nnbd tidying

lib/src/ast.dart

@@ -99,8 +99,10 @@ bool inPrivateMember(AstNode node) {
 }
 
 /// Returns `true` if the given [declaration] is annotated `@deprecated`.
-bool isDeprecated(Declaration declaration) =>
-    declaration.declaredElement!.hasDeprecated;
+bool isDeprecated(Declaration declaration) {
+  var declaredElement = declaration.declaredElement;
+  return declaredElement != null && declaredElement.hasDeprecated;
+}
 
 /// Returns `true` if this element is the `==` method declaration.
 bool isEquals(ClassMember element) =>
@@ -121,7 +123,8 @@ bool isHashCode(ClassMember element) =>
 /// [package]'s `lib/` directory tree.
 bool isInLibDir(CompilationUnit node, WorkspacePackage? package) {
   if (package == null) return false;
-  final cuPath = node.declaredElement!.library.source.fullName;
+  final cuPath = node.declaredElement?.library.source.fullName;
+  if (cuPath == null) return false;
   final libDir = path.join(package.root, 'lib');
   return path.isWithin(libDir, cuPath);
 }
@@ -146,8 +149,10 @@ bool isProtected(Declaration declaration) =>
     declaration.metadata.any((Annotation a) => a.name.name == 'protected');
 
 /// Returns `true` if the given [ClassMember] is a public method.
-bool isPublicMethod(ClassMember m) =>
-    isMethod(m) && m.declaredElement!.isPublic;
+bool isPublicMethod(ClassMember m) {
+  var declaredElement = m.declaredElement;
+  return declaredElement != null && isMethod(m) && declaredElement.isPublic;
+}
 
 /// Returns `true` if the given method [declaration] is a "simple getter".
 ///
@@ -287,8 +292,8 @@ bool _checkForSimpleSetter(MethodDeclaration setter, Expression expression) {
       return false;
     }
 
-    var parameters = setter.parameters!.parameters;
-    if (parameters.length == 1) {
+    var parameters = setter.parameters?.parameters;
+    if (parameters != null && parameters.length == 1) {
       return rightElement == parameters[0].declaredElement;
     }
   }

lib/src/formatter.dart

@@ -60,7 +60,7 @@ Future writeBenchmarks(
   final pedanticRuleset = await pedanticRules;
   final stats = timings.keys.map((t) {
     final details = pedanticRuleset.contains(t) ? ' [pedantic]' : '';
-    return _Stat('$t$details', timings[t]);
+    return _Stat('$t$details', timings[t] ?? 0);
   }).toList();
   _writeTimings(out, stats, 0);
 }
@@ -95,7 +95,7 @@ void _writeTimings(IOSink out, List<_Stat> timings, int summaryLength) {
 
   timings.sort();
   for (var stat in timings) {
-    totalTime += stat.elapsed!;
+    totalTime += stat.elapsed;
     // TODO: Shame timings slower than 100ms?
     // TODO: Present both total times and time per count?
     out.writeln(
@@ -266,8 +266,9 @@ class SimpleFormatter implements ReportFormatter {
   }
 
   void writeLints() {
+    var filter = this.filter;
     errors.forEach((info) => (info.errors.toList()..sort(compare)).forEach((e) {
-          if (filter != null && filter!.filter(e)) {
+          if (filter != null && filter.filter(e)) {
             filteredLintCount++;
           } else {
             ++errorCount;
@@ -299,7 +300,7 @@ class SimpleFormatter implements ReportFormatter {
   void writeTimings() {
     final timers = lintRegistry.timers;
     final timings = timers.keys
-        .map((t) => _Stat(t, timers[t]!.elapsedMilliseconds))
+        .map((t) => _Stat(t, timers[t]?.elapsedMilliseconds ?? 0))
         .toList();
     _writeTimings(out, timings, _summaryLength);
   }
@@ -322,10 +323,10 @@ class SimpleFormatter implements ReportFormatter {
 
 class _Stat implements Comparable<_Stat> {
   final String name;
-  final int? elapsed;
+  final int elapsed;
 
   _Stat(this.name, this.elapsed);
 
   @override
-  int compareTo(_Stat other) => other.elapsed! - elapsed!;
+  int compareTo(_Stat other) => other.elapsed - elapsed;
 }

lib/src/rules/always_put_required_named_parameters_first.dart

@@ -51,8 +51,8 @@ class _Visitor extends SimpleAstVisitor<void> {
   void visitFormalParameterList(FormalParameterList node) {
     var nonRequiredSeen = false;
     for (var param in node.parameters.where((p) => p.isNamed)) {
-      var element = param.declaredElement!;
-      if (element.hasRequired || element.isRequiredNamed) {
+      var element = param.declaredElement;
+      if (element != null && (element.hasRequired || element.isRequiredNamed)) {
         if (nonRequiredSeen) {
           var identifier = param.identifier;
           if (identifier != null) {

lib/src/rules/always_require_non_null_named_parameters.dart

@@ -73,10 +73,12 @@ class _Visitor extends SimpleAstVisitor<void> {
         // Only named parameters
         if (p.isNamed) {
           final parameter = p as DefaultFormalParameter;
-          // Without a default value or marked @required
-          if (parameter.defaultValue == null &&
-              !parameter.declaredElement!.hasRequired) {
-            params.add(parameter);
+          // Without a default value or marked required
+          if (parameter.defaultValue == null) {
+            var declaredElement = parameter.declaredElement;
+            if (declaredElement != null && !declaredElement.hasRequired) {
+              params.add(parameter);
+            }
           }
         }
       }
@@ -97,8 +99,10 @@ class _Visitor extends SimpleAstVisitor<void> {
   void _checkAssert(
       Expression assertExpression, List<DefaultFormalParameter> params) {
     for (final param in params) {
-      if (_hasAssertNotNull(assertExpression, param.identifier!.name)) {
-        rule.reportLintForToken(param.identifier!.beginToken);
+      var identifier = param.identifier;
+      if (identifier != null &&
+          _hasAssertNotNull(assertExpression, identifier.name)) {
+        rule.reportLintForToken(identifier.beginToken);
         params.remove(param);
         return;
       }

lib/src/rules/avoid_unnecessary_containers.dart

@@ -75,8 +75,8 @@ class _Visitor extends SimpleAstVisitor {
     }
     final parent = node.parent;
     if (parent is NamedExpression && parent.name.label.name == 'child') {
-      final args = parent.thisOrAncestorOfType<ArgumentList>()!;
-      if (args.arguments.length == 1) {
+      final args = parent.thisOrAncestorOfType<ArgumentList>();
+      if (args?.arguments.length == 1) {
         final parentCreation =
             parent.thisOrAncestorOfType<InstanceCreationExpression>();
         if (parentCreation != null) {

lib/src/rules/cast_nullable_to_non_nullable.dart

@@ -67,9 +67,10 @@ class _Visitor extends SimpleAstVisitor<void> {
 
   @override
   void visitAsExpression(AsExpression node) {
-    final expressionType = node.expression.staticType!;
+    final expressionType = node.expression.staticType;
     final type = node.type.type;
-    if (!expressionType.isDynamic &&
+    if (expressionType != null &&
+        !expressionType.isDynamic &&
         context.typeSystem.isNullable(expressionType) &&
         context.typeSystem.isNonNullable(type!)) {
       rule.reportLint(node);

lib/src/rules/deprecated_consistency.dart

@@ -74,8 +74,9 @@ class _Visitor extends SimpleAstVisitor<void> {
 
   @override
   void visitConstructorDeclaration(ConstructorDeclaration node) {
-    var constructorElement = node.declaredElement!;
-    if (constructorElement.enclosingElement.hasDeprecated &&
+    var constructorElement = node.declaredElement;
+    if (constructorElement != null &&
+        constructorElement.enclosingElement.hasDeprecated &&
         !constructorElement.hasDeprecated) {
       rule.reportLint(node);
     }

lib/src/rules/invariant_booleans.dart

@@ -141,12 +141,12 @@ class _InvariantBooleansVisitor extends ConditionScopeVisitor {
   @override
   void visitCondition(Expression? node) {
     // Right part discards reporting a subexpression already reported.
-    if (node?.staticType?.isDartCoreBool != true) {
+    if (node == null || node.staticType?.isDartCoreBool != true) {
       return;
     }
 
-    final testedNodes = _findPreviousTestedExpressions(node!);
-    testedNodes.evaluateInvariant()!.forEach((ContradictoryComparisons e) {
+    final testedNodes = _findPreviousTestedExpressions(node);
+    testedNodes?.evaluateInvariant()?.forEach((ContradictoryComparisons e) {
       final reportRule = _ContradictionReportRule(e);
       reportRule
         ..reporter = rule.reporter
@@ -166,10 +166,13 @@ class _InvariantBooleansVisitor extends ConditionScopeVisitor {
     }
   }
 
-  TestedExpressions _findPreviousTestedExpressions(Expression node) {
+  TestedExpressions? _findPreviousTestedExpressions(Expression node) {
     final elements = _getElementsInExpression(node);
-    final conjunctions = getTrueExpressions(elements).toSet();
-    final negations = getFalseExpressions(elements).toSet();
+    final conjunctions = getTrueExpressions(elements)?.toSet();
+    final negations = getFalseExpressions(elements)?.toSet();
+    if (conjunctions == null || negations == null) {
+      return null;
+    }
     return TestedExpressions(node, conjunctions, negations);
   }
 }

lib/src/rules/lines_longer_than_80_chars.dart

@@ -159,11 +159,11 @@ class _AllowedLongLineVisitor extends RecursiveAstVisitor {
 }
 
 class _LineInfo {
-  final int? index;
-  final int? offset;
-  final int? end;
-  _LineInfo({this.index, this.offset, this.end});
-  int get length => end! - offset!;
+  final int index;
+  final int offset;
+  final int end;
+  _LineInfo({required this.index, required this.offset, required this.end});
+  int get length => end - offset;
 }
 
 class _Visitor extends SimpleAstVisitor {
@@ -175,7 +175,10 @@ class _Visitor extends SimpleAstVisitor {
 
   @override
   void visitCompilationUnit(CompilationUnit node) {
-    final lineInfo = node.lineInfo!;
+    final lineInfo = node.lineInfo;
+    if (lineInfo == null) {
+      return;
+    }
     final lineCount = lineInfo.lineCount;
     final longLines = <_LineInfo>[];
     for (var i = 0; i < lineCount; i++) {
@@ -213,9 +216,9 @@ class _Visitor extends SimpleAstVisitor {
     ];
 
     for (final line in longLines) {
-      if (allowedLines.contains(line.index! + 1)) continue;
+      if (allowedLines.contains(line.index + 1)) continue;
       rule.reporter
-          .reportErrorForOffset(rule.lintCode, line.offset!, line.length);
+          .reportErrorForOffset(rule.lintCode, line.offset, line.length);
     }
   }
 }

lib/src/rules/prefer_asserts_in_initializer_lists.dart

@@ -51,7 +51,7 @@ class PreferAssertsInInitializerLists extends LintRule implements NodeLintRule {
 }
 
 class _AssertVisitor extends RecursiveAstVisitor {
-  final ConstructorElement? constructorElement;
+  final ConstructorElement constructorElement;
   final _ClassAndSuperClasses? classAndSuperClasses;
 
   bool needInstance = false;
@@ -71,7 +71,7 @@ class _AssertVisitor extends RecursiveAstVisitor {
         element is PropertyAccessorElement &&
             !element.isStatic &&
             _hasAccessor(element) &&
-            !constructorElement!.parameters
+            !constructorElement.parameters
                 .whereType<FieldFormalParameterElement>()
                 .any((p) => p.field?.getter == element);
   }
@@ -81,11 +81,15 @@ class _AssertVisitor extends RecursiveAstVisitor {
     needInstance = true;
   }
 
-  bool _hasAccessor(PropertyAccessorElement element) =>
-      classAndSuperClasses!.classes.contains(element.enclosingElement);
+  bool _hasAccessor(PropertyAccessorElement element) {
+    var classes = classAndSuperClasses?.classes;
+    return classes != null && classes.contains(element.enclosingElement);
+  }
 
-  bool _hasMethod(MethodElement element) =>
-      classAndSuperClasses!.classes.contains(element.enclosingElement);
+  bool _hasMethod(MethodElement element) {
+    var classes = classAndSuperClasses?.classes;
+    return classes != null && classes.contains(element.enclosingElement);
+  }
 }
 
 /// Lazy cache of elements.
@@ -126,15 +130,16 @@ class _Visitor extends SimpleAstVisitor<void> {
 
   @override
   void visitConstructorDeclaration(ConstructorDeclaration node) {
-    if (node.declaredElement!.isFactory) return;
+    var declaredElement = node.declaredElement;
+    if (declaredElement == null || declaredElement.isFactory) return;
 
     final body = node.body;
     if (body is BlockFunctionBody) {
       for (final statement in body.block.statements) {
         if (statement is! AssertStatement) break;
 
         final assertVisitor =
-            _AssertVisitor(node.declaredElement, _classAndSuperClasses);
+            _AssertVisitor(declaredElement, _classAndSuperClasses);
         statement.visitChildren(assertVisitor);
         if (!assertVisitor.needInstance) {
           rule.reportLintForToken(statement.beginToken);

lib/src/rules/prefer_bool_in_asserts.dart

@@ -70,8 +70,9 @@ class _Visitor extends SimpleAstVisitor<void> {
 
   @override
   void visitAssertStatement(AssertStatement node) {
-    var conditionType = _unbound(node.condition.staticType)!;
-    if (!typeSystem.isAssignableTo(conditionType, boolType)) {
+    var conditionType = _unbound(node.condition.staticType);
+    if (conditionType != null &&
+        !typeSystem.isAssignableTo(conditionType, boolType)) {
       rule.reportLint(node.condition);
     }
   }

lib/src/rules/prefer_const_constructors_in_immutables.dart

@@ -75,14 +75,17 @@ class _Visitor extends SimpleAstVisitor<void> {
 
   @override
   void visitConstructorDeclaration(ConstructorDeclaration node) {
-    final element = node.declaredElement!;
+    final element = node.declaredElement;
+    if (element == null) {
+      return;
+    }
     final isRedirected =
         element.isFactory && element.redirectedConstructor != null;
     if (node.body is EmptyFunctionBody &&
         !element.isConst &&
         !_hasMixin(element.enclosingElement) &&
         _hasImmutableAnnotation(element.enclosingElement) &&
-        (isRedirected && element.redirectedConstructor!.isConst ||
+        (isRedirected && element.redirectedConstructor?.isConst == true ||
             (!isRedirected &&
                 _hasConstConstructorInvocation(node) &&
                 context.canBeConstConstructor(node)))) {
@@ -91,23 +94,29 @@ class _Visitor extends SimpleAstVisitor<void> {
   }
 
   bool _hasConstConstructorInvocation(ConstructorDeclaration node) {
-    final clazz = node.declaredElement!.enclosingElement;
+    var declaredElement = node.declaredElement;
+    if (declaredElement == null) {
+      return false;
+    }
+    final clazz = declaredElement.enclosingElement;
     // construct with super
     final superInvocation = node.initializers
             .firstWhereOrNull((e) => e is SuperConstructorInvocation)
         as SuperConstructorInvocation?;
-    if (superInvocation != null) return superInvocation.staticElement!.isConst;
+    if (superInvocation != null) {
+      return superInvocation.staticElement?.isConst == true;
+    }
     // construct with this
     final redirectInvocation = node.initializers
             .firstWhereOrNull((e) => e is RedirectingConstructorInvocation)
         as RedirectingConstructorInvocation?;
     if (redirectInvocation != null) {
-      return redirectInvocation.staticElement!.isConst;
+      return redirectInvocation.staticElement?.isConst == true;
     }
     // construct with implicit super()
-    return clazz.supertype!.constructors
-        .firstWhere((e) => e.name.isEmpty)
-        .isConst;
+    var supertype = clazz.supertype;
+    return supertype != null &&
+        supertype.constructors.firstWhere((e) => e.name.isEmpty).isConst;
   }
 
   bool _hasImmutableAnnotation(ClassElement clazz) {

lib/src/rules/prefer_const_literals_to_create_immutables.dart

@@ -119,7 +119,7 @@ class _Visitor extends SimpleAstVisitor<void> {
             node is SetOrMapLiteral ||
             node is MapLiteralEntry ||
             node is NamedExpression)) {
-      node = node!.parent;
+      node = node?.parent;
     }
     if (!(node is InstanceCreationExpression &&
         _hasImmutableAnnotation(node.staticType))) {