fix(compiler): generated code should pass `noUnusedLocals` check

Closes #14797

packages/compiler-cli/integrationtest/src/basic.ts

@@ -6,7 +6,6 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {NgFor, NgIf} from '@angular/common';
 import {Component, Inject, LOCALE_ID, TRANSLATIONS_FORMAT} from '@angular/core';
 
 

packages/compiler-cli/integrationtest/src/bootstrap.ts

@@ -6,7 +6,6 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {platformBrowser} from '@angular/platform-browser';
 import {BasicComp} from './basic';
 import {MainModuleNgFactory} from './module.ngfactory';
 

packages/compiler-cli/integrationtest/src/module_fixtures.ts

@@ -6,8 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {LowerCasePipe, NgIf} from '@angular/common';
+import {ANALYZE_FOR_ENTRY_COMPONENTS, Component, Directive, Injectable, InjectionToken, Input, NgModule, Pipe} from '@angular/core';
-import {ANALYZE_FOR_ENTRY_COMPONENTS, Component, ComponentFactoryResolver, Directive, Inject, Injectable, InjectionToken, Input, ModuleWithProviders, NgModule, Pipe} from '@angular/core';
 
 @Injectable()
 export class SomeService {

packages/compiler-cli/integrationtest/src/queries.ts

@@ -6,7 +6,6 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {NgFor} from '@angular/common';
 import {Component, Directive, QueryList, ViewChild, ViewChildren} from '@angular/core';
 
 @Component({selector: 'comp-for-child-query', template: 'child'})

packages/compiler-cli/integrationtest/test/query_spec.ts

@@ -7,7 +7,7 @@
  */
 
 import './init';
-import {DebugElement, QueryList} from '@angular/core';
+import {QueryList} from '@angular/core';
 import {By} from '@angular/platform-browser';
 import {CompForChildQuery, CompWithChildQuery} from '../src/queries';
 import {createComponent} from './util';
@@ -16,7 +16,7 @@ describe('child queries', () => {
   it('should support compiling child queries', () => {
     const childQueryCompFixture = createComponent(CompWithChildQuery);
     const debugElement = childQueryCompFixture.debugElement;
-    const compWithChildren = debugElement.query(By.directive(CompWithChildQuery));
+    debugElement.query(By.directive(CompWithChildQuery));
     expect(childQueryCompFixture.componentInstance.child).toBeDefined();
     expect(childQueryCompFixture.componentInstance.child instanceof CompForChildQuery).toBe(true);
 
@@ -25,7 +25,7 @@ describe('child queries', () => {
   it('should support compiling children queries', () => {
     const childQueryCompFixture = createComponent(CompWithChildQuery);
     const debugElement = childQueryCompFixture.debugElement;
-    const compWithChildren = debugElement.query(By.directive(CompWithChildQuery));
+    debugElement.query(By.directive(CompWithChildQuery));
 
     childQueryCompFixture.detectChanges();
 

packages/compiler-cli/integrationtest/test/test_ngtools_api.ts

@@ -15,7 +15,7 @@ import * as path from 'path';
 import * as ts from 'typescript';
 import * as assert from 'assert';
 import {tsc} from '@angular/tsc-wrapped/src/tsc';
-import {AngularCompilerOptions, CodeGenerator, CompilerHostContext, NodeCompilerHostContext, __NGTOOLS_PRIVATE_API_2} from '@angular/compiler-cli';
+import {NodeCompilerHostContext, __NGTOOLS_PRIVATE_API_2} from '@angular/compiler-cli';
 
 const glob = require('glob');
 

packages/compiler-cli/integrationtest/test/util.ts

@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {NgModuleFactory, NgModuleRef} from '@angular/core';
+import {NgModuleRef} from '@angular/core';
 import {ComponentFixture} from '@angular/core/testing';
 import {platformServer} from '@angular/platform-server';
 

packages/compiler-cli/integrationtest/tsconfig-build.json

@@ -16,7 +16,8 @@
     "lib": ["es6", "dom"],
     "baseUrl": ".",
     // Prevent scanning up the directory tree for types
-    "typeRoots": ["node_modules/@types"]
+    "typeRoots": ["node_modules/@types"],
+    "noUnusedLocals": true
   },
 
   "files": [

packages/compiler/src/jit/compiler.ts

@@ -258,15 +258,17 @@ export class JitCompiler implements Compiler {
         usedPipes);
     const statements =
         stylesCompileResult.componentStylesheet.statements.concat(compileResult.statements);
+    let viewClassAndRendererTypeVars = compMeta.isHost ?
+        [compileResult.viewClassVar] :
+        [compileResult.viewClassVar, compileResult.rendererTypeVar];
     let viewClass: any;
     let rendererType: any;
     if (!this._compilerConfig.useJit) {
-      [viewClass, rendererType] = interpretStatements(
+      [viewClass, rendererType] = interpretStatements(statements, viewClassAndRendererTypeVars);
-          statements, [compileResult.viewClassVar, compileResult.rendererTypeVar]);
     } else {
       [viewClass, rendererType] = jitStatements(
           templateJitUrl(template.ngModule.type, template.compMeta), statements,
-          [compileResult.viewClassVar, compileResult.rendererTypeVar]);
+          viewClassAndRendererTypeVars);
     }
     template.compiled(viewClass, rendererType);
   }

packages/compiler/src/output/output_ast.ts

@@ -1001,6 +1001,28 @@ export class RecursiveAstVisitor implements StatementVisitor, ExpressionVisitor
   }
 }
 
+export function findReadVarNames(stmts: Statement[]): Set<string> {
+  const visitor = new _ReadVarVisitor();
+  visitor.visitAllStatements(stmts, null);
+  return visitor.varNames;
+}
+
+class _ReadVarVisitor extends RecursiveAstVisitor {
+  varNames = new Set<string>();
+  visitDeclareFunctionStmt(stmt: DeclareFunctionStmt, context: any): any {
+    // Don't descend into nested functions
+    return stmt;
+  }
+  visitDeclareClassStmt(stmt: ClassStmt, context: any): any {
+    // Don't descend into nested classes
+    return stmt;
+  }
+  visitReadVarExpr(ast: ReadVarExpr, context: any): any {
+    this.varNames.add(ast.name);
+    return null;
+  }
+}
+
 export function applySourceSpanToStatementIfNeeded(
     stmt: Statement, sourceSpan: ParseSourceSpan): Statement {
   if (!sourceSpan) {

packages/compiler/src/view_compiler/view_compiler.ts

@@ -44,6 +44,8 @@ export class ViewCompiler {
 
     const statements: o.Statement[] = [];
 
+    let renderComponentVarName: string;
+    if (!component.isHost) {
       const customRenderData: o.LiteralMapEntry[] = [];
       if (component.template.animations && component.template.animations.length) {
         customRenderData.push(new o.LiteralMapEntry(
@@ -51,17 +53,20 @@ export class ViewCompiler {
       }
 
       const renderComponentVar = o.variable(rendererTypeName(component.type.reference));
+      renderComponentVarName = renderComponentVar.name;
       statements.push(
           renderComponentVar
-            .set(o.importExpr(createIdentifier(Identifiers.createRendererType2)).callFn([
+              .set(o.importExpr(createIdentifier(Identifiers.createRendererType2))
-              new o.LiteralMapExpr([
+                       .callFn([new o.LiteralMapExpr([
-                new o.LiteralMapEntry('encapsulation', o.literal(component.template.encapsulation)),
+                         new o.LiteralMapEntry(
+                             'encapsulation', o.literal(component.template.encapsulation)),
                          new o.LiteralMapEntry('styles', styles),
                          new o.LiteralMapEntry('data', new o.LiteralMapExpr(customRenderData))
-              ])
+                       ])]))
-            ]))
               .toDeclStmt(
-                o.importType(createIdentifier(Identifiers.RendererType2)), [o.StmtModifier.Final]));
+                  o.importType(createIdentifier(Identifiers.RendererType2)),
+                  [o.StmtModifier.Final]));
+    }
 
     const viewBuilderFactory = (parent: ViewBuilder): ViewBuilder => {
       const embeddedViewIndex = embeddedViewCount++;
@@ -74,7 +79,7 @@ export class ViewCompiler {
 
     statements.push(...visitor.build());
 
-    return new ViewCompileResult(statements, visitor.viewName, renderComponentVar.name);
+    return new ViewCompileResult(statements, visitor.viewName, renderComponentVarName);
   }
 }
 
@@ -204,7 +209,7 @@ class ViewBuilder implements TemplateAstVisitor, LocalResolver {
     let updateFn: o.Expression;
     if (updateStmts.length > 0) {
       const preStmts: o.Statement[] = [];
-      if (!this.component.isHost) {
+      if (!this.component.isHost && o.findReadVarNames(updateStmts).has(COMP_VAR.name)) {
         preStmts.push(COMP_VAR.set(VIEW_VAR.prop('component')).toDeclStmt(this.compType));
       }
       updateFn = o.fn(
@@ -835,7 +840,7 @@ class ViewBuilder implements TemplateAstVisitor, LocalResolver {
     if (handleEventStmts.length > 0) {
       const preStmts: o.Statement[] =
           [ALLOW_DEFAULT_VAR.set(o.literal(true)).toDeclStmt(o.BOOL_TYPE)];
-      if (!this.component.isHost) {
+      if (!this.component.isHost && o.findReadVarNames(handleEventStmts).has(COMP_VAR.name)) {
         preStmts.push(COMP_VAR.set(VIEW_VAR.prop('component')).toDeclStmt(this.compType));
       }
       handleEventFn = o.fn(