The driver searchpath is srcd-first (srcd = the entry file's directory).
A co-located black-box test lib/<mod>/<mod>test.ww makes srcd=lib/<mod>,
so resolving `import <mod>` hit the sibling-FILE branch lib/<mod>/<mod>.ww
and folded it inline into the consumer unit under the wrong module tag
("package <mod> does not match import path <importer>") — 7 lib-run tests
fail under separate compilation. The combined amalgamator tolerated the
co-location; only sep surfaced it.
Resolve a package directory-first: walk ALL searchpath entries for a
directory match, and only fall back to a file match if no directory
exists anywhere. A dir-package now beats a same-named sibling file (fixes
the self-named shadow), while a leaf package with no directory (e.g.
lib/encoding/hex) still resolves via its file. This realizes the driver's
"a module is the directory" intent; the originally-specced per-directory
suppression was rejected because it broke leaf packages (rob-pike). Both
stages (cmd/ww/main.c + selfhost twin). The dir-beats-earlier-file
precedence change is latent and loud-failing (#101).
Move-set: ww + ww_ww (driver) only; w6c_ww/wwdump_ww/w6a_ww/w6l_ww HOLD.
Gate: test/wcc/989_coloimport_sep.c (table-driven, both stages).
Hojun-Cho
200f51ca94