diff --git a/src/backend/tsearch/wparser_def.c b/src/backend/tsearch/wparser_def.c
index fa73dff..6728212 100644
*** a/src/backend/tsearch/wparser_def.c
--- b/src/backend/tsearch/wparser_def.c
*************** TParserCopyClose(TParser *prs)
*** 432,438 ****
   *	  or give wrong result.
   *	- multibyte encoding and C-locale often are used for
   *	  Asian languages.
!  *	- if locale is C the we use pgwstr instead of wstr
   */
  
  #ifdef USE_WIDE_UPPER_LOWER
--- 432,438 ----
   *	  or give wrong result.
   *	- multibyte encoding and C-locale often are used for
   *	  Asian languages.
!  *	- if locale is C then we use pgwstr instead of wstr.
   */
  
  #ifdef USE_WIDE_UPPER_LOWER
*************** p_is##type(TParser *prs) {													\
*** 444,452 ****
  	if ( prs->usewide )														\
  	{																		\
  		if ( prs->pgwstr )													\
! 			return is##type( 0xff & *( prs->pgwstr + prs->state->poschar) );\
! 																			\
! 		return isw##type( *(wint_t*)( prs->wstr + prs->state->poschar ) );	\
  	}																		\
  																			\
  	return is##type( *(unsigned char*)( prs->str + prs->state->posbyte ) ); \
--- 444,456 ----
  	if ( prs->usewide )														\
  	{																		\
  		if ( prs->pgwstr )													\
! 		{																	\
! 			unsigned int c = *(prs->pgwstr + prs->state->poschar);			\
! 			if ( c > 0x7f )													\
! 				return 0;													\
! 			return is##type( c );											\
! 		}																	\
! 		return isw##type( *( prs->wstr + prs->state->poschar ) );			\
  	}																		\
  																			\
  	return is##type( *(unsigned char*)( prs->str + prs->state->posbyte ) ); \
*************** p_isalnum(TParser *prs)
*** 475,484 ****
  			if (c > 0x7f)
  				return 1;
  
! 			return isalnum(0xff & c);
  		}
  
! 		return iswalnum((wint_t) *(prs->wstr + prs->state->poschar));
  	}
  
  	return isalnum(*(unsigned char *) (prs->str + prs->state->posbyte));
--- 479,488 ----
  			if (c > 0x7f)
  				return 1;
  
! 			return isalnum(c);
  		}
  
! 		return iswalnum(*(prs->wstr + prs->state->poschar));
  	}
  
  	return isalnum(*(unsigned char *) (prs->str + prs->state->posbyte));
*************** p_isalpha(TParser *prs)
*** 507,516 ****
  			if (c > 0x7f)
  				return 1;
  
! 			return isalpha(0xff & c);
  		}
  
! 		return iswalpha((wint_t) *(prs->wstr + prs->state->poschar));
  	}
  
  	return isalpha(*(unsigned char *) (prs->str + prs->state->posbyte));
--- 511,520 ----
  			if (c > 0x7f)
  				return 1;
  
! 			return isalpha(c);
  		}
  
! 		return iswalpha(*(prs->wstr + prs->state->poschar));
  	}
  
  	return isalpha(*(unsigned char *) (prs->str + prs->state->posbyte));