typeInformation in CreateInstance is a kind of TypeExpression

pkg/compiler/lib/src/tree_ir/optimization/statement_rewriter.dart

 // Copyright (c) 2014, 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 tree_ir.optimization.statement_rewriter;
 
 import 'optimization.dart' show Pass;
 import '../tree_ir_nodes.dart';
 import '../../io/source_information.dart';
 import '../../elements/elements.dart';
@@ skipping 235 matching lines @@
   Constant getRightHandConstant(Expression e) {
     Expression value = getValueSubexpression(e);
     return value is Constant ? value : null;
   }
 
   /// True if the given expression (taken from [constantEnvironment]) uses a
   /// variable that might have been reassigned since [node] was evaluated.
   bool hasUnsafeVariableUse(Expression node) {
     bool wasFound = false;
     VariableUseVisitor.visit(node, (VariableUse use) {
+        if (dominatingAssignments[use.variable] == null) {
+          print('${use}   ${use.variable}   ${dominatingAssignments}');
+        }

[asgerf, 2016/01/26 10:30:00]

Debug code.

I'm guessing the this was related to the missing traversal of typeInformation on
CreateInstance?

[sra1, 2016/01/26 22:21:08]

Removed.  Yes, you guessed right.

       if (dominatingAssignments[use.variable] > 1) {
         wasFound = true;
       }
     });
     return wasFound;
   }
 
   void pushDominatingAssignment(Variable variable) {
     if (variable != null) {
       dominatingAssignments.putIfAbsent(variable, () => 0);
@@ skipping 99 matching lines @@
   /// any given activation of the enclosing method.
   bool isEffectivelyConstant(Expression exp) {
     // TODO(asgerf): Can be made more aggressive e.g. by checking conditional
     // expressions recursively. Determine if that is a valuable optimization
     // and/or if it is better handled at the CPS level.
     return exp is Constant ||
            exp is This ||
            exp is CreateInvocationMirror ||
            exp is CreateInstance ||
            exp is CreateBox ||
+           exp is TypeExpression ||
            exp is GetStatic && exp.element.isFunction ||
            exp is Interceptor ||
            exp is ApplyBuiltinOperator ||
            exp is VariableUse && constantEnvironment.containsKey(exp.variable);
   }
 
   /// True if [node] is an assignment that can be propagated as a constant.
   bool isEffectivelyConstantAssignment(Expression node) {
     return node is Assign &&
            node.variable.writeCount == 1 &&
@@ skipping 431 matching lines @@
     node.object = visitExpression(node.object);
     return node;
   }
 
   Expression visitCreateBox(CreateBox node) {
     return node;
   }
 
   Expression visitCreateInstance(CreateInstance node) {
     _rewriteList(node.arguments);
+    if (node.typeInformation != null) {
+      node.typeInformation = visitExpression(node.typeInformation);
+    }

[asgerf, 2016/01/26 10:30:01]

In this pass traversal of expressions is right-to-left, so move this above the
traversal of arguments.

Thanks for fixing it btw, the missing traversal was a bug.

[sra1, 2016/01/26 22:21:08]

Done.

Interestingly, it makes no difference, perhaps because the whole type expression
tree is effectivelyConstant.

     return node;
   }
 
   Expression visitReifyRuntimeType(ReifyRuntimeType node) {
     node.value = visitExpression(node.value);
     return node;
   }
 
   Expression visitReadTypeVariable(ReadTypeVariable node) {
     node.target = visitExpression(node.target);
@@ skipping 541 matching lines @@
 }
 
 /// Decrement the reference count for [e] if it is a variable use.
 void destroyPrimaryExpression(Expression e) {
   if (e is VariableUse) {
     --e.variable.readCount;
   } else {
     assert(e is This);
   }
 }