Always apply new type arguments in InterfaceTypeImpl.substitute2().

pkg/analyzer/lib/src/dart/element/type.dart

Index: pkg/analyzer/lib/src/dart/element/type.dart
diff --git a/pkg/analyzer/lib/src/dart/element/type.dart b/pkg/analyzer/lib/src/dart/element/type.dart
index 55075e8489698e1ba15879034d26b40fd65ac934..0a47f064287c0204c1b91c4d2b85d50ebca847cf 100644
--- a/pkg/analyzer/lib/src/dart/element/type.dart
+++ b/pkg/analyzer/lib/src/dart/element/type.dart
@@ -14,7 +14,6 @@ import 'package:analyzer/src/dart/element/member.dart';
 import 'package:analyzer/src/generated/engine.dart'
     show AnalysisContext, AnalysisEngine;
 import 'package:analyzer/src/generated/type_system.dart';
-import 'package:analyzer/src/generated/utilities_collection.dart';
 import 'package:analyzer/src/generated/utilities_dart.dart';
 
 /**
@@ -2039,9 +2038,6 @@ class InterfaceTypeImpl extends TypeImpl implements InterfaceType {
     }
     List<DartType> newTypeArguments = TypeImpl.substitute(
         typeArguments, argumentTypes, parameterTypes, prune);
-    if (listsEqual(newTypeArguments, typeArguments)) {
-      return this;
-    }
 
     if (isDartAsyncFuture && newTypeArguments.isNotEmpty) {
       //