From fb5a4dca328798ec30fa001aed16f19ceb32e000 Mon Sep 17 00:00:00 2001
From: Zalathar <Zalathar@users.noreply.github.com>
Date: Sat, 7 Feb 2026 23:16:12 +1100
Subject: [PATCH] Regression test for `let x = offset_of!(..) else { .. }` span

---
 tests/ui/span/let-offset-of.rs     | 19 +++++++++++++++++++
 tests/ui/span/let-offset-of.stderr | 17 +++++++++++++++++
 2 files changed, 36 insertions(+)
 create mode 100644 tests/ui/span/let-offset-of.rs
 create mode 100644 tests/ui/span/let-offset-of.stderr

diff --git a/tests/ui/span/let-offset-of.rs b/tests/ui/span/let-offset-of.rs
new file mode 100644
index 000000000000..99b34a192847
--- /dev/null
+++ b/tests/ui/span/let-offset-of.rs
@@ -0,0 +1,19 @@
+#![crate_type = "rlib"]
+//@ edition: 2024
+//@ check-pass
+
+// Using `offset_of` in the RHS of a let-else statement should not produce
+// malformed spans or a blank diagnostic snippet.
+//
+// Regression test for <https://github.com/rust-lang/rust/pull/152284>.
+
+fn init_to_offset_of() {
+    use std::mem::offset_of;
+    struct Foo { field: u32 }
+
+    if let x = offset_of!(Foo, field) {}
+    //~^ WARN irrefutable `if let` pattern
+
+    let x = offset_of!(Foo, field) else { return; };
+    //~^ WARN irrefutable `let...else` pattern
+}
diff --git a/tests/ui/span/let-offset-of.stderr b/tests/ui/span/let-offset-of.stderr
new file mode 100644
index 000000000000..a0ef3fcc5ef5
--- /dev/null
+++ b/tests/ui/span/let-offset-of.stderr
@@ -0,0 +1,17 @@
+warning: irrefutable `if let` pattern
+  --> $DIR/let-offset-of.rs:14:8
+   |
+LL |     if let x = offset_of!(Foo, field) {}
+   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: this pattern will always match, so the `if let` is useless
+   = help: consider replacing the `if let` with a `let`
+   = note: `#[warn(irrefutable_let_patterns)]` on by default
+
+warning: irrefutable `let...else` pattern
+   |
+   = note: this pattern will always match, so the `else` clause is useless
+   = help: consider removing the `else` clause
+
+warning: 2 warnings emitted
+