Remove some unnecessary null checks

These were found using the unnecessary-null-checks lint. It has a bug
that prevents us from enabling it at the moment, but we should consider
enabling it once the bug has been fixed.

Change-Id: Ice250b5a6a8723c5f08dec5b07ae738e17c842cc
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/196550
Reviewed-by: Konstantin Shcheglov <scheglov@google.com>
Commit-Queue: Brian Wilkerson <brianwilkerson@google.com>

pkg/analysis_server/lib/src/services/kythe/kythe_visitors.dart

@@ -440,7 +440,7 @@ class KytheDartVisitor extends GeneralizingAstVisitor<void> with OutputUtils {
   void visitEnumConstantDeclaration(EnumConstantDeclaration node) {
     // constant node
     var constDeclVName =
-        addNodeAndFacts(schema.CONSTANT_KIND, element: node.declaredElement!);
+        addNodeAndFacts(schema.CONSTANT_KIND, element: node.declaredElement);
 
     // anchor- defines/binding, defines
     addAnchorEdgesContainingEdge(

pkg/analysis_server/test/lsp/code_actions_fixes_test.dart

@@ -123,7 +123,7 @@ class FixesCodeActionsTest extends AbstractCodeActionsTest {
         CodeActionKind('quickfix.create.file'), "Create file 'newfile.dart'")!;
 
     final edit = fixAction.edit!;
-    expect(edit.documentChanges!, isNotNull);
+    expect(edit.documentChanges, isNotNull);
 
     // Ensure applying the changes creates the file and with the expected content.
     final contents = {

pkg/analysis_server/test/socket_server_test.dart

@@ -110,7 +110,7 @@ class SocketServerTest {
         null);
 
     server.createAnalysisServer(channel);
-    errorNotifier.server = server.analysisServer!;
+    errorNotifier.server = server.analysisServer;
     AnalysisEngine.instance.instrumentationService = errorNotifier;
 
     return server;

pkg/analyzer/lib/file_system/physical_file_system.dart

@@ -23,7 +23,7 @@ const String _SERVER_DIR = ".dartServer";
 String? _getStandardStateLocation() {
   final Map<String, String> env = io.Platform.environment;
   if (env.containsKey('ANALYZER_STATE_LOCATION_OVERRIDE')) {
-    return env['ANALYZER_STATE_LOCATION_OVERRIDE']!;
+    return env['ANALYZER_STATE_LOCATION_OVERRIDE'];
   }
 
   final home = io.Platform.isWindows ? env['LOCALAPPDATA'] : env['HOME'];

pkg/analyzer/lib/src/dart/analysis/index.dart

@@ -94,7 +94,7 @@ class ElementNameComponents {
     String? classMemberName;
     if (element.enclosingElement is ClassElement ||
         element.enclosingElement is ExtensionElement) {
-      classMemberName = element.name!;
+      classMemberName = element.name;
       element = element.enclosingElement!;
     }
 

pkg/analyzer/lib/src/error/unused_local_elements_verifier.dart

@@ -85,7 +85,7 @@ class GatherUsedLocalElementsVisitor extends RecursiveAstVisitor<void> {
   @override
   void visitFunctionExpression(FunctionExpression node) {
     if (node.parent is! FunctionDeclaration) {
-      usedElements.addElement(node.declaredElement!);
+      usedElements.addElement(node.declaredElement);
     }
     super.visitFunctionExpression(node);
   }

pkg/analyzer/lib/src/fasta/ast_builder.dart

@@ -467,10 +467,10 @@ class AstBuilder extends StackListener {
         target = target.function;
       } else if (target is MethodInvocation) {
         argumentList = target.argumentList;
-        target = target.target!;
+        target = target.target;
       } else if (target is PropertyAccess) {
         argumentList = null;
-        target = target.target!;
+        target = target.target;
       } else {
         break;
       }

pkg/analyzer/lib/src/generated/error_verifier.dart

@@ -561,7 +561,7 @@ class ErrorVerifier extends RecursiveAstVisitor<void>
   void visitEnumDeclaration(EnumDeclaration node) {
     var outerEnum = _enclosingEnum;
     try {
-      _enclosingEnum = node.declaredElement!;
+      _enclosingEnum = node.declaredElement;
       _duplicateDefinitionVerifier.checkEnum(node);
       super.visitEnumDeclaration(node);
     } finally {

pkg/analyzer/lib/src/generated/resolver.dart

@@ -1221,7 +1221,7 @@ class ResolverVisitor extends ScopedVisitor with ErrorDetectionHelpers {
   @override
   void visitConstructorDeclaration(ConstructorDeclaration node) {
     var outerFunction = _enclosingFunction;
-    _enclosingFunction = node.declaredElement!;
+    _enclosingFunction = node.declaredElement;
 
     flowAnalysis!.topLevelDeclaration_enter(node, node.parameters, node.body);
     flowAnalysis!.executableDeclaration_enter(node, node.parameters, false);
@@ -1510,7 +1510,7 @@ class ResolverVisitor extends ScopedVisitor with ErrorDetectionHelpers {
   @override
   void visitFunctionExpression(covariant FunctionExpressionImpl node) {
     var outerFunction = _enclosingFunction;
-    _enclosingFunction = node.declaredElement!;
+    _enclosingFunction = node.declaredElement;
 
     if (node.parent is FunctionDeclaration) {
       _functionExpressionResolver.resolve(node);
@@ -1711,7 +1711,7 @@ class ResolverVisitor extends ScopedVisitor with ErrorDetectionHelpers {
   @override
   void visitMethodDeclaration(MethodDeclaration node) {
     var outerFunction = _enclosingFunction;
-    _enclosingFunction = node.declaredElement!;
+    _enclosingFunction = node.declaredElement;
 
     flowAnalysis!.topLevelDeclaration_enter(node, node.parameters, node.body);
     flowAnalysis!.executableDeclaration_enter(node, node.parameters, false);

pkg/analyzer/lib/src/lint/pub.dart

@@ -303,7 +303,7 @@ class _PSNode implements PSNode {
   @override
   Source get source => (resourceProvider ?? PhysicalResourceProvider.INSTANCE)
       .getFile(span.sourceUrl!.toFilePath())
-      .createSource(span.sourceUrl!);
+      .createSource(span.sourceUrl);
 
   @override
   String toString() => '$text';

pkg/analyzer/lib/src/summary2/reference_resolver.dart

@@ -62,7 +62,7 @@ class ReferenceResolver extends ThrowingAstVisitor<void> {
     var outerReference = reference;
 
     var element = node.declaredElement as ClassElementImpl;
-    reference = element.reference!;
+    reference = element.reference;
     element.accessors; // create elements
     element.constructors; // create elements
     element.methods; // create elements
@@ -91,7 +91,7 @@ class ReferenceResolver extends ThrowingAstVisitor<void> {
     var outerReference = reference;
 
     var element = node.declaredElement as ClassElementImpl;
-    reference = element.reference!;
+    reference = element.reference;
 
     _createTypeParameterElements(element, node.typeParameters);
     scope = TypeParameterScope(scope, element.typeParameters);
@@ -119,7 +119,7 @@ class ReferenceResolver extends ThrowingAstVisitor<void> {
     var outerReference = reference;
 
     var element = node.declaredElement as ConstructorElementImpl;
-    reference = element.reference!;
+    reference = element.reference;
     element.parameters; // create elements
 
     scope = TypeParameterScope(scope, element.typeParameters);
@@ -153,7 +153,7 @@ class ReferenceResolver extends ThrowingAstVisitor<void> {
     var outerReference = reference;
 
     var element = node.declaredElement as ExtensionElementImpl;
-    reference = element.reference!;
+    reference = element.reference;
 
     _createTypeParameterElements(element, node.typeParameters);
     scope = TypeParameterScope(scope, element.typeParameters);
@@ -208,7 +208,7 @@ class ReferenceResolver extends ThrowingAstVisitor<void> {
     var outerReference = reference;
 
     var element = node.declaredElement as ExecutableElementImpl;
-    reference = element.reference!;
+    reference = element.reference;
     element.parameters; // create elements
 
     _createTypeParameterElements(
@@ -238,7 +238,7 @@ class ReferenceResolver extends ThrowingAstVisitor<void> {
     var outerReference = reference;
 
     var element = node.declaredElement as TypeAliasElementImpl;
-    reference = element.reference!;
+    reference = element.reference;
 
     _createTypeParameterElements(element, node.typeParameters);
     scope = TypeParameterScope(outerScope, element.typeParameters);
@@ -247,7 +247,7 @@ class ReferenceResolver extends ThrowingAstVisitor<void> {
     node.typeParameters?.accept(this);
 
     var function = element.aliasedElement as GenericFunctionTypeElementImpl;
-    reference = function.reference!;
+    reference = function.reference;
     function.parameters; // create elements
     node.parameters.accept(this);
 
@@ -291,7 +291,7 @@ class ReferenceResolver extends ThrowingAstVisitor<void> {
 
     var element = GenericFunctionTypeElementImpl.forLinkedNode(
       unitReference.element as CompilationUnitElementImpl,
-      reference!,
+      reference,
       node,
     );
     element.parameters; // create elements
@@ -318,7 +318,7 @@ class ReferenceResolver extends ThrowingAstVisitor<void> {
     var outerReference = reference;
 
     var element = node.declaredElement as TypeAliasElementImpl;
-    reference = element.reference!;
+    reference = element.reference;
 
     _createTypeParameterElements(element, node.typeParameters);
     scope = TypeParameterScope(outerScope, element.typeParameters);
@@ -349,7 +349,7 @@ class ReferenceResolver extends ThrowingAstVisitor<void> {
     var outerReference = reference;
 
     var element = node.declaredElement as ExecutableElementImpl;
-    reference = element.reference!;
+    reference = element.reference;
     element.parameters; // create elements
 
     _createTypeParameterElements(element, node.typeParameters);
@@ -372,7 +372,7 @@ class ReferenceResolver extends ThrowingAstVisitor<void> {
     var outerReference = reference;
 
     var element = node.declaredElement as MixinElementImpl;
-    reference = element.reference!;
+    reference = element.reference;
     element.accessors; // create elements
     element.constructors; // create elements
     element.methods; // create elements

pkg/analyzer/test/src/dart/analysis/driver_test.dart

@@ -1636,7 +1636,7 @@ class B {}
     expect(result.units, hasLength(1));
     expect(result.units![0].path, testFile);
     expect(result.units![0].content, content);
-    expect(result.units![0].unit!, isNotNull);
+    expect(result.units![0].unit, isNotNull);
     expect(result.units![0].errors, isEmpty);
   }
 
@@ -1689,7 +1689,7 @@ class B {}
     expect(result.uri.toString(), 'package:test/test.dart');
     expect(result.state, ResultState.VALID);
     expect(result.content, content);
-    expect(result.unit!, isNotNull);
+    expect(result.unit, isNotNull);
     expect(result.errors, hasLength(0));
 
     var f = result.unit!.declarations[0] as FunctionDeclaration;
@@ -2135,7 +2135,7 @@ var A2 = B1;
 
     var result = await resultFuture;
     expect(result.path, testFile);
-    expect(result.unit!, isNotNull);
+    expect(result.unit, isNotNull);
   }
 
   test_getResult_twoPendingFutures() async {
@@ -2150,7 +2150,7 @@ var A2 = B1;
     ResolvedUnitResult result2 = await future2;
     expect(result2, same(result1));
     expect(result1.path, testFile);
-    expect(result1.unit!, isNotNull);
+    expect(result1.unit, isNotNull);
   }
 
   @deprecated
@@ -3158,7 +3158,7 @@ var b = new B();
     // A and B references.
     ResolvedUnitResult result = await driver.getResultValid(c);
     expect(result.errors, isNotEmpty);
-    expect(result.unit!, isNotNull);
+    expect(result.unit, isNotNull);
   }
 
   test_part_getUnitElement2_afterLibrary() async {
@@ -3536,7 +3536,7 @@ var b = new B();
     // analyze the delayed parts.
     ResolvedUnitResult result = allResults.lastWhere((r) => r.path == c);
     expect(result.errors, isEmpty);
-    expect(result.unit!, isNotNull);
+    expect(result.unit, isNotNull);
   }
 
   test_removeFile_changeFile_implicitlyAnalyzed() async {
@@ -3786,7 +3786,7 @@ class F extends X {}
     expect(result.path, testFile);
     expect(result.uri.toString(), 'package:test/test.dart');
     expect(result.content, content);
-    expect(result.unit!, isNotNull);
+    expect(result.unit, isNotNull);
     expect(result.errors, hasLength(0));
 
     var f = result.unit!.declarations[0] as FunctionDeclaration;
@@ -3811,7 +3811,7 @@ class F extends X {}
     expect(allResults, hasLength(3));
     ResolvedUnitResult result = allResults[0];
     expect(result.path, b);
-    expect(result.unit!, isNotNull);
+    expect(result.unit, isNotNull);
     expect(result.errors, hasLength(0));
   }
 

pkg/analyzer/test/src/dart/resolution/resolution.dart

@@ -324,7 +324,7 @@ mixin ResolutionTest implements ResourceProviderMixin {
   }) {
     assertElement(node, element);
     assertType(node.extendedType, extendedType);
-    assertElementTypeStrings(node.typeArgumentTypes!, typeArgumentTypes);
+    assertElementTypeStrings(node.typeArgumentTypes, typeArgumentTypes);
   }
 
   void assertFunctionExpressionInvocation(

pkg/analyzer/test/src/diagnostics/receiver_of_type_never_test.dart

@@ -569,7 +569,7 @@ void f() {
     assertBinaryExpression(
       findNode.binary('=='),
       element: elementMatcher(
-        objectElement.getMethod('==')!,
+        objectElement.getMethod('=='),
         isLegacy: isNullSafetySdkAndLegacyLibrary,
       ),
       type: 'bool',
@@ -619,7 +619,7 @@ void f() {
     assertSimpleIdentifier(
       findNode.simple('toString'),
       element: elementMatcher(
-        objectElement.getMethod('toString')!,
+        objectElement.getMethod('toString'),
         isLegacy: isNullSafetySdkAndLegacyLibrary,
       ),
       type: 'String Function()',
@@ -636,7 +636,7 @@ void f() {
     assertSimpleIdentifier(
       findNode.simple('hashCode'),
       element: elementMatcher(
-        objectElement.getGetter('hashCode')!,
+        objectElement.getGetter('hashCode'),
         isLegacy: isNullSafetySdkAndLegacyLibrary,
       ),
       type: 'int',

pkg/analyzer/test/src/diagnostics/use_of_nullable_value_test.dart

@@ -504,7 +504,7 @@ m(B b) {
       writeElement: findElement.setter('x'),
       writeType: 'int',
       operatorElement: elementMatcher(
-        numElement.getMethod('+')!,
+        numElement.getMethod('+'),
         isLegacy: isNullSafetySdkAndLegacyLibrary,
       ),
       type: 'int',
@@ -517,7 +517,7 @@ m(B b) {
       writeElement: findElement.setter('y'),
       writeType: 'int?',
       operatorElement: elementMatcher(
-        numElement.getMethod('+')!,
+        numElement.getMethod('+'),
         isLegacy: isNullSafetySdkAndLegacyLibrary,
       ),
       type: 'int',
@@ -560,7 +560,7 @@ m(B b) {
       writeElement: findElement.setter('x'),
       writeType: 'int',
       operatorElement: elementMatcher(
-        numElement.getMethod('+')!,
+        numElement.getMethod('+'),
         isLegacy: isNullSafetySdkAndLegacyLibrary,
       ),
       type: 'int?',
@@ -573,7 +573,7 @@ m(B b) {
       writeElement: findElement.setter('x'),
       writeType: 'int',
       operatorElement: elementMatcher(
-        numElement.getMethod('+')!,
+        numElement.getMethod('+'),
         isLegacy: isNullSafetySdkAndLegacyLibrary,
       ),
       type: 'int',
@@ -607,7 +607,7 @@ m(int x, int? y) {
       writeElement: findElement.parameter('x'),
       writeType: 'int',
       operatorElement: elementMatcher(
-        numElement.getMethod('+')!,
+        numElement.getMethod('+'),
         isLegacy: isNullSafetySdkAndLegacyLibrary,
       ),
       type: 'int',
@@ -620,7 +620,7 @@ m(int x, int? y) {
       writeElement: findElement.parameter('y'),
       writeType: 'int?',
       operatorElement: elementMatcher(
-        numElement.getMethod('+')!,
+        numElement.getMethod('+'),
         isLegacy: isNullSafetySdkAndLegacyLibrary,
       ),
       type: 'int',

pkg/analyzer/test/src/summary/element_text.dart

@@ -583,7 +583,7 @@ class _ElementWriter {
       writeNode(e.name);
       if (e.constructorName != null) {
         buffer.write('.');
-        writeNode(e.constructorName!);
+        writeNode(e.constructorName);
       }
       if (e.arguments != null) {
         writeList('(', ')', e.arguments!.arguments, ', ', writeNode,
@@ -598,7 +598,7 @@ class _ElementWriter {
       writeNode(e.condition);
       if (e.message != null) {
         buffer.write(', ');
-        writeNode(e.message!);
+        writeNode(e.message);
       }
       buffer.write(')');
     } else if (e is BinaryExpression) {
@@ -623,13 +623,13 @@ class _ElementWriter {
       writeNode(e.type);
       if (e.name != null) {
         buffer.write('.');
-        writeNode(e.name!);
+        writeNode(e.name);
       }
     } else if (e is DoubleLiteral) {
       buffer.write(e.value);
     } else if (e is GenericFunctionType) {
       if (e.returnType != null) {
-        writeNode(e.returnType!);
+        writeNode(e.returnType);
         buffer.write(' ');
       }
       buffer.write('Function');