Add a test for issue-132874

Author: m-ysk

tests/ui/lint/dead-code/issue-132874-false-positive.rs

@@ -0,0 +1,13 @@
+//@ check-pass
+
+// Make sure we don't have any false positives here.
+
+#![deny(dead_code)]
+
+struct Foo(usize);
+
+fn get_thing<T>() -> T { todo!() }
+
+pub fn main() {
+    let Foo(_x) = get_thing();
+}