code: private function isShortArray(Tokens $tokens, $index)
      {
          if (!$tokens[$index]->equals('[')) {
              return false;
          }
  
          static $disallowedPrevTokens = [
              ')',
              ']',
              '}',
              '"',
              [T_CONSTANT_ENCAPSED_STRING],
              [T_STRING],
              [T_STRING_VARNAME],
              [T_VARIABLE],
              [CT::T_ARRAY_SQUARE_BRACE_CLOSE],
              [CT::T_DYNAMIC_PROP_BRACE_CLOSE],
              [CT::T_DYNAMIC_VAR_BRACE_CLOSE],
              [CT::T_ARRAY_INDEX_CURLY_BRACE_CLOSE],
          ];
  
          $prevToken = $tokens[$tokens->getPrevMeaningfulToken($index)];
          if ($prevToken->equalsAny($disallowedPrevTokens)) {
              return false;
          }
  
          $nextToken = $tokens[$tokens->getNextMeaningfulToken($index)];
          if ($nextToken->equals(']')) {
              return true;
          }
  
          return !$this->isArrayDestructing($tokens, $index);
      }
docs: Check if token under given index is short array opening.
  
  @param Tokens $tokens
  @param int    $index
  
  @return bool