[paavohtl]

Ehhh, not really. It really depends on what you mean by convergence. You could add every single one of F#'s features into C#, and I still wouldn't consider them to be same language or the other to be irrelevant. The strength of F# is the primary coding style: mostly functional, mostly immutable, expression-based, strongly typed with global type inference. The way most C# is written is almost the polar opposite: mostly OOP/imperative, mostly mutable, statement-based, statically typed but with a less expressive type system (no sum types, exceptions and nulls over Result and Option) and very limited local type inference.

The F# style is enabled by a set of features - some of which would be really hard to add to C# (such as currying and global type inference) - but even if they were added, the millions(?) of C# developers would be unlikely adopt the functional style just because it was possible. A language is not just a list of features; each language has its own culture and "idiomatic" way of doing things.

[iddan]

Look at JavaScript though. A few years back it was all about loose typing, mutation, OOP (with prototype), etc and now TypeScript is king, React and Rx are promoting functional idioms (immutability, purity). So I think that can teach us that when a language can be typed and functional there could be a vibrant community that uses it that way while there’s another that doesn’t