struct ExcessiveArg

A macro from the ACTION* family (defined later in gmock-generated-actions.h)

defines an action that can be used in a mock function. Typically,

these actions only care about a subset of the arguments of the mock

function. For example, if such an action only uses the second

argument, it can be used in any mock function that takes >= 2

arguments where the type of the second argument is compatible.

Therefore, the action implementation must be prepared to take more

arguments than it needs. The ExcessiveArg type is used to

represent those excessive arguments. In order to keep the compiler

error messages tractable, we define it in the testing namespace

instead of testing::internal. However, this is an INTERNAL TYPE

and subject to change without notice, so a user MUST NOT USE THIS

TYPE DIRECTLY.