# Check that all fields are concrete types?
**URL:** https://discourse.julialang.org/t/check-that-all-fields-are-concrete-types/10225
**Category:** General Usage
**Created:** [April 7, 2018, 6:17pm UTC](https://discourse.julialang.org/t/check-that-all-fields-are-concrete-types/10225 "2018-04-07T18:17:09Z")
**Posts on this page:** 8
**Page:** 1
### Author:  [@Stephen\_Vavasis](https://discourse.julialang.org/u/Stephen_Vavasis)
#### Post date: [April 7, 2018, 6:17pm UTC](https://discourse.julialang.org/t/check-that-all-fields-are-concrete-types/10225/1 "2018-04-07T18:17:09Z")
I’ve discovered that I may have introduced some performance-sapping code into my project because of the following issue. I have two structs `A` and `B` like this:
```julia
struct A
field1::Int
end
struct B
containedA::A
end
```
Later I decide to rewrite `A` with a parameter:
```julia
struct A{T}
field1::T
end
```
According to my understanding of the language, I should now also parametrize `B` with `T`, else the contained field `A` is an abstract type and anything that uses `B` will involve run-time dispatch. However, in many places in my code, I forgot to do this and am just now noticing the issue.
First, is my understanding correct? Is there a performance hit for not parameterizing `B`?
Second, if this is indeed the case, is there a technique to discover this problem (i.e., a technique to confirm that all fields of a `struct` are concrete) aside from running `code_warntype` and poring over the output?
---
### Author:  [@kristoffer.carlsson](https://discourse.julialang.org/u/kristoffer.carlsson)
#### Post date: [April 7, 2018, 6:43pm UTC](https://discourse.julialang.org/t/check-that-all-fields-are-concrete-types/10225/2 "2018-04-07T18:43:53Z")
> [@Stephen\_Vavasis](#):
>
> First, is my understanding correct? Is there a performance hit for not parameterizing B?
Yes,
you could use a macro (only tested on 0.7):
```julia
macro concrete(expr)
@assert expr.head == :struct
S = expr.args[2]
return quote
$(esc(expr))
for n in fieldnames($S)
if !isconcretetype(fieldtype($S, n))
error("field $n is not concrete")
end
end
end
end
```
```julia
julia> @concrete struct Foo
v::Array{Int}
end
ERROR: field v is not concrete
Stacktrace:
[1] error(::String) at ./error.jl:33
[2] top-level scope at REPL[1]:9
julia> struct Bar{Int} end
julia> @concrete struct Foob
v::Bar
end
ERROR: field v is not concrete
Stacktrace:
[1] error(::String) at ./error.jl:33
[2] top-level scope at REPL[1]:9
julia> @concrete struct Foobar
v::Bar{Float64}
end
```
---
### Author:  [@Stephen\_Vavasis](https://discourse.julialang.org/u/Stephen_Vavasis)
#### Post date: [April 14, 2018, 1:52pm UTC](https://discourse.julialang.org/t/check-that-all-fields-are-concrete-types/10225/3 "2018-04-14T13:52:18Z")
A quick question about this macro: could it be simplified by invoking `isconcretetype` on S itself instead of on the fields?
---
### Author:  [@kristoffer.carlsson](https://discourse.julialang.org/u/kristoffer.carlsson)
#### Post date: [April 14, 2018, 2:45pm UTC](https://discourse.julialang.org/t/check-that-all-fields-are-concrete-types/10225/4 "2018-04-14T14:45:40Z")
```julia
struct S
...
end
```
is always concrete.
---
### Author:  [@kapple](https://discourse.julialang.org/u/kapple)
#### Post date: [April 23, 2021, 12:50am UTC](https://discourse.julialang.org/t/check-that-all-fields-are-concrete-types/10225/5 "2021-04-23T00:50:52Z")
Resurrecting this old topic.
`isabstract` and `isconcrete` and with their `Base.` prefixes are not defined for me in Julia 1.6, has it been deprecated?
> [@kristoffer.carlsson](#):
>
> ```julia
> struct S
> ...
> end
>
> ```
Can I confirm that, I thought the idea of personalising structs was that the struct is concrete only if all of its properties are concrete types?
---
### Author:  [@jzr](https://discourse.julialang.org/u/jzr)
#### Post date: [April 23, 2021, 3:31am UTC](https://discourse.julialang.org/t/check-that-all-fields-are-concrete-types/10225/6 "2021-04-23T03:31:06Z")
> [@kapple](#):
>
> `isabstract` and `isconcrete` and with their `Base.` prefixes are not defined for me in Julia 1.6, has it been deprecated?
`Base.isconcretetype` is in 1.5
---
### Author:  [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)
#### Post date: [April 23, 2021, 8:55am UTC](https://discourse.julialang.org/t/check-that-all-fields-are-concrete-types/10225/7 "2021-04-23T08:55:18Z")
> [@kapple](#):
>
> `isabstract` and `isconcrete` and with their `Base.` prefixes are not defined for me in Julia 1.6
Maybe you are looking for `isabstracttype` and `isconcretetype`?
---
### Author:  [@kapple](https://discourse.julialang.org/u/kapple)
#### Post date: [April 23, 2021, 2:25pm UTC](https://discourse.julialang.org/t/check-that-all-fields-are-concrete-types/10225/8 "2021-04-23T14:25:21Z")
Yes, thanks guys.
I kicked myself when, after reading your two replies, I tried `?isconcrete` and it suggested `isconcretetype`.