Separate HTypeConversion checked type from output type.

sdk/lib/_internal/compiler/implementation/ssa/nodes.dart

Index: sdk/lib/_internal/compiler/implementation/ssa/nodes.dart
diff --git a/sdk/lib/_internal/compiler/implementation/ssa/nodes.dart b/sdk/lib/_internal/compiler/implementation/ssa/nodes.dart
index e05bc81cbdfaebb52ecd4a9f209229a282ddab97..16d628ffd030bf3add9499b03c1167c16516e200 100644
--- a/sdk/lib/_internal/compiler/implementation/ssa/nodes.dart
+++ b/sdk/lib/_internal/compiler/implementation/ssa/nodes.dart
@@ -2327,6 +2327,7 @@ class HTypeConversion extends HCheck {
   final int kind;
   final Selector receiverTypeCheckSelector;
   final bool contextIsTypeArguments;
+  HType checkedType;  // Not final because we refine it.
 
   static const int CHECKED_MODE_CHECK = 0;
   static const int ARGUMENT_TYPE_CHECK = 1;
@@ -2338,6 +2339,7 @@ class HTypeConversion extends HCheck {
                   HType type, HInstruction input,
                   [this.receiverTypeCheckSelector])
       : contextIsTypeArguments = false,
+        checkedType = type,
         super(<HInstruction>[input]) {
     assert(!isReceiverTypeCheck || receiverTypeCheckSelector != null);
     assert(typeExpression == null ||
@@ -2350,6 +2352,7 @@ class HTypeConversion extends HCheck {
                                          HType type, HInstruction input,
                                          HInstruction typeRepresentation)
       : contextIsTypeArguments = false,
+        checkedType = type,
         super(<HInstruction>[input, typeRepresentation]),
         receiverTypeCheckSelector = null {
     assert(typeExpression.kind != TypeKind.TYPEDEF);
@@ -2362,6 +2365,7 @@ class HTypeConversion extends HCheck {
                               HInstruction context,
                               {bool this.contextIsTypeArguments})
       : super(<HInstruction>[input, context]),
+        checkedType = type,
         receiverTypeCheckSelector = null {
     assert(typeExpression.kind != TypeKind.TYPEDEF);
     sourceElement = input.sourceElement;
@@ -2404,7 +2408,7 @@ class HTypeConversion extends HCheck {
   bool dataEquals(HTypeConversion other) {
     return kind == other.kind
         && typeExpression == other.typeExpression
-        && instructionType == other.instructionType;
+        && checkedType == other.checkedType;
   }
 }