diff --git a/Cargo.lock b/Cargo.lock
index dc2bf3a7694..49f39537c01 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1470,12 +1470,12 @@ dependencies = [
 
 [[package]]
 name = "ra-ap-rustc_index"
-version = "0.36.0"
+version = "0.37.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f8a41dee58608b1fc93779ea365edaa70ac9927e3335ae914b675be0fa063cd7"
+checksum = "df5a0ba0d08af366cf235dbe8eb7226cced7a4fe502c98aa434ccf416defd746"
 dependencies = [
  "arrayvec",
- "ra-ap-rustc_index_macros 0.36.0",
+ "ra-ap-rustc_index_macros 0.37.0",
  "smallvec",
 ]
 
@@ -1493,9 +1493,9 @@ dependencies = [
 
 [[package]]
 name = "ra-ap-rustc_index_macros"
-version = "0.36.0"
+version = "0.37.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fbfe98def54c4337a2f7d8233850bd5d5349972b185fe8a0db2b979164b30ed8"
+checksum = "1971ebf9a701e0e68387c264a32517dcb4861ad3a4862f2e2803c1121ade20d5"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -1525,11 +1525,11 @@ dependencies = [
 
 [[package]]
 name = "ra-ap-rustc_pattern_analysis"
-version = "0.36.0"
+version = "0.37.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b5529bffec7530b4a3425640bfdfd9b95d87c4c620f740266c0de6572561aab4"
+checksum = "2c3c0e7ca9c5bdc66e3b590688e237a22ac47a48e4eac7f46b05b2abbfaf0abd"
 dependencies = [
- "ra-ap-rustc_index 0.36.0",
+ "ra-ap-rustc_index 0.37.0",
  "rustc-hash",
  "rustc_apfloat",
  "smallvec",
diff --git a/Cargo.toml b/Cargo.toml
index 2b81f7b11b2..49c7d369190 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -84,7 +84,7 @@ ra-ap-rustc_lexer = { version = "0.35.0", default-features = false }
 ra-ap-rustc_parse_format = { version = "0.35.0", default-features = false }
 ra-ap-rustc_index = { version = "0.35.0", default-features = false }
 ra-ap-rustc_abi = { version = "0.35.0", default-features = false }
-ra-ap-rustc_pattern_analysis = { version = "0.36.0", default-features = false }
+ra-ap-rustc_pattern_analysis = { version = "0.37.0", default-features = false }
 
 # local crates that aren't published to crates.io. These should not have versions.
 sourcegen = { path = "./crates/sourcegen" }
diff --git a/crates/hir-ty/src/diagnostics/expr.rs b/crates/hir-ty/src/diagnostics/expr.rs
index 7f8fb7f4b52..84070ee07b5 100644
--- a/crates/hir-ty/src/diagnostics/expr.rs
+++ b/crates/hir-ty/src/diagnostics/expr.rs
@@ -223,7 +223,7 @@ impl ExprValidator {
             ValidityConstraint::ValidOnly,
         ) {
             Ok(report) => report,
-            Err(void) => match void {},
+            Err(()) => return,
         };
 
         // FIXME Report unreachable arms
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 712842372b6..8d976894c83 100644
--- a/crates/hir-ty/src/diagnostics/match_check/pat_analysis.rs
+++ b/crates/hir-ty/src/diagnostics/match_check/pat_analysis.rs
@@ -26,7 +26,7 @@ use Constructor::*;
 
 // Re-export r-a-specific versions of all these types.
 pub(crate) type DeconstructedPat<'p> =
-    rustc_pattern_analysis::pat::DeconstructedPat<'p, MatchCheckCtx<'p>>;
+    rustc_pattern_analysis::pat::DeconstructedPat<MatchCheckCtx<'p>>;
 pub(crate) type MatchArm<'p> = rustc_pattern_analysis::MatchArm<'p, MatchCheckCtx<'p>>;
 pub(crate) type WitnessPat<'p> = rustc_pattern_analysis::pat::WitnessPat<MatchCheckCtx<'p>>;
 
@@ -131,15 +131,15 @@ impl<'p> MatchCheckCtx<'p> {
     }
 
     pub(crate) fn lower_pat(&self, pat: &Pat) -> DeconstructedPat<'p> {
-        let singleton = |pat| std::slice::from_ref(self.pattern_arena.alloc(pat));
+        let singleton = |pat| vec![pat];
         let ctor;
-        let fields: &[_];
+        let fields: Vec<_>;
 
         match pat.kind.as_ref() {
             PatKind::Binding { subpattern: Some(subpat), .. } => return self.lower_pat(subpat),
             PatKind::Binding { subpattern: None, .. } | PatKind::Wild => {
                 ctor = Wildcard;
-                fields = &[];
+                fields = Vec::new();
             }
             PatKind::Deref { subpattern } => {
                 ctor = match pat.ty.kind(Interner) {
@@ -157,7 +157,7 @@ impl<'p> MatchCheckCtx<'p> {
                 match pat.ty.kind(Interner) {
                     TyKind::Tuple(_, substs) => {
                         ctor = Struct;
-                        let mut wilds: SmallVec<[_; 2]> = substs
+                        let mut wilds: Vec<_> = substs
                             .iter(Interner)
                             .map(|arg| arg.assert_ty_ref(Interner).clone())
                             .map(DeconstructedPat::wildcard)
@@ -166,7 +166,7 @@ impl<'p> MatchCheckCtx<'p> {
                             let idx: u32 = pat.field.into_raw().into();
                             wilds[idx as usize] = self.lower_pat(&pat.pattern);
                         }
-                        fields = self.pattern_arena.alloc_extend(wilds)
+                        fields = wilds
                     }
                     TyKind::Adt(adt, substs) if is_box(self.db, adt.0) => {
                         // The only legal patterns of type `Box` (outside `std`) are `_` and box
@@ -216,33 +216,29 @@ impl<'p> MatchCheckCtx<'p> {
                                 field_id_to_id[field_idx as usize] = Some(i);
                                 ty
                             });
-                        let mut wilds: SmallVec<[_; 2]> =
-                            tys.map(DeconstructedPat::wildcard).collect();
+                        let mut wilds: Vec<_> = tys.map(DeconstructedPat::wildcard).collect();
                         for pat in subpatterns {
                             let field_idx: u32 = pat.field.into_raw().into();
                             if let Some(i) = field_id_to_id[field_idx as usize] {
                                 wilds[i] = self.lower_pat(&pat.pattern);
                             }
                         }
-                        fields = self.pattern_arena.alloc_extend(wilds);
+                        fields = wilds;
                     }
                     _ => {
                         never!("pattern has unexpected type: pat: {:?}, ty: {:?}", pat, &pat.ty);
                         ctor = Wildcard;
-                        fields = &[];
+                        fields = Vec::new();
                     }
                 }
             }
             &PatKind::LiteralBool { value } => {
                 ctor = Bool(value);
-                fields = &[];
+                fields = Vec::new();
             }
             PatKind::Or { pats } => {
                 ctor = Or;
-                // Collect here because `Arena::alloc_extend` panics on reentrancy.
-                let subpats: SmallVec<[_; 2]> =
-                    pats.iter().map(|pat| self.lower_pat(pat)).collect();
-                fields = self.pattern_arena.alloc_extend(subpats);
+                fields = pats.iter().map(|pat| self.lower_pat(pat)).collect();
             }
         }
         let data = PatData { db: self.db };
@@ -307,7 +303,7 @@ impl<'p> MatchCheckCtx<'p> {
 }
 
 impl<'p> TypeCx for MatchCheckCtx<'p> {
-    type Error = Void;
+    type Error = ();
     type Ty = Ty;
     type VariantIdx = EnumVariantId;
     type StrLit = Void;
@@ -463,7 +459,7 @@ impl<'p> TypeCx for MatchCheckCtx<'p> {
 
     fn write_variant_name(
         f: &mut fmt::Formatter<'_>,
-        pat: &rustc_pattern_analysis::pat::DeconstructedPat<'_, Self>,
+        pat: &rustc_pattern_analysis::pat::DeconstructedPat<Self>,
     ) -> fmt::Result {
         let variant =
             pat.ty().as_adt().and_then(|(adt, _)| Self::variant_id_for_adt(pat.ctor(), adt));
@@ -485,8 +481,8 @@ impl<'p> TypeCx for MatchCheckCtx<'p> {
         Ok(())
     }
 
-    fn bug(&self, fmt: fmt::Arguments<'_>) -> ! {
-        panic!("{}", fmt)
+    fn bug(&self, fmt: fmt::Arguments<'_>) {
+        never!("{}", fmt)
     }
 }