feat(language-service): add support for @boundary blocks

Add support for the new `@boundary` and `@error` control flow blocks in the Angular Language Service.

This includes:
- Updating outlining spans to handle boundary blocks correctly.
- Adding classification visitor methods for semantic tokens.
- Adding template target visitor methods for navigation and hover support.
- Updating the TextMate grammar to recognize `@boundary` and the `when` clause.

Author: alxhub

packages/core/test/render3/error_boundary_spec.ts

@@ -6,6 +6,7 @@ import {
   EnvironmentInjector,
   Input,
   signal,
+  ErrorHandler,
 } from '@angular/core';
 import {TestBed, ComponentFixture} from '@angular/core/testing';
 import {ɵɵdefineComponent} from '../../src/render3/definition';

packages/language-service/src/outlining_spans.ts

@@ -16,6 +16,7 @@ import {
   TmplAstNode,
   TmplAstRecursiveVisitor,
   TmplAstSwitchBlockCase,
+  TmplAstBoundaryBlock,
   tmplAstVisitAll,
 } from '@angular/compiler';
 import {isExternalResource, isNamedClassDeclaration, NgCompiler} from '@angular/compiler-cli';
@@ -90,6 +91,8 @@ class BlockVisitor extends TmplAstRecursiveVisitor {
       node instanceof TmplAstBlockNode &&
       // Omit `IfBlock` because we include the branches individually
       !(node instanceof TmplAstIfBlock) &&
+      // Omit `BoundaryBlock` because we include the branches individually
+      !(node instanceof TmplAstBoundaryBlock) &&
       // Omit `SwitchBlockCase` because we include the groups
       !(node instanceof TmplAstSwitchBlockCase)
     ) {

packages/language-service/src/semantic_tokens.ts

@@ -38,6 +38,8 @@ import {
   TmplAstUnknownBlock,
   TmplAstVariable,
   TmplAstVisitor,
+  TmplAstBoundaryBlock,
+  TmplAstBoundaryErrorBlock,
 } from '@angular/compiler';
 import {NgCompiler, PotentialDirective} from '@angular/compiler-cli';
 
@@ -200,6 +202,15 @@ class ClassificationVisitor implements TmplAstVisitor {
     this.visitAll(block.children);
   }
 
+  visitBoundaryBlock(block: TmplAstBoundaryBlock) {
+    this.visitAll(block.children);
+    this.visitAll(block.errorBlocks);
+  }
+
+  visitBoundaryErrorBlock(block: TmplAstBoundaryErrorBlock) {
+    this.visitAll(block.children);
+  }
+
   visitTemplate(template: TmplAstTemplate) {
     this.visitAll(template.children);
   }

packages/language-service/src/template_target.ts

@@ -50,6 +50,8 @@ import {
   TmplAstUnknownBlock,
   TmplAstVariable,
   TmplAstViewportDeferredTrigger,
+  TmplAstBoundaryBlock,
+  TmplAstBoundaryErrorBlock,
   tmplAstVisitAll,
   TmplAstVisitor,
 } from '@angular/compiler';
@@ -698,6 +700,17 @@ class TemplateTargetVisitor implements TmplAstVisitor {
     this.visitAll(block.children);
   }
 
+  visitBoundaryBlock(block: TmplAstBoundaryBlock) {
+    this.visitAll(block.children);
+    this.visitAll(block.errorBlocks);
+  }
+
+  visitBoundaryErrorBlock(block: TmplAstBoundaryErrorBlock) {
+    block.expression && this.visitBinding(block.expression);
+    block.errorAlias && this.visit(block.errorAlias);
+    this.visitAll(block.children);
+  }
+
   visitUnknownBlock(block: TmplAstUnknownBlock) {}
 
   visitLetDeclaration(decl: TmplAstLetDeclaration) {

vscode-ng-language-service/syntaxes/template-blocks.json

@@ -12,7 +12,7 @@
       "name": "keyword.control.block.transition.ng"
     },
     "block": {
-      "begin": "(@)(if|else if|else|defer|placeholder|loading|error|switch|for|empty)(?:\\s*)",
+      "begin": "(@)(if|else if|else|defer|placeholder|loading|error|boundary|switch|for|empty)(?:\\s*)",
       "beginCaptures": {
         "1": {
           "patterns": [
@@ -108,6 +108,9 @@
         {
           "include": "#blockExpressionTrackClause"
         },
+        {
+          "include": "#blockExpressionWhenClause"
+        },
         {
           "include": "expression.ng"
         }
@@ -119,6 +122,20 @@
         }
       }
     },
+    "blockExpressionWhenClause": {
+      "begin": "\\bwhen\\b",
+      "beginCaptures": {
+        "0": {
+          "name": "keyword.control.when.ng"
+        }
+      },
+      "end": "(?=[$)])|(?<=;)",
+      "patterns": [
+        {
+          "include": "expression.ng"
+        }
+      ]
+    },
     "blockExpressionOfClause": {
       "begin": "([_$[:alpha:]][_$[:alnum:]]*)\\s+(of)\\b",
       "beginCaptures": {