Parse for-look statements with Fasta.

pkg/front_end/lib/src/fasta/analyzer/ast_builder.dart

Index: pkg/front_end/lib/src/fasta/analyzer/ast_builder.dart
diff --git a/pkg/front_end/lib/src/fasta/analyzer/ast_builder.dart b/pkg/front_end/lib/src/fasta/analyzer/ast_builder.dart
index 922da2b97c80c80994494ab509a2707d0284bccf..11ec061cd722eac598402d4ef56c87bb0e32bbf6 100644
--- a/pkg/front_end/lib/src/fasta/analyzer/ast_builder.dart
+++ b/pkg/front_end/lib/src/fasta/analyzer/ast_builder.dart
@@ -415,8 +415,8 @@ class AstBuilder extends ScopeListener {
     debugEvent("WhileStatement");
     Statement body = pop();
     ParenthesizedExpression condition = pop();
-    pop(); // continue target
-    pop(); // break target
+    exitContinueTarget();
+    exitBreakTarget();
     push(ast.whileStatement(
         toAnalyzerToken(whileKeyword),
         condition.leftParenthesis,
@@ -475,25 +475,43 @@ class AstBuilder extends ScopeListener {
         toAnalyzerToken(beginToken), statements, toAnalyzerToken(endToken)));
   }
 
-  void endForStatement(
-      int updateExpressionCount, Token beginToken, Token endToken) {
+  void endForStatement(Token forKeyword, Token leftSeparator,
+      int updateExpressionCount, Token endToken) {
     debugEvent("ForStatement");
     Statement body = pop();
     List<Expression> updates = popList(updateExpressionCount);
-    ExpressionStatement condition = pop();
-    VariableDeclarationStatement variables = pop();
+    Statement conditionStatement = pop();
+    Object initializerPart = pop();
+    exitLocalScope();
     exitContinueTarget();
     exitBreakTarget();
-    exitLocalScope();
-    BeginGroupToken leftParenthesis = beginToken.next;
+    BeginGroupToken leftParenthesis = forKeyword.next;
+
+    VariableDeclarationList variableList;
+    Expression initializer;
+    if (initializerPart is VariableDeclarationStatement) {
+      variableList = initializerPart.variables;
+    } else {
+      initializer = initializerPart as Expression;
+    }
+
+    Expression condition;
+    analyzer.Token rightSeparator;
+    if (conditionStatement is ExpressionStatement) {
+      condition = conditionStatement.expression;
+      rightSeparator = conditionStatement.semicolon;
+    } else {
+      rightSeparator = (conditionStatement as EmptyStatement).semicolon;
+    }
+
     push(ast.forStatement(
-        toAnalyzerToken(beginToken),
+        toAnalyzerToken(forKeyword),
         toAnalyzerToken(leftParenthesis),
-        variables?.variables,
-        null, // initialization.
-        variables?.semicolon,
-        condition.expression,
-        condition.semicolon,
+        variableList,
+        initializer,
+        toAnalyzerToken(leftSeparator),
+        condition,
+        rightSeparator,
         updates,
         toAnalyzerToken(leftParenthesis.endGroup),
         body));
@@ -701,9 +719,9 @@ class AstBuilder extends ScopeListener {
     Statement body = pop();
     Expression iterator = pop();
     Object variableOrDeclaration = pop();
-    pop(); // local scope
-    pop(); // continue target
-    pop(); // break target
+    exitLocalScope();
+    exitContinueTarget();
+    exitBreakTarget();
     if (variableOrDeclaration is SimpleIdentifier) {
       push(ast.forEachStatementWithReference(
           toAnalyzerToken(awaitToken),
@@ -1068,8 +1086,8 @@ class AstBuilder extends ScopeListener {
     debugEvent("DoWhileStatement");
     ParenthesizedExpression condition = pop();
     Statement body = pop();
-    pop(); // continue target
-    pop(); // break target
+    exitContinueTarget();
+    exitBreakTarget();
     push(ast.doStatement(
         toAnalyzerToken(doKeyword),
         body,