19.3 Array element access

Array elements are accessed using element-access expressions (§14.5.6.1) of
the form A[I1, I2, ?, IN],
where A is an expression of an array type and each IX is an expression of
type int, uint, long, ulong, or
of a type that can be implicitly converted to one or more of these types.
The result of an array element access
is a variable, namely the array element selected by the indices.
The elements of an array can be enumerated using a foreach statement (§15.8.
4).