ERROR: LoadError: type DataType has no field mutable

[suiato]

When "using MuJoCo", the following error is issued:

julia> using MuJoCo
[ Info: Precompiling MuJoCo [93189219-7048-461c-94ec-443a161ed927]
ERROR: LoadError: type DataType has no field mutable
Stacktrace:
...
in expression starting at C:\Users\homma\.julia\packages\MuJoCo\wV1fC\src\MJCore\MJCore.jl:1
in expression starting at C:\Users\homma\.julia\packages\MuJoCo\wV1fC\src\MuJoCo.jl:1
ERROR: Failed to precompile MuJoCo [93189219-7048-461c-94ec-443a161ed927] to C:\Users\homma\.julia\compiled\v1.7\MuJoCo\jl_CD6C.tmp.
Stacktrace:
...

Running julia 1.7.0 on Windows 10.
I'll appreciate any advice or hint to resolve the issue.

[suiato]

On Ubuntu 18.04 (Jetson Xavier NX), I got another error:

julia> import Pkg; Pkg.precompile()
Precompiling project...
  ✗ MuJoCo
  0 dependencies successfully precompiled in 17 seconds (242 already precompiled)

ERROR: The following 1 direct dependency failed to precompile:

MuJoCo [93189219-7048-461c-94ec-443a161ed927]

Failed to precompile MuJoCo [93189219-7048-461c-94ec-443a161ed927] to /home/aoi/.julia/compiled/v1.7/MuJoCo/jl_NeHP0R.
ERROR: LoadError: UndefVarError: libmujoco not defined
Stacktrace:
...

[paulobruno]

Hi @suiato!
I got the same error with Julia 1.7.2.
As a workaround, I went to the source code of MJCore.jl and changed T->T.mutable to T->ismutable(T) in line 145.
In my case, I found MJCore.jl in ~/.julia/packages/MuJoCo/wV1fC/src/MJCore/.