Compute variance of type parameter tparam' in all type arguments
<code>tps</code> which correspond to formal type parameters
tparams1'.
Compute variance of type parameter tparam' in type annotation
annot'.
Compute variance of type parameter tparam' in all type annotations
annots'.
Compute variance of type parameter tparam' in type of symbol
sym'.
Compute variance of type parameter tparam' in types of all symbols
sym'.
Compute variance of type parameter tparam
in type tp
.
Compute variance of type parameter tparam' in all types
tps'.
Variances form a lattice, 0 <= COVARIANT <= Variances, 0 <= CONTRAVARIANT <= VARIANCES