diff options
Diffstat (limited to 'compiler/rustc_pattern_analysis/src/rustc.rs')
| -rw-r--r-- | compiler/rustc_pattern_analysis/src/rustc.rs | 18 |
1 files changed, 12 insertions, 6 deletions
diff --git a/compiler/rustc_pattern_analysis/src/rustc.rs b/compiler/rustc_pattern_analysis/src/rustc.rs index 7c12f69f14c..050b48d082b 100644 --- a/compiler/rustc_pattern_analysis/src/rustc.rs +++ b/compiler/rustc_pattern_analysis/src/rustc.rs @@ -269,6 +269,7 @@ impl<'p, 'tcx: 'p> RustcPatCtxt<'p, 'tcx> { } _ => bug!("bad slice pattern {:?} {:?}", ctor, ty), }, + DerefPattern(pointee_ty) => reveal_and_alloc(cx, once(pointee_ty.inner())), Bool(..) | IntRange(..) | F16Range(..) | F32Range(..) | F64Range(..) | F128Range(..) | Str(..) | Opaque(..) | Never | NonExhaustive | Hidden | Missing | PrivateUninhabited | Wildcard => &[], @@ -296,7 +297,7 @@ impl<'p, 'tcx: 'p> RustcPatCtxt<'p, 'tcx> { } _ => bug!("Unexpected type for constructor `{ctor:?}`: {ty:?}"), }, - Ref => 1, + Ref | DerefPattern(_) => 1, Slice(slice) => slice.arity(), Bool(..) | IntRange(..) | F16Range(..) | F32Range(..) | F64Range(..) | F128Range(..) | Str(..) | Opaque(..) | Never | NonExhaustive | Hidden | Missing @@ -493,11 +494,15 @@ impl<'p, 'tcx: 'p> RustcPatCtxt<'p, 'tcx> { ), }; } - PatKind::DerefPattern { .. } => { - // FIXME(deref_patterns): At least detect that `box _` is irrefutable. - fields = vec![]; - arity = 0; - ctor = Opaque(OpaqueId::new()); + PatKind::DerefPattern { subpattern, .. } => { + // NB(deref_patterns): This assumes the deref pattern is matching on a trusted + // `DerefPure` type. If the `Deref` impl isn't trusted, exhaustiveness must take + // into account that multiple calls to deref may return different results. Hence + // multiple deref! patterns cannot be exhaustive together unless each is exhaustive + // by itself. + fields = vec![self.lower_pat(subpattern).at_index(0)]; + arity = 1; + ctor = DerefPattern(cx.reveal_opaque_ty(subpattern.ty)); } PatKind::Leaf { subpatterns } | PatKind::Variant { subpatterns, .. } => { match ty.kind() { @@ -874,6 +879,7 @@ impl<'p, 'tcx: 'p> RustcPatCtxt<'p, 'tcx> { print::write_ref_like(&mut s, pat.ty().inner(), &print(&pat.fields[0])).unwrap(); s } + DerefPattern(_) => format!("deref!({})", print(&pat.fields[0])), Slice(slice) => { let (prefix_len, has_dot_dot) = match slice.kind { SliceKind::FixedLen(len) => (len, false), |