Provide better error message when passing wrong number of arguments.

runtime/vm/dart_api_impl_test.cc

 // 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.
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "platform/json.h"
 #include "platform/utils.h"
 #include "vm/class_finalizer.h"
 #include "vm/dart_api_impl.h"
@@ skipping 3343 matching lines @@
   result = Dart_New(cls, Dart_NewString("named"), -1, args);
   EXPECT_ERROR(
       result,
       "Dart_New expects argument 'number_of_arguments' to be non-negative.");
 
   // Pass the wrong arg count.
   result = Dart_New(cls, Dart_NewString("named"), 0, NULL);
   EXPECT_ERROR(
       result,
       "Dart_New: wrong argument count for constructor 'MyClass.named': "
-      "expected 1 but saw 0.");
+      "0 passed, 1 expected.");
 
   // Pass a bad argument.  Error is passed through.
   result = Dart_New(cls, Dart_NewString("named"), 1, bad_args);
   EXPECT_ERROR(result, "myerror");
 
   // Pass a bad constructor name.
   result = Dart_New(cls, Dart_NewInteger(55), 1, args);
   EXPECT_ERROR(
       result,
       "Dart_New expects argument 'constructor_name' to be of type String.");
@@ skipping 207 matching lines @@
   name = Dart_NewString("topMethod");
   EXPECT(Dart_IsError(Dart_Invoke(cls, name, 1, args)));
   EXPECT(Dart_IsError(Dart_Invoke(instance, name, 1, args)));
   result = Dart_Invoke(lib, name, 1, args);
   EXPECT_VALID(result);
   result = Dart_StringToCString(result, &str);
   EXPECT_STREQ("top !!!", str);
 
   // Top-level method, wrong arg count.
   EXPECT_ERROR(Dart_Invoke(lib, name, 2, bad_args),
-               "did not find top-level function 'topMethod'");
+               "Dart_Invoke: wrong argument count for function 'topMethod': "
+               "2 passed, 1 expected.");
 
   // Hidden top-level method.
   name = Dart_NewString("_topMethod");
   EXPECT(Dart_IsError(Dart_Invoke(cls, name, 1, args)));
   EXPECT(Dart_IsError(Dart_Invoke(instance, name, 1, args)));
   result = Dart_Invoke(lib, name, 1, args);
   EXPECT_VALID(result);
   result = Dart_StringToCString(result, &str);
   EXPECT_STREQ("hidden top !!!", str);
 }
@@ skipping 2556 matching lines @@
   EXPECT_VALID(result);
   EXPECT(Dart_IsInteger(result));
   int64_t value = 0;
   EXPECT_VALID(Dart_IntegerToInt64(result, &value));
   EXPECT_EQ(0, value);
 }
 
 #endif  // defined(TARGET_ARCH_IA32) || defined(TARGET_ARCH_X64).
 
 }  // namespace dart