From 2e691a5c12f4d96da6938f26cbf3de7d404edc87 Mon Sep 17 00:00:00 2001
From: Mohammad Omidvar <m_omidvart@sfu.ca>
Date: Wed, 14 Feb 2024 17:38:36 +0000
Subject: [PATCH] Rewrite foreign item kind query using `DefKind`

---
 compiler/rustc_smir/src/rustc_smir/context.rs | 34 +++++++------------
 compiler/stable_mir/src/compiler_interface.rs |  2 +-
 compiler/stable_mir/src/ty.rs                 |  2 +-
 tests/ui-fulldeps/stable-mir/check_foreign.rs |  2 +-
 4 files changed, 16 insertions(+), 24 deletions(-)

diff --git a/compiler/rustc_smir/src/rustc_smir/context.rs b/compiler/rustc_smir/src/rustc_smir/context.rs
index 24dd7ad6d7e..0d1424bbc0b 100644
--- a/compiler/rustc_smir/src/rustc_smir/context.rs
+++ b/compiler/rustc_smir/src/rustc_smir/context.rs
@@ -258,27 +258,19 @@ impl<'tcx> Context for TablesWrapper<'tcx> {
         tables.tcx.is_foreign_item(tables[item])
     }
 
-    fn foreign_item_kind(&self, def: ForeignDef) -> Option<ForeignItemKind> {
-        let (def_id, hir_kind) = {
-            let tables = self.0.borrow();
-            let def_id = tables[def.def_id()];
-            let hir_kind = tables
-                .tcx
-                .hir()
-                .expect_foreign_item(rustc_hir::OwnerId { def_id: def_id.as_local()? })
-                .kind;
-            (def_id, hir_kind)
-        };
-        let kind = match hir_kind {
-            rustc_hir::ForeignItemKind::Fn(..) => {
-                ForeignItemKind::Fn(self.0.borrow_mut().fn_def(def_id))
-            }
-            rustc_hir::ForeignItemKind::Static(..) => {
-                ForeignItemKind::Static(self.0.borrow_mut().static_def(def_id))
-            }
-            rustc_hir::ForeignItemKind::Type => ForeignItemKind::Type(self.def_ty(def.def_id())),
-        };
-        Some(kind)
+    fn foreign_item_kind(&self, def: ForeignDef) -> ForeignItemKind {
+        let mut tables = self.0.borrow_mut();
+        let def_id = tables[def.def_id()];
+        let tcx = tables.tcx;
+        use rustc_hir::def::DefKind;
+        match tcx.def_kind(def_id) {
+            DefKind::Fn => ForeignItemKind::Fn(tables.fn_def(def_id)),
+            DefKind::Static(..) => ForeignItemKind::Static(tables.static_def(def_id)),
+            DefKind::ForeignTy => ForeignItemKind::Type(
+                tables.intern_ty(rustc_middle::ty::Ty::new_foreign(tcx, def_id)),
+            ),
+            def_kind => unreachable!("Unexpected kind for a foreign item: {:?}", def_kind),
+        }
     }
 
     fn adt_kind(&self, def: AdtDef) -> AdtKind {
diff --git a/compiler/stable_mir/src/compiler_interface.rs b/compiler/stable_mir/src/compiler_interface.rs
index f55e0f9481f..59c79ddf8da 100644
--- a/compiler/stable_mir/src/compiler_interface.rs
+++ b/compiler/stable_mir/src/compiler_interface.rs
@@ -71,7 +71,7 @@ pub trait Context {
     fn is_foreign_item(&self, item: DefId) -> bool;
 
     /// Returns the kind of a given foreign item.
-    fn foreign_item_kind(&self, def: ForeignDef) -> Option<ForeignItemKind>;
+    fn foreign_item_kind(&self, def: ForeignDef) -> ForeignItemKind;
 
     /// Returns the kind of a given algebraic data type
     fn adt_kind(&self, def: AdtDef) -> AdtKind;
diff --git a/compiler/stable_mir/src/ty.rs b/compiler/stable_mir/src/ty.rs
index f043ce9d898..658e8aa28b5 100644
--- a/compiler/stable_mir/src/ty.rs
+++ b/compiler/stable_mir/src/ty.rs
@@ -566,7 +566,7 @@ crate_def! {
 }
 
 impl ForeignDef {
-    pub fn kind(&self) -> Option<ForeignItemKind> {
+    pub fn kind(&self) -> ForeignItemKind {
         with(|cx| cx.foreign_item_kind(*self))
     }
 }
diff --git a/tests/ui-fulldeps/stable-mir/check_foreign.rs b/tests/ui-fulldeps/stable-mir/check_foreign.rs
index 22770a56e32..e6c59354d5e 100644
--- a/tests/ui-fulldeps/stable-mir/check_foreign.rs
+++ b/tests/ui-fulldeps/stable-mir/check_foreign.rs
@@ -43,7 +43,7 @@ fn test_foreign() -> ControlFlow<()> {
     let c_items = c_mod.items();
     assert_eq!(c_items.len(), 3);
     for item in c_items {
-        let kind = item.kind().unwrap();
+        let kind = item.kind();
         match item.name().as_str() {
             "foo" => assert_matches!(kind, ForeignItemKind::Fn(..)),
             "bar" => assert_matches!(kind, ForeignItemKind::Static(..)),