Re: Bison 3.5 - y.tab.c generates compiler warnings

[Andy Fiddaman]

On Wed, 18 Dec 2019, Paul Eggert wrote:

; On 12/18/19 10:22 PM, Akim Demaille wrote:
; > I was unable to reproduce that warning 
(https://travis-ci.org/akimd/bison/builds/626034753)
;
; I suspect you need a platform where plain 'char' is unsigned, so that 'typedef
; yytype_uint8 yy_state_t;' is treated as if it were 'typedef char yy_state_t;'
; which means yy_state_t indexes provoke the diagnostic. (A GCC bug, if you ask 
me.)

Given this in the template:

        #if defined __UINT_LEAST8_MAX__ && __UINT_LEAST8_MAX__ <= __INT_MAX__
        typedef __UINT_LEAST8_TYPE__ yytype_uint8;
        #elif (!defined __UINT_LEAST8_MAX__ && defined YY_STDINT_H \
               && UINT_LEAST8_MAX <= INT_MAX)
        typedef uint_least8_t yytype_uint8;
        #elif !defined __UINT_LEAST8_MAX__ && UCHAR_MAX <= INT_MAX
        typedef unsigned char yytype_uint8;
        #else
        typedef short yytype_uint8;
        #endif

and this from gcc:

        #define __UINT_LEAST8_MAX__ 0xff
        #define __INT_MAX__ 0x7fffffff
        #define __UINT_LEAST8_TYPE__ unsigned char

It's the first part of the clause that is being selected and ending up with

        typedef unsigned char yytype_uint8;

Andy