Remove redundant verbiage on inference failure errors.

pkg/analyzer/lib/src/task/strong/info.dart

Index: pkg/analyzer/lib/src/task/strong/info.dart
diff --git a/pkg/analyzer/lib/src/task/strong/info.dart b/pkg/analyzer/lib/src/task/strong/info.dart
index 82954395b981c280bf19aa23b365d4ea816a45c9..c3a58396d83da95d1cac5966860aa57397a84129 100644
--- a/pkg/analyzer/lib/src/task/strong/info.dart
+++ b/pkg/analyzer/lib/src/task/strong/info.dart
@@ -107,8 +107,7 @@ abstract class DownCast extends CoercionInfo {
 
   // Factory to create correct DownCast variant.
   static StaticInfo create(
-      StrongTypeSystemImpl rules, Expression expression, Cast cast,
-      {String reason}) {
+      StrongTypeSystemImpl rules, Expression expression, Cast cast) {
     final fromT = cast.fromType;
     final toT = cast.toType;
 
@@ -127,14 +126,15 @@ abstract class DownCast extends CoercionInfo {
     if (expression is Literal || expression is FunctionExpression) {
       // fromT should be an exact type - this will almost certainly fail at
       // runtime.
-      return new StaticTypeError(rules, expression, toT, reason: reason);
+      return new StaticTypeError(rules, expression, toT);
     }
+
     if (expression is InstanceCreationExpression) {
       ConstructorElement e = expression.staticElement;
       if (e == null || !e.isFactory) {
         // fromT should be an exact type - this will almost certainly fail at
         // runtime.
-        return new StaticTypeError(rules, expression, toT, reason: reason);
+        return new StaticTypeError(rules, expression, toT);
       }
     }
 
@@ -148,7 +148,7 @@ abstract class DownCast extends CoercionInfo {
     // declaration, will have an exact type, so we know a downcast will fail.
     if (element is FunctionElement ||
         element is MethodElement && element.isStatic) {
-      return new StaticTypeError(rules, expression, toT, reason: reason);
+      return new StaticTypeError(rules, expression, toT);
     }
 
     // TODO(vsm): Change this to an assert when we have generic methods and
@@ -556,19 +556,15 @@ abstract class StaticInfo {
 class StaticTypeError extends StaticError {
   final DartType baseType;
   final DartType expectedType;
-  String reason = null;
 
-  StaticTypeError(TypeSystem rules, Expression expression, this.expectedType,
-      {this.reason})
+  StaticTypeError(TypeSystem rules, Expression expression, this.expectedType)
       : baseType = expression.staticType ?? DynamicTypeImpl.instance,
         super(expression);
 
   @override
   List<Object> get arguments => [node, baseType, expectedType];
   @override
-  String get message =>
-      'Type check failed: {0} ({1}) is not of type {2}' +
-      ((reason == null) ? '' : ' because $reason');
+  String get message => 'Type check failed: {0} ({1}) is not of type {2}';
 
   @override
   String get name => 'STRONG_MODE_STATIC_TYPE_ERROR';