Release Notes

spec/v3.1.0-12

New Features

• The types bool and (scalar) bit are now explicitly described as being completely interchangeable in expression (r-value) positions, and that bit and bit[1] are distinct types. The difference between the types bool and bit is only in their intended storage mechanisms; bit is the scalar of the register-type bit[n], which is explicitly a bit-packed type, so cannot be used as the base type of an array, while bool is a byte-aligned single-bit integer-like type. bit[1] is a register (sequence) type that happens to be of length one.

Upgrade Notes

• The qubit type is no longer a valid base type for an array, and it is no longer stated that the register type qubit[n] is equivalent to an array; there is no need for these semantics, and they clashed with the classical considerations and alignment concerns of arrays in general.

Bug Fixes

• Some minor mathematical errors in the descriptions of the explicit gate actions in sdg, rx, ry, rz, crx and cry were corrected. The gates have not changed their intended meanings.