An access is physical; a grant prefix is a logical spelling

An access is resolved as the kernel resolves it; a grant prefix is a logical spelling, folded before it is resolved. The two meet on their real forms. This sharpens object-not-name: the policy side and the access side now resolve a name by one code path.

Context

• The lenient canonicaliser kept a dangling link’s own name while the walk resolved its target, so a deny on such a link did not hold for a write through it.
• Anchoring folded .. lexically and dropped a trailing separator before the disk was asked, so resolve-path 'link/../f' and > 'file/' disagreed with the kernel; and the root, having no leaf, was not an object at all.

Decision

• Anchoring and folding are separate. A LexicalPath is absolute and anchored, ., .. and a trailing separator kept. LexicalPath::folded is the explicit fold, asked by the logical consumers: cd, within [dir: …], absolute-path, a display base, the device predicates.
• One physical resolution. walk is the resolver: from the root, by directory handles, every link spliced, every .. taken after the links before it, a trailing separator demanding a directory. Under Missing::Refuse it is an open; under Missing::Tolerate (resolve_lenient) it stops at the first name it cannot enter and appends the rest lexically. The lenient canonicaliser is the second mode.
• Grant prefixes are logical. FrozenPath::mint folds the surface, then resolves it: `cwd link/../x names <cwd>/x.
• A directory is an object. The root, a name ending in a separator and a trailing .. locate the directory through its own handle (leaf .), so every query answers for /, and a write to one fails with EISDIR.

Rejected

• Folding on the access side: it answers for a name the kernel never reads.
• The ancestor walk over realpath(3): a second resolver, which disagreed with the first on exactly the names an attacker chooses.

Where

• core/src/path/walk.rs — walk, resolve_lenient, Missing, the directory-itself Located.
• core/src/path/canon.rs — canonicalise_lenient over resolve_lenient.
• core/src/path/forms.rs — LexicalPath::folded, FrozenPath::mint.