weird comments in Memoize nodes

Consider:

typedef struct Memoize
{
Plan plan;

int numKeys; /* size of the two arrays below */

Oid *hashOperators; /* hash operators for each key */
Oid *collations; /* cache keys */
List *param_exprs; /* exprs containing parameters */
...

I think the comment "cache keys" is weird here. Maybe it was copied from

typedef struct MemoizePath
{
Path path;
Path *subpath; /* outerpath to cache tuples from */
List *hash_operators; /* hash operators for each key */
List *param_exprs; /* cache keys */
...

but it's attached to a different field there.

Is this a mistake, or could this be clarified?