fix(errors): Report errors on unknown #[serde(...)] attributes

Closes #51, #175, and #187

serde_codegen/src/field.rs

@@ -2,16 +2,29 @@ use syntax::ast;
 use syntax::ext::base::ExtCtxt;
 
 use aster;
-use attr::{FieldAttrs, FieldAttrsBuilder};
+use attr;
 
 pub fn struct_field_attrs(
-    _cx: &ExtCtxt,
+    cx: &ExtCtxt,
     builder: &aster::AstBuilder,
     fields: &[ast::StructField],
-) -> Vec<FieldAttrs> {
-    fields.iter()
-        .map(|field| {
-            FieldAttrsBuilder::new(builder).field(field).build()
-        })
-        .collect()
+) -> Result<Vec<attr::FieldAttrs>, ()> {
+    let mut attrs = vec![];
+    for field in fields {
+        let builder = attr::FieldAttrsBuilder::new(cx, builder);
+        let builder = try!(builder.field(field));
+        let attr = builder.build();
+        attrs.push(attr);
+    }
+
+    Ok(attrs)
+}
+
+pub fn container_attrs(
+    cx: &ExtCtxt,
+    container: &ast::Item,
+) -> Result<attr::ContainerAttrs, ()> {
+    let builder = attr::ContainerAttrsBuilder::new(cx);
+    let builder = try!(builder.attrs(container.attrs()));
+    Ok(builder.build())
 }