dart2dart backend: AST and unparser for backend.

tests/compiler/dart2js/dart_printer_test.dart

+library dart_printer_test;
+
+import '../../../sdk/lib/_internal/compiler/implementation/dart_backend/dart_printer.dart';
+import '../../../sdk/lib/_internal/compiler/implementation/scanner/scannerlib.dart';
+import '../../../sdk/lib/_internal/compiler/implementation/source_file.dart';
+import '../../../sdk/lib/_internal/compiler/implementation/dart2jslib.dart';
+import '../../../sdk/lib/_internal/compiler/implementation/tree/tree.dart' show DartString;
+import 'dart:mirrors';
+import '../../../sdk/lib/_internal/compiler/implementation/tree/tree.dart' as tree;
+import '../../../sdk/lib/_internal/compiler/implementation/string_validator.dart';
+
+/// For debugging the [AstBuilder] stack. Prints information about [x].
+void show(x) {
+  StringBuffer buf = new StringBuffer();
+  Unparser unparser = new Unparser(buf);
+  void unparse(x) {
+    if (x is Expression)
+      unparser.writeExpression(x);
+    else if (x is TypeAnnotation)
+      unparser.writeType(x);
+    else if (x is Statement)
+      unparser.writeStatement(x);
+    else if (x is List) {
+      buf.write('[');
+      bool first = true;
+      for (var y in x) {
+        if (first)
+          first = false;
+        else
+          buf.write(', ');
+        unparse(y);
+      }
+      buf.write(']');
+    }
+  }
+  unparse(x);
+  print("${x.runtimeType}: ${buf.toString()}");
+}
+
+class PrintDiagnosticListener implements DiagnosticListener {
+  void log(message) {
+    print(message);
+  }
+
+  void internalError(Spannable spannable, message) {
+    print(message);
+  }
+
+  SourceSpan spanFromSpannable(Spannable node) {
+    return new SourceSpan(null, 0, 0);
+  }
+
+  void reportFatalError(Spannable node, MessageKind errorCode,
+                        [Map arguments = const {}]) {
+    print(errorCode);
+    throw new Error();
+  }
+
+  void reportError(Spannable node, MessageKind errorCode,
+                   [Map arguments = const {}]) {
+    print(errorCode);
+  }
+
+  void reportWarning(Spannable node, MessageKind errorCode,
+                     [Map arguments = const {}]) {
+    print(errorCode);
+  }
+
+  void reportHint(Spannable node, MessageKind errorCode,
+                  [Map arguments = const {}]) {
+    print(errorCode);
+  }
+
+  void reportInfo(Spannable node, MessageKind errorCode,
+                  [Map arguments = const {}]) {
+    print(errorCode);
+  }
+
+  withCurrentElement(element, f()) {
+    f();
+  }
+}
+
+class AstBuilder extends Listener {
+  final List stack = [];
+  final StringValidator stringValidator 
+         = new StringValidator(new PrintDiagnosticListener()); 
+  
+  String asName(e) {
+    if (e is Identifier)
+      return e.name;
+    else if (e == null)
+      return null;
+    else
+      throw 'Expression is not a name: ${e.runtimeType}';
+  }
+  
+  TypeAnnotation asType(x) {
+    if (x is TypeAnnotation)
+      return x;
+    if (x is Identifier)
+      return new TypeAnnotation(x.name);
+    if (x == null)
+      return null;
+    else
+      throw "Not a type: ${x.runtimeType}";
+  }
+  
+  Parameter asParameter(x) {
+    if (x is Parameter)
+      return x;
+    if (x is Identifier)
+      return new Parameter(x.name);
+    else
+      throw "Not a parameter: ${x.runtimeType}";
+  }
+  
+  void push(node) {
+    stack.add(node);
+  }
+  dynamic peek() {
+    return stack.last;
+  }
+  dynamic pop([coerce(x) = null]) {
+    var x = stack.removeLast();
+    if (coerce != null)
+      return coerce(x);
+    else
+      return x;
+  }
+  List popList(int count, [List result, coerce(x) = null]) {
+    if (result == null)
+      result = <Node>[];
+    for (int i=0; i<count; i++) {
+      var x = stack[stack.length-count+i];
+      if (coerce != null) {
+        x = coerce(x);
+      }
+      result.add(x);
+    }
+    stack.removeRange(stack.length-count, stack.length);
+    return result;
+  }
+  popTypeAnnotation() {
+    List<TypeAnnotation> args = pop();
+    if (args == null)
+      return null;
+    String name = pop(asName);
+    return new TypeAnnotation(name, args);
+  }
+  
+  // EXPRESSIONS
+  endCascade() {
+    throw "Cascade not supported yet";
+  }
+  endIdentifierList(int count) {
+    push(popList(count, <Identifier>[]));
+  }
+  endTypeList(int count) {
+    push(popList(count, <TypeAnnotation>[], asType));
+  }
+  beginLiteralString(Token token) {
+    String source = token.value;
+    tree.StringQuoting quoting = StringValidator.quotingFromString(source);
+    push(quoting);
+    push(token); // collect token at the end
+  }
+  handleStringPart(Token token) {
+    push(token); // collect token at the end
+  }
+  endLiteralString(int interpCount) {
+    List parts = popList(2 * interpCount + 1, []);
+    tree.StringQuoting quoting = pop();
+    List<Expression> members = <Expression>[];
+    for (var i=0; i<parts.length; i++) {
+      var part = parts[i];
+      if (part is Expression) {
+        members.add(part);
+      } else { 
+        assert(part is Token);
+        DartString str = stringValidator.validateInterpolationPart(
+            part as Token, 
+            quoting,
+            isFirst: i == 0,
+            isLast: i == parts.length - 1);
+        members.add(new Literal(new StringConstant(str)));
+      }
+    }
+    push(new StringConcat(members));
+  }
+  handleStringJuxtaposition(int litCount) {
+    push(new StringConcat(popList(litCount, <Expression>[])));
+  }
+  endArguments(int count, begin, end) {
+    push(popList(count, <Argument>[]));
+  }
+  handleNoArguments(token) {
+    push(null);
+  }
+  handleNoTypeArguments(token) {
+    push(<TypeAnnotation>[]);
+  }
+  endTypeArguments(int count, t, y) {
+    List<TypeAnnotation> args = <TypeAnnotation>[];
+    for (var i=0; i<count; i++) {
+      args.add(popTypeAnnotation());
+    }
+    push(args.reversed.toList(growable:false));
+  }
+  handleVoidKeyword(token) {
+    push(new Identifier("void"));
+    push(<TypeAnnotation>[]); // prepare for popTypeAnnotation
+  }
+  handleQualified(Token period) {
+    String last = pop(asName);
+    String first = pop(asName);
+    push(new Identifier('$first.$last'));
+  }
+  endSend(t) {
+    List<Argument> arguments = pop();
+    if (arguments == null)
+      return; // not a function call
+    Expression selector = pop();
+    push(new CallFunction(selector, arguments));
+  }
+  endThrowExpression(t, tt) {
+    push(new Throw(pop()));
+  }
+  handleAssignmentExpression(Token token) {
+    Expression right = pop();
+    Expression left = pop();
+    push(new Assignment(left, token.value, right));
+  }
+  handleBinaryExpression(Token token) {
+    Expression right = pop();
+    Receiver left = pop();
+    String tokenString = token.stringValue;
+    if (tokenString == '.') {
+      if (right is CallFunction) {
+        String name = (right.callee as Identifier).name;
+        push(new CallMethod(left, name, right.arguments));
+      } else {
+        push(new FieldExpression(left, (right as Identifier).name));
+      }
+    } else {
+      push(new BinaryOperator(left, tokenString, right));
+    }
+  }
+  handleConditionalExpression(question, colon) {
+    Expression elseExpression = pop();
+    Expression thenExpression = pop();
+    Expression condition = pop();
+    push(new Conditional(condition, thenExpression, elseExpression));
+  }
+  handleIdentifier(Token t) {
+    push(new Identifier(t.value));
+  }
+  handleOperator(t) {
+    push(new Identifier(t.value));
+  }
+  handleIndexedExpression(open, close) {
+    Expression index = pop();
+    Receiver object = pop();
+    push(new IndexExpression(object, index));
+  }
+  handleIsOperator(operathor, not, endToken) {
+    TypeAnnotation type = popTypeAnnotation();
+    Expression exp = pop();
+    TypeOperator r = new TypeOperator(exp, 'is', type);
+    if (not != null) {
+      push(new UnaryOperator('!', r));
+    } else {
+      push(r);
+    }
+  }
+  handleAsOperator(operathor, endToken) {
+    TypeAnnotation type = popTypeAnnotation();
+    Expression exp = pop();
+    push(new TypeOperator(exp, 'as', type));
+  }
+  handleLiteralBool(Token t) {
+    bool value = t.value == 'true';
+    push(new Literal(value ? new TrueConstant() : new FalseConstant()));
+  }
+  handleLiteralDouble(t) {
+    push(new Literal(new DoubleConstant(double.parse(t.value))));
+  }
+  handleLiteralInt(Token t) {
+    push(new Literal(new IntConstant(int.parse(t.value))));
+  }
+  handleLiteralNull(t) {
+    push(new Literal(new NullConstant()));
+  }
+  endLiteralSymbol(Token hash, int idCount) {
+    List<Identifier> ids = popList(idCount, <Identifier>[]);
+    push(new LiteralSymbol(ids.map((id) => id.name).join('.')));
+  }
+  handleLiteralList(int count, begin, constKeyword, end) {
+    List<Expression> exps = popList(count, <Expression>[]);
+    List<TypeAnnotation> types = pop();
+    assert(types.length <= 1);
+    push(new LiteralList(exps,
+      isConst: constKeyword != null,
+      typeArgument: types.length == 0 ? null : types[0]
+    ));
+  }
+  handleLiteralMap(int count, begin, constKeyword, end) {
+    List<LiteralMapEntry> entries = popList(count, <LiteralMapEntry>[]);
+    List<TypeAnnotation> types = pop();
+    assert(types.length == 0 || types.length == 2);
+    push(new LiteralMap(entries,
+        isConst: constKeyword != null,
+        typeArguments: types
+    ));
+  }
+  endLiteralMapEntry(colon, endToken) {
+    Expression value = pop();
+    Expression key = pop();
+    push(new LiteralMapEntry(key,value));
+  }
+  handleNamedArgument(colon) {
+    Expression exp = pop();
+    Identifier name = pop();
+    push(new NamedArgument(name.name, exp));
+  }
+  endConstructorReference(Token start, Token period, Token end) {
+    if (period == null) {
+      push(null); // indicate missing constructor name
+    }
+  }
+  handleNewExpression(t) {
+    List<Argument> args = pop();
+    String constructorName = pop(asName);
+    TypeAnnotation type = popTypeAnnotation();
+    push(new CallNew(type, args, constructorName: constructorName));
+  }
+  handleConstExpression(t) {
+    List<Argument> args = pop();
+    String constructorName = pop(asName);
+    TypeAnnotation type = popTypeAnnotation();
+    push(new CallNew(type, args, constructorName: constructorName, 
+                     isConst:true));
+  }
+  handleParenthesizedExpression(t) {
+    // do nothing, just leave expression on top of stack
+  }
+  handleSuperExpression(t) {
+    push(new SuperReceiver());
+  }
+  handleThisExpression(t) {
+    push(new This());
+  }
+  handleUnaryPostfixAssignmentExpression(Token t) {
+    push(new Increment.postfix(pop(), t.value));
+  }
+  handleUnaryPrefixAssignmentExpression(Token t) {
+    push(new Increment.prefix(pop(), t.value));
+  }
+  handleUnaryPrefixExpression(Token t) {
+    push(new UnaryOperator(t.value, pop()));
+  }
+  
+  handleFunctionTypedFormalParameter(tok) {
+    // handled in endFormalParameter
+  }
+  endFormalParameter(thisKeyword) {
+    Expression defaultValue = null;
+    var x = pop();
+    if (x is DefaultValue) {
+      defaultValue = x.expression;
+      x = pop();
+    }
+    if (x is Parameters) {
+      String name = pop(asName);
+      TypeAnnotation returnType = popTypeAnnotation();
+      push(new Parameter.function(name, returnType, x, defaultValue));
+    } else {
+      String name = asName(x);
+      TypeAnnotation type = popTypeAnnotation();
+      push(new Parameter(name, type:type, defaultValue:defaultValue));
+    }
+  }
+  handleValuedFormalParameter(eq, tok) {
+    push(new DefaultValue(pop()));
+  }
+  endOptionalFormalParameters(int count, begin, end) {
+    bool isNamed = end.value == '}';
+    push(popList(count, <Parameter>[], asParameter));
+    push(isNamed); // Indicate optional parameters to endFormalParameters.
+  }
+  endFormalParameters(count, begin, end) {
+    if (count == 0) {
+      push(new Parameters([]));
+      return;
+    }
+    var last = pop();   // Detect if optional parameters are present.
+    if (last is bool) { // See endOptionalFormalParameters.
+      List<Parameter> optional = pop();
+      List<Parameter> required = popList(count-1, <Parameter>[], asParameter);
+      push(new Parameters(required, optional, last));
+    } else {
+      // No optional parameters.
+      List<Parameter> required = popList(count-1, <Parameter>[], asParameter);
+      required.add(last);
+      push(new Parameters(required));
+    }
+  }
+  handleNoFormalParameters(tok) {
+    push(new Parameters([]));
+  }
+  endUnamedFunction(t) {
+    Statement body = pop();
+    Parameters parameters = pop();
+    push(new FunctionExpression(parameters, body));
+  }
+  handleNoType(Token token) {
+    push(null);
+  }
+  
+  endReturnStatement(bool hasExpression, begin, end) {
+    // This is also called for functions whose body is "=> expression"
+    if (hasExpression) {
+      push(new Return(pop()));
+    } else {
+      push(new Return());
+    }
+  }
+  
+  endExpressionStatement(Token token) {
+    push(new ExpressionStatement(pop()));
+  }
+  
+  endDoWhileStatement(Token doKeyword, Token whileKeyword, Token end) {
+    Expression condition = pop();
+    Statement body = pop();
+    push(new DoWhile(body, condition));
+  }
+  
+  endWhileStatement(Token whileKeyword, Token end) {
+    Statement body = pop();
+    Expression condition = pop();
+    push(new While(condition, body));
+  }
+  
+  endBlock(int count, Token begin, Token end) {
+    push(new Block(popList(count, <Statement>[])));
+  }
+  
+  endRethrowStatement(Token throwToken, Token endToken) {
+    push(new Rethrow());
+  }
+  
+  endTryStatement(int catchCount, Token tryKeyword, Token finallyKeyword) {
+    Statement finallyBlock = null;
+    if (finallyKeyword != null) {
+      finallyBlock = pop();
+    }
+    List<CatchBlock> catchBlocks = popList(catchCount, <CatchBlock>[]);
+    Statement tryBlock = pop();
+    push(new Try(tryBlock, catchBlocks, finallyBlock));
+  }
+  
+  void handleCatchBlock(Token onKeyword, Token catchKeyword) {
+    Statement block = pop();
+    String exceptionVar = null;
+    String stackVar = null;
+    if (catchKeyword != null) {
+      Parameters params = pop();
+      exceptionVar = params.requiredParameters[0].name;
+      if (params.requiredParameters.length > 1) {
+        stackVar = params.requiredParameters[1].name;
+      }
+    }
+    TypeAnnotation type = onKeyword == null ? null : pop();
+    push(new CatchBlock(block, 
+      onType: type,
+      exceptionVar: exceptionVar,
+      stackVar: stackVar
+    ));
+  }
+  
+  endSwitchStatement(Token switchKeyword, Token end) {
+    List<SwitchCase> cases = pop();
+    Expression expression = pop();
+    push(new Switch(expression, cases));
+  }
+  
+  endSwitchBlock(int caseCount, Token begin, Token end) {
+    push(popList(caseCount, <SwitchCase>[]));
+  }
+  
+  handleSwitchCase(int labelCount, int caseCount, Token defaultKeyword,
+                   int statementCount, Token first, Token end) {
+    List<Statement> statements = popList(statementCount, <Statement>[]);
+    List<Expression> cases = popList(caseCount, <Expression>[]);
+    if (defaultKeyword != null) {
+      cases = null;
+    }
+    push(new SwitchCase(cases, statements));
+  }
+  
+  handleCaseMatch(Token caseKeyword, Token colon) {
+    // do nothing, leave case expression on stack
+  }
+  
+  handleBreakStatement(bool hasTarget, Token breakKeyword, Token end) {
+    String target = hasTarget ? pop(asName) : null;
+    push(new Break(target));
+  }
+  
+  handleContinueStatement(bool hasTarget, Token continueKeyword, Token end) {
+    String target = hasTarget ? pop(asName) : null;
+    push(new Continue(target));
+  }
+  
+  handleEmptyStatement(Token token) {
+    push(new EmptyStatement());
+  }
+  
+  
+  VariableDefinition asVariableDefinition(x) {
+    if (x is VariableDefinition)
+      return x;
+    if (x is Identifier)
+      return new VariableDefinition(x.name);
+    throw "Not a variable definition: ${x.runtimeType}";
+  }
+  
+  endVariablesDeclaration(int count, Token end) {
+    List<VariableDefinition> variables = 
+        popList(count, <VariableDefinition>[], asVariableDefinition);
+    TypeAnnotation type = popTypeAnnotation();
+    push(new VariableDefinitions(variables, 
+      type: type,
+      isFinal: false, // TODO(asgerf): Parse modifiers.
+      isConst: false
+    ));
+  }
+  
+  endInitializer(Token assign) {
+    Expression init = pop();
+    String name = pop(asName);
+    push(new VariableDefinition(name, init));
+  }
+  
+  endIfStatement(Token ifToken, Token elseToken) {
+    Statement elsePart = (elseToken == null) ? null : pop();
+    Statement thenPart = pop();
+    Expression condition = pop();
+    push(new If(condition, thenPart, elsePart));
+  }
+  
+  endForStatement(int updateCount, Token begin, Token end) {
+    Statement body = pop();
+    List<Expression> updates = popList(updateCount, <Expression>[]);
+    ExpressionStatement condition = pop(); // parsed as expression statement
+    Expression exp = condition == null ? null : condition.expression;
+    Node initializer = pop();
+    push(new For(initializer, exp, updates, body));
+  }
+  
+  handleNoExpression(Token token) {
+    push(null);
+  }
+  
+  endForIn(Token begin, Token inKeyword, Token end) {
+    Statement body = pop();
+    Expression exp = pop();
+    Node declaredIdentifier = pop();
+    push(new ForIn(declaredIdentifier, exp, body));
+  }
+  
+  handleAssertStatement(Token assertKeyword, Token semicolonToken) {
+    Expression exp = pop();
+    Expression call = new CallFunction(new Identifier("assert"), [exp]);
+    push(new ExpressionStatement(call));
+  }
+  
+  endLabeledStatement(int labelCount) {
+    Statement statement = pop();
+    for (int i=0; i<labelCount; i++) {
+      String label = pop(asName);
+      statement = new LabeledStatement(label, statement);
+    }
+    push(statement);
+  }
+  
+  endFunctionDeclaration(Token end) {
+    Statement body = pop();
+    Parameters parameters = pop();
+    String name = pop(asName);
+    TypeAnnotation returnType = popTypeAnnotation();
+    push(new FunctionStatement(name, parameters, body, returnType));
+  }
+  
+  endFunctionBody(int count, Token begin, Token end) {
+    push(new Block(popList(count, <Statement>[])));
+  }
+}
+
+class DefaultValue {
+  final Expression expression;
+  DefaultValue(this.expression);
+}
+
+/// Compares ASTs for structural equality.
+void checkDeepEqual(x, y) {
+  if (x is List && y is List) {
+    if (x.length != y.length)
+      return;
+    for (var i=0; i<x.length; i++) {
+      checkDeepEqual(x[i], y[i]);
+    }
+  }
+  else if (x is Node && y is Node) {
+    if (x.runtimeType != y.runtimeType)
+      throw new Error();
+    InstanceMirror xm = reflect(x);
+    InstanceMirror ym = reflect(y);
+    for (Symbol name in xm.type.instanceMembers.keys) {
+      if (reflectClass(Object).declarations.containsKey(name)) {
+        continue; // do not check things from Object, such as hashCode
+      }
+      MethodMirror mm = xm.type.instanceMembers[name];
+      if (mm.isGetter) { 
+        var xv = xm.getField(name).reflectee;
+        var yv = ym.getField(name).reflectee;
+        checkDeepEqual(xv,yv);
+      }
+    }
+  }
+  else if (x is PrimitiveConstant && y is PrimitiveConstant) {
+    checkDeepEqual(x.value, y.value);
+  }
+  else if (x is DartString && y is DartString) {
+    if (x.slowToString() != y.slowToString()) {
+      throw new Error();
+    }
+  }
+  else {
+    if (x != y) {
+      throw new Error();
+    }
+  }
+}
+
+Expression parseExpression(String code) {
+  SourceFile file = new StringSourceFile('', code);
+  Scanner scan = new Scanner(file);
+  Token tok = scan.tokenize();
+  AstBuilder builder = new AstBuilder();
+  Parser parser = new Parser(builder);
+  tok = parser.parseExpression(tok);
+  if (builder.stack.length != 1 || tok.kind != EOF_TOKEN) {
+    throw "Parse error in $code";
+  }
+  return builder.pop();
+}
+Statement parseStatement(String code) {
+  SourceFile file = new StringSourceFile('', code);
+  Scanner scan = new Scanner(file);
+  Token tok = scan.tokenize();
+  AstBuilder builder = new AstBuilder();
+  Parser parser = new Parser(builder);
+  tok = parser.parseStatement(tok);
+  if (builder.stack.length != 1 || tok.kind != EOF_TOKEN) {
+    throw "Parse error in $code";
+  }
+  return builder.pop();
+}
+
+String unparseExpression(Expression exp) {
+  StringBuffer buf = new StringBuffer();
+  new Unparser(buf).writeExpression(exp);
+  return buf.toString();
+}
+String unparseStatement(Statement stmt) {
+  StringBuffer buf = new StringBuffer();
+  new Unparser(buf).writeStatement(stmt);
+  return buf.toString();
+}
+
+/// Parses [code], unparses the resulting AST, then parses the unparsed text.
+/// The ASTs from the first and second parse are then compared for structural
+/// equality. Alternatively, if [expected] is not an empty string, the second
+/// parse must match the AST of parsing [expected].
+void checkFn(String code, String expected, Function parse, Function unparse) {
+  String unparsed = "";
+  try {
+    var firstParse = parse(code);
+    unparsed = unparse(firstParse);
+    var secondParse = parse(unparsed);
+    var baseline = expected == "" ? firstParse : parse(expected);
+    checkDeepEqual(baseline, secondParse);

[Kevin Millikin (Google), 2014/04/24 13:27:25]

I guess this should be Expect.isTrue(checkDeepEqual(baseline, secondparse)). 
You can give a second argument that is a string reason.

+  } catch (e, stack) {
+    print("INPUT:  ${code}");
+    print("OUTPUT: ${unparsed}");
+    print("ERROR:  $e");
+    if (e is! String)
+      print(stack);
+    print("-----------");
+  }
+}
+
+void checkExpression(String code, [String expected=""]) {
+  checkFn(code, expected, parseExpression, unparseExpression);
+}
+void checkStatement(String code, [String expected=""]) {
+  checkFn(code, expected, parseStatement, unparseStatement);
+}
+
+void debugTokens(String code) {
+  SourceFile file = new StringSourceFile('', code);
+  Scanner scan = new Scanner(file);
+  Token tok = scan.tokenize();
+  while (tok.next != tok) {
+    print(tok.toString());
+    tok = tok.next;
+  }
+}
+
+void main() {
+  // To check if these tests are effective, one should manually alter 
+  // something in [Unparser] and see if a test fails.  
+  
+  checkExpression(" a +  b  + c");
+  checkExpression("(a +  b) + c");
+  checkExpression(" a + (b  + c)");
+  
+  checkExpression(" a +  b  - c");
+  checkExpression("(a +  b) - c");
+  checkExpression(" a + (b  - c)");
+  
+  checkExpression(" a -  b  + c");
+  checkExpression("(a -  b) + c");
+  checkExpression(" a - (b  + c)");
+  
+  checkExpression(" a *  b  + c");
+  checkExpression("(a *  b) + c");
+  checkExpression(" a * (b  + c)");
+  
+  checkExpression(" a +  b  * c");
+  checkExpression("(a +  b) * c");
+  checkExpression(" a + (b  * c)");
+  
+  checkExpression(" a *  b  * c");
+  checkExpression("(a *  b) * c");
+  checkExpression(" a * (b  * c)");
+
+  checkExpression("a is T");
+  checkExpression("a is! T");
+  checkExpression("!(a is T)");
+  
+  checkExpression("a is T.x");
+  checkExpression("a is! T.x");
+  checkExpression("!(a is T.x)");
+  checkExpression("!(a is T).x");
+
+  checkExpression("a as T.x");
+  checkExpression("(a as T).x");
+  
+  checkExpression("a == b");
+  checkExpression("a != b");
+  checkExpression("!(a == b)", "a != b");
+
+  checkExpression("a && b ? c : d");
+  checkExpression("(a && b) ? c : d");
+  checkExpression("a && (b ? c : d)");
+  
+  checkExpression("a || b ? c : d");
+  checkExpression("(a || b) ? c : d");
+  checkExpression("a || (b ? c : d)");
+
+  checkExpression(" a ? b :  c && d");
+  checkExpression(" a ? b : (c && d)");
+  checkExpression("(a ? b :  c) && d");
+
+  checkExpression(" a ? b : c = d");
+  checkExpression(" a ? b : (c = d)");
+  
+  checkExpression("(a == b) == c");
+  checkExpression("a == (b == c)");
+  
+  checkExpression(" a <  b  == c");
+  checkExpression("(a <  b) == c");
+  checkExpression(" a < (b  == c)");
+
+  checkExpression(" a ==  b  < c");
+  checkExpression("(a ==  b) < c");
+  checkExpression(" a == (b  < c)");
+  
+  checkExpression("x.f()");
+  checkExpression("(x.f)()");
+  
+  checkExpression("x.f()()");
+  checkExpression("(x.f)()()");
+  
+  checkExpression("x.f().g()");
+  checkExpression("(x.f)().g()");
+  
+  checkExpression("x.f()");
+  checkExpression("x.f(1 + 2)");
+  checkExpression("x.f(1 + 2, 3 + 4)");
+  checkExpression("x.f(1 + 2, foo:3 + 4)");
+  checkExpression("x.f(1 + 2, foo:3 + 4, bar: 5)");
+  checkExpression("x.f(foo:3 + 4)");
+  checkExpression("x.f(foo:3 + 4, bar: 5)");
+  
+  checkExpression("x.f.g.h");
+  checkExpression("(x.f).g.h");
+  checkExpression("(x.f.g).h");
+  
+  checkExpression(" a =  b  + c");
+  checkExpression(" a = (b  + c)");
+  checkExpression("(a =  b) + c");
+
+  checkExpression("a + (b = c)");
+  
+  checkExpression("dx * dx + dy * dy < r * r", 
+                  "((dx * dx) + (dy * dy)) < (r * r)");
+  checkExpression("mid = left + right << 1", 
+                  "mid = ((left + right) << 1)");
+  checkExpression("a + b % c * -d ^  e - f  ~/ x & ++y / z++ | w > a ? b : c");
+  checkExpression("a + b % c * -d ^ (e - f) ~/ x & ++y / z++ | w > a ? b : c");
+  
+  checkExpression("'foo'");
+  checkExpression("'foo' 'bar'", "'foobar'");
+
+  checkExpression("{}.length");
+  checkExpression("{x: 1+2}.length");
+  checkExpression("<String,int>{}.length");
+  checkExpression("<String,int>{x: 1+2}.length");
+  
+  checkExpression("[].length");
+  checkExpression("[1+2].length");
+  checkExpression("<num>[].length");
+  checkExpression("<num>[1+2].length");
+
+  checkExpression("x + -y");
+  checkExpression("x + --y");
+  checkExpression("x++ + y");
+  checkExpression("x + ++y");
+  checkExpression("x-- - y");
+  checkExpression("x-- - -y");
+  checkExpression("x - --y");
+  
+  checkExpression("x && !y");
+  checkExpression("!x && y");
+  checkExpression("!(x && y)");
+
+  checkExpression(" super +  1  * 2");
+  checkExpression("(super +  1) * 2");
+  checkExpression(" super + (1  * 2)");
+  checkExpression("x + -super");
+  checkExpression("x-- - -super");
+  checkExpression("x - -super");
+  checkExpression("x && !super");
+  
+  checkExpression("super.f(1, 2) + 3");
+  checkExpression("super.f + 3");
+  
+  checkExpression(r"'foo\nbar'");
+  checkExpression(r"'foo\r\nbar'");
+  checkExpression(r"'foo\rbar'");
+  checkExpression(r"'foo\'bar'");
+  checkExpression(r"""'foo"bar'""");
+  checkExpression(r"r'foo\nbar'");
+  checkExpression("''");
+  checkExpression("r''");
+  
+  var sq = "'";
+  var dq = '"';
+  checkExpression("'$dq$dq' \"$sq$sq\"");
+  checkExpression("'$dq$dq$dq$dq' \"$sq$sq$sq$sq\"");
+  checkExpression(r"'\$\$\$\$\$\$\$\$\$'");
+  checkExpression("'$dq$dq$dq' '\\n\\n\\n\\n\\n\\n\\n\\n\\n\\n' \"$sq$sq$sq\"");
+  checkExpression("'$dq$dq$dq' '\\r\\r\\r\\r\\r\\r\\r\\r\\r\\r' \"$sq$sq$sq\"");
+  checkExpression("'$dq$dq$dq' '\\r\\n\\r\\n\\r\\n\\r\\n\\r\\n' \"$sq$sq$sq\"");
+  
+  checkExpression(r"'$foo'");
+  checkExpression(r"'${foo}x'");
+  checkExpression(r"'${foo}x\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\'");
+  checkExpression(r"'abc' '${foo}' r'\\\\\\\'");
+  
+  checkExpression(r"'${$x}'");
+  checkExpression(r"'${$x}y'");
+  
+  checkStatement("var x, y, z;");
+  checkStatement("final x, y, z;");
+  checkStatement("dynamic x, y, z;");
+  checkStatement("String x, y, z;");
+  checkStatement("List<int> x, y, z;");
+  checkStatement("final dynamic x, y, z;");
+  checkStatement("final String x, y, z;");
+  checkStatement("final List<int> x, y, z;");
+  
+  checkStatement("var x = y, z;");
+  checkStatement("var x, y = z;");
+  checkStatement("var x = y = z;");
+  
+  // Note: We sometimes have to pass an expected string to account for
+  //       block flattening which does not preserve structural AST equality
+  checkStatement("if (x)   if (y) foo();   else bar();  ");
+  checkStatement("if (x) { if (y) foo(); } else bar();  ");
+  checkStatement("if (x) { if (y) foo();   else bar(); }",
+                 "if (x)   if (y) foo();   else bar();  ");
+
+  checkStatement("if (x) while (y)   if (z) foo();   else bar();  ");
+  checkStatement("if (x) while (y) { if (z) foo(); } else bar();  ");
+  checkStatement("if (x) while (y) { if (z) foo();   else bar(); }",
+                 "if (x) while (y)   if (z) foo();   else bar();  ");
+  
+  checkStatement("{var x = 1; {var x = 2;} return x;}");
+  checkStatement("{var x = 1; {x = 2;} return x;}",
+                 "{var x = 1;  x = 2;  return x;}");
+  
+  checkStatement("if (x) {var x = 1;}");
+  
+  checkStatement("({'foo': 1}).bar();");
+  checkStatement("({'foo': 1}).length;");
+  checkStatement("({'foo': 1}).length + 1;");
+  checkStatement("({'foo': 1})['foo'].toString();");
+  checkStatement("({'foo': 1})['foo'] = 3;");
+  checkStatement("({'foo': 1}['foo']());");
+  checkStatement("({'foo': 1}['foo'])();");
+  checkStatement("({'foo': 1})['foo'].x++;");
+  checkStatement("({'foo': 1}) is Map;");
+  checkStatement("({'foo': 1}) as Map;");
+  checkStatement("({'foo': 1}) is util.Map;");
+  checkStatement("({'foo': 1}) + 1;");
+  
+  checkStatement("[1].bar();");
+  checkStatement("1.bar();");
+  checkStatement("'foo'.bar();");
+
+  checkStatement("do while(x); while (y);");
+  checkStatement("{do; while(x); while (y);}");
+  
+}
+