Kconfig: '+config' valid syntax?

Valentin Rothberg
2015-07-02T08:09:20Z

Hi,

commit ed013214afa7 ("ACPI / init: Make it possible to override _REV")
is in today's linux-next tree (i.e., next-20150702) adding the
following hunk to drivers/acpi/Kconfig:

--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -428,6 +428,26 @@ config XPOWER_PMIC_OPREGION
help
This config adds ACPI operation region support for XPower AXP288 PMIC.

++config ACPI_REV_OVERRIDE_POSSIBLE
+ bool "Allow supported ACPI revision to be overriden"
+ depends on X86
+ default y
[...]

By having a close look at the first added line, we can see that
'+config ACPI_...' is added. To my great surprise, it's valid Kconfig
syntax. How is that possible? IMHO it's an invalid token, such that
Kconfig should complain about it. Or do I miss something?

Kind regards,
Valentin