microchip MPLAB X IDE v2.15 "can't generate code for this expression" - ide

Question

I´m trying to compile a simple piece code, but i run into a error "can't generate code for this expression".
i adapted to code from "http://www.barrysoft.it/blog/midi-with-pic-ausart.html"
could someone enlighten me about this problem?
MPLAB X IDE v2.15
xc8 v1.32
midi.c:
void midi_init(void)
{
/* MIDI uses 31250 baud/s serial speed */
uart_init(19, 1, 0, 0 ); //<---
}
midi.c:31: error: (712) can't generate code for this expression
uart.c:
void uart_init(unsigned char spbrg, unsigned bit brgh, unsigned bit sync, unsigned bit parity)
{
// Setup the baud rate
SPBRG = spbrg;
// High speed baud rate
BRGH = brgh; ////
// Synch or Async
SYNC = sync; ////
// 8bit transmission
TX9 = parity; ////
// Enable serial output
SPEN = 1;
// Enable UART out
TXEN = 1;
}
uart.c:29: error: (712) can't generate code for this expression
uart.c:32: error: (712) can't generate code for this expression
uart.c:35: error: (712) can't generate code for this expression
uart.h:
void uart_init(unsigned char spbrg, unsigned bit brgh,unsigned bit sync,unsigned bit parity);
Unable to resolve identifier bit, this seams to be a MPLAB IDE error, witch can be turned off.

Answer 1

This is probably an issue with how the compiler handles data witdths inferior to processor`s native width.
One simple fix is to use macros instead of a function. This works because you let the compiler handle the type conversions and literal data how it sees fit instead of forcing it to commit bit variables to memory locations (for the function call).
In uart.h:
#define uart_init( spbrg, brgh, sync, parity ) \
SPBRG = spbrg;\
BRGH = brgh;\
SYNC = sync;\
TX9 = parity;\
SPEN = 1;\
TXEN = 1
*Note that I intentionally left out the last line`s ';' so that the macro can be called like a function.
In midi.c: No change...
uart_init(19, 1, 0, 0 );