usage02fixtures

Overview ¶

Package usage02fixtures holds typed-loadable .go fixtures for SCANNER-FRAMEWORK-USAGE-02 (main detector + BS1/BS2/BS3 reverse self-tests + BS4/BS5 main-detector-handled forms, on both EachInChildren and EachInSubtree depth axes).

Files in this package are loaded by tools/archtest/scanner_framework_usage_test.go via typeseval.SharedResolver — the same typed pipeline the live archtest scan runs on production archtest *_test.go files. There is no syntactic fallback: callee identity in fixtures resolves through *types.Info exactly as it does for the live scan, removing the PR-505 Soft fallback that previously served inline-source fixtures.

This package is intentionally placed at tools/archtest/internal/usage02fixtures/ (a non-_test.go internal sub-package) rather than under testdata/, for two reasons:

1. typed-load reachability: go/packages typed mode skips testdata directories by default; an internal sub-package is loaded reliably by the same ./tools/archtest/... pattern the live scan uses.

2. live-scan exclusion: the USAGE-02 live scan keeps only files whose parent directory is exactly "tools/archtest" AND whose name ends in _test.go. Fixture files live one directory deeper and are not _test.go, so they are filtered out — no risk of self-detection cycle.

Each .go file in this package corresponds to one fixture case; the basename (without .go) is the case identifier passed to loadFixture02. Functions are declared as func _(...) so each file can drop the body in without naming pressure; multiple func _() per package are permitted by the Go spec.

Fixture naming convention ¶

Files are named `<role>_<callee>[_<axis>]_<shape>.go`:

<role>: one of
  red_   — exercises the MAIN detector; loadFixture02 expects wantHits ≥ 1
  green_ — exercises GREEN form (canonical FindFirstChild/FindFirstInSubtree
           or sentinel-free EachIn* iteration); wantHits = 0
  bs1_/bs2_/bs3_ — BS1/BS2/BS3 blind-spot shape; MAIN detector
           expects wantHits = 0, the BS reverse detector
           (closureDoneSentinelBlindSpots) expects wantHits ≥ 1
  bs4_   — BS4 nested-walker shape; caught by MAIN detector (outer + inner)
<callee>: scanner or archtest (the package façade under test)
<axis>:   omitted for the original EachInChildren axis; added as
          _eachinsubtree_ for the EachInSubtree axis. The shape is
          depth-agnostic — the same detector covers both axes — but
          having an axis-tagged fixture per BS shape anchors that both
          depth axes are validated end-to-end through the typed pipeline.
<shape>:  short shape descriptor (done_sentinel, nonliteral_rhs,
          else_guard, assign_outside, nested_inner_sentinel,
          bs5_helper, ...).