Assert-error inside %json-type-to-cffi-type

[C-Entropy]

I'm trying to use cffi/c2ffi to generate wrap for vulkan_core.h
And run into error:

The assertion
(NOT #1=(ALEXANDRIA:STARTS-WITH #\: CFFI/C2FFI::TAG)) failed
with #1# = T.
   [Condition of type SIMPLE-ERROR]

Restarts:
 0: [CONTINUE] Retry assertion.
 1: [RETRY] Retry #<GENERATE-LISP-OP > on #<C2FFI-FILE "clkan" "vulkan-specs" "vulkan_core.h">.
 2: [ACCEPT] Continue, treating #<GENERATE-LISP-OP > on #<C2FFI-FILE "clkan" "vulkan-specs" "vulkan_core.h"> as having been successful.
 3: [RETRY] Retry ASDF operation.
 4: [CLEAR-CONFIGURATION-AND-RETRY] Retry ASDF operation after resetting the configuration.
 5: [ABORT] Give up on "clkan"
 --more--

Backtrace:
  0: (SB-KERNEL:ASSERT-ERROR (NOT (ALEXANDRIA:STARTS-WITH #\: CFFI/C2FFI::TAG)) 1 (ALEXANDRIA:STARTS-WITH #\: CFFI/C2FFI::TAG) T)
      Locals:
        ASSERTION = (NOT (ALEXANDRIA:STARTS-WITH #\: CFFI/C2FFI::TAG))
        REST = (1 (ALEXANDRIA:STARTS-WITH #\: CFFI/C2FFI::TAG) T)
  1: (CFFI/C2FFI::%JSON-TYPE-TO-CFFI-TYPE ((:TAG . ":bitfield") (:WIDTH . 1) (:TYPE (:TAG . "uint32_t"))))
      Locals:
        JSON-ENTRY = ((:TAG . ":bitfield") (:WIDTH . 1) (:TYPE (:TAG . "uint32_t")))
        TAG = ":bitfield"
  2: (CFFI/C2FFI::JSON-TYPE-TO-CFFI-TYPE ((:TAG . ":bitfield") (:WIDTH . 1) (:TYPE (:TAG . "uint32_t"))) (:STRUCT "StdVideoH264SpsVuiFlags" "aspect_ratio_info_present_flag"))
      Locals:
        CONTEXT = (:STRUCT "StdVideoH264SpsVuiFlags" "aspect_ratio_info_present_flag")
        CONTEXT? = T
        JSON-ENTRY = ((:TAG . ":bitfield") (:WIDTH . 1) (:TYPE (:TAG . "uint32_t")))
  3: (CFFI/C2FFI::%PROCESS-STRUCT-LIKE ((:TAG . "struct") (:NS . 0) (:NAME . "StdVideoH264SpsVuiFlags") (:ID . 0) (:LOCATION . "/usr/include/vk_video/vulkan_video_codec_h264std.h:178:16") (:BIT-SIZE . 32) ..
      Locals:
        ANON-BASE-NAME = #:ANON-STRUCT-
        FIELD-NAME = "aspect_ratio_info_present_flag"
        #:G45 = CFFI:DEFCSTRUCT
        JSON-ENTRY = ((:TAG . "struct") (:NS . 0) (:NAME . "StdVideoH264SpsVuiFlags") (:ID . 0) (:LOCATION . "/usr/include/vk_video/vulkan_video_codec_h264std.h:178:16") (:BIT-SIZE . 32) ...)
        JSON-ENTRY#1 = ((:TAG . "field") (:NAME . "aspect_ratio_info_present_flag") (:BIT-OFFSET . 0) (:BIT-SIZE . 32) (:BIT-ALIGNMENT . 32) (:TYPE (:TAG . ":bitfield") (:WIDTH . 1) (:TYPE (:TAG . "uint32_t"))))
        KIND = :STRUCT
        STRUCT-NAME = "StdVideoH264SpsVuiFlags"
        TYPE = ((:TAG . ":bitfield") (:WIDTH . 1) (:TYPE (:TAG . "uint32_t")))
  4: (CFFI/C2FFI::PROCESS-C2FFI-ENTRY ((:TAG . "struct") (:NS . 0) (:NAME . "StdVideoH264SpsVuiFlags") (:ID . 0) (:LOCATION . "/usr/include/vk_video/vulkan_video_codec_h264std.h:178:16") (:BIT-SIZE . 32) ...
  5: ((FLET "THUNK" :IN CFFI/C2FFI::PROCESS-C2FFI-SPEC-FILE))
  6: (SB-IMPL::%WITH-STANDARD-IO-SYNTAX #<FUNCTION (FLET "THUNK" :IN CFFI/C2FFI::PROCESS-C2FFI-SPEC-FILE) {7FAB0F50CB4B}>)
  7: (CFFI/C2FFI::PROCESS-C2FFI-SPEC-FILE #P"/home/nuil/.roswell/lisp/quicklisp/local-projects/clkan/vulkan-specs/vulkan_core.x86_64-pc-linux-gnu.spec" #:CLKAN.C2FFI :ALLOW-POINTER-TYPE-SIMPLIFICATION NIL ..
  8: (UIOP/STREAM:CALL-WITH-STAGING-PATHNAME #P"/home/nuil/.roswell/lisp/quicklisp/local-projects/clkan/vulkan-specs/vulkan_core.x86_64-pc-linux-gnu.lisp" #<FUNCTION (LAMBDA (CFFI/C2FFI::TMP-OUTPUT) :IN AS..
  9: ((SB-PCL::EMF ASDF/ACTION:PERFORM) #<unused argument> #<unused argument> #<CFFI/C2FFI::GENERATE-LISP-OP > #<CFFI/C2FFI:C2FFI-FILE "clkan" "vulkan-specs" "vulkan_core.h">)
 10: ((LAMBDA NIL :IN ASDF/ACTION:CALL-WHILE-VISITING-ACTION))
 11: ((:METHOD ASDF/ACTION:PERFORM-WITH-RESTARTS :AROUND (T T)) #<CFFI/C2FFI::GENERATE-LISP-OP > #<CFFI/C2FFI:C2FFI-FILE "clkan" "vulkan-specs" "vulkan_core.h">) [fast-method]
 12: ((:METHOD ASDF/PLAN:PERFORM-PLAN (T)) #<ASDF/PLAN:SEQUENTIAL-PLAN {1005DB1343}>) [fast-method]
 13: ((FLET SB-C::WITH-IT :IN SB-C::%WITH-COMPILATION-UNIT))
 14: ((:METHOD ASDF/PLAN:PERFORM-PLAN :AROUND (T)) #<ASDF/PLAN:SEQUENTIAL-PLAN {1005DB1343}>) [fast-method]
 15: ((:METHOD ASDF/OPERATE:OPERATE (ASDF/OPERATION:OPERATION ASDF/COMPONENT:COMPONENT)) #<ASDF/LISP-ACTION:LOAD-OP > #<ASDF/SYSTEM:SYSTEM "clkan"> :PLAN-CLASS NIL :PLAN-OPTIONS NIL) [fast-method]
 16: ((SB-PCL::EMF ASDF/OPERATE:OPERATE) #<unused argument> #<unused argument> #<ASDF/LISP-ACTION:LOAD-OP > #<ASDF/SYSTEM:SYSTEM "clkan"> :VERBOSE NIL)
 17: ((LAMBDA NIL :IN ASDF/OPERATE:OPERATE))
 18: ((:METHOD ASDF/OPERATE:OPERATE :AROUND (T T)) #<ASDF/LISP-ACTION:LOAD-OP > #<ASDF/SYSTEM:SYSTEM "clkan"> :VERBOSE NIL) [fast-method]
 19: ((SB-PCL::EMF ASDF/OPERATE:OPERATE) #<unused argument> #<unused argument> ASDF/LISP-ACTION:LOAD-OP "clkan" :VERBOSE NIL)
 --more--

; compilation unit aborted
;   caught 1 fatal ERROR condition
; Evaluation aborted on #<SIMPLE-ERROR "~@<The assertion ~S failed~:[.~:; ~
;                                            with ~:*~{~S = ~S~^, ~}.~]~:@>" {10025035B3}>.

Here is my .asd

(defsystem "clkan"
  :version "0.0.1"
  :author "Sherman Lau"
  :license ""
  :defsystem-depends-on (:cffi/c2ffi)
  :depends-on (:cffi
	       :cffi/c2ffi)
  :components ((:file "c2ffi"
		      :pathname "src/c2ffi")
	       (:module "src"
                :components
                ((:file "utils")
		 (:file "clkan" :depends-on ("utils"))))
	       (:module "vulkan-specs"
		:depends-on ("c2ffi")
		:components ((:cffi/c2ffi-file "vulkan_core.h"
			      :package #:clkan.c2ffi
			      :foreign-library-name "clkan.c2ffi::libvulkan"
			      :foreign-library-spec ((t (:default "libvulkan")))
			      :include-sources :all
			      :include-definitions :all
			      )))
	       )
  :description ""
  :in-order-to ((test-op (test-op "clkan/tests"))))

How should I fix it?

[C-Entropy]

json:

{ "tag": "struct", "ns": 0, "name": "StdVideoH264SpsVuiFlags", "id": 0, "location": "/usr/include/vk_video/vulkan_video_codec_h264std.h:178:16", "bit-size": 32, "bit-alignment": 32, "fields": [{ "tag": "field", "name": "aspect_ratio_info_present_flag", "bit-offset": 0, "bit-size": 32, "bit-alignment": 32, "type": { "tag": ":bitfield", "width": 1, "type": { "tag": "uint32_t" } } }, { "tag": "field", "name": "overscan_info_present_flag", "bit-offset": 1, "bit-size": 32, "bit-alignment": 32, "type": { "tag": ":bitfield", "width": 1, "type": { "tag": "uint32_t" } } }, { "tag": "field", "name": "overscan_appropriate_flag", "bit-offset": 2, "bit-size": 32, "bit-alignment": 32, "type": { "tag": ":bitfield", "width": 1, "type": { "tag": "uint32_t" } } }, { "tag": "field", "name": "video_signal_type_present_flag", "bit-offset": 3, "bit-size": 32, "bit-alignment": 32, "type": { "tag": ":bitfield", "width": 1, "type": { "tag": "uint32_t" } } }, { "tag": "field", "name": "video_full_range_flag", "bit-offset": 4, "bit-size": 32, "bit-alignment": 32, "type": { "tag": ":bitfield", "width": 1, "type": { "tag": "uint32_t" } } }, { "tag": "field", "name": "color_description_present_flag", "bit-offset": 5, "bit-size": 32, "bit-alignment": 32, "type": { "tag": ":bitfield", "width": 1, "type": { "tag": "uint32_t" } } }, { "tag": "field", "name": "chroma_loc_info_present_flag", "bit-offset": 6, "bit-size": 32, "bit-alignment": 32, "type": { "tag": ":bitfield", "width": 1, "type": { "tag": "uint32_t" } } }, { "tag": "field", "name": "timing_info_present_flag", "bit-offset": 7, "bit-size": 32, "bit-alignment": 32, "type": { "tag": ":bitfield", "width": 1, "type": { "tag": "uint32_t" } } }, { "tag": "field", "name": "fixed_frame_rate_flag", "bit-offset": 8, "bit-size": 32, "bit-alignment": 32, "type": { "tag": ":bitfield", "width": 1, "type": { "tag": "uint32_t" } } }, { "tag": "field", "name": "bitstream_restriction_flag", "bit-offset": 9, "bit-size": 32, "bit-alignment": 32, "type": { "tag": ":bitfield", "width": 1, "type": { "tag": "uint32_t" } } }, { "tag": "field", "name": "nal_hrd_parameters_present_flag", "bit-offset": 10, "bit-size": 32, "bit-alignment": 32, "type": { "tag": ":bitfield", "width": 1, "type": { "tag": "uint32_t" } } }, { "tag": "field", "name": "vcl_hrd_parameters_present_flag", "bit-offset": 11, "bit-size": 32, "bit-alignment": 32, "type": { "tag": ":bitfield", "width": 1, "type": { "tag": "uint32_t" } } }] }