source := filepath.Join("testdata", "fma.go")
	output := filepath.Join(tmpdir, "fma.exe")
	cmd := testenv.Command(t, gocmd, "build", "-o", output, source)
	// The hash-dependence on file path name is dodged by specifying "all hashes ending in 1" plus "all hashes ending in 0"
	// i.e., all hashes.  This will print all the FMAs; this test is only interested in one of them (that should appear near the end).

	}
	if ctxt != nil {
		ctxts = append(ctxts, ctxt)
	}
	assert(len(ctxts) > 0)

	// Compute all hashes; hashes may differ across contexts due to different
	// unique IDs for Named types within the hasher.
	hashes := make([]string, len(ctxts))
	for i, ctxt := range ctxts {
		hashes[i] = ctxt.instanceHash(orig, targs)
	}

	// Record the result in all contexts.

		// nothing to do
	case s.terms.isEmpty():
		w.string(s.terms.String())
	default:
		var termHashes []string
		for _, term := range s.terms {
			// terms are not canonically sorted, so we sort their hashes instead.
			var buf bytes.Buffer
			if term.tilde {
				buf.WriteByte('~')
			}
			newTypeHasher(&buf, w.ctxt).typ(term.typ)
			termHashes = append(termHashes, buf.String())
		}
		sort.Strings(termHashes)

(see 'go help build') to force rebuilding of packages that
depend on the updated C libraries.

The go command also caches successful package test results.
See 'go help test' for details. Running 'go clean -testcache' removes
all cached test results (but not cached build results).

The go command also caches values used in fuzzing with 'go test -fuzz',
specifically, values that expanded code coverage when passed to a

//
// When the go command downloads a module zip file or go.mod file into the
// module cache, it computes a cryptographic hash and compares it with a known
// value to verify the file hasn't changed since it was first downloaded. Known
// hashes are stored in a file in the module root directory named go.sum. Hashes
// may also be downloaded from the checksum database depending on the values of
// GOSUMDB, GOPRIVATE, and GONOSUMDB.
//

//go:build unix

package tar

import (
	"io/fs"
	"os/user"
	"runtime"
	"strconv"
	"sync"
	"syscall"
)

func init() {
	sysStat = statUnix
}

// userMap and groupMap caches UID and GID lookups for performance reasons.
// The downside is that renaming uname or gname by the OS never takes effect.
var userMap, groupMap sync.Map // map[int]string

const (
	AUNK   AlgKind = iota
	ANOEQ          // Types cannot be compared
	ANOALG         // implies ANOEQ, and in addition has a part that is marked Noalg
	AMEM           // Type can be compared/hashed as regular memory.
	AMEM0          // Specific subvariants of AMEM (TODO: move to ../reflectdata?)
	AMEM8
	AMEM16
	AMEM32
	AMEM64
	AMEM128
	ASTRING
	AINTER
	ANILINTER
	AFLOAT32
	AFLOAT64
	ACPLX64

		// Do not include local development, so that people working in the
		// main branch for day-to-day work on the Go toolchain itself can
		// still have full paths for stack traces for compiler crashes and the like.
		env = append(env, "GOFLAGS=-trimpath -ldflags=-w -gcflags=cmd/...=-dwarf=false")
	}
	return env
}

var toolchain = []string{"cmd/asm", "cmd/cgo", "cmd/compile", "cmd/link", "cmd/preprofile"}

download cache, including unpacked source code of versioned
dependencies.

The -fuzzcache flag causes clean to remove files stored in the Go build
cache for fuzz testing. The fuzzing engine caches files that expand
code coverage, so removing them may make fuzzing less effective until
new inputs are found that provide the same coverage. These files are
distinct from those stored in testdata directory; clean does not remove

		// alias declarations, and then everything else. This appears to avoid most situations
		// where the type of an alias is needed before it is available.
		// There may still be cases where this is not good enough (see also go.dev/issue/25838).
		// In those cases Checker.ident will report an error ("invalid use of type alias").
		var aliasList []*TypeName
		var othersList []Object // everything that's not a type