Quartus Prime Error: pin name is an illegal or unsupported format

This is my entity

entity GCP is
 port
 (
-- {ALTERA_IO_BEGIN} DO NOT REMOVE THIS LINE!
      --spi slave 1
  M1_SPI_CLK  : in std_logic;
  M1_SPI_MOSI : in std_logic;
  M1_SPI_MISO : out std_logic;
  M1_SPI_CS   : in std_logic;
  --spi slave 0
  M0_SPI_CLK  : in std_logic;
  M0_SPI_MOSI : in std_logic;
  M0_SPI_MISO : out std_logic;
  M0_CS       : in std_logic;
     
  CLK    : in std_logic
-- {ALTERA_IO_END} DO NOT REMOVE THIS LINE!
 );
-- {ALTERA_ATTRIBUTE_BEGIN} DO NOT REMOVE THIS LINE!
-- {ALTERA_ATTRIBUTE_END} DO NOT REMOVE THIS LINE!
end GCP;

I get wornings

Warning (169133): Can't reserve pin M0_CS -- pin name is an illegal or unsupported format Warning (169140): Reserve pin assignment ignored because of existing pin with name "M0_CS"

And so on for each pn.

Why?