library /*isNonNullableByDefault*/;
//
// Problems in library:
//
// pkg/front_end/testcases/nnbd/strictly_non_nullable_warnings.dart:22:10: Warning: Operand of null-aware operation '??=' has type 'String' which excludes null.
//     super[42] ??= "bar"; // Warning.
//          ^
//
// pkg/front_end/testcases/nnbd/strictly_non_nullable_warnings.dart:27:3: Warning: Operand of null-aware operation '?.' has type 'String' which excludes null.
//   s?.length; // Warning.
//   ^
//
// pkg/front_end/testcases/nnbd/strictly_non_nullable_warnings.dart:28:3: Warning: Operand of null-aware operation '?..' has type 'String' which excludes null.
//   s?..length; // Warning.
//   ^
//
// pkg/front_end/testcases/nnbd/strictly_non_nullable_warnings.dart:29:3: Warning: Operand of null-aware operation '??' has type 'String' which excludes null.
//   s ?? "foo"; // Warning.
//   ^
//
// pkg/front_end/testcases/nnbd/strictly_non_nullable_warnings.dart:30:3: Warning: Operand of null-aware operation '??=' has type 'String' which excludes null.
//   s ??= "foo"; // Warning.
//   ^
//
// pkg/front_end/testcases/nnbd/strictly_non_nullable_warnings.dart:31:8: Warning: Operand of null-aware operation '...?' has type 'List<String>' which excludes null.
//  - 'List' is from 'dart:core'.
//   [...?l]; // Warning.
//        ^
//
// pkg/front_end/testcases/nnbd/strictly_non_nullable_warnings.dart:32:16: Warning: Operand of null-aware operation '...?' has type 'List<String>' which excludes null.
//  - 'List' is from 'dart:core'.
//   var a = {...?l}; // Warning.
//                ^
//
// pkg/front_end/testcases/nnbd/strictly_non_nullable_warnings.dart:33:16: Warning: Operand of null-aware operation '...?' has type 'List<String>' which excludes null.
//  - 'List' is from 'dart:core'.
//   <String>{...?l}; // Warning.
//                ^
//
// pkg/front_end/testcases/nnbd/strictly_non_nullable_warnings.dart:34:16: Warning: Operand of null-aware operation '...?' has type 'Map<String, int>' which excludes null.
//  - 'Map' is from 'dart:core'.
//   var b = {...?m}; // Warning.
//                ^
//
// pkg/front_end/testcases/nnbd/strictly_non_nullable_warnings.dart:35:21: Warning: Operand of null-aware operation '...?' has type 'Map<String, int>' which excludes null.
//  - 'Map' is from 'dart:core'.
//   <String, int>{...?m}; // Warning.
//                     ^
//
// pkg/front_end/testcases/nnbd/strictly_non_nullable_warnings.dart:36:3: Warning: Operand of null-aware operation '!' has type 'String' which excludes null.
//   s!; // Warning.
//   ^
//
// pkg/front_end/testcases/nnbd/strictly_non_nullable_warnings.dart:37:3: Warning: Operand of null-aware operation '?.' has type 'String' which excludes null.
//   s?.substring(0, 0); // Warning.
//   ^
//
// pkg/front_end/testcases/nnbd/strictly_non_nullable_warnings.dart:38:3: Warning: Operand of null-aware operation '?.' has type 'List<String>' which excludes null.
//  - 'List' is from 'dart:core'.
//   l?.length = 42; // Warning.
//   ^
//
// pkg/front_end/testcases/nnbd/strictly_non_nullable_warnings.dart:39:3: Warning: Operand of null-aware operation '?.' has type 'List<String>' which excludes null.
//  - 'List' is from 'dart:core'.
//   l?.length += 42; // Warning.
//   ^
//
// pkg/front_end/testcases/nnbd/strictly_non_nullable_warnings.dart:40:3: Warning: Operand of null-aware operation '?.' has type 'List<String>' which excludes null.
//  - 'List' is from 'dart:core'.
//   l?.length ??= 42; // Warning.
//   ^
//
// pkg/front_end/testcases/nnbd/strictly_non_nullable_warnings.dart:41:3: Warning: Operand of null-aware operation '?.' has type 'String' which excludes null.
//   s?.foo; // Warning.
//   ^
//
// pkg/front_end/testcases/nnbd/strictly_non_nullable_warnings.dart:42:7: Warning: Operand of null-aware operation '??=' has type 'int' which excludes null.
//   E(s)[42] ??= 42; // Warning.
//       ^
//
// pkg/front_end/testcases/nnbd/strictly_non_nullable_warnings.dart:43:4: Warning: Operand of null-aware operation '??=' has type 'String' which excludes null.
//   l[42] ??= "foo"; // Warning.
//    ^
//
// pkg/front_end/testcases/nnbd/strictly_non_nullable_warnings.dart:44:5: Warning: Operand of null-aware operation '??=' has type 'int' which excludes null.
//   l.length ??= 42; // Warning.
//     ^
//
// pkg/front_end/testcases/nnbd/strictly_non_nullable_warnings.dart:45:3: Warning: Operand of null-aware operation '?..' has type 'List<String>' which excludes null.
//  - 'List' is from 'dart:core'.
//   l?..length = 42; // Warning.
//   ^
//
// pkg/front_end/testcases/nnbd/strictly_non_nullable_warnings.dart:46:3: Warning: Operand of null-aware operation '?..' has type 'List<String>' which excludes null.
//  - 'List' is from 'dart:core'.
//   l?..length ??= 42; // Warning.
//   ^
//
// pkg/front_end/testcases/nnbd/strictly_non_nullable_warnings.dart:46:7: Warning: Operand of null-aware operation '??=' has type 'int' which excludes null.
//   l?..length ??= 42; // Warning.
//       ^
//
import self as self;
import "dart:core" as core;
import "dart:collection" as col;

class A extends core::Object {
  synthetic constructor •() → self::A
    : super core::Object::•()
    ;
  operator [](core::int index) → core::String
    return "foo";
  operator []=(core::int index, core::String value) → void {}
}
class B extends self::A {
  synthetic constructor •() → self::B
    : super self::A::•()
    ;
  method test() → void {
    let final core::int #t1 = 42 in super.{self::A::[]}(#t1).{core::String::==}(null) ?{core::String} super.{self::A::[]=}(#t1, "bar") : null;
  }
}
extension E on core::String {
  get foo = self::E|get#foo;
  operator []= = self::E|[]=;
  operator [] = self::E|[];
}
static method E|get#foo(final core::String #this) → core::int
  return 42;
static method E|[]=(final core::String #this, core::int index, core::int value) → void {}
static method E|[](final core::String #this, core::int index) → core::int
  return 42;
static method warning(core::String s, core::List<core::String> l, core::Map<core::String, core::int> m) → dynamic {
  let final core::String #t2 = s in #t2.{core::String::==}(null) ?{core::int?} null : #t2.{core::String::length};
  let final core::String #t3 = s in #t3.{core::String::==}(null) ?{core::String} null : block {
    #t3.{core::String::length};
  } =>#t3;
  let final core::String #t4 = s in #t4.{core::String::==}(null) ?{core::String} "foo" : #t4;
  s.{core::String::==}(null) ?{core::String} s = "foo" : null;
  block {
    final core::List<core::String> #t5 = <core::String>[];
    final core::Iterable<core::String>? #t6 = l;
    if(!#t6.{core::Object::==}(null))
      for (final core::String #t7 in #t6{core::Iterable<core::String>})
        #t5.{core::List::add}{Invariant}(#t7);
  } =>#t5;
  core::Set<core::String> a = block {
    final core::Set<core::String> #t8 = col::LinkedHashSet::•<core::String>();
    final core::Iterable<dynamic>? #t9 = l;
    if(!#t9.{core::Object::==}(null))
      for (final dynamic #t10 in #t9{core::Iterable<dynamic>}) {
        final core::String #t11 = #t10 as{TypeError,ForNonNullableByDefault} core::String;
        #t8.{core::Set::add}{Invariant}(#t11);
      }
  } =>#t8;
  block {
    final core::Set<core::String> #t12 = col::LinkedHashSet::•<core::String>();
    final core::Iterable<core::String>? #t13 = l;
    if(!#t13.{core::Object::==}(null))
      for (final core::String #t14 in #t13{core::Iterable<core::String>})
        #t12.{core::Set::add}{Invariant}(#t14);
  } =>#t12;
  core::Map<core::String, core::int> b = block {
    final core::Map<core::String, core::int> #t15 = <core::String, core::int>{};
    final core::Map<core::String, core::int>? #t16 = m;
    if(!#t16.{core::Object::==}(null))
      for (final core::MapEntry<core::String, core::int> #t17 in #t16{core::Map<core::String, core::int>}.{core::Map::entries})
        #t15.{core::Map::[]=}{Invariant}(#t17.{core::MapEntry::key}, #t17.{core::MapEntry::value});
  } =>#t15;
  block {
    final core::Map<core::String, core::int> #t18 = <core::String, core::int>{};
    final core::Map<core::String, core::int>? #t19 = m;
    if(!#t19.{core::Object::==}(null))
      for (final core::MapEntry<core::String, core::int> #t20 in #t19{core::Map<core::String, core::int>}.{core::Map::entries})
        #t18.{core::Map::[]=}{Invariant}(#t20.{core::MapEntry::key}, #t20.{core::MapEntry::value});
  } =>#t18;
  s!;
  let final core::String #t21 = s in #t21.{core::String::==}(null) ?{core::String?} null : #t21.{core::String::substring}(0, 0);
  let final core::List<core::String> #t22 = l in #t22.{core::List::==}(null) ?{core::int?} null : #t22.{core::List::length} = 42;
  let final core::List<core::String> #t23 = l in #t23.{core::List::==}(null) ?{core::int?} null : #t23.{core::List::length} = #t23.{core::List::length}.{core::num::+}(42);
  let final core::List<core::String> #t24 = l in #t24.{core::List::==}(null) ?{core::int?} null : #t24.{core::List::length}.{core::num::==}(null) ?{core::int} #t24.{core::List::length} = 42 : null;
  let final core::String #t25 = s in #t25.{core::String::==}(null) ?{core::int?} null : self::E|get#foo(#t25);
  let final core::String #t26 = s in let final core::int #t27 = 42 in self::E|[](#t26, #t27).{core::num::==}(null) ?{core::int} self::E|[]=(#t26, #t27, 42) : null;
  let final core::List<core::String> #t28 = l in let final core::int #t29 = 42 in #t28.{core::List::[]}(#t29).{core::String::==}(null) ?{core::String} #t28.{core::List::[]=}(#t29, "foo") : null;
  let final core::List<core::String> #t30 = l in #t30.{core::List::length}.{core::num::==}(null) ?{core::int} #t30.{core::List::length} = 42 : null;
  let final core::List<core::String> #t31 = l in #t31.{core::List::==}(null) ?{core::List<core::String>} null : block {
    #t31.{core::List::length} = 42;
  } =>#t31;
  let final core::List<core::String> #t32 = l in #t32.{core::List::==}(null) ?{core::List<core::String>} null : block {
    let final core::List<core::String> #t33 = #t32 in #t33.{core::List::length}.{core::num::==}(null) ?{core::int} #t33.{core::List::length} = 42 : null;
  } =>#t32;
}
static method main() → dynamic {}