Add test for struct variant

tests/ui/lint/dead-code/unused-variant.rs

@@ -1,20 +1,27 @@
 #![deny(dead_code)]
 
 #[derive(Clone)]
-enum Enum1 {
+enum Enum {
     Variant1, //~ ERROR: variant `Variant1` is never constructed
     Variant2,
 }
 
 #[derive(Debug)]
-enum Enum2 {
+enum TupleVariant {
     Variant1(i32), //~ ERROR: variant `Variant1` is never constructed
     Variant2,
 }
 
+#[derive(Debug)]
+enum StructVariant {
+    Variant1 { id: i32 }, //~ ERROR: variant `Variant1` is never constructed
+    Variant2,
+}
+
 fn main() {
-    let e = Enum1::Variant2;
+    let e = Enum::Variant2;
     e.clone();
 
-    let _ = Enum2::Variant2;
+    let _ = TupleVariant::Variant2;
+    let _ = StructVariant::Variant2;
 }

tests/ui/lint/dead-code/unused-variant.stderr

@@ -1,12 +1,12 @@
 error: variant `Variant1` is never constructed
   --> $DIR/unused-variant.rs:5:5
    |
-LL | enum Enum1 {
-   |      ----- variant in this enum
+LL | enum Enum {
+   |      ---- variant in this enum
 LL |     Variant1,
    |     ^^^^^^^^
    |
-   = note: `Enum1` has a derived impl for the trait `Clone`, but this is intentionally ignored during dead code analysis
+   = note: `Enum` has a derived impl for the trait `Clone`, but this is intentionally ignored during dead code analysis
 note: the lint level is defined here
   --> $DIR/unused-variant.rs:1:9
    |
@@ -16,12 +16,22 @@ LL | #![deny(dead_code)]
 error: variant `Variant1` is never constructed
   --> $DIR/unused-variant.rs:11:5
    |
-LL | enum Enum2 {
-   |      ----- variant in this enum
+LL | enum TupleVariant {
+   |      ------------ variant in this enum
 LL |     Variant1(i32),
    |     ^^^^^^^^
    |
-   = note: `Enum2` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
+   = note: `TupleVariant` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
 
-error: aborting due to 2 previous errors
+error: variant `Variant1` is never constructed
+  --> $DIR/unused-variant.rs:17:5
+   |
+LL | enum StructVariant {
+   |      ------------- variant in this enum
+LL |     Variant1 { id: i32 },
+   |     ^^^^^^^^
+   |
+   = note: `StructVariant` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
+
+error: aborting due to 3 previous errors