Eliminate most of 'lazy' in _fe_analyzer_shared.

There are still 2 left in AbstractScanner.
The usual trick with factory constructor does not work there.

Change-Id: Iaa5d88468c8cb17c34a9f73ab93ef97251a1bd76
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/182881
Reviewed-by: Johnni Winther <johnniwinther@google.com>
Commit-Queue: Konstantin Shcheglov <scheglov@google.com>

Author: scheglov

pkg/_fe_analyzer_shared/lib/src/flow_analysis/flow_analysis.dart

@@ -3485,7 +3485,8 @@ class _FlowAnalysisImpl<Node extends Object, Statement extends Node,
   final Map<Statement, _BranchTargetContext<Variable, Type>>
       _statementToContext = {};
 
-  late FlowModel<Variable, Type> _current;
+  FlowModel<Variable, Type> _current =
+      new FlowModel<Variable, Type>(Reachability.initial);
 
   /// The most recently visited expression for which an [ExpressionInfo] object
   /// exists, or `null` if no expression has been visited that has a
@@ -3519,9 +3520,7 @@ class _FlowAnalysisImpl<Node extends Object, Statement extends Node,
       {bool allowLocalBooleanVarsToPromote = false})
       : allowLocalBooleanVarsToPromote =
             allowLocalBooleanVarsToPromoteByDefault ||
-                allowLocalBooleanVarsToPromote {
-    _current = new FlowModel<Variable, Type>(Reachability.initial);
-  }
+                allowLocalBooleanVarsToPromote;
 
   @override
   bool get isReachable => _current.reachable.overallReachable;
@@ -4141,7 +4140,7 @@ class _FlowAnalysisImpl<Node extends Object, Statement extends Node,
       Variable? exceptionVariable, Variable? stackTraceVariable) {
     _TryContext<Variable, Type> context =
         _stack.last as _TryContext<Variable, Type>;
-    _current = context._beforeCatch!;
+    _current = context._beforeCatch;
     if (exceptionVariable != null) {
       _current = _current.declare(exceptionVariable, true);
     }
@@ -4162,7 +4161,7 @@ class _FlowAnalysisImpl<Node extends Object, Statement extends Node,
   void tryCatchStatement_end() {
     _TryContext<Variable, Type> context =
         _stack.removeLast() as _TryContext<Variable, Type>;
-    _current = context._afterBodyAndCatches!.unsplit();
+    _current = context._afterBodyAndCatches.unsplit();
   }
 
   @override
@@ -4177,11 +4176,11 @@ class _FlowAnalysisImpl<Node extends Object, Statement extends Node,
     _TryFinallyContext<Variable, Type> context =
         _stack.removeLast() as _TryFinallyContext<Variable, Type>;
     if (allowLocalBooleanVarsToPromote) {
-      _current = context._afterBodyAndCatches!
+      _current = context._afterBodyAndCatches
           .attachFinally(typeOperations, context._beforeFinally, _current);
     } else {
       _current = _current.restrict(
-          typeOperations, context._afterBodyAndCatches!, info._written);
+          typeOperations, context._afterBodyAndCatches, info._written);
     }
   }
 
@@ -5122,14 +5121,14 @@ class _TryContext<Variable extends Object, Type extends Object>
     extends _SimpleContext<Variable, Type> {
   /// If the statement is a "try/catch" statement, the flow model representing
   /// program state at the top of any `catch` block.
-  FlowModel<Variable, Type>? _beforeCatch;
+  late final FlowModel<Variable, Type> _beforeCatch;
 
   /// If the statement is a "try/catch" statement, the accumulated flow model
   /// representing program state after the `try` block or one of the `catch`
   /// blocks has finished executing.  If the statement is a "try/finally"
   /// statement, the flow model representing program state after the `try` block
   /// has finished executing.
-  FlowModel<Variable, Type>? _afterBodyAndCatches;
+  late FlowModel<Variable, Type> _afterBodyAndCatches;
 
   _TryContext(FlowModel<Variable, Type> previous) : super(previous);
 
@@ -5143,7 +5142,7 @@ class _TryFinallyContext<Variable extends Object, Type extends Object>
     extends _TryContext<Variable, Type> {
   /// The flow model representing program state at the top of the `finally`
   /// block.
-  late FlowModel<Variable, Type> _beforeFinally;
+  late final FlowModel<Variable, Type> _beforeFinally;
 
   _TryFinallyContext(FlowModel<Variable, Type> previous) : super(previous);
 }

pkg/_fe_analyzer_shared/lib/src/parser/literal_entry_info_impl.dart

@@ -17,7 +17,7 @@ const LiteralEntryInfo spreadOperator = const SpreadOperator();
 
 /// The first step when processing a `for` control flow collection entry.
 class ForCondition extends LiteralEntryInfo {
-  late bool inStyle;
+  bool _inStyle = false;
 
   ForCondition() : super(false, 0);
 
@@ -39,12 +39,12 @@ class ForCondition extends LiteralEntryInfo {
 
     if (optional('in', token.next!) || optional(':', token.next!)) {
       // Process `for ( ... in ... )`
-      inStyle = true;
+      _inStyle = true;
       token = parser.parseForInLoopPartsRest(
           token, awaitToken, forToken, identifier);
     } else {
       // Process `for ( ... ; ... ; ... )`
-      inStyle = false;
+      _inStyle = false;
       token = parser.parseForLoopPartsRest(token, forToken, awaitToken);
     }
     return token;
@@ -57,17 +57,17 @@ class ForCondition extends LiteralEntryInfo {
         (optional('await', next) && optional('for', next.next!))) {
       return new Nested(
         new ForCondition(),
-        inStyle ? const ForInComplete() : const ForComplete(),
+        _inStyle ? const ForInComplete() : const ForComplete(),
       );
     } else if (optional('if', next)) {
       return new Nested(
         ifCondition,
-        inStyle ? const ForInComplete() : const ForComplete(),
+        _inStyle ? const ForInComplete() : const ForComplete(),
       );
     } else if (optional('...', next) || optional('...?', next)) {
-      return inStyle ? const ForInSpread() : const ForSpread();
+      return _inStyle ? const ForInSpread() : const ForSpread();
     }
-    return inStyle ? const ForInEntry() : const ForEntry();
+    return _inStyle ? const ForInEntry() : const ForEntry();
   }
 }
 

pkg/_fe_analyzer_shared/lib/src/parser/token_stream_rewriter.dart

@@ -3,7 +3,6 @@
 // BSD-style license that can be found in the LICENSE file.
 
 import '../scanner/error_token.dart' show UnmatchedToken;
-
 import '../scanner/token.dart'
     show
         BeginToken,
@@ -227,28 +226,21 @@ abstract class TokenStreamChange {
 }
 
 class NextTokenStreamChange implements TokenStreamChange {
-  late Token setOn;
-  Token? setOnNext;
-  late Token nextToken;
-  Token? nextTokenPrevious;
-  Token? nextTokenBeforeSynthetic;
-
-  NextTokenStreamChange(UndoableTokenStreamRewriter rewriter) {
+  final Token setOn;
+  final Token? setOnNext;
+  final Token nextToken;
+  final Token? nextTokenPrevious;
+  final Token? nextTokenBeforeSynthetic;
+
+  NextTokenStreamChange(
+      UndoableTokenStreamRewriter rewriter, this.setOn, this.nextToken)
+      : setOnNext = setOn.next,
+        nextTokenPrevious = nextToken.previous,
+        nextTokenBeforeSynthetic = nextToken.beforeSynthetic {
     rewriter._changes.add(this);
-  }
-
-  Token setNext(Token setOn, Token nextToken) {
-    this.setOn = setOn;
-    this.setOnNext = setOn.next;
-    this.nextToken = nextToken;
-    this.nextTokenPrevious = nextToken.previous;
-    this.nextTokenBeforeSynthetic = nextToken.beforeSynthetic;
-
     setOn.next = nextToken;
     nextToken.previous = setOn;
     nextToken.beforeSynthetic = setOn;
-
-    return nextToken;
   }
 
   @override
@@ -260,17 +252,13 @@ class NextTokenStreamChange implements TokenStreamChange {
 }
 
 class EndGroupTokenStreamChange implements TokenStreamChange {
-  late BeginToken setOn;
-  Token? endGroup;
+  final BeginToken setOn;
+  final Token? endGroup;
 
-  EndGroupTokenStreamChange(UndoableTokenStreamRewriter rewriter) {
+  EndGroupTokenStreamChange(
+      UndoableTokenStreamRewriter rewriter, this.setOn, Token endGroup)
+      : endGroup = setOn.endGroup {
     rewriter._changes.add(this);
-  }
-
-  void setEndGroup(BeginToken setOn, Token endGroup) {
-    this.setOn = setOn;
-    this.endGroup = setOn.endGroup;
-
     setOn.endGroup = endGroup;
   }
 
@@ -281,17 +269,13 @@ class EndGroupTokenStreamChange implements TokenStreamChange {
 }
 
 class OffsetTokenStreamChange implements TokenStreamChange {
-  late Token setOn;
-  late int offset;
+  final Token setOn;
+  final int offset;
 
-  OffsetTokenStreamChange(UndoableTokenStreamRewriter rewriter) {
+  OffsetTokenStreamChange(
+      UndoableTokenStreamRewriter rewriter, this.setOn, int offset)
+      : offset = setOn.offset {
     rewriter._changes.add(this);
-  }
-
-  void setOffset(Token setOn, int offset) {
-    this.setOn = setOn;
-    this.offset = setOn.offset;
-
     setOn.offset = offset;
   }
 
@@ -302,17 +286,13 @@ class OffsetTokenStreamChange implements TokenStreamChange {
 }
 
 class PrecedingCommentsTokenStreamChange implements TokenStreamChange {
-  late SimpleToken setOn;
-  CommentToken? comment;
+  final SimpleToken setOn;
+  final CommentToken? comment;
 
-  PrecedingCommentsTokenStreamChange(UndoableTokenStreamRewriter rewriter) {
+  PrecedingCommentsTokenStreamChange(
+      UndoableTokenStreamRewriter rewriter, this.setOn, CommentToken? comment)
+      : comment = setOn.precedingComments {
     rewriter._changes.add(this);
-  }
-
-  void setPrecedingComments(SimpleToken setOn, CommentToken? comment) {
-    this.setOn = setOn;
-    this.comment = setOn.precedingComments;
-
     setOn.precedingComments = comment;
   }
 
@@ -323,17 +303,13 @@ class PrecedingCommentsTokenStreamChange implements TokenStreamChange {
 }
 
 class PreviousTokenStreamChange implements TokenStreamChange {
-  late Token setOn;
-  late Token previous;
+  final Token setOn;
+  final Token previous;
 
-  PreviousTokenStreamChange(UndoableTokenStreamRewriter rewriter) {
+  PreviousTokenStreamChange(
+      UndoableTokenStreamRewriter rewriter, this.setOn, Token previous)
+      : previous = setOn.previous! {
     rewriter._changes.add(this);
-  }
-
-  void setPrevious(Token setOn, Token previous) {
-    this.setOn = setOn;
-    this.previous = setOn.previous!;
-
     setOn.previous = previous;
   }
 
@@ -359,27 +335,26 @@ class UndoableTokenStreamRewriter extends TokenStreamRewriter {
 
   @override
   void _setEndGroup(BeginToken setOn, Token endGroup) {
-    new EndGroupTokenStreamChange(this).setEndGroup(setOn, endGroup);
+    new EndGroupTokenStreamChange(this, setOn, endGroup);
   }
 
   @override
   Token _setNext(Token setOn, Token nextToken) {
-    return new NextTokenStreamChange(this).setNext(setOn, nextToken);
+    return new NextTokenStreamChange(this, setOn, nextToken).nextToken;
   }
 
   @override
   void _setOffset(Token setOn, int offset) {
-    new OffsetTokenStreamChange(this).setOffset(setOn, offset);
+    new OffsetTokenStreamChange(this, setOn, offset);
   }
 
   @override
   void _setPrecedingComments(SimpleToken setOn, CommentToken? comment) {
-    new PrecedingCommentsTokenStreamChange(this)
-        .setPrecedingComments(setOn, comment);
+    new PrecedingCommentsTokenStreamChange(this, setOn, comment);
   }
 
   @override
   void _setPrevious(Token setOn, Token previous) {
-    new PreviousTokenStreamChange(this).setPrevious(setOn, previous);
+    new PreviousTokenStreamChange(this, setOn, previous);
   }
 }

pkg/_fe_analyzer_shared/lib/src/parser/type_info_impl.dart

@@ -915,7 +915,7 @@ class ComplexTypeParamOrArgInfo extends TypeParamOrArgInfo {
   final bool allowsVariance;
 
   @override
-  late int typeArgumentCount;
+  int typeArgumentCount = 0;
 
   /// The `>` token which ends the type parameter or argument.
   /// This closer may be synthetic, points to the next token in the stream,
@@ -938,7 +938,6 @@ class ComplexTypeParamOrArgInfo extends TypeParamOrArgInfo {
   TypeParamOrArgInfo compute() {
     Token token;
     Token next = start;
-    typeArgumentCount = 0;
     while (true) {
       TypeInfo typeInfo =
           computeType(next, /* required = */ true, inDeclaration);

pkg/_fe_analyzer_shared/lib/src/scanner/abstract_scanner.dart

@@ -115,7 +115,7 @@ abstract class AbstractScanner implements Scanner {
    */
   Token? commentsTail;
 
-  late final List<int> lineStarts;
+  final List<int> lineStarts;
 
   /**
    * The stack of open groups, e.g [: { ... ( .. :]
@@ -1948,22 +1948,11 @@ TokenType closeBraceInfoFor(BeginToken begin) {
 }
 
 class LineStarts extends Object with ListMixin<int> {
-  late List<int> array;
+  List<int> array;
   int arrayLength = 0;
 
-  LineStarts(int? numberOfBytesHint) {
-    // Let's assume the average Dart file is 300 bytes.
-    if (numberOfBytesHint == null) numberOfBytesHint = 300;
-
-    // Let's assume we have on average 22 bytes per line.
-    final int expectedNumberOfLines = 1 + (numberOfBytesHint ~/ 22);
-
-    if (numberOfBytesHint > 65535) {
-      array = new Uint32List(expectedNumberOfLines);
-    } else {
-      array = new Uint16List(expectedNumberOfLines);
-    }
-
+  LineStarts(int? numberOfBytesHint)
+      : array = _createInitialArray(numberOfBytesHint) {
     // The first line starts at character offset 0.
     add(/* value = */ 0);
   }
@@ -2022,6 +2011,20 @@ class LineStarts extends Object with ListMixin<int> {
     newArray.setRange(/* start = */ 0, arrayLength, array);
     array = newArray;
   }
+
+  static List<int> _createInitialArray(int? numberOfBytesHint) {
+    // Let's assume the average Dart file is 300 bytes.
+    numberOfBytesHint ??= 300;
+
+    // Let's assume we have on average 22 bytes per line.
+    final int expectedNumberOfLines = 1 + (numberOfBytesHint ~/ 22);
+
+    if (numberOfBytesHint > 65535) {
+      return new Uint32List(expectedNumberOfLines);
+    } else {
+      return new Uint16List(expectedNumberOfLines);
+    }
+  }
 }
 
 /// [ScannerConfiguration] contains information for configuring which tokens

pkg/_fe_analyzer_shared/lib/src/scanner/reader.dart

@@ -60,21 +60,20 @@ class CharSequenceReader implements CharacterReader {
   /**
    * The number of characters in the string.
    */
-  late int _stringLength;
+  int _stringLength;
 
   /**
    * The index, relative to the string, of the next character to be read.
    */
-  late int _charOffset;
+  int _charOffset;
 
   /**
    * Initialize a newly created reader to read the characters in the given
    * [_sequence].
    */
-  CharSequenceReader(this._sequence) {
-    this._stringLength = _sequence.length;
-    this._charOffset = 0;
-  }
+  CharSequenceReader(this._sequence)
+      : _stringLength = _sequence.length,
+        _charOffset = 0;
 
   @override
   int get offset => _charOffset - 1;