# How to export/use a type alias?

**URL:** <https://discourse.julialang.org/t/how-to-export-use-a-type-alias/35485>\
**Category:** New to Julia\
**Created:** [March 3, 2020, 8:45pm UTC](https://discourse.julialang.org/t/how-to-export-use-a-type-alias/35485 "2020-03-03T20:45:25Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![leiteiro](https://avatars.discourse-cdn.com/v4/letter/l/b5e925/32.png) [@leiteiro](https://discourse.julialang.org/u/leiteiro)\
**Post date:** [March 3, 2020, 8:45pm UTC](https://discourse.julialang.org/t/how-to-export-use-a-type-alias/35485/1 "2020-03-03T20:45:25Z")

</div>

This is the situation:

```
module A
export myType
const myType = Array{BigInt,1}
isa([BigInt(1)], myType) |> println
end

module B
using A
isa([BigInt(1)], myType) |> println
end

```

In module A the type alias myType is defined and I want to use this alias also in module B. As written, this does not work. How to do it?

---

<div class="post-metadata">

**Author:** ![AndiMD](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/andimd/32/6531_2.png) [@AndiMD](https://discourse.julialang.org/u/AndiMD)\
**Post date:** [March 3, 2020, 8:52pm UTC](https://discourse.julialang.org/t/how-to-export-use-a-type-alias/35485/2 "2020-03-03T20:52:01Z")

</div>

Import from the parent module with two dots:  
`using ..A`

[https://docs.julialang.org/en/v1/manual/modules/index.html#Relative-and-absolute-module-paths-1](https://docs.julialang.org/en/v1/manual/modules/index.html#Relative-and-absolute-module-paths-1)

---

<div class="post-metadata">

**Author:** ![leiteiro](https://avatars.discourse-cdn.com/v4/letter/l/b5e925/32.png) [@leiteiro](https://discourse.julialang.org/u/leiteiro)\
**Post date:** [March 3, 2020, 9:12pm UTC](https://discourse.julialang.org/t/how-to-export-use-a-type-alias/35485/3 "2020-03-03T21:12:47Z")

</div>

This is what followed:

Please submit a bug report with steps to reproduce this fault, and any error messages that follow (in their entirety). Thanks.  
Exception: EXCEPTION\_ACCESS\_VIOLATION at 0x6689257a – jl\_lookup\_method\_worldset at /cygdrive/d/buildbot/worker/package\_win64/build/src/cygdrive/d/buildbot/worker/package\_win64/build/src\dump.c:3087 [inlined]  
jl\_recache\_method\_instance at /cygdrive/d/buildbot/worker/package\_win64/build/src/cygdrive/d/buildbot/worker/package\_win64/build/src\dump.c:3112 [inlined]  
jl\_recache\_other at /cygdrive/d/buildbot/worker/package\_win64/build/src/cygdrive/d/buildbot/worker/package\_win64/build/src\dump.c:3139 [inlined]  
\_jl\_restore\_incremental at /cygdrive/d/buildbot/worker/package\_win64/build/src/cygdrive/d/buildbot/worker/package\_win64/build/src\dump.c:3228  
in expression starting at C:\Users\Home\JuliaProjects\IntegerTriangles.jl\src\TrianglesTraitCard.jl:91  
jl\_lookup\_method\_worldset at /cygdrive/d/buildbot/worker/package\_win64/build/src/cygdrive/d/buildbot/worker/package\_win64/build/src\dump.c:3088 [inlined]  
jl\_recache\_method\_instance at /cygdrive/d/buildbot/worker/package\_win64/build/src/cygdrive/d/buildbot/worker/package\_win64/build/src\dump.c:3112 [inlined]  
jl\_recache\_other at /cygdrive/d/buildbot/worker/package\_win64/build/src/cygdrive/d/buildbot/worker/package\_win64/build/src\dump.c:3139 [inlined]  
\_jl\_restore\_incremental at /cygdrive/d/buildbot/worker/package\_win64/build/src/cygdrive/d/buildbot/worker/package\_win64/build/src\dump.c:3228  
jl\_restore\_incremental at /cygdrive/d/buildbot/worker/package\_win64/build/src/cygdrive/d/buildbot/worker/package\_win64/build/src\dump.c:3272  
\_include\_from\_serialized at .\loading.jl:676  
\_require\_from\_serialized at .\loading.jl:743  
\_require at .\loading.jl:1034  
require at .\loading.jl:922  
require at .\loading.jl:917  
\_jl\_invoke at /cygdrive/d/buildbot/worker/package\_win64/build/src/cygdrive/d/buildbot/worker/package\_win64/build/src\gf.c:2135 [inlined]  
jl\_apply\_generic at /cygdrive/d/buildbot/worker/package\_win64/build/src/cygdrive/d/buildbot/worker/package\_win64/build/src\gf.c:2305  
jl\_apply at /cygdrive/d/buildbot/worker/package\_win64/build/src/cygdrive/d/buildbot/worker/package\_win64/build/src\julia.h:1631 [inlined]  
call\_require at /cygdrive/d/buildbot/worker/package\_win64/build/src/cygdrive/d/buildbot/worker/package\_win64/build/src\toplevel.c:399 [inlined]  
eval\_import\_path at /cygdrive/d/buildbot/worker/package\_win64/build/src/cygdrive/d/buildbot/worker/package\_win64/build/src\toplevel.c:436  
jl\_toplevel\_eval\_flex at /cygdrive/d/buildbot/worker/package\_win64/build/src/cygdrive/d/buildbot/worker/package\_win64/build/src\toplevel.c:656  
jl\_eval\_module\_expr at /cygdrive/d/buildbot/worker/package\_win64/build/src/cygdrive/d/buildbot/worker/package\_win64/build/src\toplevel.c:181  
jl\_toplevel\_eval\_flex at /cygdrive/d/buildbot/worker/package\_win64/build/src/cygdrive/d/buildbot/worker/package\_win64/build/src\toplevel.c:640  
jl\_parse\_eval\_all at /cygdrive/d/buildbot/worker/package\_win64/build/src/cygdrive/d/buildbot/worker/package\_win64/build/src\ast.c:873  
include\_string at .\loading.jl:1075  
#139 at C:\Users\Home.julia\packages\Atom\lBERI\src\eval.jl:138  
withpath at C:\Users\Home.julia\packages\CodeTools\sf1Tz\src\utils.jl:30  
\_jl\_invoke at /cygdrive/d/buildbot/worker/package\_win64/build/src/cygdrive/d/buildbot/worker/package\_win64/build/src\gf.c:2135 [inlined]  
jl\_apply\_generic at /cygdrive/d/buildbot/worker/package\_win64/build/src/cygdrive/d/buildbot/worker/package\_win64/build/src\gf.c:2305  
withpath at C:\Users\Home.julia\packages\Atom\lBERI\src\eval.jl:47  
#138 at C:\Users\Home.julia\packages\Atom\lBERI\src\eval.jl:135 [inlined]  
with\_logstate at .\logging.jl:395  
with\_logger at .\logging.jl:491 [inlined]  
#137 at C:\Users\Home.julia\packages\Atom\lBERI\src\eval.jl:134 [inlined]  
hideprompt at C:\Users\Home.julia\packages\Atom\lBERI\src\repl.jl:85  
\_jl\_invoke at /cygdrive/d/buildbot/worker/package\_win64/build/src/cygdrive/d/buildbot/worker/package\_win64/build/src\gf.c:2141 [inlined]  
jl\_apply\_generic at /cygdrive/d/buildbot/worker/package\_win64/build/src/cygdrive/d/buildbot/worker/package\_win64/build/src\gf.c:2305  
macro expansion at C:\Users\Home.julia\packages\Atom\lBERI\src\eval.jl:133 [inlined]  
macro expansion at C:\Users\Home.julia\packages\Media\ItEPc\src\dynamic.jl:24 [inlined]  
#136 at C:\Users\Home.julia\packages\Atom\lBERI\src\eval.jl:122  
\_jl\_invoke at /cygdrive/d/buildbot/worker/package\_win64/build/src/cygdrive/d/buildbot/worker/package\_win64/build/src\gf.c:2135 [inlined]  
jl\_apply\_generic at /cygdrive/d/buildbot/worker/package\_win64/build/src/cygdrive/d/buildbot/worker/package\_win64/build/src\gf.c:2305  
handlemsg at C:\Users\Home.julia\packages\Atom\lBERI\src\comm.jl:164  
unknown function (ip: 0000000017AF3D42)  
\_jl\_invoke at /cygdrive/d/buildbot/worker/package\_win64/build/src/cygdrive/d/buildbot/worker/package\_win64/build/src\gf.c:2135 [inlined]  
jl\_apply\_generic at /cygdrive/d/buildbot/worker/package\_win64/build/src/cygdrive/d/buildbot/worker/package\_win64/build/src\gf.c:2305  
jl\_apply at /cygdrive/d/buildbot/worker/package\_win64/build/src/cygdrive/d/buildbot/worker/package\_win64/build/src\julia.h:1631 [inlined]  
jl\_f\_\_apply at /cygdrive/d/buildbot/worker/package\_win64/build/src/cygdrive/d/buildbot/worker/package\_win64/build/src\builtins.c:627  
#19 at .\task.jl:333  
unknown function (ip: 0000000017AF01FE)  
\_jl\_invoke at /cygdrive/d/buildbot/worker/package\_win64/build/src/cygdrive/d/buildbot/worker/package\_win64/build/src\gf.c:2135 [inlined]  
jl\_apply\_generic at /cygdrive/d/buildbot/worker/package\_win64/build/src/cygdrive/d/buildbot/worker/package\_win64/build/src\gf.c:2305  
jl\_apply at /cygdrive/d/buildbot/worker/package\_win64/build/src/cygdrive/d/buildbot/worker/package\_win64/build/src\julia.h:1631 [inlined]  
start\_task at /cygdrive/d/buildbot/worker/package\_win64/build/src/cygdrive/d/buildbot/worker/package\_win64/build/src\task.c:659  
Allocations: 49304797 (Pool: 49292083; Big: 12714); GC: 50

---

<div class="post-metadata">

**Author:** ![AndiMD](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/andimd/32/6531_2.png) [@AndiMD](https://discourse.julialang.org/u/AndiMD)\
**Post date:** [March 4, 2020, 8:50am UTC](https://discourse.julialang.org/t/how-to-export-use-a-type-alias/35485/4 "2020-03-04T08:50:17Z")

</div>

I cannot reproduce this error in Julia1.3.1 and 1.4-rc2 on Linux64.  
Could you please file a bug report with more details?  
[https://github.com/JuliaLang/julia/issues](https://github.com/JuliaLang/julia/issues)

---

<div class="post-metadata">

**Author:** ![leiteiro](https://avatars.discourse-cdn.com/v4/letter/l/b5e925/32.png) [@leiteiro](https://discourse.julialang.org/u/leiteiro)\
**Post date:** [March 4, 2020, 10:10am UTC](https://discourse.julialang.org/t/how-to-export-use-a-type-alias/35485/5 "2020-03-04T10:10:52Z")

</div>

As the error message shows I am on win64 and Windows10, not on Linux.  
Julia version is 1.3.1.  
I have encountered similar crashes in the past in different project.  
They are not always reproducible.

Thanks for your help, meanwhile I found a work-around for my original problem.