As languages, nothing. In design, their conservative nature.

Go is not a conservative language. A conservative language would be something like D, which is mostly a clone of C++ with a few extra features tossed in.

Go is a highly opinionated language with at least three big new ideas:

* goroutines for concurrency ("Don't communicate by sharing memory; share memory by communicating")

* a new type system which is based on structural subtyping (some people have called this static duck typing).

* use of return codes rather than exceptions for routine error conditions ("We don't want to encourage the conflation of errors and exceptions that occur in languages such as Java." See https://plus.google.com/116810148281701144465/posts/iqAiKAwP... )

Just those three things are enough to make Go code look very from what came before. And I could go on-- things like the way go does namespaces and scoping are also very different.

It's a different philosophy that leads to much better code, in my opinion at least, not dozens of gee-whiz features, which seems to be what the languages of the 1990s gave us and are continuing to give us.

Except these big new ideas have been around for decades, some of them for nearly half a century.

You're right that Go is not conservative, though, but retro, trying to mitigate the damage done by C and C++.

The ideas of Go are new to the mainstream, and at the end of the day, that's what matters. It's a programming language, not a PhD thesis.

> We don't want to encourage the conflation of errors and exceptions that occur in languages such as Java.

I'm not getting this argument:

    checked exception == error
    runtime exception == panic

None of those three "big new ideas" are big or new. Go is incredibly conservative, primitive even. It takes a few tiny things like those you mentioned from languages that have had them for decades, but leaves out so much important stuff that the language is barely useful at all.