Reapply "Refactor type propagation."

lib/compiler/implementation/ssa/tracer.dart

 // Copyright (c) 2011, 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('tracer');
 
 #import('dart:io');
 #import('ssa.dart');
 #import('../leg.dart');
 
@@ skipping 147 matching lines @@
   HInstructionStringifier(this.currentBlock);
 
   visit(HInstruction node) => node.accept(this);
 
   visitBasicBlock(HBasicBlock node) {
     unreachable();
   }
 
   String temporaryId(HInstruction instruction) {
     String prefix;
-    switch (instruction.type) {
+    HType type = instruction.propagatedType;
+    switch (type) {
       case HType.MUTABLE_ARRAY: prefix = 'a'; break;
       case HType.READABLE_ARRAY: prefix = 'roa'; break;
       case HType.BOOLEAN: prefix = 'b'; break;
       case HType.INTEGER: prefix = 'i'; break;
       case HType.DOUBLE: prefix = 'd'; break;
       case HType.NUMBER: prefix = 'n'; break;
       case HType.STRING: prefix = 's'; break;
       case HType.UNKNOWN: prefix = 'v'; break;
       case HType.CONFLICTING: prefix = 'c'; break;
       case HType.STRING_OR_ARRAY: prefix = 'sa'; break;
@@ skipping 216 matching lines @@
       finallyBlock = 'B${node.finallyBlock.id}';
     } else {
       catchBlocks.add('B${successors[successors.length - 1].id}');
       finallyBlock = 'none';
     }
     return "Try: $tryBlock, Catch: $catchBlocks, Finally: $finallyBlock";
   }
 
   String visitTypeGuard(HTypeGuard node) {
     String type;
-    switch (node.type) {
+    switch (node.propagatedType) {
       case HType.MUTABLE_ARRAY: type = "mutable_array"; break;
       case HType.READABLE_ARRAY: type = "readable_array"; break;
       case HType.BOOLEAN: type = "bool"; break;
       case HType.INTEGER: type = "integer"; break;
       case HType.DOUBLE: type = "double"; break;
       case HType.NUMBER: type = "number"; break;
       case HType.STRING: type = "string"; break;
       case HType.STRING_OR_ARRAY: type = "string_or_array"; break;
       case HType.UNKNOWN: type = 'unknown'; break;
       default: unreachable();
     }
     return "TypeGuard: ${temporaryId(node.inputs[0])} is $type";
   }
 
   String visitIs(HIs node) {
     String type = node.typeExpression.toString();
     return "TypeTest: ${temporaryId(node.expression)} is $type";
   }
 }