Well, you can start with all the functional languages that automatically are able to do these things you're talking about, like Haskell and so on. You can argue they aren't 'developer friendly' but you never defined that term to begin with, and people are certainly productive with those languages (developer friendly compared to what? Go is certainly not the most accessible language)
But in terms of more 'mass market' languages, C++ and C# both have incredibly robust generics that can be used to do real, no-foolin' functional programming, though doing it in C++ certainly takes a lot more effort and leans on modern libraries - closures are a comparatively recent introduction to the language. You've also got 'mass market' functional languages like F# to have fun with.
Then there are the more fun options, like writing your functional code in Lua or Python and running it in a high-performance runtime like LuaJIT/PyPy to get fairly competitive performance without even needing explicit typing or built-in 'generics'.
But in terms of more 'mass market' languages, C++ and C# both have incredibly robust generics that can be used to do real, no-foolin' functional programming, though doing it in C++ certainly takes a lot more effort and leans on modern libraries - closures are a comparatively recent introduction to the language. You've also got 'mass market' functional languages like F# to have fun with.
Then there are the more fun options, like writing your functional code in Lua or Python and running it in a high-performance runtime like LuaJIT/PyPy to get fairly competitive performance without even needing explicit typing or built-in 'generics'.