Speculative: Disentangle getindex and typed-array syntax

[BioTurboNick]

julia> d = Dict
Dict

julia> d[1]
ERROR: MethodError: Cannot `convert` an object of type
  Int64 to an object of type
  Dict

julia> d = Int
Int64

julia> d[1]
1-element Vector{Int64}:
 1

At first glance this is surprising - how is errantly indexing a Type trying to make a vector or do conversions?

It's happening because this is just the typed-array construction/concatenation syntax. And unfortunately, but cleverly, it overloads the getindex syntax and method to do this.

julia> Float64[1]
1-element Vector{Float64}:
 1.0

It might be nice, in 2.0, to consider separating the getindex and typed-array syntax in some way.

One available syntax could be braces (related: #8470):

{Float64}[1]

Braces are universally now used in Julia to encompass type parameters, and the typed array syntax is effectively specifying a type parameter of the constructed array. {T}[] => Vector{T}()

[vtjnash]

Almost a duplicate of #53241, except that was for setindex! of the same

[BioTurboNick]

That did inspire me to suggest this, but there the issue is straightforward - setindex! isn't ever valid for types. However, getindex is actually valid for types... but it probably shouldn't be because it's doing something completely different than getting at an index.