Move all compile-fail tests to ui tests

The update-references.sh script makes these much easier to update in
bulk compared to compile-fail tests.

test_suite/tests/ui/enum-representation/internal-tuple-variant.rs

@@ -0,0 +1,18 @@
+// Copyright 2017 Serde Developers
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#[macro_use]
+extern crate serde_derive;
+
+#[derive(Serialize)]
+#[serde(tag = "type")]
+enum E {
+    Tuple(u8, u8),
+}
+
+fn main() {}

test_suite/tests/ui/enum-representation/internal-tuple-variant.stderr

@@ -0,0 +1,8 @@
+error: #[serde(tag = "...")] cannot be used with tuple variants
+  --> $DIR/internal-tuple-variant.rs:12:10
+   |
+12 | #[derive(Serialize)]
+   |          ^^^^^^^^^
+
+error: aborting due to previous error
+

test_suite/tests/ui/enum-representation/internally-tagged-struct.rs

@@ -0,0 +1,16 @@
+// Copyright 2017 Serde Developers
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#[macro_use]
+extern crate serde_derive;
+
+#[derive(Serialize)]
+#[serde(tag = "type")]
+struct S;
+
+fn main() {}

test_suite/tests/ui/enum-representation/internally-tagged-struct.stderr

@@ -0,0 +1,8 @@
+error: #[serde(tag = "...")] can only be used on enums
+  --> $DIR/internally-tagged-struct.rs:12:10
+   |
+12 | #[derive(Serialize)]
+   |          ^^^^^^^^^
+
+error: aborting due to previous error
+

test_suite/tests/ui/enum-representation/untagged-and-internal.rs

@@ -0,0 +1,20 @@
+// Copyright 2017 Serde Developers
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#[macro_use]
+extern crate serde_derive;
+
+#[derive(Serialize)]
+#[serde(untagged)]
+#[serde(tag = "type")]
+enum E {
+    A(u8),
+    B(String),
+}
+
+fn main() {}

test_suite/tests/ui/enum-representation/untagged-and-internal.stderr

@@ -0,0 +1,8 @@
+error: enum cannot be both untagged and internally tagged
+  --> $DIR/untagged-and-internal.rs:12:10
+   |
+12 | #[derive(Serialize)]
+   |          ^^^^^^^^^
+
+error: aborting due to previous error
+

test_suite/tests/ui/enum-representation/untagged-struct.rs

@@ -0,0 +1,16 @@
+// Copyright 2017 Serde Developers
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#[macro_use]
+extern crate serde_derive;
+
+#[derive(Serialize)]
+#[serde(untagged)]
+struct S;
+
+fn main() {}

test_suite/tests/ui/enum-representation/untagged-struct.stderr

@@ -0,0 +1,8 @@
+error: #[serde(untagged)] can only be used on enums
+  --> $DIR/untagged-struct.rs:12:10
+   |
+12 | #[derive(Serialize)]
+   |          ^^^^^^^^^
+
+error: aborting due to previous error
+