From 1a1815889164a2d99a4b0734f7a9df68120c9abe Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Le=C3=B3n=20Orell=20Valerian=20Liehr?= <me@fmease.dev>
Date: Sat, 12 Aug 2023 13:33:08 +0200
Subject: [PATCH] Don't crash when reporting nice region errors for generic
 const items

---
 .../nice_region_error/named_anon_conflict.rs  | 22 +++++--------------
 .../error_reporting/nice_region_error/util.rs |  2 +-
 .../reference-outlives-referent.rs            |  9 ++++++++
 .../reference-outlives-referent.stderr        | 20 +++++++++++++++++
 4 files changed, 36 insertions(+), 17 deletions(-)
 create mode 100644 tests/ui/generic-const-items/reference-outlives-referent.rs
 create mode 100644 tests/ui/generic-const-items/reference-outlives-referent.stderr

diff --git a/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/named_anon_conflict.rs b/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/named_anon_conflict.rs
index 4e13ec90228..07f04ec1e44 100644
--- a/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/named_anon_conflict.rs
+++ b/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/named_anon_conflict.rs
@@ -29,25 +29,15 @@ pub(super) fn try_report_named_anon_conflict(
         // version new_ty of its type where the anonymous region is replaced
         // with the named one.
         let (named, anon, anon_param_info, region_info) = if sub.has_name()
-            && self.tcx().is_suitable_region(sup).is_some()
-            && self.find_param_with_region(sup, sub).is_some()
+            && let Some(region_info) = self.tcx().is_suitable_region(sup)
+            && let Some(anon_param_info) = self.find_param_with_region(sup, sub)
         {
-            (
-                sub,
-                sup,
-                self.find_param_with_region(sup, sub).unwrap(),
-                self.tcx().is_suitable_region(sup).unwrap(),
-            )
+            (sub, sup, anon_param_info, region_info)
         } else if sup.has_name()
-            && self.tcx().is_suitable_region(sub).is_some()
-            && self.find_param_with_region(sub, sup).is_some()
+            && let Some(region_info) = self.tcx().is_suitable_region(sub)
+            && let Some(anon_param_info) = self.find_param_with_region(sub, sup)
         {
-            (
-                sup,
-                sub,
-                self.find_param_with_region(sub, sup).unwrap(),
-                self.tcx().is_suitable_region(sub).unwrap(),
-            )
+            (sup, sub, anon_param_info, region_info)
         } else {
             return None; // inapplicable
         };
diff --git a/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/util.rs b/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/util.rs
index 2775b5ded03..be6d1a3750c 100644
--- a/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/util.rs
+++ b/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/util.rs
@@ -64,7 +64,7 @@ pub fn find_param_with_region<'tcx>(
     let body_id = hir.maybe_body_owned_by(def_id)?;
 
     let owner_id = hir.body_owner(body_id);
-    let fn_decl = hir.fn_decl_by_hir_id(owner_id).unwrap();
+    let fn_decl = hir.fn_decl_by_hir_id(owner_id)?;
     let poly_fn_sig = tcx.fn_sig(id).instantiate_identity();
 
     let fn_sig = tcx.liberate_late_bound_regions(id, poly_fn_sig);
diff --git a/tests/ui/generic-const-items/reference-outlives-referent.rs b/tests/ui/generic-const-items/reference-outlives-referent.rs
new file mode 100644
index 00000000000..13e4eaac39f
--- /dev/null
+++ b/tests/ui/generic-const-items/reference-outlives-referent.rs
@@ -0,0 +1,9 @@
+// Test that we catch that the reference outlives the referent and we
+// successfully emit a diagnostic. Regression test for issue #114714.
+
+#![feature(generic_const_items)]
+#![allow(incomplete_features)]
+
+const Q<'a, 'b>: &'a &'b () = &&(); //~ ERROR reference has a longer lifetime than the data it references
+
+fn main() {}
diff --git a/tests/ui/generic-const-items/reference-outlives-referent.stderr b/tests/ui/generic-const-items/reference-outlives-referent.stderr
new file mode 100644
index 00000000000..2b57713b5c1
--- /dev/null
+++ b/tests/ui/generic-const-items/reference-outlives-referent.stderr
@@ -0,0 +1,20 @@
+error[E0491]: in type `&'a &'b ()`, reference has a longer lifetime than the data it references
+  --> $DIR/reference-outlives-referent.rs:7:18
+   |
+LL | const Q<'a, 'b>: &'a &'b () = &&();
+   |                  ^^^^^^^^^^
+   |
+note: the pointer is valid for the lifetime `'a` as defined here
+  --> $DIR/reference-outlives-referent.rs:7:9
+   |
+LL | const Q<'a, 'b>: &'a &'b () = &&();
+   |         ^^
+note: but the referenced data is only valid for the lifetime `'b` as defined here
+  --> $DIR/reference-outlives-referent.rs:7:13
+   |
+LL | const Q<'a, 'b>: &'a &'b () = &&();
+   |             ^^
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0491`.