NPE in ConstVariableElement.computeConstantValue(element.dart:1653)

[scheglov]

I think this happens when a generic method is invoked, and we create synthetic ParameterElements, which don't have enclosingElement, so library is null.

Thread 0 main thread_CastError: Null check operator used on a null value
at ConstVariableElement.computeConstantValue(element.dart:1653)
at _Visitor.check(avoid_redundant_argument_values.dart:77)
at _Visitor.visitMethodInvocation(avoid_redundant_argument_values.dart:105)
at MethodInvocationImpl.accept(ast.dart:7311)
at LinterVisitor._runSubscriptions(linter_visitor.dart:764)
at LinterVisitor.visitMethodInvocation(linter_visitor.dart:488)
at MethodInvocationImpl.accept(ast.dart:7311)
at ExpressionStatementImpl.visitChildren(ast.dart:3689)
at RecursiveAstVisitor.visitExpressionStatement(visitor.dart:879)
at LinterVisitor.visitExpressionStatement(linter_visitor.dart:255)
at ExpressionStatementImpl.accept(ast.dart:3685)
at NodeListImpl.accept(ast.dart:7800)
at BlockImpl.visitChildren(ast.dart:1051)
at RecursiveAstVisitor.visitBlock(visitor.dart:705)
at LinterVisitor.visitBlock(linter_visitor.dart:81)
at BlockImpl.accept(ast.dart:1047)
at BlockFunctionBodyImpl.visitChildren(ast.dart:1006)
at RecursiveAstVisitor.visitBlockFunctionBody(visitor.dart:711)
at LinterVisitor.visitBlockFunctionBody(linter_visitor.dart:87)
at BlockFunctionBodyImpl.accept(ast.dart:1002)
at MethodDeclarationImpl.visitChildren(ast.dart:7173)
at RecursiveAstVisitor.visitMethodDeclaration(visitor.dart:1125)
at LinterVisitor.visitMethodDeclaration(linter_visitor.dart:483)
at MethodDeclarationImpl.accept(ast.dart:7164)
at NodeListImpl.accept(ast.dart:7800)
at ClassDeclarationImpl.visitChildren(ast.dart:1518)
at RecursiveAstVisitor.visitClassDeclaration(visitor.dart:741)
at LinterVisitor.visitClassDeclaration(linter_visitor.dart:117)
at ClassDeclarationImpl.accept(ast.dart:1488)
at NodeListImpl.accept(ast.dart:7800)
at CompilationUnitImpl.visitChildren(ast.dart:2092)
at RecursiveAstVisitor.visitCompilationUnit(visitor.dart:765)
at LinterVisitor.visitCompilationUnit(linter_visitor.dart:141)
at CompilationUnitImpl.accept(ast.dart:2085)
at LibraryAnalyzer._computeLints(library_analyzer.dart:443)
at LibraryAnalyzer.analyze(library_analyzer.dart:175)
at AnalysisDriver._computeAnalysisResult.<fn>(driver.dart:1455)
at PerformanceLog.run(performance_logger.dart:32)
at AnalysisDriver._computeAnalysisResult(driver.dart:1431)
at AnalysisDriver.performWork(driver.dart:1194)
at AnalysisDriverScheduler._run(driver.dart:2137)

[scheglov]

OTOH, I was not able to reproduce it, so https://dart-review.googlesource.com/c/sdk/+/223743

[scheglov]

It does not happen with latest build if Dart SDK, so I conclude that the issue was fixed.

[bwilkerson]

This is still being reported, with the extra data added in the CL referenced above:

Thread 0 [MAIN THREAD]
StateError: Bad state: [library: null][this: (DefaultParameterElementImpl) {TextStyle? textStyle}][enclosingElement: null][reference: null]
  at ConstVariableElement.computeConstantValue	(element.dart:1306)
  at _Visitor.checkArgument	(avoid_redundant_argument_values.dart:104)
  at _Visitor.check	(avoid_redundant_argument_values.dart:88)
  at _Visitor.visitFunctionExpressionInvocation	(avoid_redundant_argument_values.dart:125)
  at FunctionExpressionInvocationImpl.accept	(ast.dart:8639)
  at LinterVisitor._runSubscriptions	(linter_visitor.dart:1058)
  at LinterVisitor.visitFunctionExpressionInvocation	(linter_visitor.dart:424)
  at FunctionExpressionInvocationImpl.accept	(ast.dart:8639)
  at NamedExpressionImpl.visitChildren	(ast.dart:12623)
  at LinterVisitor.visitNamedExpression	(linter_visitor.dart:635)
  at NamedExpressionImpl.accept	(ast.dart:12613)
  at NodeListImpl.accept	(ast.dart:13037)
  at ArgumentListImpl.visitChildren	(ast.dart:511)
  at LinterVisitor.visitArgumentList	(linter_visitor.dart:41)
  at ArgumentListImpl.accept	(ast.dart:507)
  at InstanceCreationExpressionImpl.visitChildren	(ast.dart:10512)
  at LinterVisitor.visitInstanceCreationExpression	(linter_visitor.dart:515)
  at InstanceCreationExpressionImpl.accept	(ast.dart:10501)
  at NamedExpressionImpl.visitChildren	(ast.dart:12623)
  at LinterVisitor.visitNamedExpression	(linter_visitor.dart:635)
  at NamedExpressionImpl.accept	(ast.dart:12613)
  at NodeListImpl.accept	(ast.dart:13037)
  at ArgumentListImpl.visitChildren	(ast.dart:511)
  at LinterVisitor.visitArgumentList	(linter_visitor.dart:41)
  at ArgumentListImpl.accept	(ast.dart:507)
  at InstanceCreationExpressionImpl.visitChildren	(ast.dart:10512)
  at LinterVisitor.visitInstanceCreationExpression	(linter_visitor.dart:515)
  at InstanceCreationExpressionImpl.accept	(ast.dart:10501)
  at ReturnStatementImpl.visitChildren	(ast.dart:15701)
  at LinterVisitor.visitReturnStatement	(linter_visitor.dart:844)
  at ReturnStatementImpl.accept	(ast.dart:15697)
  at NodeListImpl.accept	(ast.dart:13037)
  at BlockImpl.visitChildren	(ast.dart:1980)
  at LinterVisitor.visitBlock	(linter_visitor.dart:95)
  at BlockImpl.accept	(ast.dart:1976)
  at BlockFunctionBodyImpl.visitChildren	(ast.dart:1931)
  at LinterVisitor.visitBlockFunctionBody	(linter_visitor.dart:101)
  at BlockFunctionBodyImpl.accept	(ast.dart:1923)
  at FunctionExpressionImpl.visitChildren	(ast.dart:8560)
  at LinterVisitor.visitFunctionExpression	(linter_visitor.dart:419)
  at FunctionExpressionImpl.accept	(ast.dart:8549)
  at FunctionDeclarationImpl.visitChildren	(ast.dart:8394)
  at LinterVisitor.visitFunctionDeclaration	(linter_visitor.dart:407)
  at FunctionDeclarationImpl.accept	(ast.dart:8388)
  at NodeListImpl.accept	(ast.dart:13037)
  at CompilationUnitImpl.visitChildren	(ast.dart:3662)
  at LinterVisitor.visitCompilationUnit	(linter_visitor.dart:173)
  at CompilationUnitImpl.accept	(ast.dart:3655)
  at LibraryAnalyzer._computeLints	(library_analyzer.dart:362)
  at LibraryAnalyzer._computeDiagnostics	(library_analyzer.dart:304)
  at LibraryAnalyzer.analyze	(library_analyzer.dart:97)
  at AnalysisDriver._computeAnalysisResult.<fn>	(driver.dart:1371)
  at <asynchronous gap>	(async)
  at PerformanceLog.runAsync	(performance_logger.dart:50)
  at <asynchronous gap>	(async)
  at AnalysisDriver.performWork	(driver.dart:1194)
  at <asynchronous gap>	(async)
  at AnalysisDriverScheduler._run	(driver.dart:2262)