From b61784948afb3e5d08c4f55abeb25b146beebda3 Mon Sep 17 00:00:00 2001
From: Alex Rickabaugh <alx+alxhub@alxandria.net>
Date: Fri, 24 May 2019 14:37:52 -0700
Subject: [PATCH] fix(ivy): template inputs/outputs should not be bound in
 template scope (#30669)

The R3TargetBinder "binds" an Angular template AST, computing semantic
information regarding the template and making it accessible.

One of the binding passes previously had a bug, where for the following
template:

<div *ngIf="foo as foo"></div>

which desugars to:

<ng-template ngIf [ngIf]="foo" let-foo="ngIf">
  <div></div>
</ng-template>

would have the `[ngIf]` binding processed twice - in both the scope which
contains the `<ng-template>` and the scope inside the template. The bug
arises because during the latter, `foo` is a variable defined by `let-foo`,
and so the R3TargetBinder would incorrectly learn that `foo` inside `[ngIf]`
maps to that variable.

This commit fixes the bug by only processing inputs, outputs, and
templateAttrs from `Template`s in the outer scope.

PR Close #30669
---
 .../test/ngtsc/template_typecheck_spec.ts     | 25 +++++++++++++++++++
 .../compiler/src/render3/view/t2_binder.ts    |  8 ++----
 2 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/packages/compiler-cli/test/ngtsc/template_typecheck_spec.ts b/packages/compiler-cli/test/ngtsc/template_typecheck_spec.ts
index 09116d003a..2ed017e3e9 100644
--- a/packages/compiler-cli/test/ngtsc/template_typecheck_spec.ts
+++ b/packages/compiler-cli/test/ngtsc/template_typecheck_spec.ts
@@ -270,6 +270,31 @@ describe('ngtsc type checking', () => {
     expect(diags[0].messageText).toContain('does_not_exist');
   });
 
+  it('should property type-check a microsyntax variable with the same name as the expression',
+     () => {
+       env.write('test.ts', `
+    import {CommonModule} from '@angular/common';
+    import {Component, Input, NgModule} from '@angular/core';
+
+    @Component({
+      selector: 'test',
+      template: '<div *ngIf="foo as foo">{{foo}}</div>',
+    })
+    export class TestCmp<T extends {name: string}> {
+      foo: any;
+    }
+
+    @NgModule({
+      declarations: [TestCmp],
+      imports: [CommonModule],
+    })
+    export class Module {}
+    `);
+
+       const diags = env.driveDiagnostics();
+       expect(diags.length).toBe(0);
+     });
+
   it('should properly type-check inherited directives', () => {
     env.write('test.ts', `
     import {Component, Directive, Input, NgModule} from '@angular/core';
diff --git a/packages/compiler/src/render3/view/t2_binder.ts b/packages/compiler/src/render3/view/t2_binder.ts
index d67b353551..a1eb09df4b 100644
--- a/packages/compiler/src/render3/view/t2_binder.ts
+++ b/packages/compiler/src/render3/view/t2_binder.ts
@@ -372,12 +372,8 @@ class TemplateBinder extends RecursiveAstVisitor implements Visitor {
 
   private ingest(template: Template|Node[]): void {
     if (template instanceof Template) {
-      // For <ng-template>s, process inputs, outputs, template attributes,
-      // variables, and child nodes.
-      // References were processed in the scope of the containing template.
-      template.inputs.forEach(this.visitNode);
-      template.outputs.forEach(this.visitNode);
-      template.templateAttrs.forEach(this.visitNode);
+      // For <ng-template>s, process only variables and child nodes. Inputs, outputs, templateAttrs,
+      // and references were all processed in the scope of the containing template.
       template.variables.forEach(this.visitNode);
       template.children.forEach(this.visitNode);