overlapping node declaration does not error

[paciorek]

We don't catch this this repeatedly declares a distribution for elements of y.

 code <- quote({
        for(i in 1:2) {
            x[i:5] ~ dmnorm(z[i:5], Q[i:5,i:5])
        }
    })

We do catch various other cases, so the problem seems to arise from using i.

E.g., this is caught:

code=nimbleCode({
 y[1:3]~dmnorm(mu[1:3],pr[1:3,1:3])
 y[1:4]~dmnorm(mu[1:4],pr[1:4,1:4])
})