The other day I had an interesting observation on the optional parameters in C# 4, whereby if you specify a parameter as optional on an interface you don’t actually have to make that parameter optional on any implementing class:
Which means you won’t be able to use the implementing class and the interface interchangeably:
Naturally, this bags the question of why the compiler doesn’t enforce the implementation to match the default value specified by the contract?
Luckily, my subsequent question on SO was answered by Eric Lippert from the C# compiler team, not to waste time and effort repeating what’s already been said, check out his answer and it’s clear to see the rationale here and why it would be impractical and inconvenient should the compiler does it differently.
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