|  | library; | 
|  | // | 
|  | // Problems in library: | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:37:34: Error: Operator '+' cannot be called on 'int?' because it is potentially null. | 
|  | // var topLevelBinary = nullableInt + 0; | 
|  | //                                  ^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:38:21: Error: Operator 'unary-' cannot be called on 'int?' because it is potentially null. | 
|  | // var topLevelUnary = -nullableInt; | 
|  | //                     ^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:39:35: Error: Operator '[]' cannot be called on 'Map<dynamic, dynamic>?' because it is potentially null. | 
|  | //  - 'Map' is from 'dart:core'. | 
|  | // var topLevelIndexGet = nullableMap[0]; | 
|  | //                                   ^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:40:35: Error: Operator '[]=' cannot be called on 'Map<dynamic, dynamic>?' because it is potentially null. | 
|  | //  - 'Map' is from 'dart:core'. | 
|  | // var topLevelIndexSet = nullableMap[0] = 1; | 
|  | //                                   ^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:41:38: Error: Operator '[]' cannot be called on 'Map<dynamic, dynamic>?' because it is potentially null. | 
|  | //  - 'Map' is from 'dart:core'. | 
|  | // var topLevelIndexGetSet = nullableMap[0] += 1; | 
|  | //                                      ^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:41:38: Error: Operator '[]=' cannot be called on 'Map<dynamic, dynamic>?' because it is potentially null. | 
|  | //  - 'Map' is from 'dart:core'. | 
|  | // var topLevelIndexGetSet = nullableMap[0] += 1; | 
|  | //                                      ^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:42:41: Error: Property 'property' cannot be accessed on 'Class?' because it is potentially null. | 
|  | //  - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | // Try accessing using ?. instead. | 
|  | // var topLevelPropertyGet = nullableClass.property; | 
|  | //                                         ^^^^^^^^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:43:41: Error: Property 'property' cannot be accessed on 'Class?' because it is potentially null. | 
|  | //  - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | // Try accessing using ?. instead. | 
|  | // var topLevelPropertySet = nullableClass.property = 1; | 
|  | //                                         ^^^^^^^^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:44:44: Error: Property 'property' cannot be accessed on 'Class?' because it is potentially null. | 
|  | //  - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | // Try accessing using ?. instead. | 
|  | // var topLevelPropertyGetSet = nullableClass.property += 1; | 
|  | //                                            ^^^^^^^^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:45:46: Error: Method 'method' cannot be called on 'Class?' because it is potentially null. | 
|  | //  - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | // Try calling using ?. instead. | 
|  | // var topLevelMethodInvocation = nullableClass.method(); | 
|  | //                                              ^^^^^^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:46:43: Error: Property 'method' cannot be accessed on 'Class?' because it is potentially null. | 
|  | //  - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | // Try accessing using ?. instead. | 
|  | // var topLevelMethodTearOff = nullableClass.method; | 
|  | //                                           ^^^^^^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:47:52: Error: Can't use an expression of type 'Function?' as a function because it's potentially null. | 
|  | //  - 'Function' is from 'dart:core'. | 
|  | // Try calling using ?.call instead. | 
|  | // var topLevelFunctionImplicitCall = nullableFunction(); | 
|  | //                                                    ^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:48:53: Error: Method 'call' cannot be called on 'Function?' because it is potentially null. | 
|  | //  - 'Function' is from 'dart:core'. | 
|  | // Try calling using ?. instead. | 
|  | // var topLevelFunctionExplicitCall = nullableFunction.call(); | 
|  | //                                                     ^^^^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:49:48: Error: Property 'call' cannot be accessed on 'Function?' because it is potentially null. | 
|  | //  - 'Function' is from 'dart:core'. | 
|  | // Try accessing using ?. instead. | 
|  | // var topLevelFunctionTearOff = nullableFunction.call; | 
|  | //                                                ^^^^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:50:60: Error: Can't use an expression of type 'void Function()?' as a function because it's potentially null. | 
|  | // Try calling using ?.call instead. | 
|  | // var topLevelFunctionTypeImplicitCall = nullableFunctionType(); | 
|  | //                                                            ^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:51:61: Error: Method 'call' cannot be called on 'void Function()?' because it is potentially null. | 
|  | // Try calling using ?. instead. | 
|  | // var topLevelFunctionTypeExplicitCall = nullableFunctionType.call(); | 
|  | //                                                             ^^^^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:52:56: Error: Property 'call' cannot be accessed on 'void Function()?' because it is potentially null. | 
|  | // Try accessing using ?. instead. | 
|  | // var topLevelFunctionTypeTearOff = nullableFunctionType.call; | 
|  | //                                                        ^^^^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:53:43: Error: Can't use an expression of type 'Class?' as a function because it's potentially null. | 
|  | //  - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | // Try calling using ?.call instead. | 
|  | // var topLevelFunctionField = nullableClass.functionField(); | 
|  | //                                           ^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:54:47: Error: Can't use an expression of type 'Class?' as a function because it's potentially null. | 
|  | //  - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | // Try calling using ?.call instead. | 
|  | // var topLevelFunctionTypeField = nullableClass.functionTypeField(); | 
|  | //                                               ^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:55:44: Error: Can't use an expression of type 'Class?' as a function because it's potentially null. | 
|  | //  - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | // Try calling using ?.call instead. | 
|  | // var topLevelFunctionGetter = nullableClass.functionGetter(); | 
|  | //                                            ^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:56:48: Error: Can't use an expression of type 'Class?' as a function because it's potentially null. | 
|  | //  - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | // Try calling using ?.call instead. | 
|  | // var topLevelFunctionTypeGetter = nullableClass.functionTypeGetter(); | 
|  | //                                                ^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:58:45: Error: Operator '+' cannot be called on 'Class?' because it is potentially null. | 
|  | //  - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | // var topLevelExtensionBinary = nullableClass + 0; | 
|  | //                                             ^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:59:30: Error: Operator 'unary-' cannot be called on 'Class?' because it is potentially null. | 
|  | //  - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | // var topLevelExtensionUnary = -nullableClass; | 
|  | //                              ^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:60:46: Error: Operator '[]' cannot be called on 'Class?' because it is potentially null. | 
|  | //  - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | // var topLevelExtensionIndexGet = nullableClass[0]; | 
|  | //                                              ^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:61:46: Error: Operator '[]=' cannot be called on 'Class?' because it is potentially null. | 
|  | //  - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | // var topLevelExtensionIndexSet = nullableClass[0] = 1; | 
|  | //                                              ^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:62:49: Error: Operator '[]' cannot be called on 'Class?' because it is potentially null. | 
|  | //  - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | // var topLevelExtensionIndexGetSet = nullableClass[0] += 1; | 
|  | //                                                 ^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:62:49: Error: Operator '[]=' cannot be called on 'Class?' because it is potentially null. | 
|  | //  - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | // var topLevelExtensionIndexGetSet = nullableClass[0] += 1; | 
|  | //                                                 ^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:63:50: Error: Property 'extensionProperty' cannot be accessed on 'Class?' because it is potentially null. | 
|  | //  - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | // Try accessing using ?. instead. | 
|  | // var topLevelExtensionPropertyGet = nullableClass.extensionProperty; | 
|  | //                                                  ^^^^^^^^^^^^^^^^^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:64:50: Error: Property 'extensionProperty' cannot be accessed on 'Class?' because it is potentially null. | 
|  | //  - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | // Try accessing using ?. instead. | 
|  | // var topLevelExtensionPropertySet = nullableClass.extensionProperty = 1; | 
|  | //                                                  ^^^^^^^^^^^^^^^^^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:65:53: Error: Property 'extensionProperty' cannot be accessed on 'Class?' because it is potentially null. | 
|  | //  - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | // Try accessing using ?. instead. | 
|  | // var topLevelExtensionPropertyGetSet = nullableClass.extensionProperty += 1; | 
|  | //                                                     ^^^^^^^^^^^^^^^^^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:66:55: Error: Method 'extensionMethod' cannot be called on 'Class?' because it is potentially null. | 
|  | //  - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | // Try calling using ?. instead. | 
|  | // var topLevelExtensionMethodInvocation = nullableClass.extensionMethod(); | 
|  | //                                                       ^^^^^^^^^^^^^^^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:67:52: Error: Property 'extensionMethod' cannot be accessed on 'Class?' because it is potentially null. | 
|  | //  - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | // Try accessing using ?. instead. | 
|  | // var topLevelExtensionMethodTearOff = nullableClass.extensionMethod; | 
|  | //                                                    ^^^^^^^^^^^^^^^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:68:62: Error: Can't use an expression of type 'Class?' as a function because it's potentially null. | 
|  | //  - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | // Try calling using ?.call instead. | 
|  | // var topLevelExtensionFunctionTypeImplicitCall = nullableClass(); | 
|  | //                                                              ^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:69:63: Error: Method 'call' cannot be called on 'Class?' because it is potentially null. | 
|  | //  - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | // Try calling using ?. instead. | 
|  | // var topLevelExtensionFunctionTypeExplicitCall = nullableClass.call(); | 
|  | //                                                               ^^^^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:70:58: Error: Property 'call' cannot be accessed on 'Class?' because it is potentially null. | 
|  | //  - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | // Try accessing using ?. instead. | 
|  | // var topLevelExtensionFunctionTypeTearOff = nullableClass.call; | 
|  | //                                                          ^^^^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:71:53: Error: Can't use an expression of type 'Class?' as a function because it's potentially null. | 
|  | //  - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | // Try calling using ?.call instead. | 
|  | // var topLevelExtensionFunctionGetter = nullableClass.extensionFunctionGetter(); | 
|  | //                                                     ^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:73:19: Error: Can't use an expression of type 'Class?' as a function because it's potentially null. | 
|  | //  - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | // Try calling using ?.call instead. | 
|  | //     nullableClass.extensionFunctionTypeGetter(); | 
|  | //                   ^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:76:33: Error: Operator '+' cannot be called on 'int?' because it is potentially null. | 
|  | //   var localBinary = nullableInt + 0; | 
|  | //                                 ^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:77:20: Error: Operator 'unary-' cannot be called on 'int?' because it is potentially null. | 
|  | //   var localUnary = -nullableInt; | 
|  | //                    ^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:78:34: Error: Operator '[]' cannot be called on 'Map<dynamic, dynamic>?' because it is potentially null. | 
|  | //  - 'Map' is from 'dart:core'. | 
|  | //   var localIndexGet = nullableMap[0]; | 
|  | //                                  ^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:79:34: Error: Operator '[]=' cannot be called on 'Map<dynamic, dynamic>?' because it is potentially null. | 
|  | //  - 'Map' is from 'dart:core'. | 
|  | //   var localIndexSet = nullableMap[0] = 1; | 
|  | //                                  ^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:80:37: Error: Operator '[]' cannot be called on 'Map<dynamic, dynamic>?' because it is potentially null. | 
|  | //  - 'Map' is from 'dart:core'. | 
|  | //   var localIndexGetSet = nullableMap[0] += 1; | 
|  | //                                     ^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:80:37: Error: Operator '[]=' cannot be called on 'Map<dynamic, dynamic>?' because it is potentially null. | 
|  | //  - 'Map' is from 'dart:core'. | 
|  | //   var localIndexGetSet = nullableMap[0] += 1; | 
|  | //                                     ^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:81:40: Error: Property 'property' cannot be accessed on 'Class?' because it is potentially null. | 
|  | //  - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | // Try accessing using ?. instead. | 
|  | //   var localPropertyGet = nullableClass.property; | 
|  | //                                        ^^^^^^^^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:82:40: Error: Property 'property' cannot be accessed on 'Class?' because it is potentially null. | 
|  | //  - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | // Try accessing using ?. instead. | 
|  | //   var localPropertySet = nullableClass.property = 1; | 
|  | //                                        ^^^^^^^^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:83:43: Error: Property 'property' cannot be accessed on 'Class?' because it is potentially null. | 
|  | //  - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | // Try accessing using ?. instead. | 
|  | //   var localPropertyGetSet = nullableClass.property += 1; | 
|  | //                                           ^^^^^^^^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:84:45: Error: Method 'method' cannot be called on 'Class?' because it is potentially null. | 
|  | //  - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | // Try calling using ?. instead. | 
|  | //   var localMethodInvocation = nullableClass.method(); | 
|  | //                                             ^^^^^^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:85:42: Error: Property 'method' cannot be accessed on 'Class?' because it is potentially null. | 
|  | //  - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | // Try accessing using ?. instead. | 
|  | //   var localMethodTearOff = nullableClass.method; | 
|  | //                                          ^^^^^^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:86:51: Error: Can't use an expression of type 'Function?' as a function because it's potentially null. | 
|  | //  - 'Function' is from 'dart:core'. | 
|  | // Try calling using ?.call instead. | 
|  | //   var localFunctionImplicitCall = nullableFunction(); | 
|  | //                                                   ^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:87:52: Error: Method 'call' cannot be called on 'Function?' because it is potentially null. | 
|  | //  - 'Function' is from 'dart:core'. | 
|  | // Try calling using ?. instead. | 
|  | //   var localFunctionExplicitCall = nullableFunction.call(); | 
|  | //                                                    ^^^^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:88:47: Error: Property 'call' cannot be accessed on 'Function?' because it is potentially null. | 
|  | //  - 'Function' is from 'dart:core'. | 
|  | // Try accessing using ?. instead. | 
|  | //   var localFunctionTearOff = nullableFunction.call; | 
|  | //                                               ^^^^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:89:59: Error: Can't use an expression of type 'void Function()?' as a function because it's potentially null. | 
|  | // Try calling using ?.call instead. | 
|  | //   var localFunctionTypeImplicitCall = nullableFunctionType(); | 
|  | //                                                           ^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:90:60: Error: Method 'call' cannot be called on 'void Function()?' because it is potentially null. | 
|  | // Try calling using ?. instead. | 
|  | //   var localFunctionTypeExplicitCall = nullableFunctionType.call(); | 
|  | //                                                            ^^^^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:91:55: Error: Property 'call' cannot be accessed on 'void Function()?' because it is potentially null. | 
|  | // Try accessing using ?. instead. | 
|  | //   var localFunctionTypeTearOff = nullableFunctionType.call; | 
|  | //                                                       ^^^^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:92:42: Error: Can't use an expression of type 'Class?' as a function because it's potentially null. | 
|  | //  - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | // Try calling using ?.call instead. | 
|  | //   var localFunctionField = nullableClass.functionField(); | 
|  | //                                          ^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:93:46: Error: Can't use an expression of type 'Class?' as a function because it's potentially null. | 
|  | //  - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | // Try calling using ?.call instead. | 
|  | //   var localFunctionTypeField = nullableClass.functionTypeField(); | 
|  | //                                              ^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:94:43: Error: Can't use an expression of type 'Class?' as a function because it's potentially null. | 
|  | //  - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | // Try calling using ?.call instead. | 
|  | //   var localFunctionGetter = nullableClass.functionGetter(); | 
|  | //                                           ^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:95:47: Error: Can't use an expression of type 'Class?' as a function because it's potentially null. | 
|  | //  - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | // Try calling using ?.call instead. | 
|  | //   var localFunctionTypeGetter = nullableClass.functionTypeGetter(); | 
|  | //                                               ^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:97:44: Error: Operator '+' cannot be called on 'Class?' because it is potentially null. | 
|  | //  - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | //   var localExtensionBinary = nullableClass + 0; | 
|  | //                                            ^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:98:29: Error: Operator 'unary-' cannot be called on 'Class?' because it is potentially null. | 
|  | //  - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | //   var localExtensionUnary = -nullableClass; | 
|  | //                             ^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:99:45: Error: Operator '[]' cannot be called on 'Class?' because it is potentially null. | 
|  | //  - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | //   var localExtensionIndexGet = nullableClass[0]; | 
|  | //                                             ^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:100:45: Error: Operator '[]=' cannot be called on 'Class?' because it is potentially null. | 
|  | //  - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | //   var localExtensionIndexSet = nullableClass[0] = 1; | 
|  | //                                             ^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:101:48: Error: Operator '[]' cannot be called on 'Class?' because it is potentially null. | 
|  | //  - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | //   var localExtensionIndexGetSet = nullableClass[0] += 1; | 
|  | //                                                ^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:101:48: Error: Operator '[]=' cannot be called on 'Class?' because it is potentially null. | 
|  | //  - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | //   var localExtensionIndexGetSet = nullableClass[0] += 1; | 
|  | //                                                ^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:102:49: Error: Property 'extensionProperty' cannot be accessed on 'Class?' because it is potentially null. | 
|  | //  - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | // Try accessing using ?. instead. | 
|  | //   var localExtensionPropertyGet = nullableClass.extensionProperty; | 
|  | //                                                 ^^^^^^^^^^^^^^^^^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:103:49: Error: Property 'extensionProperty' cannot be accessed on 'Class?' because it is potentially null. | 
|  | //  - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | // Try accessing using ?. instead. | 
|  | //   var localExtensionPropertySet = nullableClass.extensionProperty = 1; | 
|  | //                                                 ^^^^^^^^^^^^^^^^^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:104:52: Error: Property 'extensionProperty' cannot be accessed on 'Class?' because it is potentially null. | 
|  | //  - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | // Try accessing using ?. instead. | 
|  | //   var localExtensionPropertyGetSet = nullableClass.extensionProperty += 1; | 
|  | //                                                    ^^^^^^^^^^^^^^^^^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:105:54: Error: Method 'extensionMethod' cannot be called on 'Class?' because it is potentially null. | 
|  | //  - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | // Try calling using ?. instead. | 
|  | //   var localExtensionMethodInvocation = nullableClass.extensionMethod(); | 
|  | //                                                      ^^^^^^^^^^^^^^^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:106:51: Error: Property 'extensionMethod' cannot be accessed on 'Class?' because it is potentially null. | 
|  | //  - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | // Try accessing using ?. instead. | 
|  | //   var localExtensionMethodTearOff = nullableClass.extensionMethod; | 
|  | //                                                   ^^^^^^^^^^^^^^^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:107:61: Error: Can't use an expression of type 'Class?' as a function because it's potentially null. | 
|  | //  - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | // Try calling using ?.call instead. | 
|  | //   var localExtensionFunctionTypeImplicitCall = nullableClass(); | 
|  | //                                                             ^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:108:62: Error: Method 'call' cannot be called on 'Class?' because it is potentially null. | 
|  | //  - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | // Try calling using ?. instead. | 
|  | //   var localExtensionFunctionTypeExplicitCall = nullableClass.call(); | 
|  | //                                                              ^^^^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:109:57: Error: Property 'call' cannot be accessed on 'Class?' because it is potentially null. | 
|  | //  - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | // Try accessing using ?. instead. | 
|  | //   var localExtensionFunctionTypeTearOff = nullableClass.call; | 
|  | //                                                         ^^^^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:110:52: Error: Can't use an expression of type 'Class?' as a function because it's potentially null. | 
|  | //  - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | // Try calling using ?.call instead. | 
|  | //   var localExtensionFunctionGetter = nullableClass.extensionFunctionGetter(); | 
|  | //                                                    ^ | 
|  | // | 
|  | // pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:112:21: Error: Can't use an expression of type 'Class?' as a function because it's potentially null. | 
|  | //  - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | // Try calling using ?.call instead. | 
|  | //       nullableClass.extensionFunctionTypeGetter(); | 
|  | //                     ^ | 
|  | // | 
|  | import self as self; | 
|  | import "dart:core" as core; | 
|  |  | 
|  | class Class extends core::Object { | 
|  | field core::int property = 0; | 
|  | field core::Function functionField = () → Null {}; | 
|  | field () → void functionTypeField = () → void {}; | 
|  | synthetic constructor •() → self::Class | 
|  | : super core::Object::•() | 
|  | ; | 
|  | method method() → core::int | 
|  | return 0; | 
|  | get functionGetter() → core::Function | 
|  | return () → Null {}; | 
|  | get functionTypeGetter() → () → void | 
|  | return () → void {}; | 
|  | } | 
|  | extension Extension on self::Class { | 
|  | operator + = self::Extension|+; | 
|  | operator unary- = self::Extension|unary-; | 
|  | operator [] = self::Extension|[]; | 
|  | operator []= = self::Extension|[]=; | 
|  | method call = self::Extension|call; | 
|  | method tearoff call = self::Extension|get#call; | 
|  | get extensionProperty = self::Extension|get#extensionProperty; | 
|  | method extensionMethod = self::Extension|extensionMethod; | 
|  | method tearoff extensionMethod = self::Extension|get#extensionMethod; | 
|  | get extensionFunctionGetter = self::Extension|get#extensionFunctionGetter; | 
|  | get extensionFunctionTypeGetter = self::Extension|get#extensionFunctionTypeGetter; | 
|  | set extensionProperty = self::Extension|set#extensionProperty; | 
|  | } | 
|  | static field core::num topLevelBinary = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:37:34: Error: Operator '+' cannot be called on 'int?' because it is potentially null. | 
|  | var topLevelBinary = nullableInt + 0; | 
|  | ^" in self::nullableInt.{core::num::+}(0){(core::num) → core::num}; | 
|  | static field core::int topLevelUnary = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:38:21: Error: Operator 'unary-' cannot be called on 'int?' because it is potentially null. | 
|  | var topLevelUnary = -nullableInt; | 
|  | ^" in self::nullableInt.{core::int::unary-}(){() → core::int}; | 
|  | static field dynamic topLevelIndexGet = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:39:35: Error: Operator '[]' cannot be called on 'Map<dynamic, dynamic>?' because it is potentially null. | 
|  | - 'Map' is from 'dart:core'. | 
|  | var topLevelIndexGet = nullableMap[0]; | 
|  | ^" in self::nullableMap.{core::Map::[]}{<nullable>}.(0){(core::Object?) → dynamic}; | 
|  | static field core::int topLevelIndexSet = let final core::Map<dynamic, dynamic>? #t1 = self::nullableMap in let final core::int #t2 = 0 in let final core::int #t3 = 1 in let final void #t4 = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:40:35: Error: Operator '[]=' cannot be called on 'Map<dynamic, dynamic>?' because it is potentially null. | 
|  | - 'Map' is from 'dart:core'. | 
|  | var topLevelIndexSet = nullableMap[0] = 1; | 
|  | ^" in #t1.{core::Map::[]=}{<nullable>}.(#t2, #t3){(dynamic, dynamic) → void} in #t3; | 
|  | static field dynamic topLevelIndexGetSet = let final core::Map<dynamic, dynamic>? #t5 = self::nullableMap in let final core::int #t6 = 0 in let final dynamic #t7 = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:41:38: Error: Operator '[]' cannot be called on 'Map<dynamic, dynamic>?' because it is potentially null. | 
|  | - 'Map' is from 'dart:core'. | 
|  | var topLevelIndexGetSet = nullableMap[0] += 1; | 
|  | ^" in #t5.{core::Map::[]}{<nullable>}.(#t6){(core::Object?) → dynamic}{dynamic}.+(1) in let final void #t8 = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:41:38: Error: Operator '[]=' cannot be called on 'Map<dynamic, dynamic>?' because it is potentially null. | 
|  | - 'Map' is from 'dart:core'. | 
|  | var topLevelIndexGetSet = nullableMap[0] += 1; | 
|  | ^" in #t5.{core::Map::[]=}{<nullable>}.(#t6, #t7){(dynamic, dynamic) → void} in #t7; | 
|  | static field core::int topLevelPropertyGet = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:42:41: Error: Property 'property' cannot be accessed on 'Class?' because it is potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | Try accessing using ?. instead. | 
|  | var topLevelPropertyGet = nullableClass.property; | 
|  | ^^^^^^^^" in self::nullableClass.{self::Class::property}{<nullable>}.{core::int}; | 
|  | static field core::int topLevelPropertySet = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:43:41: Error: Property 'property' cannot be accessed on 'Class?' because it is potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | Try accessing using ?. instead. | 
|  | var topLevelPropertySet = nullableClass.property = 1; | 
|  | ^^^^^^^^" in self::nullableClass.{self::Class::property}{<nullable>}. = 1; | 
|  | static field core::int topLevelPropertyGetSet = let final self::Class? #t9 = self::nullableClass in invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:44:44: Error: Property 'property' cannot be accessed on 'Class?' because it is potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | Try accessing using ?. instead. | 
|  | var topLevelPropertyGetSet = nullableClass.property += 1; | 
|  | ^^^^^^^^" in #t9.{self::Class::property}{<nullable>}. = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:44:44: Error: Property 'property' cannot be accessed on 'Class?' because it is potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | Try accessing using ?. instead. | 
|  | var topLevelPropertyGetSet = nullableClass.property += 1; | 
|  | ^^^^^^^^" in #t9.{self::Class::property}{<nullable>}.{core::int}.{core::num::+}(1){(core::num) → core::int}; | 
|  | static field core::int topLevelMethodInvocation = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:45:46: Error: Method 'method' cannot be called on 'Class?' because it is potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | Try calling using ?. instead. | 
|  | var topLevelMethodInvocation = nullableClass.method(); | 
|  | ^^^^^^" in self::nullableClass.{self::Class::method}{<nullable>}.(){() → core::int}; | 
|  | static field () → core::int topLevelMethodTearOff = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:46:43: Error: Property 'method' cannot be accessed on 'Class?' because it is potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | Try accessing using ?. instead. | 
|  | var topLevelMethodTearOff = nullableClass.method; | 
|  | ^^^^^^" in self::nullableClass.{self::Class::method}{<nullable>}.{() → core::int}; | 
|  | static field invalid-type topLevelFunctionImplicitCall = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:47:52: Error: Can't use an expression of type 'Function?' as a function because it's potentially null. | 
|  | - 'Function' is from 'dart:core'. | 
|  | Try calling using ?.call instead. | 
|  | var topLevelFunctionImplicitCall = nullableFunction(); | 
|  | ^" in self::nullableFunction{<nullable>}.(); | 
|  | static field invalid-type topLevelFunctionExplicitCall = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:48:53: Error: Method 'call' cannot be called on 'Function?' because it is potentially null. | 
|  | - 'Function' is from 'dart:core'. | 
|  | Try calling using ?. instead. | 
|  | var topLevelFunctionExplicitCall = nullableFunction.call(); | 
|  | ^^^^" in self::nullableFunction{<nullable>}.(); | 
|  | static field core::Function? topLevelFunctionTearOff = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:49:48: Error: Property 'call' cannot be accessed on 'Function?' because it is potentially null. | 
|  | - 'Function' is from 'dart:core'. | 
|  | Try accessing using ?. instead. | 
|  | var topLevelFunctionTearOff = nullableFunction.call; | 
|  | ^^^^" in self::nullableFunction.call; | 
|  | static field void topLevelFunctionTypeImplicitCall = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:50:60: Error: Can't use an expression of type 'void Function()?' as a function because it's potentially null. | 
|  | Try calling using ?.call instead. | 
|  | var topLevelFunctionTypeImplicitCall = nullableFunctionType(); | 
|  | ^" in self::nullableFunctionType{<nullable>}.(){() →? void}; | 
|  | static field void topLevelFunctionTypeExplicitCall = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:51:61: Error: Method 'call' cannot be called on 'void Function()?' because it is potentially null. | 
|  | Try calling using ?. instead. | 
|  | var topLevelFunctionTypeExplicitCall = nullableFunctionType.call(); | 
|  | ^^^^" in self::nullableFunctionType{<nullable>}.(){() →? void}; | 
|  | static field () →? void topLevelFunctionTypeTearOff = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:52:56: Error: Property 'call' cannot be accessed on 'void Function()?' because it is potentially null. | 
|  | Try accessing using ?. instead. | 
|  | var topLevelFunctionTypeTearOff = nullableFunctionType.call; | 
|  | ^^^^" in self::nullableFunctionType.call; | 
|  | static field dynamic topLevelFunctionField = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:53:43: Error: Can't use an expression of type 'Class?' as a function because it's potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | Try calling using ?.call instead. | 
|  | var topLevelFunctionField = nullableClass.functionField(); | 
|  | ^" in self::nullableClass.{self::Class::functionField}{<nullable>}.{core::Function}(); | 
|  | static field void topLevelFunctionTypeField = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:54:47: Error: Can't use an expression of type 'Class?' as a function because it's potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | Try calling using ?.call instead. | 
|  | var topLevelFunctionTypeField = nullableClass.functionTypeField(); | 
|  | ^" in self::nullableClass.{self::Class::functionTypeField}{<nullable>}.{() → void}(){() → void}; | 
|  | static field dynamic topLevelFunctionGetter = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:55:44: Error: Can't use an expression of type 'Class?' as a function because it's potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | Try calling using ?.call instead. | 
|  | var topLevelFunctionGetter = nullableClass.functionGetter(); | 
|  | ^" in self::nullableClass.{self::Class::functionGetter}{<nullable>}.{core::Function}(); | 
|  | static field void topLevelFunctionTypeGetter = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:56:48: Error: Can't use an expression of type 'Class?' as a function because it's potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | Try calling using ?.call instead. | 
|  | var topLevelFunctionTypeGetter = nullableClass.functionTypeGetter(); | 
|  | ^" in self::nullableClass.{self::Class::functionTypeGetter}{<nullable>}.{() → void}(){() → void}; | 
|  | static field core::int topLevelExtensionBinary = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:58:45: Error: Operator '+' cannot be called on 'Class?' because it is potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | var topLevelExtensionBinary = nullableClass + 0; | 
|  | ^" in self::Extension|+(self::nullableClass, 0); | 
|  | static field core::int topLevelExtensionUnary = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:59:30: Error: Operator 'unary-' cannot be called on 'Class?' because it is potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | var topLevelExtensionUnary = -nullableClass; | 
|  | ^" in self::Extension|unary-(self::nullableClass); | 
|  | static field core::int topLevelExtensionIndexGet = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:60:46: Error: Operator '[]' cannot be called on 'Class?' because it is potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | var topLevelExtensionIndexGet = nullableClass[0]; | 
|  | ^" in self::Extension|[](self::nullableClass, 0); | 
|  | static field core::int topLevelExtensionIndexSet = let final self::Class? #t10 = self::nullableClass in let final core::int #t11 = 0 in let final core::int #t12 = 1 in let final void #t13 = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:61:46: Error: Operator '[]=' cannot be called on 'Class?' because it is potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | var topLevelExtensionIndexSet = nullableClass[0] = 1; | 
|  | ^" in self::Extension|[]=(#t10, #t11, #t12) in #t12; | 
|  | static field core::int topLevelExtensionIndexGetSet = let final self::Class? #t14 = self::nullableClass in let final core::int #t15 = 0 in let final core::int #t16 = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:62:49: Error: Operator '[]' cannot be called on 'Class?' because it is potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | var topLevelExtensionIndexGetSet = nullableClass[0] += 1; | 
|  | ^" in self::Extension|[](#t14, #t15).{core::num::+}(1){(core::num) → core::int} in let final void #t17 = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:62:49: Error: Operator '[]=' cannot be called on 'Class?' because it is potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | var topLevelExtensionIndexGetSet = nullableClass[0] += 1; | 
|  | ^" in self::Extension|[]=(#t14, #t15, #t16) in #t16; | 
|  | static field core::int topLevelExtensionPropertyGet = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:63:50: Error: Property 'extensionProperty' cannot be accessed on 'Class?' because it is potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | Try accessing using ?. instead. | 
|  | var topLevelExtensionPropertyGet = nullableClass.extensionProperty; | 
|  | ^^^^^^^^^^^^^^^^^" in self::Extension|get#extensionProperty(self::nullableClass); | 
|  | static field core::int topLevelExtensionPropertySet = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:64:50: Error: Property 'extensionProperty' cannot be accessed on 'Class?' because it is potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | Try accessing using ?. instead. | 
|  | var topLevelExtensionPropertySet = nullableClass.extensionProperty = 1; | 
|  | ^^^^^^^^^^^^^^^^^" in let final core::int #t18 = 1 in let final void #t19 = self::Extension|set#extensionProperty(self::nullableClass, #t18) in #t18; | 
|  | static field core::int topLevelExtensionPropertyGetSet = let final self::Class? #t20 = self::nullableClass in invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:65:53: Error: Property 'extensionProperty' cannot be accessed on 'Class?' because it is potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | Try accessing using ?. instead. | 
|  | var topLevelExtensionPropertyGetSet = nullableClass.extensionProperty += 1; | 
|  | ^^^^^^^^^^^^^^^^^" in let final core::int #t21 = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:65:53: Error: Property 'extensionProperty' cannot be accessed on 'Class?' because it is potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | Try accessing using ?. instead. | 
|  | var topLevelExtensionPropertyGetSet = nullableClass.extensionProperty += 1; | 
|  | ^^^^^^^^^^^^^^^^^" in self::Extension|get#extensionProperty(#t20).{core::num::+}(1){(core::num) → core::int} in let final void #t22 = self::Extension|set#extensionProperty(#t20, #t21) in #t21; | 
|  | static field core::int topLevelExtensionMethodInvocation = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:66:55: Error: Method 'extensionMethod' cannot be called on 'Class?' because it is potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | Try calling using ?. instead. | 
|  | var topLevelExtensionMethodInvocation = nullableClass.extensionMethod(); | 
|  | ^^^^^^^^^^^^^^^" in self::Extension|extensionMethod(self::nullableClass); | 
|  | static field () → core::int topLevelExtensionMethodTearOff = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:67:52: Error: Property 'extensionMethod' cannot be accessed on 'Class?' because it is potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | Try accessing using ?. instead. | 
|  | var topLevelExtensionMethodTearOff = nullableClass.extensionMethod; | 
|  | ^^^^^^^^^^^^^^^" in self::Extension|get#extensionMethod(self::nullableClass); | 
|  | static field core::int topLevelExtensionFunctionTypeImplicitCall = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:68:62: Error: Can't use an expression of type 'Class?' as a function because it's potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | Try calling using ?.call instead. | 
|  | var topLevelExtensionFunctionTypeImplicitCall = nullableClass(); | 
|  | ^" in self::Extension|call(self::nullableClass); | 
|  | static field core::int topLevelExtensionFunctionTypeExplicitCall = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:69:63: Error: Method 'call' cannot be called on 'Class?' because it is potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | Try calling using ?. instead. | 
|  | var topLevelExtensionFunctionTypeExplicitCall = nullableClass.call(); | 
|  | ^^^^" in self::Extension|call(self::nullableClass); | 
|  | static field () → core::int topLevelExtensionFunctionTypeTearOff = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:70:58: Error: Property 'call' cannot be accessed on 'Class?' because it is potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | Try accessing using ?. instead. | 
|  | var topLevelExtensionFunctionTypeTearOff = nullableClass.call; | 
|  | ^^^^" in self::Extension|get#call(self::nullableClass); | 
|  | static field dynamic topLevelExtensionFunctionGetter = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:71:53: Error: Can't use an expression of type 'Class?' as a function because it's potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | Try calling using ?.call instead. | 
|  | var topLevelExtensionFunctionGetter = nullableClass.extensionFunctionGetter(); | 
|  | ^" in self::Extension|get#extensionFunctionGetter(self::nullableClass)(); | 
|  | static field void topLevelExtensionFunctionTypeGetter = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:73:19: Error: Can't use an expression of type 'Class?' as a function because it's potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | Try calling using ?.call instead. | 
|  | nullableClass.extensionFunctionTypeGetter(); | 
|  | ^" in self::Extension|get#extensionFunctionTypeGetter(self::nullableClass)(){() → void}; | 
|  | static extension-member method Extension|+(lowered final self::Class #this, core::int value) → core::int | 
|  | return 0; | 
|  | static extension-member method Extension|unary-(lowered final self::Class #this) → core::int | 
|  | return 0; | 
|  | static extension-member method Extension|[](lowered final self::Class #this, core::int index) → core::int | 
|  | return 0; | 
|  | static extension-member method Extension|[]=(lowered final self::Class #this, core::int index, core::int value) → void {} | 
|  | static extension-member method Extension|call(lowered final self::Class #this) → core::int | 
|  | return 0; | 
|  | static extension-member method Extension|get#call(lowered final self::Class #this) → () → core::int | 
|  | return () → core::int => self::Extension|call(#this); | 
|  | static extension-member method Extension|get#extensionProperty(lowered final self::Class #this) → core::int | 
|  | return 0; | 
|  | static extension-member method Extension|set#extensionProperty(lowered final self::Class #this, core::int value) → void {} | 
|  | static extension-member method Extension|extensionMethod(lowered final self::Class #this) → core::int | 
|  | return 0; | 
|  | static extension-member method Extension|get#extensionMethod(lowered final self::Class #this) → () → core::int | 
|  | return () → core::int => self::Extension|extensionMethod(#this); | 
|  | static extension-member method Extension|get#extensionFunctionGetter(lowered final self::Class #this) → core::Function | 
|  | return () → Null {}; | 
|  | static extension-member method Extension|get#extensionFunctionTypeGetter(lowered final self::Class #this) → () → void | 
|  | return () → void {}; | 
|  | static get nullableFunction() → core::Function? | 
|  | return () → Null {}; | 
|  | static get nullableFunctionType() → () →? void | 
|  | return () → void {}; | 
|  | static get nullableInt() → core::int? | 
|  | return 0; | 
|  | static get nullableMap() → core::Map<dynamic, dynamic>? | 
|  | return <dynamic, dynamic>{}; | 
|  | static get nullableClass() → self::Class? | 
|  | return new self::Class::•(); | 
|  | static method test() → dynamic { | 
|  | core::num localBinary = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:76:33: Error: Operator '+' cannot be called on 'int?' because it is potentially null. | 
|  | var localBinary = nullableInt + 0; | 
|  | ^" in self::nullableInt.{core::num::+}(0){(core::num) → core::num}; | 
|  | core::int localUnary = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:77:20: Error: Operator 'unary-' cannot be called on 'int?' because it is potentially null. | 
|  | var localUnary = -nullableInt; | 
|  | ^" in self::nullableInt.{core::int::unary-}(){() → core::int}; | 
|  | dynamic localIndexGet = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:78:34: Error: Operator '[]' cannot be called on 'Map<dynamic, dynamic>?' because it is potentially null. | 
|  | - 'Map' is from 'dart:core'. | 
|  | var localIndexGet = nullableMap[0]; | 
|  | ^" in self::nullableMap.{core::Map::[]}{<nullable>}.(0){(core::Object?) → dynamic}; | 
|  | core::int localIndexSet = let final core::Map<dynamic, dynamic>? #t23 = self::nullableMap in let final core::int #t24 = 0 in let final core::int #t25 = 1 in let final void #t26 = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:79:34: Error: Operator '[]=' cannot be called on 'Map<dynamic, dynamic>?' because it is potentially null. | 
|  | - 'Map' is from 'dart:core'. | 
|  | var localIndexSet = nullableMap[0] = 1; | 
|  | ^" in #t23.{core::Map::[]=}{<nullable>}.(#t24, #t25){(dynamic, dynamic) → void} in #t25; | 
|  | dynamic localIndexGetSet = let final core::Map<dynamic, dynamic>? #t27 = self::nullableMap in let final core::int #t28 = 0 in let final dynamic #t29 = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:80:37: Error: Operator '[]' cannot be called on 'Map<dynamic, dynamic>?' because it is potentially null. | 
|  | - 'Map' is from 'dart:core'. | 
|  | var localIndexGetSet = nullableMap[0] += 1; | 
|  | ^" in #t27.{core::Map::[]}{<nullable>}.(#t28){(core::Object?) → dynamic}{dynamic}.+(1) in let final void #t30 = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:80:37: Error: Operator '[]=' cannot be called on 'Map<dynamic, dynamic>?' because it is potentially null. | 
|  | - 'Map' is from 'dart:core'. | 
|  | var localIndexGetSet = nullableMap[0] += 1; | 
|  | ^" in #t27.{core::Map::[]=}{<nullable>}.(#t28, #t29){(dynamic, dynamic) → void} in #t29; | 
|  | core::int localPropertyGet = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:81:40: Error: Property 'property' cannot be accessed on 'Class?' because it is potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | Try accessing using ?. instead. | 
|  | var localPropertyGet = nullableClass.property; | 
|  | ^^^^^^^^" in self::nullableClass.{self::Class::property}{<nullable>}.{core::int}; | 
|  | core::int localPropertySet = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:82:40: Error: Property 'property' cannot be accessed on 'Class?' because it is potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | Try accessing using ?. instead. | 
|  | var localPropertySet = nullableClass.property = 1; | 
|  | ^^^^^^^^" in self::nullableClass.{self::Class::property}{<nullable>}. = 1; | 
|  | core::int localPropertyGetSet = let final self::Class? #t31 = self::nullableClass in invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:83:43: Error: Property 'property' cannot be accessed on 'Class?' because it is potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | Try accessing using ?. instead. | 
|  | var localPropertyGetSet = nullableClass.property += 1; | 
|  | ^^^^^^^^" in #t31.{self::Class::property}{<nullable>}. = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:83:43: Error: Property 'property' cannot be accessed on 'Class?' because it is potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | Try accessing using ?. instead. | 
|  | var localPropertyGetSet = nullableClass.property += 1; | 
|  | ^^^^^^^^" in #t31.{self::Class::property}{<nullable>}.{core::int}.{core::num::+}(1){(core::num) → core::int}; | 
|  | core::int localMethodInvocation = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:84:45: Error: Method 'method' cannot be called on 'Class?' because it is potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | Try calling using ?. instead. | 
|  | var localMethodInvocation = nullableClass.method(); | 
|  | ^^^^^^" in self::nullableClass.{self::Class::method}{<nullable>}.(){() → core::int}; | 
|  | () → core::int localMethodTearOff = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:85:42: Error: Property 'method' cannot be accessed on 'Class?' because it is potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | Try accessing using ?. instead. | 
|  | var localMethodTearOff = nullableClass.method; | 
|  | ^^^^^^" in self::nullableClass.{self::Class::method}{<nullable>}.{() → core::int}; | 
|  | invalid-type localFunctionImplicitCall = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:86:51: Error: Can't use an expression of type 'Function?' as a function because it's potentially null. | 
|  | - 'Function' is from 'dart:core'. | 
|  | Try calling using ?.call instead. | 
|  | var localFunctionImplicitCall = nullableFunction(); | 
|  | ^" in self::nullableFunction{<nullable>}.(); | 
|  | invalid-type localFunctionExplicitCall = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:87:52: Error: Method 'call' cannot be called on 'Function?' because it is potentially null. | 
|  | - 'Function' is from 'dart:core'. | 
|  | Try calling using ?. instead. | 
|  | var localFunctionExplicitCall = nullableFunction.call(); | 
|  | ^^^^" in self::nullableFunction{<nullable>}.(); | 
|  | core::Function? localFunctionTearOff = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:88:47: Error: Property 'call' cannot be accessed on 'Function?' because it is potentially null. | 
|  | - 'Function' is from 'dart:core'. | 
|  | Try accessing using ?. instead. | 
|  | var localFunctionTearOff = nullableFunction.call; | 
|  | ^^^^" in self::nullableFunction.call; | 
|  | void localFunctionTypeImplicitCall = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:89:59: Error: Can't use an expression of type 'void Function()?' as a function because it's potentially null. | 
|  | Try calling using ?.call instead. | 
|  | var localFunctionTypeImplicitCall = nullableFunctionType(); | 
|  | ^" in self::nullableFunctionType{<nullable>}.(){() →? void}; | 
|  | void localFunctionTypeExplicitCall = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:90:60: Error: Method 'call' cannot be called on 'void Function()?' because it is potentially null. | 
|  | Try calling using ?. instead. | 
|  | var localFunctionTypeExplicitCall = nullableFunctionType.call(); | 
|  | ^^^^" in self::nullableFunctionType{<nullable>}.(){() →? void}; | 
|  | () →? void localFunctionTypeTearOff = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:91:55: Error: Property 'call' cannot be accessed on 'void Function()?' because it is potentially null. | 
|  | Try accessing using ?. instead. | 
|  | var localFunctionTypeTearOff = nullableFunctionType.call; | 
|  | ^^^^" in self::nullableFunctionType.call; | 
|  | dynamic localFunctionField = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:92:42: Error: Can't use an expression of type 'Class?' as a function because it's potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | Try calling using ?.call instead. | 
|  | var localFunctionField = nullableClass.functionField(); | 
|  | ^" in self::nullableClass.{self::Class::functionField}{<nullable>}.{core::Function}(); | 
|  | void localFunctionTypeField = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:93:46: Error: Can't use an expression of type 'Class?' as a function because it's potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | Try calling using ?.call instead. | 
|  | var localFunctionTypeField = nullableClass.functionTypeField(); | 
|  | ^" in self::nullableClass.{self::Class::functionTypeField}{<nullable>}.{() → void}(){() → void}; | 
|  | dynamic localFunctionGetter = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:94:43: Error: Can't use an expression of type 'Class?' as a function because it's potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | Try calling using ?.call instead. | 
|  | var localFunctionGetter = nullableClass.functionGetter(); | 
|  | ^" in self::nullableClass.{self::Class::functionGetter}{<nullable>}.{core::Function}(); | 
|  | void localFunctionTypeGetter = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:95:47: Error: Can't use an expression of type 'Class?' as a function because it's potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | Try calling using ?.call instead. | 
|  | var localFunctionTypeGetter = nullableClass.functionTypeGetter(); | 
|  | ^" in self::nullableClass.{self::Class::functionTypeGetter}{<nullable>}.{() → void}(){() → void}; | 
|  | core::int localExtensionBinary = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:97:44: Error: Operator '+' cannot be called on 'Class?' because it is potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | var localExtensionBinary = nullableClass + 0; | 
|  | ^" in self::Extension|+(self::nullableClass, 0); | 
|  | core::int localExtensionUnary = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:98:29: Error: Operator 'unary-' cannot be called on 'Class?' because it is potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | var localExtensionUnary = -nullableClass; | 
|  | ^" in self::Extension|unary-(self::nullableClass); | 
|  | core::int localExtensionIndexGet = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:99:45: Error: Operator '[]' cannot be called on 'Class?' because it is potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | var localExtensionIndexGet = nullableClass[0]; | 
|  | ^" in self::Extension|[](self::nullableClass, 0); | 
|  | core::int localExtensionIndexSet = let final self::Class? #t32 = self::nullableClass in let final core::int #t33 = 0 in let final core::int #t34 = 1 in let final void #t35 = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:100:45: Error: Operator '[]=' cannot be called on 'Class?' because it is potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | var localExtensionIndexSet = nullableClass[0] = 1; | 
|  | ^" in self::Extension|[]=(#t32, #t33, #t34) in #t34; | 
|  | core::int localExtensionIndexGetSet = let final self::Class? #t36 = self::nullableClass in let final core::int #t37 = 0 in let final core::int #t38 = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:101:48: Error: Operator '[]' cannot be called on 'Class?' because it is potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | var localExtensionIndexGetSet = nullableClass[0] += 1; | 
|  | ^" in self::Extension|[](#t36, #t37).{core::num::+}(1){(core::num) → core::int} in let final void #t39 = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:101:48: Error: Operator '[]=' cannot be called on 'Class?' because it is potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | var localExtensionIndexGetSet = nullableClass[0] += 1; | 
|  | ^" in self::Extension|[]=(#t36, #t37, #t38) in #t38; | 
|  | core::int localExtensionPropertyGet = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:102:49: Error: Property 'extensionProperty' cannot be accessed on 'Class?' because it is potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | Try accessing using ?. instead. | 
|  | var localExtensionPropertyGet = nullableClass.extensionProperty; | 
|  | ^^^^^^^^^^^^^^^^^" in self::Extension|get#extensionProperty(self::nullableClass); | 
|  | core::int localExtensionPropertySet = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:103:49: Error: Property 'extensionProperty' cannot be accessed on 'Class?' because it is potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | Try accessing using ?. instead. | 
|  | var localExtensionPropertySet = nullableClass.extensionProperty = 1; | 
|  | ^^^^^^^^^^^^^^^^^" in let final core::int #t40 = 1 in let final void #t41 = self::Extension|set#extensionProperty(self::nullableClass, #t40) in #t40; | 
|  | core::int localExtensionPropertyGetSet = let final self::Class? #t42 = self::nullableClass in invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:104:52: Error: Property 'extensionProperty' cannot be accessed on 'Class?' because it is potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | Try accessing using ?. instead. | 
|  | var localExtensionPropertyGetSet = nullableClass.extensionProperty += 1; | 
|  | ^^^^^^^^^^^^^^^^^" in let final core::int #t43 = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:104:52: Error: Property 'extensionProperty' cannot be accessed on 'Class?' because it is potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | Try accessing using ?. instead. | 
|  | var localExtensionPropertyGetSet = nullableClass.extensionProperty += 1; | 
|  | ^^^^^^^^^^^^^^^^^" in self::Extension|get#extensionProperty(#t42).{core::num::+}(1){(core::num) → core::int} in let final void #t44 = self::Extension|set#extensionProperty(#t42, #t43) in #t43; | 
|  | core::int localExtensionMethodInvocation = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:105:54: Error: Method 'extensionMethod' cannot be called on 'Class?' because it is potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | Try calling using ?. instead. | 
|  | var localExtensionMethodInvocation = nullableClass.extensionMethod(); | 
|  | ^^^^^^^^^^^^^^^" in self::Extension|extensionMethod(self::nullableClass); | 
|  | () → core::int localExtensionMethodTearOff = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:106:51: Error: Property 'extensionMethod' cannot be accessed on 'Class?' because it is potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | Try accessing using ?. instead. | 
|  | var localExtensionMethodTearOff = nullableClass.extensionMethod; | 
|  | ^^^^^^^^^^^^^^^" in self::Extension|get#extensionMethod(self::nullableClass); | 
|  | core::int localExtensionFunctionTypeImplicitCall = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:107:61: Error: Can't use an expression of type 'Class?' as a function because it's potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | Try calling using ?.call instead. | 
|  | var localExtensionFunctionTypeImplicitCall = nullableClass(); | 
|  | ^" in self::Extension|call(self::nullableClass); | 
|  | core::int localExtensionFunctionTypeExplicitCall = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:108:62: Error: Method 'call' cannot be called on 'Class?' because it is potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | Try calling using ?. instead. | 
|  | var localExtensionFunctionTypeExplicitCall = nullableClass.call(); | 
|  | ^^^^" in self::Extension|call(self::nullableClass); | 
|  | () → core::int localExtensionFunctionTypeTearOff = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:109:57: Error: Property 'call' cannot be accessed on 'Class?' because it is potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | Try accessing using ?. instead. | 
|  | var localExtensionFunctionTypeTearOff = nullableClass.call; | 
|  | ^^^^" in self::Extension|get#call(self::nullableClass); | 
|  | dynamic localExtensionFunctionGetter = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:110:52: Error: Can't use an expression of type 'Class?' as a function because it's potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | Try calling using ?.call instead. | 
|  | var localExtensionFunctionGetter = nullableClass.extensionFunctionGetter(); | 
|  | ^" in self::Extension|get#extensionFunctionGetter(self::nullableClass)(); | 
|  | void localExtensionFunctionTypeGetter = invalid-expression "pkg/front_end/testcases/nnbd/potentially_nullable_access.dart:112:21: Error: Can't use an expression of type 'Class?' as a function because it's potentially null. | 
|  | - 'Class' is from 'pkg/front_end/testcases/nnbd/potentially_nullable_access.dart'. | 
|  | Try calling using ?.call instead. | 
|  | nullableClass.extensionFunctionTypeGetter(); | 
|  | ^" in self::Extension|get#extensionFunctionTypeGetter(self::nullableClass)(){() → void}; | 
|  | } | 
|  | static method main() → dynamic {} |