basic: public function across units.
pubfld: public type and public field across units.
dotted and alias: canonical dotted unit paths, last-segment binding, and explicit import aliases.
dotpriv: a dotted unit prefix does not grant access to another unit's private declarations.
errsame: two units use the same anonymous error.Name; the driver must assign one deterministic core.Error code.
errdet: the same anonymous error-name set appears in a different source/import order; generated fe_errors.h must be byte-identical to errsame modulo the intentionally different unit graph.

Fail cases:

privfn: private declaration access.
privfld: private field access.
missing: unresolved import.
cycle: cyclic imports.
unitbad: filename/unit-name mismatch.
badupper and badlong: DOS-safe lowercase, eight-character unit-segment limit.
bindconf: two imports with the same last-segment binding require an alias.
pubpriv: a public signature cannot expose a private nominal type.
errnom: nominal error cannot flow into core.Error via try.

The current M5 TEST-DOS.BAT is intentionally unchanged. M8 should add procedural checks for .fei creation/hash invalidation and deterministic fe_errors.h using these fixtures.

The M8 DOS gate must additionally construct two separate -I roots containing the same canonical unit and require an ambiguity error; repeat the case with two paths to the same canonical file and require deduplication. It must also verify that std.* resolves only from the built-in std root, ordinary user units never do, and that changing a private non-generic implementation preserves the dependent interface-cache hit. Those checks need temporary roots/cache inspection and deliberately remain procedural rather than encoding host paths in fixtures.