diff -up tre-c2f5d130c91b1696385a6ae0b5bcfd5214bcc9ca/lib/tre-parse.c.issue50 tre-c2f5d130c91b1696385a6ae0b5bcfd5214bcc9ca/lib/tre-parse.c
--- tre-c2f5d130c91b1696385a6ae0b5bcfd5214bcc9ca/lib/tre-parse.c.issue50	2019-02-23 17:36:40.940463693 +0100
+++ tre-c2f5d130c91b1696385a6ae0b5bcfd5214bcc9ca/lib/tre-parse.c	2019-02-23 18:40:41.111544430 +0100
@@ -1341,7 +1341,7 @@ tre_parse(tre_parse_ctx_t *ctx)
 
 	    case CHAR_RPAREN:  /* end of current subexpression */
 	      if ((ctx->cflags & REG_EXTENDED && depth > 0)
-		  || (ctx->re > ctx->re_start
+		  || (!(ctx->cflags & REG_EXTENDED) && ctx->re > ctx->re_start
 		      && *(ctx->re - 1) == CHAR_BACKSLASH))
 		{
 		  DPRINT(("tre_parse:	    empty: '%.*" STRF "'\n",