# Weird Tuple types that seem like they should be disallowed?

**URL:** <https://discourse.julialang.org/t/weird-tuple-types-that-seem-like-they-should-be-disallowed/57080>\
**Category:** New to Julia\
**Tags:** question, type, tuple, parametric-types\
**Created:** [March 13, 2021, 3:44pm UTC](https://discourse.julialang.org/t/weird-tuple-types-that-seem-like-they-should-be-disallowed/57080 "2021-03-13T15:44:13Z")\
**Posts on this page:** 1\
**Showing post:** 1

<div class="post-metadata">

**Author:** ![nsajko](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/nsajko/32/221187_2.png) [@nsajko](https://discourse.julialang.org/u/nsajko)\
**Post date:** [March 13, 2021, 3:44pm UTC](https://discourse.julialang.org/t/weird-tuple-types-that-seem-like-they-should-be-disallowed/57080/1 "2021-03-13T15:44:13Z")

</div>

I noticed that some Tuple types that are parameterized by non-types exist, but seem useless. I wonder if they:

1. May have instances at all?

2. Should be disallowed?

Example:

```julia
               _
   _ _ _(_)_ | Documentation: https://docs.julialang.org
  (_) | (_) (_) |
   _ _ _| |_ __ _ | Type "?" for help, "]?" for Pkg help.
  | | | | | | |/ _` | |
  | | |_| | | | (_| | | Version 1.5.4 (2021-03-11)
 _/ |\ __'_|_|_|\__'_| |
|__/ |

julia> Tuple{1243} <: Tuple{Any}
true

julia> Tuple{(124310, 983724)} <: Tuple{Any}
true

```

It’s relevant that similar constructions are not permissible in function type signatures:

```julia
julia> function f(x::423)
       5
       end
ERROR: ArgumentError: invalid type for argument x in method definition for f at REPL[2]:1
Stacktrace:
 [1] top-level scope at REPL[2]:1
 [2] run_repl(::REPL.AbstractREPL, ::Any) at /build/julia/src/julia-1.5.4/usr/share/julia/stdlib/v1.5/REPL/src/REPL.jl:288

```

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