From 6721f9122e7139ce691ce87b226112c1ac9ecfd0 Mon Sep 17 00:00:00 2001
From: Wafarm <qinyy07@gmail.com>
Date: Sun, 18 Aug 2024 10:44:17 +0800
Subject: [PATCH] Check if enclosing body owner exists in
 `get_fn_id_for_return_block`

---
 compiler/rustc_middle/src/hir/map/mod.rs      | 18 +++++++---
 .../async-fn/recurse-ice-129215.rs            |  9 +++++
 .../async-fn/recurse-ice-129215.stderr        | 34 +++++++++++++++++++
 3 files changed, 57 insertions(+), 4 deletions(-)
 create mode 100644 tests/ui/async-await/async-fn/recurse-ice-129215.rs
 create mode 100644 tests/ui/async-await/async-fn/recurse-ice-129215.stderr

diff --git a/compiler/rustc_middle/src/hir/map/mod.rs b/compiler/rustc_middle/src/hir/map/mod.rs
index 0f85998204ccb..33f14ee6e1a07 100644
--- a/compiler/rustc_middle/src/hir/map/mod.rs
+++ b/compiler/rustc_middle/src/hir/map/mod.rs
@@ -246,14 +246,22 @@ impl<'hir> Map<'hir> {
         self.tcx.hir_node(hir_id).fn_sig()
     }
 
-    #[track_caller]
-    pub fn enclosing_body_owner(self, hir_id: HirId) -> LocalDefId {
+    pub fn opt_enclosing_body_owner(self, hir_id: HirId) -> Option<LocalDefId> {
         for (_, node) in self.parent_iter(hir_id) {
             if let Some((def_id, _)) = node.associated_body() {
-                return def_id;
+                return Some(def_id);
             }
         }
 
+        None
+    }
+
+    #[track_caller]
+    pub fn enclosing_body_owner(self, hir_id: HirId) -> LocalDefId {
+        if let Some(hir_id) = self.opt_enclosing_body_owner(hir_id) {
+            return hir_id;
+        }
+
         bug!("no `enclosing_body_owner` for hir_id `{}`", hir_id);
     }
 
@@ -554,7 +562,9 @@ impl<'hir> Map<'hir> {
     /// }
     /// ```
     pub fn get_fn_id_for_return_block(self, id: HirId) -> Option<HirId> {
-        let enclosing_body_owner = self.tcx.local_def_id_to_hir_id(self.enclosing_body_owner(id));
+        // Id may not have a owner if it's a fn itself
+        let enclosing_body_owner =
+            self.tcx.local_def_id_to_hir_id(self.opt_enclosing_body_owner(id)?);
 
         // Return `None` if the `id` expression is not the returned value of the enclosing body
         let mut iter = [id].into_iter().chain(self.parent_id_iter(id)).peekable();
diff --git a/tests/ui/async-await/async-fn/recurse-ice-129215.rs b/tests/ui/async-await/async-fn/recurse-ice-129215.rs
new file mode 100644
index 0000000000000..06a2d7be9efb5
--- /dev/null
+++ b/tests/ui/async-await/async-fn/recurse-ice-129215.rs
@@ -0,0 +1,9 @@
+//@ edition: 2021
+
+async fn a() {
+    //~^ ERROR `()` is not a future
+    //~| ERROR mismatched types
+    a() //~ ERROR `()` is not a future
+}
+
+fn main() {}
diff --git a/tests/ui/async-await/async-fn/recurse-ice-129215.stderr b/tests/ui/async-await/async-fn/recurse-ice-129215.stderr
new file mode 100644
index 0000000000000..98c7be2a5a3f2
--- /dev/null
+++ b/tests/ui/async-await/async-fn/recurse-ice-129215.stderr
@@ -0,0 +1,34 @@
+error[E0277]: `()` is not a future
+  --> $DIR/recurse-ice-129215.rs:6:5
+   |
+LL |     a()
+   |     ^^^ `()` is not a future
+   |
+   = help: the trait `Future` is not implemented for `()`
+
+error[E0277]: `()` is not a future
+  --> $DIR/recurse-ice-129215.rs:3:1
+   |
+LL | async fn a() {
+   | ^^^^^^^^^^^^ `()` is not a future
+   |
+   = help: the trait `Future` is not implemented for `()`
+
+error[E0308]: mismatched types
+  --> $DIR/recurse-ice-129215.rs:3:14
+   |
+LL |   async fn a() {
+   |  ______________^
+LL | |
+LL | |
+LL | |     a()
+LL | | }
+   | |_^ expected `()`, found `async` fn body
+   |
+   = note:    expected unit type `()`
+           found `async` fn body `{async fn body of a()}`
+
+error: aborting due to 3 previous errors
+
+Some errors have detailed explanations: E0277, E0308.
+For more information about an error, try `rustc --explain E0277`.