chore: fix prefer moving to variable issues (#787)

* feat: add static code diagnostic prefer-moving-to-variable

* fix: cover edge-cases

* chore: fix new rule issue

* chore: fix analyzer issues

* Update CHANGELOG.md

Co-authored-by: Dmitry Krutskikh <dmitry.krutskikh@gmail.com>

Author: incendial

CHANGELOG.md

@@ -5,11 +5,12 @@
 * feat: add static code diagnostic [`prefer-commenting-analyzer-ignores`](https://dartcodemetrics.dev/docs/rules/common/prefer-commenting-analyzer-ignores).
 * feat: add static code diagnostic [`prefer-moving-to-variable`](https://dartcodemetrics.dev/docs/rules/common/prefer-moving-to-variable).
 * fix: add check for supertypes for [`avoid-non-null-assertions`](https://dartcodemetrics.dev/docs/rules/common/avoid-non-null-assertion) rule.
+* fix: correctly handle nullable types of collections for [`avoid-collection-methods-with-unrelated-types`](https://dartcodemetrics.dev/docs/rules/common/avoid-collection-methods-with-unrelated-types).
 * fix: cover more cases in [`prefer-immediate-return`](https://dartcodemetrics.dev/docs/rules/common/prefer-immediate-return) rule
 * fix: support index expressions for [`no-magic-number`](https://dartcodemetrics.dev/docs/rules/common/no-magic-number) rule.
-* chore: restrict `analyzer` version to `>=2.4.0 <3.4.0`.
-* fix: correctly handle nullable types of collections for [`avoid-collection-methods-with-unrelated-types`](https://dartcodemetrics.dev/docs/rules/common/avoid-collection-methods-with-unrelated-types)
 * docs: update `prefer-async-await` rule.
+* chore: `fix prefer-moving-to-variable` issues.
+* chore: restrict `analyzer` version to `>=2.4.0 <3.4.0`.
 
 ## 4.13.0
 

lib/src/analyzer_plugin/analyzer_plugin.dart

@@ -154,14 +154,14 @@ class AnalyzerPlugin extends ServerPlugin {
         return plugin.EditGetFixesResult([]);
       }
 
-      final fixes = _check(driver, analysisResult)
-          .where((fix) =>
-              fix.error.location.file == parameters.file &&
-              fix.error.location.offset <= parameters.offset &&
-              parameters.offset <=
-                  fix.error.location.offset + fix.error.location.length &&
-              fix.fixes.isNotEmpty)
-          .toList();
+      final fixes = _check(driver, analysisResult).where((fix) {
+        final location = fix.error.location;
+
+        return location.file == parameters.file &&
+            location.offset <= parameters.offset &&
+            parameters.offset <= location.offset + location.length &&
+            fix.fixes.isNotEmpty;
+      }).toList();
 
       return plugin.EditGetFixesResult(fixes);
     } on Exception catch (e, stackTrace) {

lib/src/analyzer_plugin/analyzer_plugin_utils.dart

@@ -14,19 +14,22 @@ plugin.AnalysisErrorFixes codeIssueToAnalysisErrorFixes(
   ResolvedUnitResult? unitResult,
 ) {
   final fileWithIssue = uriToPath(issue.location.sourceUrl) ?? '';
+  final location = issue.location;
+  final locationStart = location.start;
+  final locationEnd = location.end;
 
   return plugin.AnalysisErrorFixes(
     plugin.AnalysisError(
       _severityMapping[issue.severity]!,
       plugin.AnalysisErrorType.LINT,
       plugin.Location(
         fileWithIssue,
-        issue.location.start.offset,
-        issue.location.length,
-        issue.location.start.line,
-        issue.location.start.column,
-        endLine: issue.location.end.line,
-        endColumn: issue.location.end.column,
+        locationStart.offset,
+        location.length,
+        locationStart.line,
+        locationStart.column,
+        endLine: locationEnd.line,
+        endColumn: locationEnd.column,
       ),
       issue.message,
       issue.ruleId,
@@ -47,8 +50,8 @@ plugin.AnalysisErrorFixes codeIssueToAnalysisErrorFixes(
               unitResult.exists ? 0 : -1,
               edits: [
                 plugin.SourceEdit(
-                  issue.location.start.offset,
-                  issue.location.length,
+                  locationStart.offset,
+                  location.length,
                   issue.suggestion!.replacement,
                 ),
               ],

lib/src/analyzers/lint_analyzer/metrics/metrics_list/halstead_volume/halstead_volume_ast_visitor.dart

@@ -45,7 +45,8 @@ class HalsteadVolumeAstVisitor extends RecursiveAstVisitor<void> {
     var token = firstToken;
     while (token != lastToken && token != null) {
       if (token.isOperator) {
-        _operators[token.type.name] = (_operators[token.type.name] ?? 0) + 1;
+        final name = token.type.name;
+        _operators[name] = (_operators[name] ?? 0) + 1;
       }
 
       if (token.isIdentifier) {

lib/src/analyzers/lint_analyzer/metrics/metrics_list/maximum_nesting_level/nesting_level_visitor.dart

@@ -20,15 +20,17 @@ class NestingLevelVisitor extends RecursiveAstVisitor<void> {
 
     AstNode? astNode = node;
     do {
+      final parent = astNode?.parent;
+      final grandParent = parent?.parent;
       if (astNode is Block &&
-          (astNode.parent is! BlockFunctionBody ||
-              astNode.parent?.parent is ConstructorDeclaration ||
-              astNode.parent?.parent is FunctionExpression ||
-              astNode.parent?.parent is MethodDeclaration)) {
+          (parent is! BlockFunctionBody ||
+              grandParent is ConstructorDeclaration ||
+              grandParent is FunctionExpression ||
+              grandParent is MethodDeclaration)) {
         nestedNodesChain.add(astNode);
       }
 
-      astNode = astNode?.parent;
+      astNode = parent;
     } while (astNode?.parent != _functionNode);
 
     if (nestedNodesChain.length > _deepestNestedNodesChain.length) {

lib/src/analyzers/lint_analyzer/models/suppression.dart

@@ -24,10 +24,9 @@ class Suppression {
       final ids = match.group(1)!.split(',').map(_canonicalize);
       final location = info.getLocation(match.start);
       final lineNumber = location.lineNumber;
-      final beforeMatch = content.substring(
-        info.getOffsetOfLine(lineNumber - 1),
-        info.getOffsetOfLine(lineNumber - 1) + location.columnNumber - 1,
-      );
+      final offset = info.getOffsetOfLine(lineNumber - 1);
+      final beforeMatch =
+          content.substring(offset, offset + location.columnNumber - 1);
 
       // If comment sits next to code, so it refers to its own line, otherwise it refers to the next line.
       final ignoredNextLine = beforeMatch.trim().isEmpty;

lib/src/analyzers/lint_analyzer/reporters/reporters_list/checkstyle/lint_checkstyle_reporter.dart

@@ -42,12 +42,13 @@ class LintCheckstyleReporter extends CheckstyleReporter<LintFileReport,
               final issues = [...record.issues, ...record.antiPatternCases];
 
               for (final issue in issues) {
+                final locationStart = issue.location.start;
                 builder.element(
                   'error',
                   attributes: {
-                    'line': '${issue.location.start.line}',
-                    if (issue.location.start.column > 0)
-                      'column': '${issue.location.start.column}',
+                    'line': '${locationStart.line}',
+                    if (locationStart.column > 0)
+                      'column': '${locationStart.column}',
                     'severity': _severityMapping[issue.severity] ?? 'ignore',
                     'message': issue.message,
                     'source': issue.ruleId,

lib/src/analyzers/lint_analyzer/reporters/reporters_list/console/lint_console_reporter_helper.dart

@@ -32,8 +32,9 @@ class LintConsoleReporterHelper {
   /// Converts an [issue] to the issue message string.
   Iterable<String> getIssueMessage(Issue issue, String relativePath) {
     final severity = _getSeverity(issue.severity);
+    final locationStart = issue.location.start;
     final location = _linkPen(
-      '$relativePath:${issue.location.start.line}:${issue.location.start.column}',
+      '$relativePath:${locationStart.line}:${locationStart.column}',
     );
     final tabulation = _normalize('');
 

lib/src/analyzers/lint_analyzer/reporters/reporters_list/html/lint_html_reporter.dart

@@ -349,9 +349,12 @@ class LintHtmlReporter extends HtmlReporter<LintFileReport,
       final complexityValueElement = Element.tag('div')
         ..classes.add('metrics-source-code__text');
 
-      final classReport = record.classes.entries.firstWhereOrNull((report) =>
-          report.value.location.start.line <= lineIndex &&
-          report.value.location.end.line >= lineIndex);
+      final classReport = record.classes.entries.firstWhereOrNull((report) {
+        final location = report.value.location;
+
+        return location.start.line <= lineIndex &&
+            location.end.line >= lineIndex;
+      });
       if (classReport != null &&
           classReport.value.location.start.line == lineIndex) {
         complexityValueElement
@@ -435,6 +438,8 @@ class LintHtmlReporter extends HtmlReporter<LintFileReport,
       cyclomaticValues.append(complexityValueElement);
     }
 
+    final from = p.dirname(record.relativePath);
+
     final codeBlock = Element.tag('td')
       ..classes.add('metrics-source-code__code')
       ..append(Element.tag('pre')
@@ -445,13 +450,12 @@ class LintHtmlReporter extends HtmlReporter<LintFileReport,
       ..append(Element.tag('h1')
         ..classes.add('metric-header')
         ..append(Element.tag('a')
-          ..attributes['href'] =
-              p.relative('index.html', from: p.dirname(record.relativePath))
+          ..attributes['href'] = p.relative('index.html', from: from)
           ..text = 'All files')
         ..append(Element.tag('span')..text = ' : ')
         ..append(Element.tag('a')
           ..attributes['href'] = 'index.html'
-          ..text = p.dirname(record.relativePath))
+          ..text = from)
         ..append(
           Element.tag('span')..text = '/${p.basename(record.relativePath)}',
         ))
@@ -488,20 +492,16 @@ class LintHtmlReporter extends HtmlReporter<LintFileReport,
       ..append(Element.tag('meta')..attributes['charset'] = 'utf-8')
       ..append(Element.tag('link')
         ..attributes['rel'] = 'stylesheet'
-        ..attributes['href'] =
-            p.relative('variables.css', from: p.dirname(record.relativePath)))
+        ..attributes['href'] = p.relative('variables.css', from: from))
       ..append(Element.tag('link')
         ..attributes['rel'] = 'stylesheet'
-        ..attributes['href'] =
-            p.relative('normalize.css', from: p.dirname(record.relativePath)))
+        ..attributes['href'] = p.relative('normalize.css', from: from))
       ..append(Element.tag('link')
         ..attributes['rel'] = 'stylesheet'
-        ..attributes['href'] =
-            p.relative('base.css', from: p.dirname(record.relativePath)))
+        ..attributes['href'] = p.relative('base.css', from: from))
       ..append(Element.tag('link')
         ..attributes['rel'] = 'stylesheet'
-        ..attributes['href'] =
-            p.relative('main.css', from: p.dirname(record.relativePath)));
+        ..attributes['href'] = p.relative('main.css', from: from));
 
     final html = Element.tag('html')
       ..attributes['lang'] = 'en'

lib/src/analyzers/lint_analyzer/reporters/reporters_list/html/utility_functions.dart

@@ -43,55 +43,59 @@ Element renderSummaryMetric(
 }
 
 Element renderTableRecord(ReportTableRecord record) {
+  final report = record.report;
   final recordHaveCyclomaticComplexityViolations =
-      record.report.cyclomaticComplexityViolations > 0;
+      report.cyclomaticComplexityViolations > 0;
   final recordHaveSourceLinesOfCodeViolations =
-      record.report.sourceLinesOfCodeViolations > 0;
+      report.sourceLinesOfCodeViolations > 0;
   final recordHaveMaintainabilityIndexViolations =
-      record.report.maintainabilityIndexViolations > 0;
+      report.maintainabilityIndexViolations > 0;
   final recordHaveArgumentsCountViolations =
-      record.report.argumentsCountViolations > 0;
+      report.argumentsCountViolations > 0;
   final recordHaveMaximumNestingLevelViolations =
-      record.report.maximumNestingLevelViolations > 0;
+      report.maximumNestingLevelViolations > 0;
   final recordHaveTechDebtViolations =
       record.report.technicalDebtViolations > 0;
 
+  final averageMaintainabilityIndex =
+      report.averageMaintainabilityIndex.toInt();
+
   return Element.tag('tr')
     ..append(Element.tag('td')
       ..append(Element.tag('a')
         ..attributes['href'] = record.link
         ..text = record.title))
     ..append(Element.tag('td')
       ..text = recordHaveCyclomaticComplexityViolations
-          ? '${record.report.totalCyclomaticComplexity} / ${record.report.cyclomaticComplexityViolations}'
-          : '${record.report.totalCyclomaticComplexity}'
+          ? '${report.totalCyclomaticComplexity} / ${report.cyclomaticComplexityViolations}'
+          : '${report.totalCyclomaticComplexity}'
       ..classes.add(
         recordHaveCyclomaticComplexityViolations ? 'with-violations' : '',
       ))
     ..append(Element.tag('td')
       ..text = recordHaveSourceLinesOfCodeViolations
-          ? '${record.report.totalSourceLinesOfCode} / ${record.report.sourceLinesOfCodeViolations}'
-          : '${record.report.totalSourceLinesOfCode}'
+          ? '${report.totalSourceLinesOfCode} / ${report.sourceLinesOfCodeViolations}'
+          : '${report.totalSourceLinesOfCode}'
       ..classes.add(
         recordHaveSourceLinesOfCodeViolations ? 'with-violations' : '',
       ))
     ..append(Element.tag('td')
       ..text = recordHaveMaintainabilityIndexViolations
-          ? '${record.report.averageMaintainabilityIndex.toInt()} / ${record.report.maintainabilityIndexViolations}'
-          : '${record.report.averageMaintainabilityIndex.toInt()}'
+          ? '$averageMaintainabilityIndex / ${record.report.maintainabilityIndexViolations}'
+          : '$averageMaintainabilityIndex'
       ..classes.add(
         recordHaveMaintainabilityIndexViolations ? 'with-violations' : '',
       ))
     ..append(Element.tag('td')
       ..text = recordHaveArgumentsCountViolations
-          ? '${record.report.averageArgumentsCount} / ${record.report.argumentsCountViolations}'
-          : '${record.report.averageArgumentsCount}'
+          ? '${report.averageArgumentsCount} / ${report.argumentsCountViolations}'
+          : '${report.averageArgumentsCount}'
       ..classes
           .add(recordHaveArgumentsCountViolations ? 'with-violations' : ''))
     ..append(Element.tag('td')
       ..text = recordHaveMaximumNestingLevelViolations
-          ? '${record.report.averageMaximumNestingLevel} / ${record.report.maximumNestingLevelViolations}'
-          : '${record.report.averageMaximumNestingLevel}'
+          ? '${report.averageMaximumNestingLevel} / ${report.maximumNestingLevelViolations}'
+          : '${report.averageMaximumNestingLevel}'
       ..classes.add(
         recordHaveMaximumNestingLevelViolations ? 'with-violations' : '',
       ))