When the Wio Terminal is configured as a slave mode, there is a conflicting definition of the IRQ handler:
In variant.h WIRE_IT_HANDLER is defined as SERCOM4 handler whatever the ROLE is. This is used by Wire.cpp included library
In variant.c Depends on ROLE, SERCOM4 is also defined and associated to Serial port1
As a consequence, you can't compile with Wire included when in slave mode.
When the Wio Terminal is configured as a slave mode, there is a conflicting definition of the IRQ handler: In variant.h WIRE_IT_HANDLER is defined as SERCOM4 handler whatever the ROLE is. This is used by Wire.cpp included library
In variant.c Depends on ROLE, SERCOM4 is also defined and associated to Serial port1
As a consequence, you can't compile with Wire included when in slave mode.