[thomas-weissschuh:b4/rust-dyndbg 15/15] error[E0277]: the `?` operator can only be used in a closure that returns `Result` or `Option` (or another type that implements `FromResidual`)

[kernel test robot <lkp@intel.com>]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/thomas.weissschuh/linux.git b4/rust-dyndbg
head:   e0f643bcb55eadaa7c1b9d23ea0569cf7b5377a8
commit: e0f643bcb55eadaa7c1b9d23ea0569cf7b5377a8 [15/15] rust: device: enable dynamic debug for dev_dbg!()
config: x86_64-buildonly-randconfig-1003-20261002 (https://download.01.org/0day-ci/archive/20261002/202610021540.mJ8YCCMD-lkp@intel.com/config)
compiler: clang version 22.1.3 (https://github.com/llvm/llvm-project e9846648fd6183ee6d8cbdb4502213fcf902a211)
rustc: rustc 1.96.0 (ac68faa20 2026-05-25)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20261002/202610021540.mJ8YCCMD-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202610021540.mJ8YCCMD-lkp@intel.com/

All errors (new ones prefixed by >>):

>> error[E0277]: the `?` operator can only be used in a closure that returns `Result` or `Option` (or another type that implements `FromResidual`)
   --> drivers/gpu/nova-core/firmware/gsp.rs:77:79
   |
   77 |             dev_dbg!(dev, "loaded gsp firmware v{}\n", tlv.get_string(b"VERS")?);
   |                                                                               ^ cannot use the `?` operator in a closure that returns `()`
   |
   ::: rust/kernel/dynamic_debug.rs:227:72
   |
   227 |         $crate::dynamic_func_call!($crate::__format_string!($($arg)+), || {
   |                                                                        -- this function should return `Result` or `Option` to accept `?`
--
>> error[E0277]: the `?` operator can only be used in a closure that returns `Result` or `Option` (or another type that implements `FromResidual`)
   --> drivers/gpu/nova-core/firmware/booter.rs:100:36
   |
   100 |             tlv.get_string(b"VERS")?
   |                                    ^ cannot use the `?` operator in a closure that returns `()`
   |
   ::: rust/kernel/dynamic_debug.rs:227:72
   |
   227 |         $crate::dynamic_func_call!($crate::__format_string!($($arg)+), || {
   |                                                                        -- this function should return `Result` or `Option` to accept `?`
--
>> error[E0277]: the `?` operator can only be used in a closure that returns `Result` or `Option` (or another type that implements `FromResidual`)
   --> drivers/gpu/nova-core/firmware/fsp.rs:53:75
   |
   53 |         dev_dbg!(dev, "loaded fsp firmware v{}\n", tlv.get_string(b"VERS")?);
   |                                                                           ^ cannot use the `?` operator in a closure that returns `()`
   |
   ::: rust/kernel/dynamic_debug.rs:227:72
   |
   227 |         $crate::dynamic_func_call!($crate::__format_string!($($arg)+), || {
   |                                                                        -- this function should return `Result` or `Option` to accept `?`
--
>> error[E0277]: the `?` operator can only be used in a closure that returns `Result` or `Option` (or another type that implements `FromResidual`)
   --> drivers/gpu/nova-core/firmware/fwsec/bootloader.rs:129:36
   |
   129 |             tlv.get_string(b"VERS")?
   |                                    ^ cannot use the `?` operator in a closure that returns `()`
   |
   ::: rust/kernel/dynamic_debug.rs:227:72
   |
   227 |         $crate::dynamic_func_call!($crate::__format_string!($($arg)+), || {
   |                                                                        -- this function should return `Result` or `Option` to accept `?`
--
>> error[E0277]: the `?` operator can only be used in a closure that returns `Result` or `Option` (or another type that implements `FromResidual`)
   --> drivers/gpu/nova-core/firmware/riscv.rs:36:36
   |
   36 |             tlv.get_string(b"VERS")?
   |                                    ^ cannot use the `?` operator in a closure that returns `()`
   |
   ::: rust/kernel/dynamic_debug.rs:227:72
   |
   227 |         $crate::dynamic_func_call!($crate::__format_string!($($arg)+), || {
   |                                                                        -- this function should return `Result` or `Option` to accept `?`

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