[Vala] CRITICAL `VALA_IS_TYPESYMBOL (sym)' failed

[picca <picca synchrotron-soleil Fr>]

hello

when I am compiling my project walla send a CRITICAL message.
How can I help find the responsible of this message.

Thanks

Frederic

valac -C -d debug/linux2/src src/hkl-constants.vala src/hkl-vector.vala
src/hkl-interval.vala src/hkl-source.vala src/hkl-axis.vala
src/hkl-list.vala src/hkl-holder.vala src/hkl-geometry.vala
src/hkl-detector.vala src/hkl-parameter.vala src/hkl-lattice.vala
src/hkl-sample.vala src/hkl-pseudoaxis.vala
src/hkl-pseudoaxis-auto.vala src/gsl.vapi

** (valac:31555): CRITICAL **:
vala_ccode_generator_get_data_type_for_symbol: assertion
`VALA_IS_TYPESYMBOL (sym)' failed