Fix type instability in LinMPC and NonLinMPC (introduced in 1.1.0)

[franckgaga]

ControllerConstraint{NT} is no longer concrete
ControllerConstraint{NT, GCfunc} is

[franckgaga]

oh well it happens!

I will work on that a little bit tomorrow. But I have a party on Saturday. so not Saturday. And not Sunday while we're at it XD

🎉 🎉 🎉
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[baggepinnen]

It's a common pitfall. Ways to protect yourself against future such changes are

• Test type stability using JET.jl in the tests, e.g., like is done for LowLevelParticleFilters.jl and DiscretePIDs.jl
• Use a type parameter for the entire field, i.e., con::T instead of con::ControllerConstraint{NT, GCfunc}

[franckgaga]

Yeah I'll implement your second option instead.

I did not know that JET.jl was able to do that. Great idea!