc_pattern_analysis/src/usefulness.rs b/compiler/rustc_pattern_analysis/src/usefulness.rs index b1c646e9884..91377b2f2bd 100644 --- a/compiler/rustc_pattern_analysis/src/usefulness.rs +++ b/compiler/rustc_pattern_analysis/src/usefulness.rs @@ -1747,7 +1747,9 @@ fn compute_exhaustiveness_and_usefulness<'a, 'p, Cx: PatCx>( // `ctor` is *irrelevant* if there's another constructor in `split_ctors` that matches // strictly fewer rows. In that case we can sometimes skip it. See the top of the file for // details. - let ctor_is_relevant = matches!(ctor, Constructor::Missing) || missing_ctors.is_empty(); + let ctor_is_relevant = matches!(ctor, Constructor::Missing) + || missing_ctors.is_empty() + || mcx.tycx.exhaustive_witnesses(); let mut spec_matrix = matrix.specialize_constructor(pcx, &ctor, ctor_is_relevant)?; let mut witnesses = ensure_sufficient_stack(|| { compute_exhaustiveness_and_usefulness(mcx, &mut spec_matrix) -- cgit 1.4.1-3-g733a5