Fix bug 557: Disallow user side allocation of ImmutableArray. Also added "instantiation-checks" f...

runtime/lib/integers.dart

Index: runtime/lib/integers.dart
===================================================================
--- runtime/lib/integers.dart	(revision 1806)
+++ runtime/lib/integers.dart	(working copy)
@@ -5,6 +5,10 @@
 // TODO(srdjan): fix limitations.
 // - shift amount must be a Smi.
 class IntegerImplementation {
+  factory IntegerImplementation._uninstantiable() {
+    throw const UnsupportedOperationException(
+        "IntegerImplementation can only be allocated by the VM");
+  }
   num operator +(num other) {
     return other.addFromInteger(this);
   }
@@ -156,6 +160,10 @@
 }
 
 class Smi extends IntegerImplementation implements int {
+  factory Smi._uninstantiable() {
+    throw const UnsupportedOperationException(
+        "Smi can only be allocated by the VM");
+  }
   int hashCode() {
     return this;
   }
@@ -166,6 +174,10 @@
 
 // Represents integers that cannot be represented by Smi but fit into 64bits.
 class Mint extends IntegerImplementation implements int {
+  factory Mint._uninstantiable() {
+    throw const UnsupportedOperationException(
+        "Mint can only be allocated by the VM");
+  }
   int hashCode() {
     return this;
   }
@@ -175,6 +187,10 @@
 // A number that can be represented as Smi or Mint will never be represented as
 // Bigint.
 class Bigint extends IntegerImplementation implements int {
+  factory Bigint._uninstantiable() {
+    throw const UnsupportedOperationException(
+        "Bigint can only be allocated by the VM");
+  }
   int hashCode() {
     return this;
   }