From 906d2b172c936674b8fbf727c556e5b41df86ef1 Mon Sep 17 00:00:00 2001
From: Michael Goulet <michael@errs.io>
Date: Thu, 6 Jul 2023 05:39:39 +0000
Subject: [PATCH] Structurally normalize again for byte string lit pat checking

---
 compiler/rustc_hir_typeck/src/pat.rs                  |  4 ++--
 tests/ui/traits/new-solver/slice-match-byte-lit.rs    |  2 +-
 .../ui/traits/new-solver/slice-match-byte-lit.stderr  | 11 -----------
 3 files changed, 3 insertions(+), 14 deletions(-)
 delete mode 100644 tests/ui/traits/new-solver/slice-match-byte-lit.stderr

diff --git a/compiler/rustc_hir_typeck/src/pat.rs b/compiler/rustc_hir_typeck/src/pat.rs
index 96d03b471252f..275e35d4ba538 100644
--- a/compiler/rustc_hir_typeck/src/pat.rs
+++ b/compiler/rustc_hir_typeck/src/pat.rs
@@ -394,8 +394,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         let mut pat_ty = ty;
         if let hir::ExprKind::Lit(Spanned { node: ast::LitKind::ByteStr(..), .. }) = lt.kind {
             let expected = self.structurally_resolve_type(span, expected);
-            if let ty::Ref(_, inner_ty, _) = expected.kind()
-                && matches!(inner_ty.kind(), ty::Slice(_))
+            if let ty::Ref(_, inner_ty, _) = *expected.kind()
+                && self.try_structurally_resolve_type(span, inner_ty).is_slice()
             {
                 let tcx = self.tcx;
                 trace!(?lt.hir_id.local_id, "polymorphic byte string lit");
diff --git a/tests/ui/traits/new-solver/slice-match-byte-lit.rs b/tests/ui/traits/new-solver/slice-match-byte-lit.rs
index 5f9c0df645036..4f848062595da 100644
--- a/tests/ui/traits/new-solver/slice-match-byte-lit.rs
+++ b/tests/ui/traits/new-solver/slice-match-byte-lit.rs
@@ -1,5 +1,5 @@
 // compile-flags: -Ztrait-solver=next
-// known-bug: rust-lang/trait-system-refactor-initiative#38
+// check-pass
 
 fn test(s: &[u8]) {
     match &s[0..3] {
diff --git a/tests/ui/traits/new-solver/slice-match-byte-lit.stderr b/tests/ui/traits/new-solver/slice-match-byte-lit.stderr
deleted file mode 100644
index cd48a6d184339..0000000000000
--- a/tests/ui/traits/new-solver/slice-match-byte-lit.stderr
+++ /dev/null
@@ -1,11 +0,0 @@
-error[E0271]: type mismatch resolving `[u8; 3] <: <[u8] as Index<Range<usize>>>::Output`
-  --> $DIR/slice-match-byte-lit.rs:6:9
-   |
-LL |     match &s[0..3] {
-   |           -------- this expression has type `&<[u8] as Index<std::ops::Range<usize>>>::Output`
-LL |         b"uwu" => {}
-   |         ^^^^^^ types differ
-
-error: aborting due to previous error
-
-For more information about this error, try `rustc --explain E0271`.