Evaluating this (to update the definition that merlin mode uses) should 
fix your problem:

(defun merlin/unmake-point (point)
  "Destruct POINT to line / col."
  (save-excursion
    (goto-char point)
    (beginning-of-line)
    `((assoc . nil) (line . ,(line-number-at-pos nil)) (col . ,(- point 
(point))))))

We will ship this fix in the next version.

On Mon, Aug 29, 2016 at 6:50 PM, Matej Kosik 
<5764c029b688c1c0d24a2e97cd764f@gmail.com> wrote:
> Dear all,
> 
> I use Merlin for displaying types of terms or for jumping to the 
> definition of various terms/types.
> This normally works as long as a given identifier/term is not 
> preceded by TAB characters.
> If there are some TAB characters, Merlin's usability is degraded.
> 
> As a non-invasive solution, is there a way how I could tell Merlin 
> how my Emacs interprets TAB characters so that it interprets it in a 
> consistent way?
> (i.e. it will assume that TAB character moves the cursor by 8, not 1, 
> positions to the right).
> 
> Thank you in advance for help.
> 
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