Support legacy '#[error]' and 'errors!' macros.

Their use now emits a deprecation warning.

Fixes #419.

codegen/src/decorators/catch.rs

@@ -98,3 +98,17 @@ pub fn catch_decorator(
 
     output
 }
+
+pub fn error_decorator(
+    ecx: &mut ExtCtxt,
+    sp: Span,
+    meta_item: &MetaItem,
+    annotated: Annotatable
+) -> Vec<Annotatable> {
+    ecx.struct_span_warn(sp, "use of deprecated Rocket attribute `error` \
+                              (deprecated since v0.3.15)")
+        .help("the `error` attribute was replaced by the `catch` attribute: \
+               `#[catch(..)]`")
+        .emit();
+    catch_decorator(ecx, sp, meta_item, annotated)
+}

codegen/src/lib.rs

@@ -199,6 +199,7 @@ pub fn plugin_registrar(reg: &mut Registry) {
     }
 
     reg.register_macro("routes", macros::routes);
+    reg.register_macro("errors", macros::errors);
     reg.register_macro("catchers", macros::catchers);
 
     register_derives!(reg,
@@ -206,6 +207,7 @@ pub fn plugin_registrar(reg: &mut Registry) {
     );
 
     register_decorators!(reg,
+        "error" => error_decorator,
         "catch" => catch_decorator,
         "route" => route_decorator,
         "get" => get_decorator,

codegen/src/macros/mod.rs

@@ -60,3 +60,14 @@ pub fn catchers(ecx: &mut ExtCtxt, sp: Span, args: &[TokenTree])
         quote_expr!(ecx, rocket::Catcher::from(&$path))
     }, ecx, sp, args)
 }
+
+#[rustfmt_skip]
+pub fn errors(ecx: &mut ExtCtxt, sp: Span, args: &[TokenTree])
+        -> Box<MacResult + 'static> {
+    ecx.struct_span_warn(sp, "use of deprecated Rocket macro `errors` \
+                              (deprecated since v0.3.15)")
+        .help("the `errors` macro was replaced by the `catchers` macro: \
+               `catchers![..]`")
+        .emit();
+    catchers(ecx, sp, args)
+}

codegen/tests/compile-fail/deprecated-error.rs

@@ -0,0 +1,20 @@
+// must-compile-successfully
+#![feature(plugin)]
+#![plugin(rocket_codegen)]
+
+extern crate rocket;
+
+use rocket::response::content;
+
+#[error(404)]
+//~^ WARNING use of deprecated Rocket attribute `error` (deprecated since v0.3.15)
+fn not_found(req: &rocket::Request) -> content::Html<String> {
+    content::Html(format!("<p>whappen?</p>"))
+}
+
+fn main() {
+    let e = rocket::ignite()
+        .catch(errors![not_found])
+        //~^ WARNING use of deprecated Rocket macro `errors` (deprecated since v0.3.15)
+        .launch();
+}