[short] skip
# Reset all experiments so fieldtrack is definitely off.
env GOEXPERIMENT=none
go run m
stderr 'fieldtrack off'
# Turn fieldtrack on.
env GOEXPERIMENT=none,fieldtrack
go run m
stderr 'fieldtrack on'

-- ft_off.go --
// +build !goexperiment.fieldtrack

package main

func main() {
	println("fieldtrack off")
}

-- ft_on.go --
// +build goexperiment.fieldtrack

package main

func main() {

# Test GOEXPERIMENT variable

# go env shows default empty GOEXPERIMENT
go env
stdout GOEXPERIMENT=

# go env shows valid experiments
env GOEXPERIMENT=fieldtrack,staticlockranking
go env GOEXPERIMENT
stdout '.*fieldtrack.*staticlockranking.*'
go env
stdout 'GOEXPERIMENT=.*fieldtrack.*staticlockranking.*'

# go env rejects unknown experiments
env GOEXPERIMENT=bad
! go env GOEXPERIMENT

// runindir -goexperiment fieldtrack -ldflags -k=main.fieldTrackInfo

// Copyright 2021 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// Code generated by mkconsts.go. DO NOT EDIT.

//go:build goexperiment.fieldtrack

package goexperiment

const FieldTrack = true

// runindir -goexperiment fieldtrack

// Copyright 2019 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// Test case for issue 30862.  This test as written will
// fail for the main 'gc' compiler unless GOEXPERIMENT=fieldtrack
// is set when building it, whereas gccgo has field tracking
// enabled by default (hence the build tag below).

// Code generated by mkconsts.go. DO NOT EDIT.

//go:build !goexperiment.fieldtrack

package goexperiment

const FieldTrack = false

# Test that experiments appear in "go version <binary>"

# This test requires rebuilding the runtime, which takes a while.
[short] skip

env GOEXPERIMENT=fieldtrack
go build -o main$GOEXE version.go
go version main$GOEXE
stdout 'X:fieldtrack$'
exec ./main$GOEXE
stderr 'X:fieldtrack$'

-- version.go --
package main
import "runtime"

// errorcheck -goexperiment fieldtrack

// Copyright 2023 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package p

func f(interface{ m() }) {}
func g()                 { f(new(T)) } // ERROR "m method is marked 'nointerface'"

type T struct{}

//go:nointerface

	// turn them into weak relocs.
	if fn.IsPackageInit() && base.Debug.WrapGlobalMapCtl != 1 {
		weakenGlobalMapInitRelocs(fn)
	}

	// fieldtrack must be called after pp.Flush. See issue 20014.
	fieldtrack(pp.Text.From.Sym, fn.FieldTrack)
}

// globalMapInitLsyms records the LSym of each map.init.NNN outlined
// map initializer function created by the compiler.

# Test that [GOEXPERIMENT:x] is accepted.
# Here fieldtrack is picked arbitrarily.

[GOEXPERIMENT:nofieldtrack] env

[GOEXPERIMENT:fieldtrack] env