From a134f1624cd011703378f5f7597854375d74e135 Mon Sep 17 00:00:00 2001
From: Nadrieril <nadrieril+git@gmail.com>
Date: Sat, 21 Oct 2023 23:04:17 +0200
Subject: [PATCH] Fix #117033

---
 compiler/rustc_mir_build/src/thir/pattern/usefulness.rs   | 3 +++
 tests/ui/rfcs/rfc-2008-non-exhaustive/omitted-patterns.rs | 7 +++++++
 2 files changed, 10 insertions(+)

diff --git a/compiler/rustc_mir_build/src/thir/pattern/usefulness.rs b/compiler/rustc_mir_build/src/thir/pattern/usefulness.rs
index a8cee5a61edb5..5218f772484fd 100644
--- a/compiler/rustc_mir_build/src/thir/pattern/usefulness.rs
+++ b/compiler/rustc_mir_build/src/thir/pattern/usefulness.rs
@@ -884,6 +884,9 @@ fn collect_nonexhaustive_missing_variants<'p, 'tcx>(
     cx: &MatchCheckCtxt<'p, 'tcx>,
     column: &[&DeconstructedPat<'p, 'tcx>],
 ) -> Vec<WitnessPat<'tcx>> {
+    if column.is_empty() {
+        return Vec::new();
+    }
     let ty = column[0].ty();
     let pcx = &PatCtxt { cx, ty, span: DUMMY_SP, is_top_level: false };
 
diff --git a/tests/ui/rfcs/rfc-2008-non-exhaustive/omitted-patterns.rs b/tests/ui/rfcs/rfc-2008-non-exhaustive/omitted-patterns.rs
index ecfeb3f9b98b0..e0a6051a81fab 100644
--- a/tests/ui/rfcs/rfc-2008-non-exhaustive/omitted-patterns.rs
+++ b/tests/ui/rfcs/rfc-2008-non-exhaustive/omitted-patterns.rs
@@ -251,3 +251,10 @@ fn main() {
 pub fn takes_non_exhaustive(_: NonExhaustiveEnum) {
     let _closure = |_: NonExhaustiveEnum| {};
 }
+
+// ICE #117033
+enum Void {}
+#[deny(non_exhaustive_omitted_patterns)]
+pub fn void(v: Void) -> ! {
+    match v {}
+}