fix(compiler): report errors for queries without selectors (#9018)

Fixes #4489

modules/@angular/compiler/src/metadata_resolver.ts

@@ -161,8 +161,8 @@ export class CompileMetadataResolver {
       var queries = [];
       var viewQueries = [];
       if (isPresent(dirMeta.queries)) {
-        queries = this.getQueriesMetadata(dirMeta.queries, false);
+        queries = this.getQueriesMetadata(dirMeta.queries, false, directiveType);
-        viewQueries = this.getQueriesMetadata(dirMeta.queries, true);
+        viewQueries = this.getQueriesMetadata(dirMeta.queries, true, directiveType);
       }
       meta = cpl.CompileDirectiveMetadata.create({
         selector: dirMeta.selector,
@@ -314,8 +314,8 @@ export class CompileMetadataResolver {
         isSelf: isSelf,
         isSkipSelf: isSkipSelf,
         isOptional: isOptional,
-        query: isPresent(query) ? this.getQueryMetadata(query, null) : null,
+        query: isPresent(query) ? this.getQueryMetadata(query, null, typeOrFunc) : null,
-        viewQuery: isPresent(viewQuery) ? this.getQueryMetadata(viewQuery, null) : null,
+        viewQuery: isPresent(viewQuery) ? this.getQueryMetadata(viewQuery, null, typeOrFunc) : null,
         token: this.getTokenMetadata(token)
       });
 
@@ -381,21 +381,24 @@ export class CompileMetadataResolver {
   }
 
   getQueriesMetadata(queries: {[key: string]: QueryMetadata},
-                     isViewQuery: boolean): cpl.CompileQueryMetadata[] {
+                     isViewQuery: boolean, directiveType: Type): cpl.CompileQueryMetadata[] {
     var compileQueries = [];
     StringMapWrapper.forEach(queries, (query, propertyName) => {
       if (query.isViewQuery === isViewQuery) {
-        compileQueries.push(this.getQueryMetadata(query, propertyName));
+        compileQueries.push(this.getQueryMetadata(query, propertyName, directiveType));
       }
     });
     return compileQueries;
   }
 
-  getQueryMetadata(q: QueryMetadata, propertyName: string): cpl.CompileQueryMetadata {
+  getQueryMetadata(q: QueryMetadata, propertyName: string, typeOrFunc: Type | Function): cpl.CompileQueryMetadata {
     var selectors;
     if (q.isVarBindingQuery) {
       selectors = q.varBindings.map(varName => this.getTokenMetadata(varName));
     } else {
+      if (!isPresent(q.selector)) {
+        throw new BaseException(`Can't construct a query for the property "${propertyName}" of "${stringify(typeOrFunc)}" since the query selector wasn't defined.`);
+      }
       selectors = [this.getTokenMetadata(q.selector)];
     }
     return new cpl.CompileQueryMetadata({

modules/@angular/core/test/linker/query_integration_spec.ts

@@ -11,7 +11,7 @@ import {
 import {TestComponentBuilder} from '@angular/compiler/testing';
 import {AsyncTestCompleter} from '@angular/core/testing/testing_internal';
 
-import {isPresent} from '../../src/facade/lang';
+import {isPresent, stringify} from '../../src/facade/lang';
 import {ObservableWrapper} from '../../src/facade/async';
 
 import {
@@ -262,6 +262,17 @@ export function main() {
                  async.done();
                });
          }));
+
+      it('should throw with descriptive error when query selectors are not present',
+         inject([TestComponentBuilder, AsyncTestCompleter], (tcb: TestComponentBuilder, async) => {
+           tcb.overrideTemplate(MyCompBroken0, '<has-null-query-condition></has-null-query-condition>')
+               .createAsync(MyCompBroken0)
+               .catch((e) => {
+                  expect(e.message).toEqual(
+                 `Can't construct a query for the property "errorTrigger" of "${stringify(HasNullQueryCondition)}" since the query selector wasn't defined.`);   
+                 async.done();
+               });
+         }));
     });
 
     describe('query for TemplateRef', () => {
@@ -1086,6 +1097,11 @@ class NeedsViewContainerWithRead {
   createView() { this.vc.createEmbeddedView(this.template); }
 }
 
+@Component({selector: 'has-null-query-condition', template: '<div></div>'})
+class HasNullQueryCondition {
+  @ContentChildren(null) errorTrigger;
+}
+
 @Component({
   selector: 'my-comp',
   directives: [
@@ -1128,3 +1144,12 @@ class MyComp0 {
     this.list = ['1d', '2d', '3d'];
   }
 }
+
+@Component({
+  selector: 'my-comp',
+  directives: [HasNullQueryCondition],
+  template: ''
+})
+@Injectable()
+class MyCompBroken0 {
+}