fix: i18n attribute bindings should not inflate xref IDs for @for index variables

In Angular's TS compiler, BindingOp.i18nMessage stores a direct object
reference to the i18n.Message -- no XrefId is allocated during ingest.
The xref for the i18n context is only allocated later in the
create_i18n_contexts phase.

Oxc was allocating xrefs for i18n messages during ingest, inflating the
xref counter and causing @for body views to get higher xref values than
Angular. This made generated variable names like ɵ$index_N use the wrong
N value (e.g., ɵ$index_70 instead of ɵ$index_66).

Change i18n_message fields from Option<XrefId> to Option<u32> across all
ops, using the i18n message's instance_id as a dedup key instead of
allocating xrefs. This matches Angular TS's approach of using object
identity for dedup without consuming xref slots.

Fixes 8 mismatched files in the ClickUp comparison (158 → 150).

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: Brooooooklyn

crates/oxc_angular_compiler/src/ir/ops.rs

@@ -1264,8 +1264,8 @@ pub struct I18nStartOp<'a> {
     pub slot: Option<SlotId>,
     /// I18n context.
     pub context: Option<XrefId>,
-    /// Message.
-    pub message: Option<XrefId>,
+    /// Message instance ID for metadata lookup.
+    pub message: Option<u32>,
     /// I18n placeholder data (start_name and close_name for i18n blocks).
     pub i18n_placeholder: Option<I18nPlaceholder<'a>>,
     /// Sub-template index for nested templates inside i18n blocks.
@@ -1289,8 +1289,8 @@ pub struct I18nOp<'a> {
     pub slot: Option<SlotId>,
     /// I18n context.
     pub context: Option<XrefId>,
-    /// Message.
-    pub message: Option<XrefId>,
+    /// Message instance ID for metadata lookup.
+    pub message: Option<u32>,
     /// I18n placeholder data (start_name and close_name for i18n blocks).
     pub i18n_placeholder: Option<I18nPlaceholder<'a>>,
     /// Sub-template index for nested templates inside i18n blocks.
@@ -1321,8 +1321,8 @@ pub struct IcuStartOp<'a> {
     pub xref: XrefId,
     /// I18n context.
     pub context: Option<XrefId>,
-    /// Message.
-    pub message: Option<XrefId>,
+    /// Message instance ID for metadata lookup.
+    pub message: Option<u32>,
     /// ICU placeholder.
     pub icu_placeholder: Option<Atom<'a>>,
 }
@@ -1365,8 +1365,11 @@ pub struct I18nContextOp<'a> {
     /// Maps ICU placeholder names to their formatted string values.
     /// These are string literals like "Hello ${�0�}!" generated from IcuPlaceholderOp.
     pub icu_placeholder_literals: oxc_allocator::HashMap<'a, Atom<'a>, Atom<'a>>,
-    /// Message reference.
-    pub message: Option<XrefId>,
+    /// Message instance ID reference (for metadata lookup).
+    ///
+    /// Stores the i18n message's instance_id (not an XrefId) to look up metadata
+    /// in the job's i18n_message_metadata map.
+    pub message: Option<u32>,
 }
 
 /// I18n attributes on an element.
@@ -1439,8 +1442,13 @@ pub struct ExtractedAttributeOp<'a> {
     pub security_context: SecurityContext,
     /// Whether expression is truthy.
     pub truthy_expression: bool,
-    /// i18n message (for i18n attributes).
-    pub i18n_message: Option<XrefId>,
+    /// i18n message instance ID (for i18n attributes).
+    ///
+    /// This stores the i18n message's instance_id rather than an XrefId to avoid
+    /// allocating xrefs during ingest. Angular TS stores a direct object reference
+    /// to the i18n.Message; we use the instance_id as a dedup key instead.
+    /// The actual xref for the i18n context is allocated later in create_i18n_contexts.
+    pub i18n_message: Option<u32>,
     /// i18n context.
     pub i18n_context: Option<XrefId>,
     /// Trusted value function for security-sensitive constant attributes.
@@ -1522,8 +1530,10 @@ pub struct PropertyOp<'a> {
     pub is_structural: bool,
     /// I18n context.
     pub i18n_context: Option<XrefId>,
-    /// I18n message.
-    pub i18n_message: Option<XrefId>,
+    /// I18n message instance ID.
+    ///
+    /// Stores the i18n message's instance_id for dedup, not an XrefId.
+    pub i18n_message: Option<u32>,
     /// Binding kind (for DomOnly mode and animation handling).
     pub binding_kind: BindingKind,
 }
@@ -1608,8 +1618,10 @@ pub struct AttributeOp<'a> {
     pub sanitizer: Option<Atom<'a>>,
     /// I18n context.
     pub i18n_context: Option<XrefId>,
-    /// I18n message.
-    pub i18n_message: Option<XrefId>,
+    /// I18n message instance ID.
+    ///
+    /// Stores the i18n message's instance_id for dedup, not an XrefId.
+    pub i18n_message: Option<u32>,
     /// Whether this is a text attribute (static attribute from template).
     ///
     /// Text attributes are extractable to the consts array and don't need
@@ -1811,8 +1823,10 @@ pub struct BindingOp<'a> {
     pub unit: Option<Atom<'a>>,
     /// Security context.
     pub security_context: SecurityContext,
-    /// I18n message.
-    pub i18n_message: Option<XrefId>,
+    /// I18n message instance ID.
+    ///
+    /// Stores the i18n message's instance_id for dedup, not an XrefId.
+    pub i18n_message: Option<u32>,
     /// Whether this binding came from a text attribute (e.g., `class="cls"` vs `[class]="expr"`).
     ///
     /// This is used for compatibility with TemplateDefinitionBuilder which treats
@@ -1843,8 +1857,10 @@ pub struct AnimationOp<'a> {
     pub handler_ops: Vec<'a, UpdateOp<'a>>,
     /// Function name for the handler.
     pub handler_fn_name: Option<Atom<'a>>,
-    /// I18n message.
-    pub i18n_message: Option<XrefId>,
+    /// I18n message instance ID.
+    ///
+    /// Stores the i18n message's instance_id for dedup, not an XrefId.
+    pub i18n_message: Option<u32>,
     /// Security context.
     pub security_context: SecurityContext,
     /// Sanitizer function.

crates/oxc_angular_compiler/src/pipeline/compilation.rs

@@ -139,16 +139,12 @@ pub struct ComponentCompilationJob<'a> {
     pub mode: TemplateCompilationMode,
     /// Whether this is for an i18n template.
     pub is_i18n_template: bool,
-    /// Metadata for i18n messages keyed by xref.
-    pub i18n_message_metadata: FxHashMap<XrefId, I18nMessageMetadata<'a>>,
-    /// Cache of i18n xrefs keyed by message identity (custom_id or computed id).
+    /// Metadata for i18n messages keyed by instance_id.
     ///
-    /// This ensures that when the same i18n message is encountered multiple times
-    /// (e.g., when copying attributes from an element to its conditional), they
-    /// share the same xref. This is crucial for correct const deduplication because
-    /// the i18n_const_collection phase assigns i18n variable names (I18N_0, I18N_1)
-    /// based on the context xref, which in turn depends on the message xref.
-    pub i18n_xref_by_message_key: FxHashMap<String, XrefId>,
+    /// The instance_id is a unique u32 assigned to each i18n message during parsing.
+    /// This avoids allocating xrefs during ingest for i18n messages on attribute bindings,
+    /// matching Angular TS which stores direct object references on BindingOp.i18nMessage.
+    pub i18n_message_metadata: FxHashMap<u32, I18nMessageMetadata<'a>>,
     /// Whether to use external message IDs in Closure Compiler variable names.
     ///
     /// When true, generates variable names like `MSG_EXTERNAL_abc123$$SUFFIX`.
@@ -227,7 +223,6 @@ impl<'a> ComponentCompilationJob<'a> {
             mode: TemplateCompilationMode::default(),
             is_i18n_template: false,
             i18n_message_metadata: FxHashMap::default(),
-            i18n_xref_by_message_key: FxHashMap::default(),
             i18n_use_external_ids: true, // Default matches Angular's JIT behavior
             relative_context_file_path: None,
             relocation_entries: Vec::new_in(allocator),
@@ -257,23 +252,6 @@ impl<'a> ComponentCompilationJob<'a> {
         id
     }
 
-    /// Gets or creates an i18n xref for a message with the given key.
-    ///
-    /// This ensures that when the same i18n message is encountered multiple times
-    /// (e.g., when copying attributes from an element to its conditional wrapper),
-    /// they share the same xref. This is crucial for correct const deduplication.
-    ///
-    /// The key should be derived from the message's identity (custom_id or computed id).
-    pub fn get_or_create_i18n_xref(&mut self, message_key: String) -> XrefId {
-        if let Some(&xref) = self.i18n_xref_by_message_key.get(&message_key) {
-            xref
-        } else {
-            let xref = self.allocate_xref_id();
-            self.i18n_xref_by_message_key.insert(message_key, xref);
-            xref
-        }
-    }
-
     /// Stores an expression and returns its ID.
     ///
     /// Use this instead of inline expressions to avoid cloning.