Need to handle mismatches in DeclarationResolver

[bwilkerson]

The line numbers are wrong, but I suspect the bug still exists.

Dart analysis server, SDK version 1.20.0-dev.4.0, server version 1.17.0, error: Task failed: BuildCompilationUnitElementTask for source x.dart
Mismatch in DeclarationResolver while resolving x.dart
Could not find element with name "S2" at 2129
Path to root: DeclaredSimpleIdentifier, TypeParameterImpl, TypeParameterListImpl, MethodDeclarationImpl, ClassDeclarationImpl, CompilationUnitImpl
#0 RecursiveAstVisitor&ExistingElementResolver._mismatch (package:analyzer/src/generated/resolver.dart:3426)
#1 DeclarationResolver._findWithNameAndOffset (package:analyzer/src/generated/resolver.dart:2795)
#2 DeclarationResolver._findIdentifier (package:analyzer/src/generated/resolver.dart:2753)
#3 DeclarationResolver.visitTypeParameter (package:analyzer/src/generated/resolver.dart:2677)
#4 TypeParameterImpl.accept (package:analyzer/src/dart/ast/ast.dart:10412)
#5 NodeListImpl.accept (package:analyzer/src/dart/ast/ast.dart:7688)
#6 TypeParameterListImpl.visitChildren (package:analyzer/src/dart/ast/ast.dart:10473)
#7 RecursiveAstVisitor.visitTypeParameterList (package:analyzer/dart/ast/visitor.dart:1948)
#8 TypeParameterListImpl.accept (package:analyzer/src/dart/ast/ast.dart:10469)
#9 MethodDeclarationImpl.visitChildren (package:analyzer/src/dart/ast/ast.dart:7194)
#10 RecursiveAstVisitor.visitMethodDeclaration (package:analyzer/dart/ast/visitor.dart:1737)
#11 DeclarationResolver.visitMethodDeclaration (package:analyzer/src/generated/resolver.dart:2600)
#12 MethodDeclarationImpl.accept (package:analyzer/src/dart/ast/ast.dart:7187)
#13 NodeListImpl.accept (package:analyzer/src/dart/ast/ast.dart:7688)
#14 ClassDeclarationImpl.visitChildren (package:analyzer/src/dart/ast/ast.dart:1915)
#15 RecursiveAstVisitor.visitClassDeclaration (package:analyzer/dart/ast/visitor.dart:1425)
#16 DeclarationResolver.visitClassDeclaration (package:analyzer/src/generated/resolver.dart:2315)
#17 ClassDeclarationImpl.accept (package:analyzer/src/dart/ast/ast.dart:1847)
#18 NodeListImpl.accept (package:analyzer/src/dart/ast/ast.dart:7688)
#19 CompilationUnitImpl.visitChildren (package:analyzer/src/dart/ast/ast.dart:2446)
#20 RecursiveAstVisitor.visitCompilationUnit (package:analyzer/dart/ast/visitor.dart:1449)
#21 CompilationUnitImpl.accept (package:analyzer/src/dart/ast/ast.dart:2439)
#22 DeclarationResolver.resolve (package:analyzer/src/generated/resolver.dart:2290)
#23 BuildCompilationUnitElementTask.internalPerform (package:analyzer/src/task/dart.dart:1077)
#24 AnalysisTask._safelyPerform (package:analyzer/task/model.dart:338)
#25 AnalysisTask.perform (package:analyzer/task/model.dart:238)
#26 AnalysisDriver.performWorkItem (package:analyzer/src/task/driver.dart:284)
#27 AnalysisDriver.performAnalysisTask (package:analyzer/src/task/driver.dart:255)
#28 AnalysisContextImpl.performAnalysisTask. (package:analyzer/src/context/context.dart:1243)
#29 _PerformanceTagImpl.makeCurrentWhile (package:analyzer/src/generated/utilities_general.dart:212)
#30 AnalysisContextImpl.performAnalysisTask (package:analyzer/src/context/context.dart:1241)
#31 PerformAnalysisOperation.perform (package:analysis_server/src/operation/operation_analysis.dart:355)
#32 AnalysisServer.performOperation (package:analysis_server/src/analysis_server.dart:894)
#33 Future.Future. (dart:async/future.dart:118)
#34 _rootRun (dart:async/zone.dart:1146)
#35 _CustomZone.run (dart:async/zone.dart:1026)
#36 _CustomZone.runGuarded (dart:async/zone.dart:924)
#37 _CustomZone.bindCallback. (dart:async/zone.dart:951)
#38 _rootRun (dart:async/zone.dart:1150)
#39 _CustomZone.run (dart:async/zone.dart:1026)
#40 _CustomZone.runGuarded (dart:async/zone.dart:924)
#41 _CustomZone.bindCallback. (dart:async/zone.dart:951)
#42 Timer._createTimer. (dart:async-patch/timer_patch.dart:16)
#43 _Timer._runTimers (dart:isolate-patch/timer_impl.dart:385)
#44 _Timer._handleMessage (dart:isolate-patch/timer_impl.dart:414)
#45 _RawReceivePortImpl._handleMessage (dart:isolate-patch/isolate_patch.dart:148)

[bwilkerson]

I'm assuming that this is stale.