pattern doesn't match

[hackoflpf]

searcch pattern is :
weggli '$a = 0;
NOT: if($a);
_ / $a;' ./src/autofit/aflatin.c -v，i add not search if($a)，but it still match,i don't known how to debug this question.
04:37:46 [INFO] normalizing query: add {}
04:37:46 [INFO] query sexp: (translation_unit (compound_statement (expression_statement (assignment_expression left: (identifier) right: (number_literal))) (labeled_statement label: (statement_identifier) (if_statement condition: (parenthesized_expression (identifier)) consequence: (expression_statement))) (expression_statement (binary_expression left: (identifier) right: (identifier)))))
04:37:46 [INFO] parsing 1 files
/home/admins/freetypes_fuzzing/freetype-2.10.1/./src/autofit/aflatin.c:1965
FT_LOCAL_DEF( void )
af_latin_hints_link_segments( AF_GlyphHints hints,
..

if ( width_count )
  max_width = widths[width_count - 1].org;
else
  max_width = 0;

/* a heuristic value to set up a minimum value for overlapping */
len_threshold = AF_LATIN_CONSTANT( hints->metrics, 8 );
if ( len_threshold == 0 )
  len_threshold = 1;

..

        if ( max_width )
        {
          /* distance demerits are based on multiples of `max_width'; */
          /* we scale by 1024 for getting more precision              */
          FT_Pos  delta = ( dist << 10 ) / max_width - ( 1 << 10 );


          if ( delta > 10000 )
            dist_demerit = 32000;
          else if ( delta > 0 )

..
}

source code is : FT_LOCAL_DEF( void )
af_latin_hints_link_segments( AF_GlyphHints hints,
FT_UInt width_count,
AF_WidthRec* widths,
AF_Dimension dim )
{
AF_AxisHints axis = &hints->axis[dim];
AF_Segment segments = axis->segments;
AF_Segment segment_limit = segments + axis->num_segments;
FT_Pos len_threshold, len_score, dist_score, max_width;
AF_Segment seg1, seg2;

if ( width_count )
  max_width = widths[width_count - 1].org;
else
  max_width = 0;

/* a heuristic value to set up a minimum value for overlapping */
len_threshold = AF_LATIN_CONSTANT( hints->metrics, 8 );
if ( len_threshold == 0 )
  len_threshold = 1;

/* a heuristic value to weight lengths */
len_score = AF_LATIN_CONSTANT( hints->metrics, 6000 );

/* a heuristic value to weight distances (no call to    */
/* AF_LATIN_CONSTANT needed, since we work on multiples */
/* of the stem width)                                   */
dist_score = 3000;

/* now compare each segment to the others */
for ( seg1 = segments; seg1 < segment_limit; seg1++ )
{
  if ( seg1->dir != axis->major_dir )
    continue;

  /* search for stems having opposite directions, */
  /* with seg1 to the `left' of seg2              */
  for ( seg2 = segments; seg2 < segment_limit; seg2++ )
  {
    FT_Pos  pos1 = seg1->pos;
    FT_Pos  pos2 = seg2->pos;


    if ( seg1->dir + seg2->dir == 0 && pos2 > pos1 )
    {
      /* compute distance between the two segments */
      FT_Pos  min = seg1->min_coord;
      FT_Pos  max = seg1->max_coord;
      FT_Pos  len;


      if ( min < seg2->min_coord )
        min = seg2->min_coord;

      if ( max > seg2->max_coord )
        max = seg2->max_coord;

      /* compute maximum coordinate difference of the two segments */
      /* (this is, how much they overlap)                          */
      len = max - min;
      if ( len >= len_threshold )
      {
        /*
         * The score is the sum of two demerits indicating the
         * `badness' of a fit, measured along the segments' main axis
         * and orthogonal to it, respectively.
         *
         * - The less overlapping along the main axis, the worse it
         *   is, causing a larger demerit.
         *
         * - The nearer the orthogonal distance to a stem width, the
         *   better it is, causing a smaller demerit.  For simplicity,
         *   however, we only increase the demerit for values that
         *   exceed the largest stem width.
         */

        FT_Pos  dist = pos2 - pos1;

        FT_Pos  dist_demerit, score;


        if ( max_width )
        {
          /* distance demerits are based on multiples of `max_width'; */
          /* we scale by 1024 for getting more precision              */
          FT_Pos  delta = ( dist << 10 ) / max_width - ( 1 << 10 );


          if ( delta > 10000 )
            dist_demerit = 32000;
          else if ( delta > 0 )
            dist_demerit = delta * delta / dist_score;
          else
            dist_demerit = 0;
        }

[hackoflpf]