From dbc472b15467e68cb138282a1b0af8b8cfc3f995 Mon Sep 17 00:00:00 2001
From: Roland Xu <rcu@live.com>
Date: Fri, 25 Sep 2026 13:15:25 +0800
Subject: [PATCH] Use get to avoid ICE on unresolved imports

---
 compiler/rustc_resolve/src/check_unused.rs    |  2 +-
 .../ui/imports/unused-import-issue-163294.rs  |  9 ++++++++
 .../imports/unused-import-issue-163294.stderr | 23 +++++++++++++++++++
 3 files changed, 33 insertions(+), 1 deletion(-)
 create mode 100644 tests/ui/imports/unused-import-issue-163294.rs
 create mode 100644 tests/ui/imports/unused-import-issue-163294.stderr

diff --git a/compiler/rustc_resolve/src/check_unused.rs b/compiler/rustc_resolve/src/check_unused.rs
index daa816c276482..aac244ad6cf22 100644
--- a/compiler/rustc_resolve/src/check_unused.rs
+++ b/compiler/rustc_resolve/src/check_unused.rs
@@ -136,7 +136,7 @@ impl<'a, 'ra, 'tcx> UnusedImportCheckVisitor<'a, 'ra, 'tcx> {
             ast::UseTreeKind::Simple(Some(ident)) => {
                 if ident.name == kw::Underscore
                     && !matches!(
-                        self.r.current_owner.import_res[&id].type_ns,
+                        self.r.current_owner.import_res.get(&id).and_then(|res| res.type_ns),
                         Some(Res::Def(DefKind::Trait | DefKind::TraitAlias, _))
                     )
                 {
diff --git a/tests/ui/imports/unused-import-issue-163294.rs b/tests/ui/imports/unused-import-issue-163294.rs
new file mode 100644
index 0000000000000..7793f1da760e2
--- /dev/null
+++ b/tests/ui/imports/unused-import-issue-163294.rs
@@ -0,0 +1,9 @@
+//@ edition: 2015
+
+#![deny(unused_imports)]
+
+pub use core as _;
+//~^ ERROR unresolved import `core`
+//~^^ ERROR unused import: `core as _`
+
+fn main() {}
diff --git a/tests/ui/imports/unused-import-issue-163294.stderr b/tests/ui/imports/unused-import-issue-163294.stderr
new file mode 100644
index 0000000000000..ebb319562189a
--- /dev/null
+++ b/tests/ui/imports/unused-import-issue-163294.stderr
@@ -0,0 +1,23 @@
+error[E0432]: unresolved import `core`
+  --> $DIR/unused-import-issue-163294.rs:5:9
+   |
+LL | pub use core as _;
+   |         ----^^^^^
+   |         |
+   |         no `core` in the root
+
+error: unused import: `core as _`
+  --> $DIR/unused-import-issue-163294.rs:5:9
+   |
+LL | pub use core as _;
+   |         ^^^^^^^^^
+   |
+note: the lint level is defined here
+  --> $DIR/unused-import-issue-163294.rs:3:9
+   |
+LL | #![deny(unused_imports)]
+   |         ^^^^^^^^^^^^^^
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0432`.