Cleanup VM error handling.

runtime/lib/error.dart

Index: runtime/lib/error.dart
diff --git a/runtime/lib/error.dart b/runtime/lib/error.dart
index acac03599089dc549bbbef96e8f2fa8c8ea49ca4..dc50c4cb26626e713c2135cba046f24fbfe3d3c0 100644
--- a/runtime/lib/error.dart
+++ b/runtime/lib/error.dart
@@ -4,13 +4,13 @@
 // Errors are created and thrown by DartVM only.
 // Changes here should also be reflected in corelib/error.dart as well
 
-class AssertionErrorImplementation extends AssertionError {
-  factory AssertionErrorImplementation._uninstantiable() {
-    throw new UnsupportedError(
-        "AssertionError can only be allocated by the VM");
-  }
+class _AssertionErrorImplementation extends AssertionError {
+  _AssertionErrorImplementation(
+    this.failedAssertion, this.url, this.line, this.column);
+
   static _throwNew(int assertionStart, int assertionEnd)
       native "AssertionError_throwNew";
+
   String toString() {
     return "'$url': Failed assertion: line $line pos $column: "
         "'$failedAssertion' is not true.";
@@ -21,21 +21,24 @@ class AssertionErrorImplementation extends AssertionError {
   final int column;
 }
 
-class TypeErrorImplementation
-    extends AssertionErrorImplementation
+class _TypeErrorImplementation
+    extends _AssertionErrorImplementation
     implements TypeError {
-  factory TypeErrorImplementation._uninstantiable() {
-    throw new UnsupportedError(
-        "TypeError can only be allocated by the VM");
-  }
+
+  _TypeErrorImplementation(
+    String failedAssertion, String url, int line, int column,
+    this.srcType, this.dstType, this.dstName, this._malformedError)
+      : super(failedAssertion, url, line, column);
+
   static _throwNew(int location,
                    Object src_value,
                    String dst_type_name,
                    String dst_name,
                    String malformed_error)
       native "TypeError_throwNew";
+
   String toString() {
-    String str = (malformedError != null) ? malformedError : "";
+    String str = (_malformedError != null) ? _malformedError : "";
     if ((dstName != null) && (dstName.length > 0)) {
       str = "${str}type '$srcType' is not a subtype of "
             "type '$dstType' of '$dstName'.";
@@ -44,23 +47,27 @@ class TypeErrorImplementation
     }
     return str;
   }
+
   final String srcType;
   final String dstType;
   final String dstName;
-  final String malformedError;
+  final String _malformedError;
 }
 
-class CastErrorImplementation
-    extends TypeErrorImplementation
+class _CastErrorImplementation
+    extends _TypeErrorImplementation
     implements CastError {
-  factory CastErrorImplementation._uninstantiable() {
-    throw new UnsupportedError(
-        "CastError can only be allocated by the VM");
-  }
+
+  _CastErrorImplementation(
+    String failedAssertion, String url, int line, int column,
+    String srcType, String dstType, String dstName, String malformedError)
+      : super(failedAssertion, url, line, column,
+              srcType, dstType, dstName, malformedError);
+
   // A CastError is allocated by TypeError._throwNew() when dst_name equals
   // Exceptions::kCastErrorDstName.
   String toString() {
-    String str = (malformedError != null) ? malformedError : "";
+    String str = (_malformedError != null) ? _malformedError : "";
     if ((dstName != null) && (dstName.length > 0)) {
       str = "${str}type '$srcType' is not a subtype of "
             "type '$dstType' in type cast.";
@@ -71,43 +78,42 @@ class CastErrorImplementation
   }
 }
 
-class FallThroughErrorImplementation extends FallThroughError {
-  factory FallThroughErrorImplementation._uninstantiable() {
-    throw new UnsupportedError(
-        "FallThroughError can only be allocated by the VM");
-  }
+class _FallThroughErrorImplementation extends FallThroughError {
+
+  _FallThroughErrorImplementation(this._url, this._line);
+
   static _throwNew(int case_clause_pos) native "FallThroughError_throwNew";
+
   String toString() {
-    return "'$url': Switch case fall-through at line $line.";
+    return "'$_url': Switch case fall-through at line $_line.";
   }
-  final String url;
-  final int line;
+
+  final String _url;
+  final int _line;
 }
 
-class InternalError {
-  const InternalError(this._msg);
+class _InternalError {
+  const _InternalError(this._msg);
   String toString() => "InternalError: '${_msg}'";
   final String _msg;
 }
 
 
-class AbstractClassInstantiationErrorImplementation
+class _AbstractClassInstantiationErrorImplementation
     extends AbstractClassInstantiationError {
 
-  factory AbstractClassInstantiationErrorImplementation._uninstantiable() {
-    throw new UnsupportedError(
-        "AbstractClassInstantiationError can only be allocated by the VM");
-  }
+  _AbstractClassInstantiationErrorImplementation(
+      String className, this._url, this._line)
+      : super(className);
 
   static _throwNew(int case_clause_pos, String className)
       native "AbstractClassInstantiationError_throwNew";
 
   String toString() {
-    return "Cannot instantiate abstract class $className: "
-           "url '$url' line $line";
+    return "Cannot instantiate abstract class $_className: "
+           "_url '$_url' line $_line";
   }
 
-  final String className;
-  final String url;
-  final int line;
+  final String _url;
+  final int _line;
 }