fix(angular): fix 3 compiler divergences from Angular reference (#30)

fix(angular): fix 3 compiler divergences from Angular reference (#30)

1. Standalone @case/@default blocks now produce "Unrecognized block" error
   and UnknownBlock node instead of being silently dropped.
2. @case blocks with extra parameters now report error but still parse
   using the first parameter, matching Angular's error recovery behavior.
3. Unexpected i18n metadata types on conditional blocks now panic with a
   descriptive message instead of being silently ignored.

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: Brooooooklyn

crates/oxc_angular_compiler/src/pipeline/ingest.rs

@@ -2351,7 +2351,8 @@ fn ingest_if_block<'a>(
 
         // Extract i18n placeholder metadata from the branch
         // Angular checks that branch.i18n is a BlockPlaceholder type
-        let i18n_placeholder = convert_i18n_meta_to_placeholder(branch.i18n);
+        let i18n_placeholder =
+            convert_i18n_meta_to_placeholder(branch.i18n, &mut job.diagnostics, branch.source_span);
 
         // Infer tag name from single root element for content projection
         let tag_name =
@@ -2932,7 +2933,8 @@ fn ingest_switch_block<'a>(
 
         // Extract i18n placeholder metadata from the group
         // Angular checks that group.i18n is a BlockPlaceholder type
-        let i18n_placeholder = convert_i18n_meta_to_placeholder(group.i18n);
+        let i18n_placeholder =
+            convert_i18n_meta_to_placeholder(group.i18n, &mut job.diagnostics, group.source_span);
 
         // Infer tag name from single root element for content projection
         let tag_name =
@@ -3082,7 +3084,11 @@ fn ingest_defer_view<'a>(
     // Convert i18n metadata to placeholder, matching Angular's ingestDeferView which passes
     // i18nMeta through to createTemplateOp. This enables propagate_i18n_blocks to wrap the
     // deferred template with i18nStart/i18nEnd when inside an i18n context.
-    let i18n_placeholder = convert_i18n_meta_to_placeholder(i18n);
+    let i18n_placeholder = convert_i18n_meta_to_placeholder(
+        i18n,
+        &mut job.diagnostics,
+        source_span.unwrap_or(oxc_span::SPAN),
+    );
 
     let template_op = CreateOp::Template(TemplateOp {
         base: CreateOpBase { source_span, ..Default::default() },
@@ -4201,15 +4207,29 @@ fn ingest_host_event<'a>(job: &mut HostBindingCompilationJob<'a>, event: R3Bound
 /// is specifically a BlockPlaceholder type and extract its start_name/close_name.
 ///
 /// Ported from Angular's i18n handling in `ingest.ts` (lines 531-537, 1088-1094).
-fn convert_i18n_meta_to_placeholder(i18n: Option<I18nMeta<'_>>) -> Option<I18nPlaceholder<'_>> {
+fn convert_i18n_meta_to_placeholder<'a>(
+    i18n: Option<I18nMeta<'a>>,
+    diagnostics: &mut std::vec::Vec<OxcDiagnostic>,
+    source_span: oxc_span::Span,
+) -> Option<I18nPlaceholder<'a>> {
     match i18n {
         Some(I18nMeta::Node(I18nNode::BlockPlaceholder(bp))) => {
             Some(I18nPlaceholder::new(bp.start_name, Some(bp.close_name)))
         }
         Some(I18nMeta::BlockPlaceholder(bp)) => {
             Some(I18nPlaceholder::new(bp.start_name, Some(bp.close_name)))
         }
-        _ => None,
+        // Reference: ingest.ts lines 533-537, 587-591
+        // Angular throws an assertion error for unexpected i18n metadata types.
+        // We report a diagnostic instead to avoid crashing the process.
+        Some(_) => {
+            diagnostics.push(
+                OxcDiagnostic::error("Unhandled i18n metadata type for conditional block")
+                    .with_label(source_span),
+            );
+            None
+        }
+        None => None,
     }
 }