Mutual assignability. Both sides are wrapped in tuples so a union does not distribute, which would let a strict subset pass.
Internal: exported so drift assertions elsewhere in src can use it, never from the package entry point.
src
Mutual assignability. Both sides are wrapped in tuples so a union does not distribute, which would let a strict subset pass.
Internal: exported so drift assertions elsewhere in
srccan use it, never from the package entry point.