Improve error messages for the derive macros

Closes #346.
librasn · Jan 5, 2025 · ac6de09 · ac6de09
1 parent 3531401
commit ac6de09
Show file tree

Hide file tree

Showing 7 changed files with 465 additions and 365 deletions.
diff --git a/macros/macros_impl/src/asn_type.rs b/macros/macros_impl/src/asn_type.rs
@@ -3,68 +3,61 @@ use itertools::Itertools;
 use crate::config::*;
 
 pub fn derive_struct_impl(
-    name: syn::Ident,
-    mut generics: syn::Generics,
+    name: &syn::Ident,
+    generics: syn::Generics,
     container: syn::DataStruct,
     config: &Config,
-) -> proc_macro2::TokenStream {
+) -> syn::Result<proc_macro2::TokenStream> {
     let crate_root = &config.crate_root;
     let tag = config.tag_for_struct(&container.fields);
-    let field_groups = container
+    let field_configs = container
         .fields
         .iter()
         .enumerate()
-        .map(|(i, f)| (i, FieldConfig::new(f, config)));
+        .map(|(i, f)| FieldConfig::new(f, config, i))
+        .collect::<Result<Vec<_>, _>>()?;
 
-    let field_metadata = field_groups
-        .clone()
-        .filter(|(_, field)| field.is_not_extension())
-        .map(|(i, field)| {
-            let metadata = field.to_field_metadata(i);
+    let field_metadata = field_configs
+        .iter()
+        .filter(|field| field.is_not_extension())
+        .map(|field| {
+            let metadata = field.to_field_metadata();
             quote!(#metadata)
         })
         .collect::<Vec<_>>();
 
-    let extension_metadata = field_groups
-        .clone()
-        .filter(|(_, field)| field.is_extension())
-        .map(|(i, field)| {
-            let metadata = field.to_field_metadata(i);
+    let extension_metadata = field_configs
+        .iter()
+        .filter(|field| field.is_extension())
+        .map(|field| {
+            let metadata = field.to_field_metadata();
             quote!(#metadata)
         })
         .collect::<Vec<_>>();
+    // TODO use partition above?
 
-    let all_optional_tags_are_unique: Vec<_> = field_groups
-        .chunk_by(|(_, config)| config.is_option_or_default_type())
+    let all_optional_tags_are_unique: Vec<_> = field_configs
+        .iter()
+        .chunk_by(|config| config.is_option_or_default_type())
         .into_iter()
         .filter_map(|(key, fields)| key.then_some(fields))
         .map(|fields| {
-            let tag_tree = fields.map(|(i, f)| f.tag_tree(i));
             let error_message = format!(
                 "{}'s fields is not a valid \
                         order of ASN.1 tags, ensure that your field's tags and \
                         OPTIONALs are correct.",
                 name
             );
 
-            quote!({
+            let tag_tree = fields.map(|f| f.tag_tree()).collect::<Vec<_>>();
+
+            Ok::<_, syn::Error>(quote!({
                 const LIST: &'static [#crate_root::types::TagTree] = &[#(#tag_tree),*];
                 const TAG_TREE: #crate_root::types::TagTree = #crate_root::types::TagTree::Choice(LIST);
                 const _: () = assert!(TAG_TREE.is_unique(), #error_message);
-            })
+            }))
         })
-        .collect::<Vec<_>>();
-
-    for param in generics.type_params_mut() {
-        param
-            .bounds
-            .push(syn::TypeParamBound::Trait(syn::TraitBound {
-                paren_token: Some(<_>::default()),
-                modifier: syn::TraitBoundModifier::None,
-                lifetimes: None,
-                path: syn::parse_quote!(#crate_root::AsnType),
-            }));
-    }
+        .collect::<Result<Vec<_>, _>>()?;
 
     let (impl_generics, ty_generics, where_clause) = generics.split_for_impl();
 
@@ -101,7 +94,7 @@ pub fn derive_struct_impl(
         |id| quote!(const IDENTIFIER: Option<&'static str> = Some(#id);),
     );
 
-    quote! {
+    Ok(quote! {
         #constructed_impl
 
         #[automatically_derived]
@@ -114,5 +107,5 @@ pub fn derive_struct_impl(
             #alt_identifier
             #constraints_def
         }
-    }
+    })
 }