[kernel] Rewrite method calls transformation

pkg/kernel/lib/transformations/method_call.dart

Index: pkg/kernel/lib/transformations/method_call.dart
diff --git a/pkg/kernel/lib/transformations/method_call.dart b/pkg/kernel/lib/transformations/method_call.dart
new file mode 100644
index 0000000000000000000000000000000000000000..d3b61e4285398469b5d1fb6f82a2407f02c4f805
--- /dev/null
+++ b/pkg/kernel/lib/transformations/method_call.dart
@@ -0,0 +1,1311 @@
+// Copyright (c) 2017, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+library kernel.transformations.method_call;
+
+import '../ast.dart';
+import '../kernel.dart';
+import '../visitor.dart';
+import '../class_hierarchy.dart';
+import '../core_types.dart';
+import 'dart:math' as math;

[kustermann, 2017/02/14 15:21:23]

nit: The core library imports go first with an empty line after it.

[jensj, 2017/02/15 11:46:21]

Done.

+
+/// Problems with the method rewrite transformation:
+///
+/// * Cannot rewrite invocations to things called "call" because of tear-offs
+///   and whatnot that when invoked turns into variableName.call(...).
+///
+/// * Cannot rewrite invocations to things sharing a name with a field because
+///   one could have called clazz.fieldName(...).
+///
+/// * Rewrites will make stacktraces look weird.
+///
+/// * Rewrites will make noSuchMethod look weird --- e.g. calling a non-existing
+///   function foo(a: 42) turns into foo%0%a(42), i.e. the method name has
+///   changed ("foo" vs "foo%0%a") and the arguments has changed (named "a" vs
+///   positional).
+///   NOTE: At least for now this can be fixed by changing the
+///   invocation_mirror_patch file. Doing this I can make all dill, language
+///   and co19 tests pass!
+///
+/// Somewhat weird:
+///
+/// * Inserts methods that redirect to the correct noSuchMethod invocation
+///   so that program #1 example below will work.
+///   The reason it otherwise wouldn't is that b.foo(499, named1: 88) is
+///   rewritten to b.foo%1%named1(499, 88) which is not legal for class B
+///   (thus the method would not be create there) but IS legal for Bs parent
+///   class (A), so it would be created there. The call will thus go to the
+///   super (A) but shouldn't as foo was overwritten in B.
+///
+/// Program #1 example:
+/// class A {
+///   foo(required1, { named1: 499}) => print("Hello from class A");
+/// }
+///
+/// class B extends A {
+///   foo(required1) => print("Hello from class B");
+/// }
+///
+/// main() {
+///   var b = new B();
+///   b.foo(499, named1: 88);
+/// }
+Program transformProgram(Program program, [debug = false]) {
+  new MethodCallTransformer(debug).visitProgram(program);
+  return program;
+}
+
+class MethodCallTransformer extends Transformer {
+  /// Keep track of "visited" procedures and constructors to not visit already
+  /// visited stuff, nor visit newly created stubs.
+  Set<Member> _visited = new Set<Member>();
+
+  /// Some things currently cannot be rewritten. Calls to methods called "call"
+  /// (because invoking tear-offs and closures and whatnot becomes .call)
+  /// as well as clashes with field names as a field can contain a function
+  /// and one can then do a clazz.fieldName(...).
+  Set<String> stopNames = new Set<String>.from(["call"]);

[kustermann, 2017/02/14 15:21:23]

Maybe rename this to blacklistedSelectors

[jensj, 2017/02/15 11:46:21]

Done.

+
+  /// Map from a "originally named" procedure to the "%original" procedure
+  /// for procedures that was moved.
+  Map<Procedure, Procedure> _movedBodies = {};
+
+  /// Map from a "originally named" constructor to the "%original"
+  /// constructor for constructors that was moved.
+  Map<Constructor, Constructor> _movedConstructors = {};
+
+  /// For static method transformations:
+  /// Maps a procedure to the mapping of argument signature to procedure stub.
+  Map<Procedure, Map<String, Procedure>> _staticProcedureCalls = {};
+
+  /// For constructor transformations:
+  /// Maps a constructor to a mapping of argument signature to constructor stub.
+  Map<Constructor, Map<String, Constructor>> _constructorCalls = {};
+
+  /// For non-static method transformations:
+  /// Maps from method name to the set of legal number of positional arguments.
+  Map<String, Set<int>> _methodToLegalPositionalArgumentCount = {};
+
+  /// For non-static method transformations:
+  /// Maps from name of method to the set of new target names seen for at least
+  /// one instance (i.e. rewriting has been performed from key to all values in
+  /// the mapped to set at least once).
+  Map<Name, Set<String>> _rewrittenMethods = {};
+
+  /// For non-static method transformations:
+  /// Maps a procedure to the mapping of argument signature to procedure stub.
+  Map<Procedure, Map<String, Procedure>> _superProcedureCalls = {};
+
+  /// Whether in debug mode, i.e. if we can insert extra print statements for
+  /// debugging purposes.
+  bool _debug;
+
+  /// For noSuchMethod calls.
+  ClassHierarchy hierarchy;
+  CoreTypes coreTypes;
+  Constructor _invocationMirrorConstructor; // cached
+  Procedure _listFrom; // cached
+
+  MethodCallTransformer(this._debug);
+
+  @override
+  TreeNode visitProgram(Program node) {
+    hierarchy = new ClassHierarchy(node);
+    coreTypes = new CoreTypes(node);
+
+    // First move body of all procedures that takes optional positional or named
+    // parameters and record which non-static procedure names have optional
+    // positional arguments.
+    // Do the same for constructors. Then also rewrite constructor initializers
+    // using LocalInitializer and sort named arguments in those initializers
+    for (final library in node.libraries) {
+      for (final procedure in new List<Procedure>.from(library.procedures)) {
+        _moveAndTransformProcedure(procedure);
+      }
+
+      for (final clazz in library.classes) {
+        for (final field in clazz.fields) {
+          stopNames.add(field.name.name);
+        }
+
+        for (final procedure in new List<Procedure>.from(clazz.procedures)) {
+          // This call creates new procedures
+          _moveAndTransformProcedure(procedure);
+          _recordNonStaticProcedureAndVariableArguments(procedure);
+        }
+
+        for (final constructor
+            in new List<Constructor>.from(clazz.constructors)) {
+          // This call creates new constructors
+          _moveAndTransformConstructor(constructor);
+        }
+
+        for (final constructor in clazz.constructors) {
+          _rewriteConstructorInitializations(constructor);
+        }
+      }
+    }
+
+    // Rewrite calls
+    node.transformChildren(this);
+
+    // Now for all method calls that was rewritten, make sure those call
+    // destinations actually exist, i.e. for each method with a matching name
+    // where the called-with-arguments is legal, create a stub
+    for (final library in node.libraries) {
+      for (final clazz in library.classes) {
+        for (final procedure in new List<Procedure>.from(clazz.procedures)) {
+          // This call creates new procedures
+          _createNeededNonStaticStubs(procedure);
+        }
+      }
+    }
+
+    return node;
+  }
+
+  @override
+  TreeNode visitProcedure(Procedure node) {
+    if (!_visited.contains(node)) {
+      _visited.add(node);
+      node.transformChildren(this);
+    }
+    return node;
+  }
+
+  @override
+  TreeNode visitConstructor(Constructor node) {
+    if (!_visited.contains(node)) {
+      _visited.add(node);
+      node.transformChildren(this);
+    }
+    return node;
+  }
+
+  @override
+  TreeNode visitStaticInvocation(StaticInvocation node) {
+    node.transformChildren(this);
+    if (!_isMethod(node.target)) return node;
+    if (!_hasAnyOptionalParameters(node.target.function)) return node;
+    if (!_callIsLegal(node.target.function, node.arguments)) return node;
+
+    // Rewrite with let if needed (without named arguments it won't do anything)
+    Expression rewrittenNode = _rewriteWithLetAndSort(node, node.arguments);
+
+    // Create/lookup target and set it as the new target
+    node.target = _getNewTargetForStaticLikeInvocation(
+        node.target, node.arguments, _staticProcedureCalls);
+
+    // Now turn any named parameters into positional parameters
+    _turnNamedArgumentsIntoPositional(node.arguments);
+    return rewrittenNode;
+  }
+
+  @override
+  TreeNode visitDirectMethodInvocation(DirectMethodInvocation node) {
+    node.transformChildren(this);
+    if (!_isMethod(node.target)) return node;
+    if (!_hasAnyOptionalParameters(node.target.function)) return node;
+    if (!_callIsLegal(node.target.function, node.arguments)) return node;
+
+    // Rewrite with let if needed (without named arguments it won't do anything)
+    Expression rewrittenNode = _rewriteWithLetAndSort(node, node.arguments);
+
+    // Create/lookup target and set it as the new target
+    node.target = _getNewTargetForStaticLikeInvocation(
+        node.target, node.arguments, _superProcedureCalls);
+
+    // Now turn any named parameters into positional parameters instead
+    _turnNamedArgumentsIntoPositional(node.arguments);
+    return rewrittenNode;
+  }
+
+  @override
+  TreeNode visitSuperMethodInvocation(SuperMethodInvocation node) {
+    // SuperMethodInvocation was changed since I originally wrote this,
+    // and now it seems to never be called anyway.
+    throw "visitSuperMethodInvocation is not implemented!";
+  }
+
+  @override
+  TreeNode visitMethodInvocation(MethodInvocation node) {
+    node.transformChildren(this);
+    final name = node.name.name;
+
+    // Don't renamed calls to methods that clashes in name with a field
+    // or is called "call" :(
+    if (stopNames.contains(name)) return node;
+
+    // Rewrite with let if needed (without named arguments it won't do anything)
+    Expression rewrittenNode = _rewriteWithLetAndSort(node, node.arguments);
+
+    String argumentsSignature = _createArgumentsSignature(node.arguments);
+    if (node.arguments.named.isEmpty) {
+      // Positional: Don't rewrite if no procedure with that name can be called
+      // with a variable number of arguments, or where the number of arguments
+      // called with here isn't a legal number of arguments to any such
+      // procedure.
+      // Note for named arguments: Named arguments are always rewritten
+      // (except for 'call' methods) so there's no such check
+      final okCounts = _methodToLegalPositionalArgumentCount[name];
+
+      if (okCounts == null ||
+          !okCounts.contains(node.arguments.positional.length)) {
+        return node;
+      }
+    }
+
+    // Rewrite this call
+    final originalName = node.name;
+    node.name = _createName(node.name, argumentsSignature);
+
+    // Remember that we rewrote this call
+    _rewrittenMethods
+        .putIfAbsent(originalName, () => new Set<String>())
+        .add(argumentsSignature);
+
+    // Now turn any named parameters into positional parameters instead
+    _turnNamedArgumentsIntoPositional(node.arguments);
+    return rewrittenNode;
+  }
+
+  @override
+  TreeNode visitConstructorInvocation(ConstructorInvocation node) {
+    node.transformChildren(this);
+    if (!_callIsLegal(node.target.function, node.arguments)) return node;
+
+    Expression rewrittenNode;
+    if (node.isConst) {
+      // Sort named arguments by name => it's const so there's no side-effects!
+      // but DO NOT rewrite with let!
+      node.arguments.named.sort((a, b) => a.name.compareTo(b.name));
+      rewrittenNode = node;
+    } else {
+      rewrittenNode = _rewriteWithLetAndSort(node, node.arguments);
+    }
+    node.target = _getNewTargetForConstructor(node.target, node.arguments);
+
+    // Now turn named parameters into positional parameters instead
+    _turnNamedArgumentsIntoPositional(node.arguments);
+    return rewrittenNode;
+  }
+
+  @override
+  TreeNode visitSuperInitializer(SuperInitializer node) {
+    // Note that sorting was done in _rewriteConstructorInitializations
+    node.transformChildren(this);
+    if (!_callIsLegal(node.target.function, node.arguments)) return node;
+
+    node.target = _getNewTargetForConstructor(node.target, node.arguments);
+
+    // Now turn named parameters into positional parameters instead
+    _turnNamedArgumentsIntoPositional(node.arguments);
+    return node;
+  }
+
+  @override
+  TreeNode visitRedirectingInitializer(RedirectingInitializer node) {
+    // Note that sorting was done in _rewriteConstructorInitializations
+    node.transformChildren(this);
+    if (!_callIsLegal(node.target.function, node.arguments)) return node;
+
+    node.target = _getNewTargetForConstructor(node.target, node.arguments);
+
+    // Now turn named parameters into positional parameters instead
+    _turnNamedArgumentsIntoPositional(node.arguments);
+    return node;
+  }
+
+  /// Gets the new target for an invocation, using cache or creating a new one.
+  ///
+  /// Assumes that any let-rewrite, named argument sorting etc has been done
+  /// already.
+  Procedure _getNewTargetForStaticLikeInvocation(Procedure target,
+      Arguments arguments, Map<Procedure, Map<String, Procedure>> cache) {
+    final createdProcedures = cache.putIfAbsent(target, () => {});
+
+    // Rewrite target
+    final argumentsSignature = _createArgumentsSignature(arguments);
+    return createdProcedures[argumentsSignature] ??
+        _createAndCacheInvocationProcedure(
+            argumentsSignature,
+            arguments.positional.length,
+            arguments.named.map((e) => e.name).toList(),
+            target,
+            _movedBodies[target],
+            createdProcedures,
+            true);
+  }
+
+  /// Rewrite the [Argument]s turning named arguments into positional arguments.
+  ///
+  /// Note that if the [Argument]s does not take any named parameters this
+  /// method does nothing.
+  void _turnNamedArgumentsIntoPositional(Arguments arguments) {
+    for (final named in arguments.named) {
+      arguments.positional.add(named.value..parent = arguments);
+    }
+    arguments.named.clear();
+  }
+
+  /// Gets the new target for an invocation, using cache or creating a new one.
+  ///
+  /// Assumes that any let-rewrite, named argument sorting etc has been done
+  /// already.
+  Constructor _getNewTargetForConstructor(
+      Constructor target, Arguments arguments) {
+    if (!_isNotExternal(target)) return target;
+    if (!_hasAnyOptionalParameters(target.function)) return target;
+
+    final argumentsSignature = _createArgumentsSignature(arguments);
+    final createdConstructor = _constructorCalls.putIfAbsent(target, () => {});
+    return createdConstructor[argumentsSignature] ??
+        _createAndCacheInvocationConstructor(
+            argumentsSignature,
+            arguments.positional.length,
+            arguments.named.map((e) => e.name).toList(),
+            target,
+            _movedConstructors[target],
+            createdConstructor,
+            true);
+  }
+
+  /// Create a signature for the [Arguments].
+  ///
+  /// Assumes that any needed sorting etc has already been done.
+  ///
+  /// Looks like x%positionalCount%named --- but it shouldn't matter if always
+  /// using these methods
+  String _createArgumentsSignature(Arguments arguments) {
+    String namedString = arguments.named.map((e) => e.name).join("%");
+    return "${arguments.positional.length}%$namedString";
+  }
+
+  /// Parse the argument signature.
+  ///
+  /// First element will be the string representation of the number of
+  /// positional arguments used.
+  /// The rest will be the named arguments, except that with no named arguments
+  /// there still is a 2nd entry: the empty string...
+  List<String> _parseArgumentsSignature(String argumentsSignature) {
+    return argumentsSignature.split("%");
+  }
+
+  /// Rewrites an expression with let, replacing expressions in the [Arguments].
+  ///
+  /// Sorts the named arguments after rewriting with let.
+  ///
+  /// Note that this method does nothing if there are no named arguments, or the
+  /// named arguments list contain only a single named argument as any sorting
+  /// would have no effect. As such, the let-rewrite will also have no effect.
+  /// In such a case the return value is [original].
+  Expression _rewriteWithLetAndSort(Expression original, Arguments arguments) {
+    final named = arguments.named;
+
+    // Only bother if names can be unordered
+    if (named.length < 2) return original;
+
+    // Rewrite named with let in given order
+    Let let;
+    for (int i = named.length - 1; i >= 0; i--) {
+      VariableDeclaration letDeclaration =
+          new VariableDeclaration.forValue(named[i].value);
+      named[i].value = new VariableGet(letDeclaration)..parent = arguments;
+      let = new Let(letDeclaration, let ?? original);
+    }
+
+    // Sort named arguments by name
+    named.sort((a, b) => a.name.compareTo(b.name));
+
+    // Now also add the given positional arguments into the let
+    final expressions = arguments.positional;
+    for (int i = expressions.length - 1; i >= 0; i--) {
+      VariableDeclaration letDeclaration =
+          new VariableDeclaration.forValue(expressions[i]);
+      expressions[i] = new VariableGet(letDeclaration)..parent = arguments;
+      let = new Let(letDeclaration, let ?? original);
+    }
+
+    return let;
+  }
+
+  /// Creates all needed stubs for non static procedures.
+  ///
+  /// More specifically: If calls have been made to a procedure with the same
+  /// name as this procedure with both 1 and 2 arguments, where both of these
+  /// are legal inputs to this procedure, create stubs for both of them,
+  /// each of which calls with whatever default parameter values are defined for
+  /// the non-given arguments.
+  void _createNeededNonStaticStubs(Procedure procedure) {
+    final incomingCalls = _rewrittenMethods[procedure.name];
+    if (incomingCalls != null &&
+        procedure.kind == ProcedureKind.Method &&
+        !procedure.isStatic) {
+      final createdOnSuper = _superProcedureCalls[procedure];
+      final names =
+          procedure.function.namedParameters.map((e) => e.name).toSet();
+
+      // A procedure with this name was called on at least one object with
+      // an argument signature like any in [incomingCalls]
+      nextArgumentSignature:
+      for (final argumentsSignature in incomingCalls) {
+        // Skip if it was created in a super call already
+        if (createdOnSuper != null &&
+            createdOnSuper.containsKey(argumentsSignature)) {
+          continue;
+        }
+
+        final elements = _parseArgumentsSignature(argumentsSignature);
+        int positional = int.parse(elements[0]);
+
+        if (positional < procedure.function.requiredParameterCount ||
+            positional > procedure.function.positionalParameters.length) {
+          // We don't take that number of positional parameters!
+          // Call noSuchMethod in case anyone called on object with wrong
+          // parameters, but where superclass does take these parameters.
+          _createNoSuchMethodStub(
+              argumentsSignature, positional, elements.sublist(1), procedure);
+          continue;
+        }
+
+        if (elements.length > 2 || elements[1] != "") {
+          // Named: Could the call be for this method?
+          for (int i = 1; i < elements.length; i++) {
+            String name = elements[i];
+            // Using a name that we don't have?
+            if (!names.contains(name)) {
+              // Call noSuchMethod in case anyone called on object with wrong
+              // parameters, but where superclass does take these parameters.
+              _createNoSuchMethodStub(argumentsSignature, positional,
+                  elements.sublist(1), procedure);
+              continue nextArgumentSignature;
+            }
+          }
+        }
+
+        // Potential legal call => make stub
+        // Note the ?? here: E.g. contains on list doesn't take optionals so it
+        // wasn't moved, but calls were rewritten because contains on string
+        // takes either 1 or 2 arguments.
+        final destination = _movedBodies[procedure] ?? procedure;
+        _createAndCacheInvocationProcedure(argumentsSignature, positional,
+            elements.sublist(1), procedure, destination, {}, false);
+      }
+    }
+  }
+
+  /// Records how this procedure can be called (if it is non-static).
+  ///
+  /// More specifically: Assuming that the procedure given is non-static taking
+  /// a variable number of positional parameters, record all number of arguments
+  /// that is legal, e.g. foo(int a, [int b]) is legal for 1 and 2 parameters.
+  /// If it takes named parameters, remember how many positional there is so
+  /// we also know to rewrite calls without the named arguments.
+  void _recordNonStaticProcedureAndVariableArguments(Procedure procedure) {
+    if (_isMethod(procedure) &&
+        !procedure.isStatic &&
+        _hasAnyOptionalParameters(procedure.function)) {
+      final name = procedure.name.name;
+      final okCounts = _methodToLegalPositionalArgumentCount.putIfAbsent(
+          name, () => new Set<int>());
+      for (int i = procedure.function.requiredParameterCount;
+          i <= procedure.function.positionalParameters.length;
+          i++) {
+        okCounts.add(i);
+      }
+    }
+  }
+
+  /// Move body of procedure to new procedure and call that from this procedure.
+  ///
+  /// More specifically: For all procedures with optional positional parameters,
+  /// or named parameters, create a new procedure without optional positional
+  /// parameters and named parameters and move the body of the original
+  /// procedure into this new procedure.
+  /// Then make the body of the original procedure call the new procedure.
+  ///
+  /// The idea is that all rewrites should call the moved procedure instead,
+  /// bypassing the optional/named arguments entirely.
+  void _moveAndTransformProcedure(Procedure procedure) {
+    if (_isMethod(procedure) && _hasAnyOptionalParameters(procedure.function)) {
+      final function = procedure.function;
+
+      // Create variable lists
+      final newParameterDeclarations = <VariableDeclaration>[];
+      final newNamedParameterDeclarations = <VariableDeclaration>[];
+      final newParameterVariableGets = <Expression>[];
+      final targetParameters = function.positionalParameters;
+      final targetNamedParameters = function.namedParameters;
+      _moveVariableInitialization(
+          targetParameters,
+          targetNamedParameters,
+          newParameterDeclarations,
+          newNamedParameterDeclarations,
+          newParameterVariableGets,
+          procedure.function);
+
+      // Create new procedure looking like the old one
+      // (with the old body and parameters)
+      FunctionNode functionNode = _createShallowFunctionCopy(function);
+      final newProcedure = new Procedure(
+          _createOriginalName(procedure), ProcedureKind.Method, functionNode,
+          isAbstract: procedure.isAbstract,
+          isStatic: procedure.isStatic,
+          isConst: procedure.isConst,
+          fileUri: procedure.fileUri);
+
+      // Add procedure to the code
+      _addMember(procedure, newProcedure);
+
+      // Map moved body
+      _movedBodies[procedure] = newProcedure;
+
+      // Transform original procedure
+      if (procedure.isAbstract && procedure.function.body == null) {
+        // do basically nothing then
+        procedure.function.positionalParameters = newParameterDeclarations;
+        procedure.function.namedParameters = newNamedParameterDeclarations;
+      } else if (procedure.isStatic) {
+        final expression = new StaticInvocation(
+            newProcedure, new Arguments(newParameterVariableGets));
+        final statement = new ReturnStatement(expression)
+          ..parent = procedure.function;
+        procedure.function.body = statement;
+        procedure.function.positionalParameters = newParameterDeclarations;
+        procedure.function.namedParameters = newNamedParameterDeclarations;
+      } else {
+        final expression = new DirectMethodInvocation(new ThisExpression(),
+            newProcedure, new Arguments(newParameterVariableGets));
+        final statement = new ReturnStatement(expression)
+          ..parent = procedure.function;
+        procedure.function.body = statement;
+        procedure.function.positionalParameters = newParameterDeclarations;
+        procedure.function.namedParameters = newNamedParameterDeclarations;
+      }
+
+      if (_debug) {
+        // Debug flag set: Print something to the terminal before returning to
+        // easily detect if rewrites are missing.
+        Expression debugPrint = _getPrintExpression(
+            "DEBUG! Procedure shouldn't have been called...", procedure);
+        procedure.function.body = new Block(
+            [new ExpressionStatement(debugPrint), procedure.function.body])
+          ..parent = procedure.function;
+      }
+
+      // Mark original procedure as seen (i.e. don't transform it further)
+      _visited.add(procedure);
+    }
+  }
+
+  /// Rewrite constructor initializers by introducing variables and sorting.
+  ///
+  /// For any* [SuperInitializer] or [RedirectingInitializer], extract the
+  /// parameters, put them into variables, then sorting the named parameters.
+  /// The idea is to sort the named parameters without changing any invocation
+  /// order.
+  ///
+  /// * only with at least 2 named arguments, otherwise sorting would do nothing
+  void _rewriteConstructorInitializations(Constructor constructor) {
+    if (_isNotExternal(constructor)) {
+      // Basically copied from "super_calls.dart"
+      List<Initializer> initializers = constructor.initializers;
+      int foundIndex = -1;
+      Arguments arguments;
+      for (int i = initializers.length - 1; i >= 0; --i) {
+        Initializer initializer = initializers[i];
+        if (initializer is SuperInitializer) {
+          foundIndex = i;
+          arguments = initializer.arguments;
+          break;
+        } else if (initializer is RedirectingInitializer) {
+          foundIndex = i;
+          arguments = initializer.arguments;
+          break;
+        }
+      }
+      if (foundIndex == -1) return;
+
+      // Rewrite using variables if using named parameters (so we can sort them)
+      // (note that with 1 named it cannot be unsorted so we don't bother)
+      if (arguments.named.length < 2) return;
+
+      int argumentCount = arguments.positional.length + arguments.named.length;
+
+      // Make room for [argumentCount] [LocalInitializer]s before the
+      // super/redirector call.
+      initializers.length += argumentCount;
+      initializers.setRange(
+          foundIndex + argumentCount, // destination start (inclusive)
+          initializers.length, // destination end (exclusive)
+          initializers, // source list
+          foundIndex); // source start index
+
+      // Fill in the [argumentCount] reserved slots with the evaluation
+      // expressions of the arguments to the super/redirector constructor call
+      int storeIndex = foundIndex;
+      for (int i = 0; i < arguments.positional.length; ++i) {
+        var variable =
+            new VariableDeclaration.forValue(arguments.positional[i]);
+        arguments.positional[i] = new VariableGet(variable)..parent = arguments;
+        initializers[storeIndex++] = new LocalInitializer(variable)
+          ..parent = constructor;
+      }
+      for (int i = 0; i < arguments.named.length; ++i) {
+        NamedExpression argument = arguments.named[i];
+        var variable = new VariableDeclaration.forValue(argument.value);
+        arguments.named[i].value = new VariableGet(variable)..parent = argument;
+        initializers[storeIndex++] = new LocalInitializer(variable)
+          ..parent = constructor;
+      }
+
+      // Sort the named arguments
+      arguments.named.sort((a, b) => a.name.compareTo(b.name));
+    }
+  }
+
+  /// Move body of constructor to new one and call that from this one.
+  ///
+  /// More specifically: For all constructors with optional positional
+  /// parameters, or named parameters, create a new constructor without optional
+  /// positional parameters and named parameters, and move the body of the
+  /// original constructor into this new constructor.
+  /// Then make the original constructor redirect to the new constructor.
+  ///
+  /// The idea is that all rewrites should call the moved constructor instead,
+  /// bypassing the optional/named arguments entirely.
+  ///
+  /// This method is very similar to _moveAndTransformProcedure
+  void _moveAndTransformConstructor(Constructor constructor) {
+    if (_isNotExternal(constructor) &&
+        _hasAnyOptionalParameters(constructor.function)) {
+      final function = constructor.function;
+
+      // Create variable lists
+      final newParameterDeclarations = <VariableDeclaration>[];
+      final newNamedParameterDeclarations = <VariableDeclaration>[];
+      final newParameterVariableGets = <Expression>[];
+      final targetParameters = function.positionalParameters;
+      final targetNamedParameters = function.namedParameters;
+      _moveVariableInitialization(
+          targetParameters,
+          targetNamedParameters,
+          newParameterDeclarations,
+          newNamedParameterDeclarations,
+          newParameterVariableGets,
+          constructor.function);
+
+      // Create new constructor looking like the old one
+      // (with the old body, parameters and initializers)
+      FunctionNode functionNode = _createShallowFunctionCopy(function);
+      final newConstructor = new Constructor(functionNode,
+          name: _createOriginalName(constructor),
+          isConst: constructor.isConst,
+          isExternal: constructor.isExternal,
+          initializers: constructor.initializers);
+
+      // Add constructor to the code
+      _addMember(constructor, newConstructor);
+
+      // Map moved body
+      _movedConstructors[constructor] = newConstructor;
+
+      // Transform original constructor
+      constructor.function.body = null;
+      constructor.function.positionalParameters = newParameterDeclarations;
+      constructor.function.namedParameters = newNamedParameterDeclarations;
+      constructor.initializers = [
+        new RedirectingInitializer(
+            newConstructor, new Arguments(newParameterVariableGets))
+          ..parent = constructor
+      ];
+
+      if (_debug) {
+        // Debug flag set: Print something to the terminal before returning to
+        // easily detect if rewrites are missing.
+        Expression debugPrint = _getPrintExpression(
+            "DEBUG! Constructor shouldn't have been called...", constructor);
+        var variable = new VariableDeclaration.forValue(debugPrint);
+        final debugInitializer = new LocalInitializer(variable)
+          ..parent = constructor;
+        final redirector = constructor.initializers[0];
+        constructor.initializers = [debugInitializer, redirector];
+      }
+
+      // Mark original procedure as seen (i.e. don't transform it further)
+      _visited.add(constructor);
+    }
+  }
+
+  /// Creates a new [FunctionNode] based on the given one.
+  ///
+  /// Parameters are taken directly (i.e. after returning the parameters will
+  /// have a new parent (the returned value), but still be referenced in the
+  /// original [FunctionNode].
+  /// The same goes for the body of the function.
+  /// The caller should take steps to remedy this after this call.
+  ///
+  /// The parameters are no longer optional and named parameters have been
+  /// sorted and turned into regular parameters in the returned [FunctionNode].
+  FunctionNode _createShallowFunctionCopy(FunctionNode function) {
+    final newParameters =
+        new List<VariableDeclaration>.from(function.positionalParameters);
+    final named = new List<VariableDeclaration>.from(function.namedParameters);
+    named.sort((a, b) => a.name.compareTo(b.name));
+    newParameters.addAll(named);
+    final functionNode = new FunctionNode(function.body,
+        positionalParameters: newParameters,
+        namedParameters: [],
+        requiredParameterCount: newParameters.length,
+        returnType: function.returnType,
+        asyncMarker: function.asyncMarker);
+    return functionNode;
+  }
+
+  /// Creates new variables, moving old initializers into them
+  ///
+  /// Specifically: Given lists for output, create new variables based on
+  /// original parameters. Any new variable will receive the original variables
+  /// initializer, and the original variable will have its initializer set to
+  /// null.
+  /// Named parameters have been sorted in [newParameterVariableGets].
+  void _moveVariableInitialization(
+      List<VariableDeclaration> originalParameters,
+      List<VariableDeclaration> originalNamedParameters,
+      List<VariableDeclaration> newParameterDeclarations,
+      List<VariableDeclaration> newNamedParameterDeclarations,
+      List<Expression> newParameterVariableGets,
+      TreeNode newStuffParent) {
+    for (final orgVar in originalParameters) {
+      final variableDeclaration = new VariableDeclaration(orgVar.name,
+          initializer: orgVar.initializer,
+          type: orgVar.type,
+          isFinal: orgVar.isFinal,
+          isConst: orgVar.isConst)..parent = newStuffParent;
+      variableDeclaration.initializer?.parent = variableDeclaration;
+      newParameterDeclarations.add(variableDeclaration);
+      orgVar.initializer = null;
+      newParameterVariableGets.add(new VariableGet(variableDeclaration));
+    }
+
+    // Named expressions in newParameterVariableGets should be sorted
+    final tmp = new List<_Pair<String, Expression>>();
+    for (final orgVar in originalNamedParameters) {
+      final variableDeclaration = new VariableDeclaration(orgVar.name,
+          initializer: orgVar.initializer,
+          type: orgVar.type,
+          isFinal: orgVar.isFinal,
+          isConst: orgVar.isConst)..parent = newStuffParent;
+      variableDeclaration.initializer?.parent = variableDeclaration;
+      newNamedParameterDeclarations.add(variableDeclaration);
+      orgVar.initializer = null;
+      tmp.add(new _Pair(orgVar.name, new VariableGet(variableDeclaration)));
+    }
+    tmp.sort((a, b) => a.key.compareTo(b.key));
+    for (final item in tmp) {
+      newParameterVariableGets.add(item.value);
+    }
+  }
+
+  /// Creates a stub redirecting to noSuchMethod.
+  ///
+  /// Needed because if B extends A, both have a foo method, but taking
+  /// different optional parameters, a call on an instance of B with parameters
+  /// for A should actually result in a noSuchMethod call, but if only A has
+  /// the rewritten method name, that method will be called...
+  /// TODO: We only have to create these stubs for arguments that a procedures
+  /// super allows, otherwise it will become a noSuchMethod automatically!
+  Procedure _createNoSuchMethodStub(
+      String argumentsSignature,
+      int positionalCount,
+      List<String> givenNamedParameters,
+      Procedure existing) {
+    // Build parameter lists
+    final newParameterDeclarations = <VariableDeclaration>[];
+    final newParameterVariableGets = <Expression>[];
+    for (int i = 0; i < positionalCount + givenNamedParameters.length; i++) {
+      final variableDeclaration = new VariableDeclaration("v%$i");
+      newParameterDeclarations.add(variableDeclaration);
+      newParameterVariableGets.add(new VariableGet(variableDeclaration));
+    }
+
+    var procedureName = _createName(existing.name, argumentsSignature);
+
+    // Find noSuchMethod to call
+    Member noSuchMethod = hierarchy.getDispatchTarget(
+        existing.enclosingClass, new Name("noSuchMethod"));
+    Arguments argumentsToNoSuchMethod;
+
+    if (noSuchMethod.function.positionalParameters.length == 1 &&
+        noSuchMethod.function.namedParameters.isEmpty) {
+      // We have a correct noSuchMethod method.
+      ConstructorInvocation invocation = _createInvocation(
+          procedureName.name, new Arguments(newParameterVariableGets));
+      argumentsToNoSuchMethod = new Arguments([invocation]);
+    } else {
+      // Get noSuchMethod on Object then...
+      noSuchMethod = hierarchy.getDispatchTarget(
+          hierarchy.rootClass, new Name("noSuchMethod"));
+      ConstructorInvocation invocation = _createInvocation(
+          procedureName.name, new Arguments(newParameterVariableGets));
+      ConstructorInvocation invocationPrime =
+          _createInvocation("noSuchMethod", new Arguments([invocation]));
+      argumentsToNoSuchMethod = new Arguments([invocationPrime]);
+    }
+
+    // Create return statement to call noSuchMethod
+    ReturnStatement statement;
+    final expression = new DirectMethodInvocation(
+        new ThisExpression(), noSuchMethod, argumentsToNoSuchMethod);
+    statement = new ReturnStatement(expression);
+
+    // Build procedure
+    final functionNode = new FunctionNode(statement,
+        positionalParameters: newParameterDeclarations,
+        namedParameters: [],
+        requiredParameterCount: newParameterDeclarations.length,
+        returnType: existing.function.returnType,
+        asyncMarker: existing.function.asyncMarker);
+    final procedure = new Procedure(
+        procedureName, ProcedureKind.Method, functionNode,
+        isStatic: existing.isStatic, fileUri: existing.fileUri);
+
+    // Add procedure to the code
+    _addMember(existing, procedure);
+
+    // Mark the new procedure as visited already (i.e. don't rewrite it again!)
+    _visited.add(procedure);
+
+    return procedure;
+  }
+
+  /// Creates an "new _InvocationMirror(...)" invocation.
+  ConstructorInvocation _createInvocation(
+      String methodName, Arguments callArguments) {
+    if (_invocationMirrorConstructor == null) {
+      Class clazz = coreTypes.getCoreClass('dart:core', '_InvocationMirror');
+      _invocationMirrorConstructor = clazz.constructors[0];
+    }
+
+    // The _InvocationMirror constructor takes the following arguments:
+    // * Method name (a string).
+    // * An arguments descriptor - a list consisting of:
+    //   - number of arguments (including receiver).
+    //   - number of positional arguments (including receiver).
+    //   - pairs (2 entries in the list) of
+    //     * named arguments name.
+    //     * index of named argument in arguments list.
+    // * A list of arguments, where the first ones are the positional arguments.
+    // * Whether it's a super invocation or not.
+
+    int numPositionalArguments = callArguments.positional.length + 1;
+    int numArguments = numPositionalArguments + callArguments.named.length;
+    List<Expression> argumentsDescriptor = [
+      new IntLiteral(numArguments),
+      new IntLiteral(numPositionalArguments)
+    ];
+    List<Expression> arguments = [];
+    arguments.add(new ThisExpression());
+    for (Expression pos in callArguments.positional) {
+      arguments.add(pos);
+    }
+    for (NamedExpression named in callArguments.named) {
+      argumentsDescriptor.add(new StringLiteral(named.name));
+      argumentsDescriptor.add(new IntLiteral(arguments.length));
+      arguments.add(named.value);
+    }
+
+    return new ConstructorInvocation(
+        _invocationMirrorConstructor,
+        new Arguments([
+          new StringLiteral(methodName),
+          _fixedLengthList(argumentsDescriptor),
+          _fixedLengthList(arguments),
+          new BoolLiteral(false)
+        ]));
+  }
+
+  /// Create a fixed length list containing given expressions.
+  Expression _fixedLengthList(List<Expression> list) {
+    if (_listFrom == null) {
+      Class clazz = coreTypes.getCoreClass('dart:core', 'List');
+      _listFrom = clazz.procedures.firstWhere((c) => c.name.name == "from");
+    }
+    return new StaticInvocation(
+        _listFrom,
+        new Arguments([new ListLiteral(list)],
+            named: [new NamedExpression("growable", new BoolLiteral(false))],
+            types: [const DynamicType()]));
+  }
+
+  /// Creates a new procedure taking given arguments, caching it.
+  ///
+  /// Copies any non-given default values for parameters into the new procedure
+  /// to be able to call the [realTarget] without using optionals and named
+  /// parameters.
+  Procedure _createAndCacheInvocationProcedure(
+      String argumentsSignature,
+      int positionalCount,
+      List<String> givenNamedParameters,
+      Procedure target,
+      Procedure realTarget,
+      Map<String, Procedure> createdProcedures,
+      bool doSpecialCaseForAllParameters) {
+    // Special case: Calling with all parameters
+    if (doSpecialCaseForAllParameters &&
+        positionalCount == target.function.positionalParameters.length &&
+        givenNamedParameters.length == target.function.namedParameters.length) {
+      // We don't cache this procedure as this could make it look like
+      // something with name argumentsSignature actually exists
+      // while it doesn't (which is bad as we could then decide that we don't
+      // need to create a stub even though we do!)
+      return realTarget;
+    }
+
+    // Create and cache (save) constructor
+
+    // Build parameter lists
+    final newParameterDeclarations = <VariableDeclaration>[];
+    final newParameterVariableGets = <Expression>[];
+    _extractAndCreateParameters(positionalCount, newParameterDeclarations,
+        newParameterVariableGets, target, givenNamedParameters);
+
+    // Create return statement to call real target
+    ReturnStatement statement;
+    if (target.isAbstract && target.function?.body == null) {
+      // statement should just be null then
+    } else if (target.isStatic) {
+      final expression = new StaticInvocation(
+          realTarget, new Arguments(newParameterVariableGets));
+      statement = new ReturnStatement(expression);
+    } else {
+      final expression = new DirectMethodInvocation(new ThisExpression(),
+          realTarget, new Arguments(newParameterVariableGets));
+      statement = new ReturnStatement(expression);
+    }
+
+    // Build procedure
+    final functionNode = new FunctionNode(statement,
+        positionalParameters: newParameterDeclarations,
+        namedParameters: [],
+        requiredParameterCount: newParameterDeclarations.length,
+        returnType: target.function.returnType,
+        asyncMarker: target.function.asyncMarker);
+    final procedure = new Procedure(
+        _createName(target.name, argumentsSignature),
+        ProcedureKind.Method,
+        functionNode,
+        isAbstract: target.isAbstract,
+        isStatic: target.isStatic,
+        isConst: target.isConst,
+        fileUri: target.fileUri);
+
+    // Add procedure to the code
+    _addMember(target, procedure);
+
+    // Cache it for future reference
+    createdProcedures[argumentsSignature] = procedure;
+
+    // Mark the new procedure as visited already (i.e. don't rewrite it again!)
+    _visited.add(procedure);
+
+    return procedure;
+  }
+
+  /// Creates a new constructor taking given arguments, caching it.
+  ///
+  /// Copies any non-given default values for parameters into the new
+  /// constructor to be able to call the [realTarget] without using optionals
+  /// and named parameters.
+  Constructor _createAndCacheInvocationConstructor(
+      String argumentsSignature,
+      int positionalCount,
+      List<String> givenNamedParameters,
+      Constructor target,
+      Constructor realTarget,
+      Map<String, Constructor> createdConstructor,
+      bool doSpecialCaseForAllParameters) {
+    // Special case: Calling with all parameters
+    if (doSpecialCaseForAllParameters &&
+        positionalCount == target.function.positionalParameters.length &&
+        givenNamedParameters.length == target.function.namedParameters.length) {
+      createdConstructor[argumentsSignature] = realTarget;
+      return realTarget;
+    }
+
+    // Create and cache (save) constructor
+
+    // Build parameter lists
+    final newParameterDeclarations = <VariableDeclaration>[];
+    final newParameterVariableGets = <Expression>[];
+    _extractAndCreateParameters(positionalCount, newParameterDeclarations,
+        newParameterVariableGets, target, givenNamedParameters);
+
+    // Build constructor
+    final functionNode = new FunctionNode(null,
+        positionalParameters: newParameterDeclarations,
+        namedParameters: [],
+        requiredParameterCount: newParameterDeclarations.length,
+        returnType: target.function.returnType,
+        asyncMarker: target.function.asyncMarker);
+    final constructor = new Constructor(functionNode,
+        name: _createName(target.name, argumentsSignature),
+        isConst: target.isConst,
+        isExternal: target.isExternal,
+        initializers: [
+          new RedirectingInitializer(
+              realTarget, new Arguments(newParameterVariableGets))
+        ]);
+
+    // Add procedure to the code
+    _addMember(target, constructor);
+
+    // Cache it for future reference
+    createdConstructor[argumentsSignature] = constructor;
+
+    // Mark the new procedure as visited already (i.e. don't rewrite it again!)
+    _visited.add(constructor);
+
+    return constructor;
+  }
+
+  /// Extracts and creates parameters into the first two given lists.
+  ///
+  /// What is done:
+  /// Step 1: Re-create the parameters given (i.e. the non-optional positional
+  /// ones) - i.e. create a new variable with the same name etc, put it in
+  /// [newParameterDeclarations]; create VariableGet for that and put it in
+  /// [newParameterVariableGets]
+  /// Step 2: Re-create the positional parameters NOT given, i.e. insert
+  /// defaults and add to [newParameterVariableGets] only.
+  /// Step 3: Re-create the named arguments (in sorted order). For actually
+  /// given named parameters, do as in step 1, for not-given named parameters
+  /// do as in step 2.
+  ///
+  /// NOTE: [newParameterDeclarations] and [newParameterVariableGets] are OUTPUT
+  /// lists.
+  void _extractAndCreateParameters(
+      int positionalCount,
+      List<VariableDeclaration> newParameterDeclarations,
+      List<Expression> newParameterVariableGets,
+      Member target,
+      List<String> givenNamedParameters) {
+    // First re-create the parameters given (i.e. the non-optional positional ones)
+    final targetParameters = target.function.positionalParameters;
+    positionalCount = math.min(positionalCount, targetParameters.length);
+    for (int i = 0; i < positionalCount; i++) {
+      final orgVar = targetParameters[i];
+      final variableDeclaration = new VariableDeclaration(orgVar.name,
+          type: orgVar.type, isFinal: orgVar.isFinal, isConst: orgVar.isConst);
+      newParameterDeclarations.add(variableDeclaration);
+      newParameterVariableGets.add(new VariableGet(variableDeclaration));
+    }
+
+    // Default parameters for the rest of them
+    _fillInPositionalParameters(
+        positionalCount, target, newParameterVariableGets);
+
+    // Then all named parameters (given here or not)
+    final orgNamed =
+        new List<VariableDeclaration>.from(target.function.namedParameters);
+    orgNamed.sort((a, b) => a.name.compareTo(b.name));
+    final givenArgumentsIterator = givenNamedParameters.iterator;
+    givenArgumentsIterator.moveNext();
+    for (VariableDeclaration named in orgNamed) {
+      if (givenArgumentsIterator.current == named.name) {
+        // We have that one: Use it and move the iterator
+        final variableDeclaration = new VariableDeclaration(named.name);
+        newParameterDeclarations.add(variableDeclaration);
+        newParameterVariableGets.add(new VariableGet(variableDeclaration));
+        givenArgumentsIterator.moveNext();
+      } else {
+        // We don't have that one: Fill it in
+        _fillInSingleParameter(named, newParameterVariableGets, target);
+      }
+    }
+  }
+
+  /// Adds the new member the same place as the existing member
+  void _addMember(Member existingMember, Member newMember) {
+    if (existingMember.enclosingClass != null) {
+      existingMember.enclosingClass.addMember(newMember);
+    } else {
+      existingMember.enclosingLibrary.addMember(newMember);
+    }
+  }
+
+  /// Create expressions based on the default values from the given [Member].
+  ///
+  /// More specifically: static gets and nulls will be "copied" whereas other
+  /// things (e.g. literals or things like "a+b") will be moved from the
+  /// original member as argument initializers to const fields and both the
+  /// original member and the expression-copy will use static gets to these.
+  void _fillInPositionalParameters(
+      int startFrom, Member copyFrom, List<Expression> fillInto) {
+    final targetParameters = copyFrom.function.positionalParameters;
+    for (int i = startFrom; i < targetParameters.length; i++) {
+      final parameter = targetParameters[i];
+      _fillInSingleParameter(parameter, fillInto, copyFrom);
+    }
+  }
+
+  /// Create expression based on the default values from the given variable.
+  ///
+  /// More specifically: a static get or null will be "copied" whereas other
+  /// things (e.g. literals or things like "a+b") will be moved from the
+  /// original member as an argument initializer to a const field and both the
+  /// original member and the expression-copy will use a static get to it.
+  void _fillInSingleParameter(VariableDeclaration parameter,
+      List<Expression> fillInto, Member copyFrom) {
+    if (parameter.initializer is StaticGet) {
+      // Reference to const => recreate it
+      StaticGet staticGet = parameter.initializer;
+      fillInto.add(new StaticGet(staticGet.target));
+    } else if (parameter.initializer == null) {
+      // No default given => output null
+      fillInto.add(new NullLiteral());
+    } else if (parameter.initializer is IntLiteral) {
+      // Int literal => recreate (or else class ByteBuffer in typed_data will
+      // get 2 fields and the C++ code will complain!)
+      IntLiteral value = parameter.initializer;
+      fillInto.add(new IntLiteral(value.value));
+    } else {
+      // Advanced stuff => move to static const field and reference that
+      final initializer = parameter.initializer;
+      final f = new Field(
+          new Name('${copyFrom.name.name}%_${parameter.name}',
+              copyFrom.enclosingLibrary),
+          type: parameter.type,
+          initializer: initializer,
+          isFinal: false,
+          isConst: true,
+          isStatic: true,
+          fileUri: copyFrom.enclosingClass?.fileUri ??
+              copyFrom.enclosingLibrary.fileUri);
+      initializer.parent = f;
+
+      // Add field to the code
+      if (copyFrom.enclosingClass != null) {
+        copyFrom.enclosingClass.addMember(f);
+      } else {
+        copyFrom.enclosingLibrary.addMember(f);
+      }
+
+      // Use it at the call site
+      fillInto.add(new StaticGet(f));
+
+      // Now replace the initializer in the method to a StaticGet
+      parameter.initializer = new StaticGet(f)..parent = parameter;
+    }
+  }
+
+  /// Create an "original name" for a member.
+  ///
+  /// Specifically, for a member "x" just returns "x%original";
+  Name _createOriginalName(Member member) {
+    return new Name("${member.name.name}%original", member.enclosingLibrary);
+  }
+
+  /// Create a [Name] based on current name and argument signature.
+  Name _createName(Name name, String argumentsSignature) {
+    String nameString = '${name.name}%$argumentsSignature';
+    return new Name(nameString, name.library);
+  }
+
+  /// Is the procedure a method?
+  bool _isMethod(Procedure procedure) => procedure.kind == ProcedureKind.Method;
+
+  /// Is the procedure NOT marked as external?
+  bool _isNotExternal(Constructor constructor) => !constructor.isExternal;
+
+  /// Does the target function have any optional arguments? (positional/named)
+  bool _hasAnyOptionalParameters(FunctionNode targetFunction) =>
+      _hasOptionalParameters(targetFunction) ||
+      _hasNamedParameters(targetFunction);
+
+  /// Does the target function have optional positional arguments?
+  bool _hasOptionalParameters(FunctionNode targetFunction) =>
+      targetFunction.positionalParameters.length >
+      targetFunction.requiredParameterCount;
+
+  /// Does the target function have named parameters?
+  bool _hasNamedParameters(FunctionNode targetFunction) =>
+      targetFunction.namedParameters.isNotEmpty;
+
+  bool _callIsLegal(FunctionNode targetFunction, Arguments arguments) {
+    if ((targetFunction.requiredParameterCount > arguments.positional.length) ||
+        (targetFunction.positionalParameters.length <
+            arguments.positional.length)) {
+      // Given too few or too many positional arguments
+      return false;
+    }
+
+    // Do we give named that we don't take?
+    Set<String> givenNamed = arguments.named.map((v) => v.name).toSet();
+    Set<String> takenNamed =
+        targetFunction.namedParameters.map((v) => v.name).toSet();
+    givenNamed.removeAll(takenNamed);
+    return givenNamed.isEmpty;
+  }
+
+  // Below methods used to add debug prints etc
+
+  Library _getDartCoreLibrary(Program program) {
+    if (program == null) return null;
+    return program.libraries.firstWhere((lib) =>
+        lib.importUri.scheme == 'dart' && lib.importUri.path == 'core');
+  }
+
+  Procedure _getProcedureInLib(Library lib, String name) {
+    if (lib == null) return null;
+    return lib.procedures
+        .firstWhere((procedure) => procedure.name.name == name);
+  }
+
+  Procedure _getProcedureInClassInLib(
+      Library lib, String className, String procedureName) {
+    if (lib == null) return null;
+    Class clazz = lib.classes.firstWhere((clazz) => clazz.name == className);
+    return clazz.procedures
+        .firstWhere((procedure) => procedure.name.name == procedureName);
+  }
+
+  Expression _getPrintExpression(String msg, TreeNode treeNode) {
+    TreeNode program = treeNode;
+    while (program is! Program) program = program.parent;
+    var finalMsg = msg;
+    if (treeNode is Member) {
+      finalMsg += " [ ${treeNode.name.name} ]";
+      if (treeNode.enclosingClass != null) {
+        finalMsg += " [ class ${treeNode.enclosingClass.name} ]";
+      }
+      if (treeNode.enclosingLibrary != null) {
+        finalMsg += " [ lib ${treeNode.enclosingLibrary.name} ]";
+      }
+    }
+
+    var stacktrace = new StaticGet(_getProcedureInClassInLib(
+        _getDartCoreLibrary(program), 'StackTrace', 'current'));
+    var printStackTrace = new StaticInvocation(
+        _getProcedureInLib(_getDartCoreLibrary(program), 'print'),
+        new Arguments([
+          new StringConcatenation([
+            new StringLiteral(finalMsg),
+            new StringLiteral("\n"),
+            stacktrace,
+            new StringLiteral("\n")
+          ])
+        ]));
+
+    return printStackTrace;
+  }
+}
+
+class _Pair<K, V> {
+  K key;
+  V value;

[kustermann, 2017/02/14 15:21:23]

final

[jensj, 2017/02/15 11:46:21]

Done.

+
+  _Pair(this.key, this.value);
+}