VHDL-2008: Error when checking locally static statement

[bpadalino]

The following code fails with a SEVG_MAPERR:

library ieee ;
    use ieee.numeric_std.all ;

entity saturate is
  port (
    x   :   in  signed(31 downto 0) ;
    y   :   out signed(15 downto 0)
  ) ;
end entity ;

architecture ifarch of saturate is

    constant sat_high : signed := to_signed(2**(y'length-1) - 1, y'length) ;
    constant sat_low  : signed := to_signed(-(2**(y'length-1)), y'length) ;

    constant too_high : integer := to_integer(sat_high) ;
    constant too_low  : integer := to_integer(sat_low) ;

begin

    process(all)
    begin
        if( x >= too_high ) then
            y <= sat_high ;
        elsif( x <= sat_low ) then
            y <= sat_low ;
        else
            y <= resize(x, y'length) ;
        end if ;
    end process ;

end architecture ;

architecture casearch of saturate is

    subtype too_high is integer range 2**(y'length-1)-1 to integer'high ;
    subtype too_low is integer range integer'low to -(2**(y'length-1)) ;

    constant sat_high : signed := to_signed(2**y'length - 1, y'length) ;
    constant sat_low : signed := to_signed(0, y'length) - sat_high - to_signed(1, y'length) ;

begin

    process(all)
    begin
        case to_integer(x) is
            when too_high => y <= sat_high ;
            when too_low  => y <= sat_low ;
            when others   => y <= resize(x, y'length) ;
        end case ;
    end process ;

end architecture ;

The failure is:

$ nvc --std=2008 -a saturate.vhdl 

*** Caught signal 11 (SEGV_MAPERR) [address=(nil), ip=0x5619b7c6f5ac] ***

[0x5619b7c2aead] ../src/util.c:837 signal_handler
[0x7f7aa331a51f] (/usr/lib/x86_64-linux-gnu/libc.so.6) 
[0x5619b7c6f5ac] ../src/tree.c:607 tree_type
[0x5619b7c6f5ac] ../src/tree.c:4316 sem_locally_static.lto_priv.0
[0x5619b7c7795f] ../src/sem.c:4850 sem_check_case
[0x5619b7c4eab1] ../src/parse.c:9191 p_sequential_statement
[0x5619b7c4eab1] ../src/parse.c:7153 p_sequence_of_statements.lto_priv.0
[0x5619b7c537b3] ../src/parse.c:7350 p_process_statement_part
[0x5619b7c537b3] ../src/parse.c:7412 p_process_statement.lto_priv.0
[0x5619b7c5b2d7] ../src/parse.c:10609 p_concurrent_statement.lto_priv.0
[0x5619b7c5d50e] ../src/parse.c:10675 p_architecture_body
[0x5619b7c5d50e] ../src/parse.c:10916 p_secondary_unit
[0x5619b7c5e3df] ../src/parse.c:10942 p_design_unit
[0x5619b7c5e3df] ../src/parse.c:11015 parse
[0x5619b7c338a0] ../src/nvc.c:211 analyse
[0x5619b7c338a0] ../src/nvc.c:1429 process_command
[0x5619b7c275b6] ../src/nvc.c:1553 main