Cleanup unused vars in VM patch files

Change-Id: Ibc548921113d979df5b0ed8eb7f6ad48a553fc86
Reviewed-on: https://dart-review.googlesource.com/c/84121
Commit-Queue: Kevin Moore <kevmoo@google.com>
Reviewed-by: Lasse R.H. Nielsen <lrn@google.com>

pkg/build_integration/pubspec.yaml

@@ -5,5 +5,8 @@ description: >
 # This package is not intended to be published - yet
 publish_to: none
 
+environment:
+  sdk: '>=2.0.0 <3.0.0'
+
 dependencies:
   front_end: ^0.1.0

pkg/vm/pubspec.yaml

@@ -6,8 +6,8 @@ description: VM specific Dart code and helper scripts
 dependencies:
   build_integration:
     path: ../build_integration
-  front_end: 0.1.6
-  kernel: 0.3.6
+  front_end: ^0.1.6
+  kernel: ^0.3.6
 
 dev_dependencies:
   args: ^1.4.4

runtime/lib/async_patch.dart

@@ -200,8 +200,7 @@ class _AsyncStarStreamController<T> {
     // If stream is cancelled, tell caller to exit the async generator.
     if (!controller.hasListener) return true;
     isAdding = true;
-    var whenDoneAdding =
-        controller.addStream(stream as Stream<T>, cancelOnError: false);
+    var whenDoneAdding = controller.addStream(stream, cancelOnError: false);
     whenDoneAdding.then((_) {
       isAdding = false;
       scheduleGenerator();

runtime/lib/bigint_patch.dart

@@ -2572,9 +2572,6 @@ class _BigIntMontgomeryReduction implements _BigIntReduction {
   //   args[_rhoDigit.._rhoHighDigit] =
   //     1/args[_xDigit.._xHighDigit] mod _digitBase^2.
   static void _invDigitPair(Uint32List args) {
-    var two = _BigIntImpl.two;
-    var mask32 = _BigIntImpl._oneDigitMask;
-    var mask64 = _BigIntImpl._twoDigitMask;
     var xl = args[_xDigit]; // Lower 32-bit digit of x.
     var y = xl & 3; // y == 1/x mod 2^2
     y = (y * (2 - (xl & 0xf) * y)) & 0xf; // y == 1/x mod 2^4

runtime/lib/collection_patch.dart

@@ -34,17 +34,11 @@ class HashMap<K, V> {
             identical(identical, equals)) {
           return new _IdentityHashMap<K, V>();
         }
-        if (equals == null) {
-          equals = _defaultEquals;
-        }
+        equals ??= _defaultEquals;
       }
     } else {
-      if (hashCode == null) {
-        hashCode = _defaultHashCode;
-      }
-      if (equals == null) {
-        equals = _defaultEquals;
-      }
+      hashCode ??= _defaultHashCode;
+      equals ??= _defaultEquals;
     }
     return new _CustomHashMap<K, V>(equals, hashCode, isValidKey);
   }
@@ -536,17 +530,11 @@ class HashSet<E> {
             identical(identical, equals)) {
           return new _IdentityHashSet<E>();
         }
-        if (equals == null) {
-          equals = _defaultEquals;
-        }
+        equals ??= _defaultEquals;
       }
     } else {
-      if (hashCode == null) {
-        hashCode = _defaultHashCode;
-      }
-      if (equals == null) {
-        equals = _defaultEquals;
-      }
+      hashCode ??= _defaultHashCode;
+      equals ??= _defaultEquals;
     }
     return new _CustomHashSet<E>(equals, hashCode, isValidKey);
   }
@@ -637,9 +625,7 @@ class _HashSet<E> extends _HashSetBase<E> implements HashSet<E> {
   }
 
   void addAll(Iterable<E> objects) {
-    int ctr = 0;
     for (E object in objects) {
-      ctr++;
       add(object);
     }
   }
@@ -879,17 +865,11 @@ class LinkedHashMap<K, V> {
             identical(identical, equals)) {
           return new _CompactLinkedIdentityHashMap<K, V>();
         }
-        if (equals == null) {
-          equals = _defaultEquals;
-        }
+        equals ??= _defaultEquals;
       }
     } else {
-      if (hashCode == null) {
-        hashCode = _defaultHashCode;
-      }
-      if (equals == null) {
-        equals = _defaultEquals;
-      }
+      hashCode ??= _defaultHashCode;
+      equals ??= _defaultEquals;
     }
     return new _CompactLinkedCustomHashMap<K, V>(equals, hashCode, isValidKey);
   }
@@ -916,17 +896,11 @@ class LinkedHashSet<E> {
             identical(identical, equals)) {
           return new _CompactLinkedIdentityHashSet<E>();
         }
-        if (equals == null) {
-          equals = _defaultEquals;
-        }
+        equals ??= _defaultEquals;
       }
     } else {
-      if (hashCode == null) {
-        hashCode = _defaultHashCode;
-      }
-      if (equals == null) {
-        equals = _defaultEquals;
-      }
+      hashCode ??= _defaultHashCode;
+      equals ??= _defaultEquals;
     }
     return new _CompactLinkedCustomHashSet<E>(equals, hashCode, isValidKey);
   }

runtime/lib/compact_hash.dart

@@ -256,7 +256,6 @@ abstract class _LinkedHashMapMixin<K, V> implements _HashBase {
 
   void operator []=(K key, V value) {
     final int size = _index.length;
-    final int sizeMask = size - 1;
     final int fullHash = _hashCode(key);
     final int hashPattern = _HashBase._hashPattern(fullHash, _hashMask, size);
     final int d = _findValueOrInsertPoint(key, fullHash, hashPattern, size);
@@ -270,8 +269,6 @@ abstract class _LinkedHashMapMixin<K, V> implements _HashBase {
 
   V putIfAbsent(K key, V ifAbsent()) {
     final int size = _index.length;
-    final int sizeMask = size - 1;
-    final int maxEntries = size >> 1;
     final int fullHash = _hashCode(key);
     final int hashPattern = _HashBase._hashPattern(fullHash, _hashMask, size);
     final int d = _findValueOrInsertPoint(key, fullHash, hashPattern, size);

runtime/lib/convert_patch.dart

@@ -177,7 +177,6 @@ class _BuildJsonListener extends _JsonListener {
   }
 
   void arrayElement() {
-    List list = currentContainer;
     currentContainer.add(value);
     value = null;
   }

runtime/lib/date_patch.dart

@@ -57,7 +57,7 @@ class DateTime {
   @patch
   DateTime._now()
       : isUtc = false,
-        _value = _getCurrentMicros() {}
+        _value = _getCurrentMicros();
 
   @patch
   String get timeZoneName {
@@ -180,9 +180,7 @@ class DateTime {
   }
 
   get _parts {
-    if (__parts == null) {
-      __parts = _computeUpperPart(_localDateInUtcMicros);
-    }
+    __parts ??= _computeUpperPart(_localDateInUtcMicros);
     return __parts;
   }
 

runtime/lib/developer.dart

@@ -35,9 +35,7 @@ void log(String message,
   if (message is! String) {
     throw new ArgumentError.value(message, "message", "Must be a String");
   }
-  if (time == null) {
-    time = new DateTime.now();
-  }
+  time ??= new DateTime.now();
   if (time is! DateTime) {
     throw new ArgumentError.value(time, "time", "Must be a DateTime");
   }

runtime/lib/function.dart

@@ -9,9 +9,7 @@ class _Closure implements Function {
   bool operator ==(Object other) native "Closure_equals";
 
   int get hashCode {
-    if (_hash == null) {
-      _hash = _computeHash();
-    }
+    _hash ??= _computeHash();
     return _hash;
   }
 

runtime/lib/growable_array.dart

@@ -224,7 +224,6 @@ class _GrowableList<T> extends ListBase<T> {
     if (length == 1) return this[0];
     if (length == 0) throw IterableElementError.noElement();
     throw IterableElementError.tooMany();
-    ;
   }
 
   // Shared array used as backing for new empty growable arrays.

runtime/lib/isolate_patch.dart

@@ -458,7 +458,7 @@ class Isolate {
           packageRootString,
           packageConfigString);
       return await _spawnCommon(readyPort);
-    } catch (e, st) {
+    } catch (e) {
       if (readyPort != null) {
         readyPort.close();
       }
@@ -632,7 +632,7 @@ class Isolate {
   static Uri _getCurrentRootUri() {
     try {
       return Uri.parse(_getCurrentRootUriStr());
-    } catch (e, s) {
+    } catch (e) {
       return null;
     }
   }

runtime/lib/lib_prefix.dart

@@ -54,7 +54,6 @@ _completeDeferredLoads() {
   // which have not completed, remember them for next time in
   // stillOutstandingLoadRequests.
   var stillOutstandingLoadRequests = new List<List>();
-  var completedLoadRequests = new List<List>();
 
   // Make a copy of the outstandingRequests because the call to _load below
   // may recursively trigger another call to |_completeDeferredLoads|, which

runtime/lib/math_patch.dart

@@ -245,7 +245,7 @@ class _Random implements Random {
   static const _POW2_27_D = 1.0 * (1 << 27);
 
   // Use a singleton Random object to get a new seed if no seed was passed.
-  static var _prng = new _Random._withState(_initialSeed());
+  static final _prng = new _Random._withState(_initialSeed());
 
   // This is a native to prevent 64-bit operations in Dart, which
   // fail with --throw_on_javascript_int_overflow.

runtime/lib/string_patch.dart

@@ -124,7 +124,6 @@ abstract class _StringBase implements String {
     if (charCodes == null) throw new ArgumentError(charCodes);
     // TODO(srdjan): Also skip copying of wide typed arrays.
     final ccid = ClassID.getID(charCodes);
-    bool isOneByteString = false;
     if ((ccid != ClassID.cidArray) &&
         (ccid != ClassID.cidGrowableObjectArray) &&
         (ccid != ClassID.cidImmutableArray)) {
@@ -139,9 +138,7 @@ abstract class _StringBase implements String {
     end = RangeError.checkValidRange(start, end, codeCount);
     final len = end - start;
     if (len == 0) return "";
-    if (limit == null) {
-      limit = _scanCodeUnits(charCodes, start, end);
-    }
+    limit ??= _scanCodeUnits(charCodes, start, end);
     if (limit < 0) {
       throw new ArgumentError(charCodes);
     }
@@ -368,7 +365,7 @@ abstract class _StringBase implements String {
   }
 
   String substring(int startIndex, [int endIndex]) {
-    if (endIndex == null) endIndex = this.length;
+    endIndex ??= this.length;
 
     if ((startIndex < 0) || (startIndex > this.length)) {
       throw new RangeError.value(startIndex);
@@ -623,7 +620,6 @@ abstract class _StringBase implements String {
     int replacementLength = replacement.length;
     int startIndex = 0;
     if (replacementLength == 0) {
-      int count = 0;
       for (Match match in pattern.allMatches(this)) {
         length += _addReplaceSlice(matches, startIndex, match.start);
         startIndex = match.end;
@@ -782,8 +778,8 @@ abstract class _StringBase implements String {
     if (pattern is! Pattern) {
       throw new ArgumentError("${pattern} is not a Pattern");
     }
-    if (onMatch == null) onMatch = _matchString;
-    if (onNonMatch == null) onNonMatch = _stringIdentity;
+    onMatch ??= _matchString;
+    onNonMatch ??= _stringIdentity;
     if (pattern is String) {
       String stringPattern = pattern;
       if (stringPattern.isEmpty) {

runtime/lib/timer_impl.dart

@@ -124,7 +124,7 @@ class _Timer implements Timer {
 
   // Timers are ordered by wakeup time. Timers with a timeout value of > 0 do
   // end up on the TimerHeap. Timers with a timeout of 0 are queued in a list.
-  static _TimerHeap _heap = new _TimerHeap();
+  static final _heap = new _TimerHeap();
   static _Timer _firstZeroTimer;
   static _Timer _lastZeroTimer;
 

runtime/lib/timer_patch.dart

@@ -26,9 +26,7 @@ class Timer {
   static Timer _createPeriodicTimer(
       Duration duration, void callback(Timer timer)) {
     // TODO(iposva): Remove _TimerFactory and use VMLibraryHooks exclusively.
-    if (_TimerFactory._factory == null) {
-      _TimerFactory._factory = VMLibraryHooks.timerFactory;
-    }
+    _TimerFactory._factory ??= VMLibraryHooks.timerFactory;
     if (_TimerFactory._factory == null) {
       throw new UnsupportedError("Timer interface not supported.");
     }

runtime/lib/typed_data_patch.dart

@@ -165,7 +165,7 @@ abstract class _IntListMixin implements List<int> {
   }
 
   void shuffle([Random random]) {
-    if (random == null) random = new Random();
+    random ??= new Random();
     var i = this.length;
     while (i > 1) {
       int pos = random.nextInt(i);
@@ -282,7 +282,6 @@ abstract class _IntListMixin implements List<int> {
   int reduce(int combine(int value, int element)) {
     var len = this.length;
     if (len == 0) throw IterableElementError.noElement();
-    var i = 0;
     var value = this[0];
     for (var i = 1; i < len; ++i) {
       value = combine(value, this[i]);
@@ -330,7 +329,6 @@ abstract class _IntListMixin implements List<int> {
   }
 
   int lastWhere(bool test(int element), {int orElse()}) {
-    var result = null;
     var len = this.length;
     for (var i = len - 1; i >= 0; --i) {
       var element = this[i];
@@ -518,7 +516,7 @@ abstract class _DoubleListMixin implements List<double> {
   }
 
   void shuffle([Random random]) {
-    if (random == null) random = new Random();
+    random ??= new Random();
     var i = this.length;
     while (i > 1) {
       int pos = random.nextInt(i);
@@ -637,7 +635,6 @@ abstract class _DoubleListMixin implements List<double> {
   double reduce(double combine(double value, double element)) {
     var len = this.length;
     if (len == 0) throw IterableElementError.noElement();
-    var i = 0;
     var value = this[0];
     for (var i = 1; i < len; ++i) {
       value = combine(value, this[i]);
@@ -686,7 +683,6 @@ abstract class _DoubleListMixin implements List<double> {
   }
 
   double lastWhere(bool test(double element), {double orElse()}) {
-    var result = null;
     var len = this.length;
     for (var i = len - 1; i >= 0; --i) {
       var element = this[i];
@@ -874,7 +870,7 @@ abstract class _Float32x4ListMixin implements List<Float32x4> {
   }
 
   void shuffle([Random random]) {
-    if (random == null) random = new Random();
+    random ??= new Random();
     var i = this.length;
     while (i > 1) {
       int pos = random.nextInt(i);
@@ -994,7 +990,6 @@ abstract class _Float32x4ListMixin implements List<Float32x4> {
   Float32x4 reduce(Float32x4 combine(Float32x4 value, Float32x4 element)) {
     var len = this.length;
     if (len == 0) throw IterableElementError.noElement();
-    var i = 0;
     var value = this[0];
     for (var i = 1; i < len; ++i) {
       value = combine(value, this[i]);
@@ -1043,7 +1038,6 @@ abstract class _Float32x4ListMixin implements List<Float32x4> {
   }
 
   Float32x4 lastWhere(bool test(Float32x4 element), {Float32x4 orElse()}) {
-    var result = null;
     var len = this.length;
     for (var i = len - 1; i >= 0; --i) {
       var element = this[i];
@@ -1234,7 +1228,7 @@ abstract class _Int32x4ListMixin implements List<Int32x4> {
   }
 
   void shuffle([Random random]) {
-    if (random == null) random = new Random();
+    random ??= new Random();
     var i = this.length;
     while (i > 1) {
       int pos = random.nextInt(i);
@@ -1353,7 +1347,6 @@ abstract class _Int32x4ListMixin implements List<Int32x4> {
   Int32x4 reduce(Int32x4 combine(Int32x4 value, Int32x4 element)) {
     var len = this.length;
     if (len == 0) throw IterableElementError.noElement();
-    var i = 0;
     var value = this[0];
     for (var i = 1; i < len; ++i) {
       value = combine(value, this[i]);
@@ -1402,7 +1395,6 @@ abstract class _Int32x4ListMixin implements List<Int32x4> {
   }
 
   Int32x4 lastWhere(bool test(Int32x4 element), {Int32x4 orElse()}) {
-    var result = null;
     var len = this.length;
     for (var i = len - 1; i >= 0; --i) {
       var element = this[i];
@@ -1593,7 +1585,7 @@ abstract class _Float64x2ListMixin implements List<Float64x2> {
   }
 
   void shuffle([Random random]) {
-    if (random == null) random = new Random();
+    random ??= new Random();
     var i = this.length;
     while (i > 1) {
       int pos = random.nextInt(i);
@@ -1713,7 +1705,6 @@ abstract class _Float64x2ListMixin implements List<Float64x2> {
   Float64x2 reduce(Float64x2 combine(Float64x2 value, Float64x2 element)) {
     var len = this.length;
     if (len == 0) throw IterableElementError.noElement();
-    var i = 0;
     var value = this[0];
     for (var i = 1; i < len; ++i) {
       value = combine(value, this[i]);
@@ -1762,7 +1753,6 @@ abstract class _Float64x2ListMixin implements List<Float64x2> {
   }
 
   Float64x2 lastWhere(bool test(Float64x2 element), {Float64x2 orElse()}) {
-    var result = null;
     var len = this.length;
     for (var i = len - 1; i >= 0; --i) {
       var element = this[i];
@@ -1913,118 +1903,88 @@ class _ByteBuffer implements ByteBuffer {
       (other is _ByteBuffer) && identical(_data, other._data);
 
   ByteData asByteData([int offsetInBytes = 0, int length]) {
-    if (length == null) {
-      length = this.lengthInBytes - offsetInBytes;
-    }
+    length ??= this.lengthInBytes - offsetInBytes;
     return new _ByteDataView(this._data, offsetInBytes, length);
   }
 
   Int8List asInt8List([int offsetInBytes = 0, int length]) {
-    if (length == null) {
-      length = this.lengthInBytes - offsetInBytes;
-    }
+    length ??= this.lengthInBytes - offsetInBytes;
     return new _Int8ArrayView(this, offsetInBytes, length);
   }
 
   Uint8List asUint8List([int offsetInBytes = 0, int length]) {
-    if (length == null) {
-      length = this.lengthInBytes - offsetInBytes;
-    }
+    length ??= this.lengthInBytes - offsetInBytes;
     return new _Uint8ArrayView(this, offsetInBytes, length);
   }
 
   Uint8ClampedList asUint8ClampedList([int offsetInBytes = 0, int length]) {
-    if (length == null) {
-      length = this.lengthInBytes - offsetInBytes;
-    }
+    length ??= this.lengthInBytes - offsetInBytes;
     return new _Uint8ClampedArrayView(this, offsetInBytes, length);
   }
 
   Int16List asInt16List([int offsetInBytes = 0, int length]) {
-    if (length == null) {
-      length =
-          (this.lengthInBytes - offsetInBytes) ~/ Int16List.bytesPerElement;
-    }
+    length ??=
+        (this.lengthInBytes - offsetInBytes) ~/ Int16List.bytesPerElement;
     return new _Int16ArrayView(this, offsetInBytes, length);
   }
 
   Uint16List asUint16List([int offsetInBytes = 0, int length]) {
-    if (length == null) {
-      length =
-          (this.lengthInBytes - offsetInBytes) ~/ Uint16List.bytesPerElement;
-    }
+    length ??=
+        (this.lengthInBytes - offsetInBytes) ~/ Uint16List.bytesPerElement;
     return new _Uint16ArrayView(this, offsetInBytes, length);
   }
 
   Int32List asInt32List([int offsetInBytes = 0, int length]) {
-    if (length == null) {
-      length =
-          (this.lengthInBytes - offsetInBytes) ~/ Int32List.bytesPerElement;
-    }
+    length ??=
+        (this.lengthInBytes - offsetInBytes) ~/ Int32List.bytesPerElement;
     return new _Int32ArrayView(this, offsetInBytes, length);
   }
 
   Uint32List asUint32List([int offsetInBytes = 0, int length]) {
-    if (length == null) {
-      length =
-          (this.lengthInBytes - offsetInBytes) ~/ Uint32List.bytesPerElement;
-    }
+    length ??=
+        (this.lengthInBytes - offsetInBytes) ~/ Uint32List.bytesPerElement;
     return new _Uint32ArrayView(this, offsetInBytes, length);
   }
 
   Int64List asInt64List([int offsetInBytes = 0, int length]) {
-    if (length == null) {
-      length =
-          (this.lengthInBytes - offsetInBytes) ~/ Int64List.bytesPerElement;
-    }
+    length ??=
+        (this.lengthInBytes - offsetInBytes) ~/ Int64List.bytesPerElement;
     return new _Int64ArrayView(this, offsetInBytes, length);
   }
 
   Uint64List asUint64List([int offsetInBytes = 0, int length]) {
-    if (length == null) {
-      length =
-          (this.lengthInBytes - offsetInBytes) ~/ Uint64List.bytesPerElement;
-    }
+    length ??=
+        (this.lengthInBytes - offsetInBytes) ~/ Uint64List.bytesPerElement;
     return new _Uint64ArrayView(this, offsetInBytes, length);
   }
 
   Float32List asFloat32List([int offsetInBytes = 0, int length]) {
-    if (length == null) {
-      length =
-          (this.lengthInBytes - offsetInBytes) ~/ Float32List.bytesPerElement;
-    }
+    length ??=
+        (this.lengthInBytes - offsetInBytes) ~/ Float32List.bytesPerElement;
     return new _Float32ArrayView(this, offsetInBytes, length);
   }
 
   Float64List asFloat64List([int offsetInBytes = 0, int length]) {
-    if (length == null) {
-      length =
-          (this.lengthInBytes - offsetInBytes) ~/ Float64List.bytesPerElement;
-    }
+    length ??=
+        (this.lengthInBytes - offsetInBytes) ~/ Float64List.bytesPerElement;
     return new _Float64ArrayView(this, offsetInBytes, length);
   }
 
   Float32x4List asFloat32x4List([int offsetInBytes = 0, int length]) {
-    if (length == null) {
-      length =
-          (this.lengthInBytes - offsetInBytes) ~/ Float32x4List.bytesPerElement;
-    }
+    length ??=
+        (this.lengthInBytes - offsetInBytes) ~/ Float32x4List.bytesPerElement;
     return new _Float32x4ArrayView(this, offsetInBytes, length);
   }
 
   Int32x4List asInt32x4List([int offsetInBytes = 0, int length]) {
-    if (length == null) {
-      length =
-          (this.lengthInBytes - offsetInBytes) ~/ Int32x4List.bytesPerElement;
-    }
+    length ??=
+        (this.lengthInBytes - offsetInBytes) ~/ Int32x4List.bytesPerElement;
     return new _Int32x4ArrayView(this, offsetInBytes, length);
   }
 
   Float64x2List asFloat64x2List([int offsetInBytes = 0, int length]) {
-    if (length == null) {
-      length =
-          (this.lengthInBytes - offsetInBytes) ~/ Float64x2List.bytesPerElement;
-    }
+    length ??=
+        (this.lengthInBytes - offsetInBytes) ~/ Float64x2List.bytesPerElement;
     return new _Float64x2ArrayView(this, offsetInBytes, length);
   }
 }
@@ -3572,7 +3532,7 @@ abstract class _TypedListView extends _TypedListBase implements TypedData {
   _TypedListView(_ByteBuffer _buffer, int _offset, int _length)
       : _typedData = _buffer._data,
         offsetInBytes = _offset,
-        length = _length {}
+        length = _length;
 
   // Method(s) implementing the TypedData interface.