GOARCH:        c.GOARCH,
		GOOS:          c.GOOS,
		GOROOT:        c.GOROOT,
		GOPATH:        c.GOPATH,
		CgoEnabled:    c.CgoEnabled,
		UseAllFiles:   c.UseAllFiles,
		Compiler:      c.Compiler,
		BuildTags:     c.BuildTags,
		ToolTags:      c.ToolTags,
		ReleaseTags:   c.ReleaseTags,
		InstallSuffix: c.InstallSuffix,
	}

	"appends":          true,
	"asmdecl":          true,
	"assign":           true,
	"atomic":           true,
	"bool":             true,
	"bools":            true,
	"buildtag":         true,
	"buildtags":        true,
	"cgocall":          true,
	"composites":       true,
	"copylocks":        true,
	"defers":           true,
	"directive":        true,
	"errorsas":         true,

env GO111MODULE=on

# Issue 35837: "go vet -<analyzer> <std package>" should use the requested
# analyzers, not the default analyzers for 'go test'.
go vet -n -buildtags=false runtime
stderr '-buildtags=false'
! stderr '-unsafeptr=false'

# Issue 37030: "go vet <std package>" without other flags should disable the
# unsafeptr check by default.
go vet -n runtime
stderr '-unsafeptr=false'
! stderr '-unreachable=false'

		cfg.BuildContext.GOOS:     true,
		cfg.BuildContext.GOARCH:   true,
		cfg.BuildContext.Compiler: true,
	}
	if cfg.BuildContext.CgoEnabled {
		tags["cgo"] = true
	}
	for _, tag := range cfg.BuildContext.BuildTags {
		tags[tag] = true
	}
	for _, tag := range cfg.BuildContext.ToolTags {
		tags[tag] = true
	}
	for _, tag := range cfg.BuildContext.ReleaseTags {
		tags[tag] = true
	}
	return tags
}

var (

var curves = []struct {
	P         string
	Element   string
	Params    *elliptic.CurveParams
	BuildTags string
}{
	{
		P:       "P224",
		Element: "fiat.P224Element",
		Params:  elliptic.P224().Params(),
	},
	{
		P:         "P256",
		Element:   "fiat.P256Element",
		Params:    elliptic.P256().Params(),
		BuildTags: "(!amd64 && !arm64 && !ppc64le && !s390x) || purego",
	},
	{
		P:       "P384",

		for GOARCH := range allGOARCH {
			context := build.Context{
				GOOS:      "linux", // darwin has custom assembly
				GOARCH:    GOARCH,
				GOROOT:    testenv.GOROOT(t),
				Compiler:  build.Default.Compiler,
				BuildTags: []string{"purego", "math_big_pure_go"},
			}

			pkg, err := context.Import(pkgName, "", 0)
			if err != nil {
				t.Fatal(err)
			}
			if len(pkg.SFiles) == 0 {
				continue
			}

	// Clients creating a new context may customize BuildTags, which
	// defaults to empty, but it is usually an error to customize ToolTags or ReleaseTags.
	// ToolTags defaults to build tags appropriate to the current Go toolchain configuration.
	// ReleaseTags defaults to the list of Go releases the current release is compatible with.
	// BuildTags is not set for the Default build Context.
	// In addition to the BuildTags, ToolTags, and ReleaseTags, build constraints

	if generateSkipFlag != "" {
		var err error
		generateSkipRE, err = regexp.Compile(generateSkipFlag)
		if err != nil {
			log.Fatalf("generate: %s", err)
		}
	}

	cfg.BuildContext.BuildTags = append(cfg.BuildContext.BuildTags, "generate")

	// Even if the arguments are .go files, this loop suffices.
	printed := false
	pkgOpts := load.PackageOpts{IgnoreImports: true}

	// Clients creating a new context may customize BuildTags, which
	// defaults to empty, but it is usually an error to customize ToolTags or ReleaseTags.
	// ToolTags defaults to build tags appropriate to the current Go toolchain configuration.
	// ReleaseTags defaults to the list of Go releases the current release is compatible with.
	// BuildTags is not set for the Default build Context.
	// In addition to the BuildTags, ToolTags, and ReleaseTags, build constraints

	nomatch(runtime.GOOS+","+runtime.GOARCH+",foo", map[string]bool{runtime.GOOS: true, runtime.GOARCH: true, "foo": true})

	what = "modified"
	ctxt.BuildTags = []string{"foo"}
	match(runtime.GOOS+","+runtime.GOARCH, map[string]bool{runtime.GOOS: true, runtime.GOARCH: true})
	match(runtime.GOOS+","+runtime.GOARCH+",foo", map[string]bool{runtime.GOOS: true, runtime.GOARCH: true, "foo": true})