_linters/src/honnef.co/go/tools/functions/pure.go
func (d *Descriptions) IsStub(fn *ssa.Function) bool {
	if len(fn.Blocks) == 0 {
		return true
	}
	if len(fn.Blocks) > 1 {
		return false
	}
	instrs := lintdsl.FilterDebug(fn.Blocks[0].Instrs)
	if len(instrs) != 1 {
		return false
	}

	switch instrs[0].(type) {
	case *ssa.Return:
		// Since this is the only instruction, the return value must
		// be a constant. We consider all constants as stubs, not just
		// the zero value. This does not, unfortunately, cover zero
		// initialised structs, as these cause additional
		// instructions.
		return true
	case *ssa.Panic:
		return true
	default:
		return false
	}
}
func (d *Descriptions) IsStub(fn *ssa.Function) bool {
	if len(fn.Blocks) == 0 {
		return true
	}
	if len(fn.Blocks) > 1 {
		return false
	}
	instrs := lintdsl.FilterDebug(fn.Blocks[0].Instrs)
	if len(instrs) != 1 {
		return false
	}

	switch instrs[0].(type) {
	case *ssa.Return:
		// Since this is the only instruction, the return value must
		// be a constant. We consider all constants as stubs, not just
		// the zero value. This does not, unfortunately, cover zero
		// initialised structs, as these cause additional
		// instructions.
		return true
	case *ssa.Panic:
		return true
	default:
		return false
	}
}
// IsStub reports whether a function is a stub. A function is
// considered a stub if it has no instructions or exactly one
// instruction, which must be either returning only constant values or
// a panic.