Improve noSuchMethod error message for type objects.

runtime/lib/errors_patch.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 @patch class Error {
   @patch static String _objectToString(Object object) {
     return Object._toString(object);
   }
 
   @patch static String _stringToSafeString(String string) {
@@ skipping 255 matching lines @@
     bool args_mismatch = _existingArgumentNames != null;
     String args_message = args_mismatch ? " with matching arguments" : "";
 
     String type_str;
     if (type >= 0 && type < 5) {
       type_str = (const ["method", "getter", "setter", "getter or setter",
           "variable"])[type];
     }
 
     StringBuffer msg_buf = new StringBuffer("NoSuchMethodError: ");
+    bool is_type_call = false;
     switch (level) {
       case _InvocationMirror._DYNAMIC: {
         if (_receiver == null) {
           if (args_mismatch) {
             msg_buf.writeln("The null object does not have a $type_str "
                 "'$memberName'$args_message.");
           } else {
             msg_buf.writeln("The $type_str '$memberName' was called on null.");
           }
         } else {
           if (_receiver is Function) {
             msg_buf.writeln("Closure call with mismatched arguments: "
                 "function '$memberName'");
+          } else if (_receiver is _Type && memberName == "call") {
+            is_type_call = true;
+            String name = _receiver.toString();
+            msg_buf.writeln("Attempted to use type '$name' as a function. "
+                "Since types do not define a method 'call', this is not "
+                "possible. Did you intend to call the $name constructor and "
+                "forget the 'new' operator?");
           } else {
             msg_buf.writeln("Class '${_receiver.runtimeType}' has no instance "
                 "$type_str '$memberName'$args_message.");
           }
         }
         break;
       }
       case _InvocationMirror._SUPER: {
         msg_buf.writeln("Super class of class '${_receiver.runtimeType}' has "
               "no instance $type_str '$memberName'$args_message.");
@@ skipping 18 matching lines @@
       }
     }
 
     if (level == _InvocationMirror._TOP_LEVEL) {
       msg_buf.writeln("Receiver: top-level");
     } else {
       msg_buf.writeln("Receiver: ${Error.safeToString(_receiver)}");
     }
 
     if (type == _InvocationMirror._METHOD) {
-      msg_buf.write("Tried calling: $memberName($arguments)");
+      String m = is_type_call ? "$_receiver" : "$memberName";
+      msg_buf.write("Tried calling: $m($arguments)");
     } else if (argumentCount == 0) {
       msg_buf.write("Tried calling: $memberName");
     } else if (type == _InvocationMirror._SETTER) {
       msg_buf.write("Tried calling: $memberName$arguments");
     } else {
       msg_buf.write("Tried calling: $memberName = $arguments");
     }
 
     if (args_mismatch) {
       StringBuffer formalParameters = new StringBuffer();
       for (int i = 0; i < _existingArgumentNames.length; i++) {
         if (i > 0) {
           formalParameters.write(", ");
         }
         formalParameters.write(_existingArgumentNames[i]);
       }
       msg_buf.write("\nFound: $memberName($formalParameters)");
     }
 
     return msg_buf.toString();
   }
 }
 
 
 class _CompileTimeError extends Error {
   final String _errorMsg;
   _CompileTimeError(this._errorMsg);
   String toString() => _errorMsg;
 }