feat(core): template-var-assignment update schematic (#29608)

Introduces a new update schematic called "template-var-assignment"
that is responsible for analyzing template files in order to warn
developers if template variables are assigned to values.

The schematic also comes with a driver for `tslint` so that the
check can be used wtihin Google.

PR Close #29608

packages/core/schematics/migrations/template-var-assignment/google3/BUILD.bazel

@@ -0,0 +1,13 @@
+load("//tools:defaults.bzl", "ts_library")
+
+ts_library(
+    name = "google3",
+    srcs = glob(["**/*.ts"]),
+    tsconfig = "//packages/core/schematics:tsconfig.json",
+    visibility = ["//packages/core/schematics/test:__pkg__"],
+    deps = [
+        "//packages/core/schematics/migrations/template-var-assignment",
+        "//packages/core/schematics/utils/tslint",
+        "@npm//tslint",
+    ],
+)

packages/core/schematics/migrations/template-var-assignment/google3/noTemplateVariableAssignmentRule.ts

@@ -0,0 +1,53 @@
+/**
+ * @license
+ * Copyright Google Inc. All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+import {RuleFailure, Rules} from 'tslint';
+import * as ts from 'typescript';
+
+import {createHtmlSourceFile} from '../../../utils/tslint/tslint_html_source_file';
+import {analyzeResolvedTemplate} from '../analyze_template';
+import {NgComponentTemplateVisitor} from '../angular/ng_component_template';
+
+const FAILURE_MESSAGE = 'Found assignment to template variable. This does not work with Ivy and ' +
+    'needs to be updated.';
+
+/**
+ * Rule that reports if an Angular template contains property assignments to template variables.
+ */
+export class Rule extends Rules.TypedRule {
+  applyWithProgram(sourceFile: ts.SourceFile, program: ts.Program): RuleFailure[] {
+    const typeChecker = program.getTypeChecker();
+    const templateVisitor = new NgComponentTemplateVisitor(typeChecker);
+    const failures: RuleFailure[] = [];
+
+    // Analyze the current source files by detecting all referenced HTML templates.
+    templateVisitor.visitNode(sourceFile);
+
+    const {resolvedTemplates} = templateVisitor;
+
+    // Analyze each resolved template and print a warning for property writes to
+    // template variables.
+    resolvedTemplates.forEach((template, filePath) => {
+      const nodes = analyzeResolvedTemplate(filePath, template);
+      const templateFile =
+          template.inline ? sourceFile : createHtmlSourceFile(filePath, template.content);
+
+      if (!nodes) {
+        return;
+      }
+
+      nodes.forEach(n => {
+        failures.push(new RuleFailure(
+            templateFile, template.start + n.start, template.start + n.end, FAILURE_MESSAGE,
+            this.ruleName));
+      });
+    });
+
+    return failures;
+  }
+}