fix(compiler-cli): escape template literal in TCB

Fixes a regression introduced by #67381 where we weren't escaping backticks in template literals.

Fixes #67675.

packages/compiler-cli/src/ngtsc/typecheck/src/expression.ts

@@ -351,17 +351,19 @@ class TcbExprTranslator implements AstVisitor {
     let result: string;
 
     if (length === 1) {
-      result = `\`${head.text}\``;
+      result = `\`${this.escapeTemplateLiteral(head.text)}\``;
     } else {
-      let parts = [`\`${head.text}`];
+      let parts = [`\`${this.escapeTemplateLiteral(head.text)}`];
       const tailIndex = length - 1;
 
       for (let i = 1; i < tailIndex; i++) {
         const expr = this.translate(ast.expressions[i - 1]);
-        parts.push(`\${${expr.print()}}${ast.elements[i].text}`);
+        parts.push(`\${${expr.print()}}${this.escapeTemplateLiteral(ast.elements[i].text)}`);
       }
       const resolvedExpression = this.translate(ast.expressions[tailIndex - 1]);
-      parts.push(`\${${resolvedExpression.print()}}${ast.elements[tailIndex].text}\``);
+      parts.push(
+        `\${${resolvedExpression.print()}}${this.escapeTemplateLiteral(ast.elements[tailIndex].text)}\``,
+      );
       result = parts.join('');
     }
     return new TcbExpr(result);
@@ -446,6 +448,10 @@ class TcbExprTranslator implements AstVisitor {
     // (a!.method(...) as any)
     return new TcbExpr(`(${expr}!(${args}) as any)`);
   }
+
+  private escapeTemplateLiteral(value: string) {
+    return value.replace(/\\/g, '\\\\').replace(/`/g, '\\`').replace(/\${/g, '$\\{');
+  }
 }
 
 /**

packages/compiler-cli/src/ngtsc/typecheck/test/type_check_block_spec.ts

@@ -220,6 +220,7 @@ describe('type check blocks', () => {
     expect(tcb('{{ `${a} - ${b} - ${c}` }}')).toContain(
       '"" + (`${((this).a)} - ${((this).b)} - ${((this).c)}`);',
     );
+    expect(tcb('{{ `a${`hello ${name}`}b` }}')).toContain('(`a${`hello ${((this).name)}`}b`)');
   });
 
   it('should handle tagged template literals', () => {
@@ -232,6 +233,13 @@ describe('type check blocks', () => {
     );
   });
 
+  it('should escape characters in template literals', () => {
+    expect(tcb('{{ `a\\`b` }}')).toContain('(`a\\`b`)');
+    expect(tcb('{{ `a\\${b}` }}')).toContain('(`a$\\{b}`)');
+    expect(tcb('{{ `a\\\\b` }}')).toContain('(`a\\\\b`)');
+    expect(tcb('{{ `a\\\`${middle}\\\`b` }}')).toContain('(`a\\\`${((this).middle)}\\\`b`)');
+  });
+
   it('should generate regular expressions', () => {
     const TEMPLATE = '{{ /\\d+/g.test("123") }}';
     expect(tcb(TEMPLATE)).toContain('(((/\\d+/g)).test("123"))');

packages/compiler-cli/test/ngtsc/template_typecheck_spec.ts

@@ -3484,6 +3484,31 @@ runInEachFileSystem(() => {
           `Argument of type 'number' is not assignable to parameter of type 'string'.`,
         );
       });
+
+      it('should check template literals with escaped characters', () => {
+        env.write(
+          'test.ts',
+          `
+          import {Component} from '@angular/core';
+
+          @Component({
+            template: '{{\\\`Hello \\\\\`\${check(name)}\\\\\`\\\`}}',
+          })
+          export class Main {
+            name = 'test';
+            check(input: number): string {
+              return String(input);
+            }
+          }
+        `,
+        );
+
+        const diags = env.driveDiagnostics();
+        expect(diags.length).toBe(1);
+        expect(diags[0].messageText).toBe(
+          `Argument of type 'string' is not assignable to parameter of type 'number'.`,
+        );
+      });
     });
 
     describe('tagged template literals', () => {