fix(Compiler): relax childIsRecursive check

Fix how the compiler checks for recursive components by also considering
component descendants. Previously, it only checked if the current
component was evaluated previously. This failed in certain cases of
mutually recursive components, causing `createAsync` in tests to not
resolve.

closes [7084](angular#7084)

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

@@ -116,6 +116,11 @@ export class RuntimeCompiler implements ComponentResolver {
       var childViewPipes: CompilePipeMetadata[] =
           this._metadataResolver.getViewPipesMetadata(dep.comp.type.runtime);
       var childIsRecursive = ListWrapper.contains(childCompilingComponentsPath, childCacheKey);
+      childViewDirectives.map(x => x.type.runtime).forEach(descendant => {
+          if (ListWrapper.contains(childCompilingComponentsPath, descendant)) {
+              childIsRecursive = true;
+          }
+      });
       childCompilingComponentsPath.push(childCacheKey);
 
       var childComp = this._loadAndCompileComponent(

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

@@ -4,7 +4,7 @@ import {AsyncTestCompleter} from '@angular/core/testing/testing_internal';
 
 import {IS_DART} from '../../src/facade/lang';
 
-import {Component, Pipe, PipeTransform, provide, ViewMetadata, PLATFORM_PIPES, OpaqueToken, Injector} from '@angular/core';
+import {Component, Pipe, PipeTransform, provide, ViewMetadata, PLATFORM_PIPES, OpaqueToken, Injector, forwardRef} from '@angular/core';
 import {NgIf, NgClass} from '@angular/common';
 import {CompilerConfig} from '@angular/compiler';
 
@@ -180,6 +180,15 @@ function declareTests(isJit: boolean) {
                  });
            }));
 
+    it('should handle mutual recursion entered from multiple sides - #7084',
+      inject([TestComponentBuilder, AsyncTestCompleter], (tcb: TestComponentBuilder, async) => {
+        tcb.createAsync(FakeRecursiveComp)
+            .then((fixture) => {
+              fixture.detectChanges();
+              expect(fixture.nativeElement).toHaveText('[]');
+              async.done();
+            });
+      }));
 
   });
 }
@@ -202,3 +211,31 @@ class CustomPipe implements PipeTransform {
 @Component({selector: 'cmp-content', template: `<ng-content></ng-content>`})
 class CmpWithNgContent {
 }
+
+@Component({
+  selector: 'left',
+  template: `L<right *ngIf="false"></right>`,
+  directives: [
+    forwardRef(() => RightComp),
+  ]
+})
+class LeftComp {}
+
+@Component({
+  selector: 'right',
+  template: `R<left *ngIf="false"></left>`,
+  directives: [
+    forwardRef(() => LeftComp),
+  ]
+})
+class RightComp {}
+
+@Component({
+  selector: 'fakeRecursiveComp',
+  template: `[<left *ngIf="false"></left><right *ngIf="false"></right>]`,
+  directives: [
+    forwardRef(() => LeftComp),
+    forwardRef(() => RightComp),
+  ]
+})
+class FakeRecursiveComp {}