Replaces a ~s or ~S sigil with the plain string literals "" and "mutare". A replacement equal to a static sigil value is omitted:
~s(hello)produces both replacements~s()produces only"mutare"~s(mutare)produces only""
Replacements are plain string literals because these sigils have no modifier that changes their value type.
Interpolated ~s sigils also receive both replacements because their runtime value cannot be compared statically. Expressions inside the interpolation remain eligible for their own mutations. ~S sigils do not interpolate.
The whole sigil is mutated only in runtime positions, not in patterns. The ignore variants are empty and sentinel.