What really happens when you run go run?

session.txt

$ cat hello.go
package main

import "fmt"

func main() {
	fmt.Println("Hello!")
}
$ go run -x hello.go
WORK=/var/folders/zh/tm1rghjn6hxdzbh5j8bnrmp80000gn/T/go-build036837237
mkdir -p $WORK/b001/
cat >$WORK/b001/importcfg.link << 'EOF' # internal
packagefile command-line-arguments=/Users/ian/Library/Caches/go-build/a9/a989766f21961ff0c1198c4684b8f66737afbfd8f608b1ff7bb411862ffd39be-d
packagefile fmt=/usr/local/go/pkg/darwin_amd64/fmt.a
packagefile runtime=/usr/local/go/pkg/darwin_amd64/runtime.a
packagefile errors=/usr/local/go/pkg/darwin_amd64/errors.a
packagefile internal/fmtsort=/usr/local/go/pkg/darwin_amd64/internal/fmtsort.a
packagefile io=/usr/local/go/pkg/darwin_amd64/io.a
packagefile math=/usr/local/go/pkg/darwin_amd64/math.a
packagefile os=/usr/local/go/pkg/darwin_amd64/os.a
packagefile reflect=/usr/local/go/pkg/darwin_amd64/reflect.a
packagefile strconv=/usr/local/go/pkg/darwin_amd64/strconv.a
packagefile sync=/usr/local/go/pkg/darwin_amd64/sync.a
packagefile unicode/utf8=/usr/local/go/pkg/darwin_amd64/unicode/utf8.a
packagefile internal/bytealg=/usr/local/go/pkg/darwin_amd64/internal/bytealg.a
packagefile internal/cpu=/usr/local/go/pkg/darwin_amd64/internal/cpu.a
packagefile runtime/internal/atomic=/usr/local/go/pkg/darwin_amd64/runtime/internal/atomic.a
packagefile runtime/internal/math=/usr/local/go/pkg/darwin_amd64/runtime/internal/math.a
packagefile runtime/internal/sys=/usr/local/go/pkg/darwin_amd64/runtime/internal/sys.a
packagefile sort=/usr/local/go/pkg/darwin_amd64/sort.a
packagefile sync/atomic=/usr/local/go/pkg/darwin_amd64/sync/atomic.a
packagefile math/bits=/usr/local/go/pkg/darwin_amd64/math/bits.a
packagefile internal/poll=/usr/local/go/pkg/darwin_amd64/internal/poll.a
packagefile internal/syscall/unix=/usr/local/go/pkg/darwin_amd64/internal/syscall/unix.a
packagefile internal/testlog=/usr/local/go/pkg/darwin_amd64/internal/testlog.a
packagefile syscall=/usr/local/go/pkg/darwin_amd64/syscall.a
packagefile time=/usr/local/go/pkg/darwin_amd64/time.a
packagefile unicode=/usr/local/go/pkg/darwin_amd64/unicode.a
packagefile internal/race=/usr/local/go/pkg/darwin_amd64/internal/race.a
EOF
mkdir -p $WORK/b001/exe/
cd .
/usr/local/go/pkg/tool/darwin_amd64/link -o $WORK/b001/exe/hello -importcfg $WORK/b001/importcfg.link -s -w -buildmode=exe -buildid=UFuQnS8shw30HlX1I04h/CGLKTgf8VYWJUa8uzHzZ/wMkQVr-prH_X1CtQtDNO/UFuQnS8shw30HlX1I04h -extld=clang /Users/ian/Library/Caches/go-build/a9/a989766f21961ff0c1198c4684b8f66737afbfd8f608b1ff7bb411862ffd39be-d
$WORK/b001/exe/hello
Hello!