# Use of @code\_warntype on a function with keyword arguments
**URL:** https://discourse.julialang.org/t/use-of-code-warntype-on-a-function-with-keyword-arguments/5521
**Category:** General Usage
**Created:** [August 23, 2017, 8:25am UTC](https://discourse.julialang.org/t/use-of-code-warntype-on-a-function-with-keyword-arguments/5521 "2017-08-23T08:25:53Z")
**Posts on this page:** 6
**Page:** 1
### Author:  [@Alexander-Barth](https://discourse.julialang.org/u/Alexander-Barth)
#### Post date: [August 23, 2017, 8:25am UTC](https://discourse.julialang.org/t/use-of-code-warntype-on-a-function-with-keyword-arguments/5521/1 "2017-08-23T08:25:53Z")
I would like to use `@code_warntype` on a function with a keyword argument.
Consider the following simple example with an intentional type instability:
```julia
function myfun(a; tol = 2)
x = (a > 42 ? a : 42.)
return x + tol
end
```
`@code_warntype myfun(2)` returns the following:
```julia
@code_warntype myfun(2)
Variables:
#self#::#myfun
a::Int64
Body:
begin
return $(Expr(:invoke, MethodInstance for #myfun#1(::Int64, ::Function, ::Int64), :(Main.#myfun#1), 2, :(#self#), :(a)))
end::Union{Float64, Int64}
```
It seems that Julia creates an internal function `#myfun#17` (maybe a barrier function?) which is invoked when myfun is called.
The following `@code_warntype myfun(2, tol = 2)` is much more verbose but it still does not reveal the problematic line `x = (a > 42 ? a : 42.)`.
```julia
Variables:
#unused#::#kw##myfun
#temp#@_2::Array{Any,1}
::#myfun
a::Int64
#temp#@_5::Int64
#temp#@_6::Int64
#temp#@_7::Any
#temp#@_8::Int64
tol::Any
Body:
begin
tol::Any = 2
SSAValue(2) = (Base.arraylen)(#temp#@_2::Array{Any,1})::Int64
SSAValue(3) = (Base.select_value)((Base.sle_int)(0, 1)::Bool, (Base.ashr_int)(SSAValue(2), (Base.bitcast)(UInt64, 1))::Int64, (Base.shl_int)(SSAValue(2), (Base.bitcast)(UInt64, (Base.neg_int)(1)::Int64))::Int64)::Int64
SSAValue(5) = (Base.select_value)((Base.sle_int)(1, SSAValue(3))::Bool, SSAValue(3), (Base.sub_int)(1, 1)::Int64)::Int64
#temp#@_8::Int64 = 1
6:
unless (Base.not_int)((#temp#@_8::Int64 === (Base.add_int)(SSAValue(5), 1)::Int64)::Bool)::Bool goto 23
SSAValue(6) = #temp#@_8::Int64
SSAValue(7) = (Base.add_int)(#temp#@_8::Int64, 1)::Int64
#temp#@_5::Int64 = SSAValue(6)
#temp#@_8::Int64 = SSAValue(7)
#temp#@_6::Int64 = (Base.sub_int)((Base.mul_int)(#temp#@_5::Int64, 2)::Int64, 1)::Int64
#temp#@_7::Any = (Core.arrayref)(#temp#@_2::Array{Any,1}, #temp#@_6::Int64)::Any
unless (#temp#@_7::Any === :tol)::Bool goto 17
tol::Any = (Core.arrayref)(#temp#@_2::Array{Any,1}, (Base.add_int)(#temp#@_6::Int64, 1)::Int64)::Any
goto 21
17:
SSAValue(8) = ::#myfun
SSAValue(9) = a::Int64
(Base.throw)($(Expr(:new, :(Base.MethodError), :((Core.getfield)((Core.getfield)((Core.getfield)(#myfun, :name)::TypeName, :mt), :kwsorter)), :((Core.tuple)(#temp#@_2, SSAValue(8), SSAValue(9))::Tuple{Array{Any,1},#myfun,Int64}), 0xffffffffffffffff)))::Union{}
21:
goto 6
23:
return (Main.#myfun#1)(tol::Any, ::#myfun, a::Int64)::Any
end::Any
```
Any ideas how can I use `@code_warntype` on these type of function?
---
### Author:  [@jw3126](https://discourse.julialang.org/u/jw3126)
#### Post date: [January 11, 2019, 1:47pm UTC](https://discourse.julialang.org/t/use-of-code-warntype-on-a-function-with-keyword-arguments/5521/2 "2019-01-11T13:47:00Z")
I have the same question. Here is how the problem looks in julia 1.0.
```julia
julia> f(x;y=4) = instable(x,y)
f (generic function with 1 method)
julia> @code_warntype f(1)
Body::Any
1 1 ─ %1 = invoke Main.:(#f#8)(4::Int64, _1::Function, _2::Int64)::Any │
└── return %1
```
---
### Author:  [@RaulDurand](https://discourse.julialang.org/u/RaulDurand)
#### Post date: [March 6, 2019, 3:28pm UTC](https://discourse.julialang.org/t/use-of-code-warntype-on-a-function-with-keyword-arguments/5521/3 "2019-03-06T15:28:27Z")
Any update on this? I have a function with keyword arguments that is being recompiled each time it is called and the macro @code\_warntype is not providing useful information, just the invoke call.
---
### Author:  [@nalimilan](https://discourse.julialang.org/u/nalimilan)
#### Post date: [March 6, 2019, 6:32pm UTC](https://discourse.julialang.org/t/use-of-code-warntype-on-a-function-with-keyword-arguments/5521/4 "2019-03-06T18:32:00Z")
Please open a new thread with a reproducible example.
---
### Author:  [@kristoffer.carlsson](https://discourse.julialang.org/u/kristoffer.carlsson)
#### Post date: [March 6, 2019, 6:56pm UTC](https://discourse.julialang.org/t/use-of-code-warntype-on-a-function-with-keyword-arguments/5521/5 "2019-03-06T18:56:36Z")
```julia
f(x; y) = x + y
f_kw = Core.kwfunc(f)
x = 2
f_kw((y = 3,), f, x)
@code_warntype f_kw((y = 3,), f, x)
```
---
### Author:  [@mbauman](https://discourse.julialang.org/u/mbauman)
#### Post date: [March 6, 2019, 7:14pm UTC](https://discourse.julialang.org/t/use-of-code-warntype-on-a-function-with-keyword-arguments/5521/6 "2019-03-06T19:14:01Z")
Or even easier, slowly descend into madness with [Cthulhu](https://github.com/JuliaDebug/Cthulhu.jl).