diff --git a/packages/compiler-cli/src/ngtsc/indexer/test/template_spec.ts b/packages/compiler-cli/src/ngtsc/indexer/test/template_spec.ts
index 15f6b521cd..6e016116cd 100644
--- a/packages/compiler-cli/src/ngtsc/indexer/test/template_spec.ts
+++ b/packages/compiler-cli/src/ngtsc/indexer/test/template_spec.ts
@@ -7,6 +7,7 @@
  */
 
 import {AbsoluteSourceSpan, IdentifierKind} from '..';
+import {runInEachFileSystem} from '../../file_system/testing';
 import {getTemplateIdentifiers} from '../src/template';
 import * as util from './util';
 
@@ -17,112 +18,114 @@ function bind(template: string) {
   });
 }
 
-describe('getTemplateIdentifiers', () => {
-  it('should generate nothing in HTML-only template', () => {
-    const refs = getTemplateIdentifiers(bind('<div></div>'));
+runInEachFileSystem(() => {
+  describe('getTemplateIdentifiers', () => {
+    it('should generate nothing in HTML-only template', () => {
+      const refs = getTemplateIdentifiers(bind('<div></div>'));
 
-    expect(refs.size).toBe(0);
-  });
-
-  it('should ignore comments', () => {
-    const refs = getTemplateIdentifiers(bind('<!-- {{comment}} -->'));
-
-    expect(refs.size).toBe(0);
-  });
-
-  it('should handle arbitrary whitespace', () => {
-    const template = '<div>\n\n   {{foo}}</div>';
-    const refs = getTemplateIdentifiers(bind(template));
-
-    const [ref] = Array.from(refs);
-    expect(ref).toEqual({
-      name: 'foo',
-      kind: IdentifierKind.Property,
-      span: new AbsoluteSourceSpan(12, 15),
+      expect(refs.size).toBe(0);
     });
-  });
 
-  it('should ignore identifiers defined in the template', () => {
-    const template = `
+    it('should ignore comments', () => {
+      const refs = getTemplateIdentifiers(bind('<!-- {{comment}} -->'));
+
+      expect(refs.size).toBe(0);
+    });
+
+    it('should handle arbitrary whitespace', () => {
+      const template = '<div>\n\n   {{foo}}</div>';
+      const refs = getTemplateIdentifiers(bind(template));
+
+      const [ref] = Array.from(refs);
+      expect(ref).toEqual({
+        name: 'foo',
+        kind: IdentifierKind.Property,
+        span: new AbsoluteSourceSpan(12, 15),
+      });
+    });
+
+    it('should ignore identifiers defined in the template', () => {
+      const template = `
       <input #model />
       {{model.valid}}
     `;
-    const refs = getTemplateIdentifiers(bind(template));
-
-    const refArr = Array.from(refs);
-    const modelId = refArr.find(ref => ref.name === 'model');
-    expect(modelId).toBeUndefined();
-  });
-
-  describe('generates identifiers for PropertyReads', () => {
-    it('should discover component properties', () => {
-      const template = '{{foo}}';
-      const refs = getTemplateIdentifiers(bind(template));
-      expect(refs.size).toBe(1);
-
-      const [ref] = Array.from(refs);
-      expect(ref).toEqual({
-        name: 'foo',
-        kind: IdentifierKind.Property,
-        span: new AbsoluteSourceSpan(2, 5),
-      });
-    });
-
-    it('should discover nested properties', () => {
-      const template = '<div><span>{{foo}}</span></div>';
       const refs = getTemplateIdentifiers(bind(template));
 
       const refArr = Array.from(refs);
-      expect(refArr).toEqual(jasmine.arrayContaining([{
-        name: 'foo',
-        kind: IdentifierKind.Property,
-        span: new AbsoluteSourceSpan(13, 16),
-      }]));
+      const modelId = refArr.find(ref => ref.name === 'model');
+      expect(modelId).toBeUndefined();
     });
 
-    it('should ignore identifiers that are not implicitly received by the template', () => {
-      const template = '{{foo.bar.baz}}';
-      const refs = getTemplateIdentifiers(bind(template));
-      expect(refs.size).toBe(1);
+    describe('generates identifiers for PropertyReads', () => {
+      it('should discover component properties', () => {
+        const template = '{{foo}}';
+        const refs = getTemplateIdentifiers(bind(template));
+        expect(refs.size).toBe(1);
 
-      const [ref] = Array.from(refs);
-      expect(ref.name).toBe('foo');
-    });
-  });
+        const [ref] = Array.from(refs);
+        expect(ref).toEqual({
+          name: 'foo',
+          kind: IdentifierKind.Property,
+          span: new AbsoluteSourceSpan(2, 5),
+        });
+      });
 
-  describe('generates identifiers for MethodCalls', () => {
-    it('should discover component method calls', () => {
-      const template = '{{foo()}}';
-      const refs = getTemplateIdentifiers(bind(template));
-      expect(refs.size).toBe(1);
+      it('should discover nested properties', () => {
+        const template = '<div><span>{{foo}}</span></div>';
+        const refs = getTemplateIdentifiers(bind(template));
 
-      const [ref] = Array.from(refs);
-      expect(ref).toEqual({
-        name: 'foo',
-        kind: IdentifierKind.Method,
-        span: new AbsoluteSourceSpan(2, 5),
+        const refArr = Array.from(refs);
+        expect(refArr).toEqual(jasmine.arrayContaining([{
+          name: 'foo',
+          kind: IdentifierKind.Property,
+          span: new AbsoluteSourceSpan(13, 16),
+        }]));
+      });
+
+      it('should ignore identifiers that are not implicitly received by the template', () => {
+        const template = '{{foo.bar.baz}}';
+        const refs = getTemplateIdentifiers(bind(template));
+        expect(refs.size).toBe(1);
+
+        const [ref] = Array.from(refs);
+        expect(ref.name).toBe('foo');
       });
     });
 
-    it('should discover nested properties', () => {
-      const template = '<div><span>{{foo()}}</span></div>';
-      const refs = getTemplateIdentifiers(bind(template));
+    describe('generates identifiers for MethodCalls', () => {
+      it('should discover component method calls', () => {
+        const template = '{{foo()}}';
+        const refs = getTemplateIdentifiers(bind(template));
+        expect(refs.size).toBe(1);
 
-      const refArr = Array.from(refs);
-      expect(refArr).toEqual(jasmine.arrayContaining([{
-        name: 'foo',
-        kind: IdentifierKind.Method,
-        span: new AbsoluteSourceSpan(13, 16),
-      }]));
-    });
+        const [ref] = Array.from(refs);
+        expect(ref).toEqual({
+          name: 'foo',
+          kind: IdentifierKind.Method,
+          span: new AbsoluteSourceSpan(2, 5),
+        });
+      });
 
-    it('should ignore identifiers that are not implicitly received by the template', () => {
-      const template = '{{foo().bar().baz()}}';
-      const refs = getTemplateIdentifiers(bind(template));
-      expect(refs.size).toBe(1);
+      it('should discover nested properties', () => {
+        const template = '<div><span>{{foo()}}</span></div>';
+        const refs = getTemplateIdentifiers(bind(template));
 
-      const [ref] = Array.from(refs);
-      expect(ref.name).toBe('foo');
+        const refArr = Array.from(refs);
+        expect(refArr).toEqual(jasmine.arrayContaining([{
+          name: 'foo',
+          kind: IdentifierKind.Method,
+          span: new AbsoluteSourceSpan(13, 16),
+        }]));
+      });
+
+      it('should ignore identifiers that are not implicitly received by the template', () => {
+        const template = '{{foo().bar().baz()}}';
+        const refs = getTemplateIdentifiers(bind(template));
+        expect(refs.size).toBe(1);
+
+        const [ref] = Array.from(refs);
+        expect(ref.name).toBe('foo');
+      });
     });
   });
 });
diff --git a/packages/compiler/src/expression_parser/ast.ts b/packages/compiler/src/expression_parser/ast.ts
index 89b8d4669e..7756fde607 100644
--- a/packages/compiler/src/expression_parser/ast.ts
+++ b/packages/compiler/src/expression_parser/ast.ts
@@ -209,7 +209,12 @@ export class ASTWithSource extends AST {
       public errors: ParserError[]) {
     super(new ParseSpan(0, source == null ? 0 : source.length));
   }
-  visit(visitor: AstVisitor, context: any = null): any { return this.ast.visit(visitor, context); }
+  visit(visitor: AstVisitor, context: any = null): any {
+    if (visitor.visitASTWithSource) {
+      return visitor.visitASTWithSource(this, context);
+    }
+    return this.ast.visit(visitor, context);
+  }
   toString(): string { return `${this.source} in ${this.location}`; }
 }
 
@@ -240,6 +245,7 @@ export interface AstVisitor {
   visitQuote(ast: Quote, context: any): any;
   visitSafeMethodCall(ast: SafeMethodCall, context: any): any;
   visitSafePropertyRead(ast: SafePropertyRead, context: any): any;
+  visitASTWithSource?(ast: ASTWithSource, context: any): any;
   visit?(ast: AST, context?: any): any;
 }