Detect if constant

[Per]

I’ve also asked about this before, and I still think that it would be a really useful thing to have.

Branch on whether a value is known to the compiler

Here’s something that I’ve been thinking about: What if there was a way to write code that works differently depending on whether some value is known to the compiler? As an example, let’s say I could write: @inline function ^(x, p::Integer) if @known p literal_pow(^, x, Val(p)) else power_by_squaring(x, p) end end where @known would be a special macro that would tell the compiler to first do some amount of inlining and constant-folding, then check whether the value o…