Return type assertions with type parameters

General Usage
1

Today I noticed that

f(x::T)::T where T = x  # throws UndefVarError for T
function f(x::T)::T where T
    x
end  # works

Is this a bug?

1 Like
2

I think it’s just a surprising operator precedence. Your first form is parsed as

julia> :(f(x::T)::T where T)
:(f(x::T)::(T where T))

whereas what you really want is:

julia> (f(x::T)::T) where T = x
f (generic function with 1 method)

julia> f(1)
1
3 Likes