How to tell what specializations are compiled for a method?

Question

In the performance tip, it says f(x::Int...) = tuple(x...) will not specialize. It also suggests to use (@which f(...)).specializations to check the specializations.

f(x::Int...) = tuple(x...)

f(1)
f(1, 2)
f(1, 2, 3)
f(1, 2, 3, 4)

a = first(methods(f)).specializations

Core.TypeMapEntry(Core.TypeMapEntry(nothing, Tuple{typeof(f),Int64}, nothing, svec(), 0x0000000000000001, 0xffffffffffffffff, MethodInstance for f(::Int64), true, true, false), Tuple{typeof(f),Int64,Vararg{Int64,N} where N}, nothing, svec(), 0x0000000000000001, 0xffffffffffffffff, MethodInstance for f(::Int64, ::Vararg{Int64,N} where N), false, true, true)

How do I interpret the TypeMapEntry? How can I access it programatically (I find it hard to read from the output)? How many specializations has it made?

Answer 1

The MethodAnalysis package, registered just this morning, should give you everything you need. (Your timing in asking this question was excellent!)