Add more tests covering more cases

Author: estebank

src/test/ui/lint/lint-dead-code-empty-unused-enum-pub.rs

@@ -0,0 +1,6 @@
+// run-pass
+#![deny(unused)]
+
+pub enum E {}
+
+fn main() {}

src/test/ui/lint/lint-dead-code-empty-unused-enum.rs

@@ -0,0 +1,5 @@
+#![deny(unused)]
+
+enum E {} //~ ERROR enum is never used
+
+fn main() {}

src/test/ui/lint/lint-dead-code-empty-unused-enum.stderr

@@ -0,0 +1,15 @@
+error: enum is never used: `E`
+  --> $DIR/lint-dead-code-empty-unused-enum.rs:3:1
+   |
+LL | enum E {}
+   | ^^^^^^
+   |
+note: lint level defined here
+  --> $DIR/lint-dead-code-empty-unused-enum.rs:1:9
+   |
+LL | #![deny(unused)]
+   |         ^^^^^^
+   = note: `#[deny(dead_code)]` implied by `#[deny(unused)]`
+
+error: aborting due to previous error
+

src/test/ui/lint/lint-dead-code-unused-enum.rs

@@ -0,0 +1,11 @@
+#![deny(unused)]
+
+struct F; //~ ERROR struct is never constructed
+struct B; //~ ERROR struct is never constructed
+
+enum E { //~ ERROR enum is never used
+    Foo(F),
+    Bar(B),
+}
+
+fn main() {}

src/test/ui/lint/lint-dead-code-unused-enum.stderr

@@ -0,0 +1,27 @@
+error: struct is never constructed: `F`
+  --> $DIR/lint-dead-code-unused-enum.rs:3:1
+   |
+LL | struct F;
+   | ^^^^^^^^^
+   |
+note: lint level defined here
+  --> $DIR/lint-dead-code-unused-enum.rs:1:9
+   |
+LL | #![deny(unused)]
+   |         ^^^^^^
+   = note: `#[deny(dead_code)]` implied by `#[deny(unused)]`
+
+error: struct is never constructed: `B`
+  --> $DIR/lint-dead-code-unused-enum.rs:4:1
+   |
+LL | struct B;
+   | ^^^^^^^^^
+
+error: enum is never used: `E`
+  --> $DIR/lint-dead-code-unused-enum.rs:6:1
+   |
+LL | enum E {
+   | ^^^^^^
+
+error: aborting due to 3 previous errors
+

src/test/ui/lint/lint-dead-code-unused-variant-pub.rs

@@ -0,0 +1,14 @@
+// run-pass
+#![deny(unused)]
+
+pub struct F;
+pub struct B;
+
+pub enum E {
+    Foo(F),
+    Bar(B),
+}
+
+fn main() {
+    let _ = E::Foo(F);
+}

src/test/ui/lint/lint-dead-code-unused-variant.rs

@@ -0,0 +1,13 @@
+#![deny(unused)]
+
+struct F;
+struct B;
+
+enum E {
+    Foo(F),
+    Bar(B), //~ ERROR variant is never constructed
+}
+
+fn main() {
+    let _ = E::Foo(F);
+}

src/test/ui/lint/lint-dead-code-unused-variant.stderr

@@ -0,0 +1,15 @@
+error: variant is never constructed: `Bar`
+  --> $DIR/lint-dead-code-unused-variant.rs:8:5
+   |
+LL |     Bar(B),
+   |     ^^^^^^
+   |
+note: lint level defined here
+  --> $DIR/lint-dead-code-unused-variant.rs:1:9
+   |
+LL | #![deny(unused)]
+   |         ^^^^^^
+   = note: `#[deny(dead_code)]` implied by `#[deny(unused)]`
+
+error: aborting due to previous error
+