Rollup merge of #56953 - oli-obk:dead_const, r=petrochenkov

Mark tuple structs as live if their constructors are used

fixes https://github.com/rust-lang/rust/issues/56281

src/test/ui/dead-code-tuple-struct-field.rs

@@ -0,0 +1,12 @@
+// compile-pass
+
+#![deny(dead_code)]
+
+const LEN: usize = 4;
+
+#[derive(Debug)]
+struct Wrapper([u8; LEN]);
+
+fn main() {
+    println!("{:?}", Wrapper([0, 1, 2, 3]));
+}