Move /src/test to /tests

tests/ui/lint/dead-code/tuple-struct-field.rs

@@ -0,0 +1,37 @@
+#![deny(unused_tuple_struct_fields)]
+//~^ NOTE: the lint level is defined here
+
+use std::marker::PhantomData;
+
+const LEN: usize = 4;
+
+struct SingleUnused(i32, [u8; LEN], String);
+//~^ ERROR: field `1` is never read
+//~| NOTE: field in this struct
+//~| HELP: consider changing the field to be of unit type
+
+struct MultipleUnused(i32, f32, String, u8);
+//~^ ERROR: fields `0`, `1`, `2`, and `3` are never read
+//~| NOTE: fields in this struct
+//~| HELP: consider changing the fields to be of unit type
+
+struct GoodUnit(());
+
+struct GoodPhantom(PhantomData<i32>);
+
+struct Void;
+struct GoodVoid(Void);
+
+fn main() {
+    let w = SingleUnused(42, [0, 1, 2, 3], "abc".to_string());
+    let _ = w.0;
+    let _ = w.2;
+
+    let m = MultipleUnused(42, 3.14, "def".to_string(), 4u8);
+
+    let gu = GoodUnit(());
+    let gp = GoodPhantom(PhantomData);
+    let gv = GoodVoid(Void);
+
+    let _ = (gu, gp, gv, m);
+}