Simplify idris-warning-overlay by

 - inline idris-get-line-region and remove cl-multiple-value-bind
 - remove extra goto-char
 - flatten body

idris-warnings.el

@@ -60,18 +60,12 @@
   (setq idris-warnings '())
   (delq (current-buffer) idris-warnings-buffers))
 
-(defun idris-get-line-region (line)
-  (goto-char (point-min))
-  (cl-values
-   (line-beginning-position line)
-   (line-end-position line)))
-
 (defun idris-warning-overlay-p (overlay)
   (overlay-get overlay 'idris-warning))
 
-(defun idris-warning-overlay-at-point ()
-  "Return the overlay for a note starting at point, otherwise nil."
-  (cl-find (point) (cl-remove-if-not 'idris-warning-overlay-p (overlays-at (point)))
+(defun idris-warning-overlay-at-point (point)
+  "Return the overlay for a note starting at POINT, otherwise nil."
+  (cl-find point (cl-remove-if-not 'idris-warning-overlay-p (overlays-at point))
         :key 'overlay-start))
 
 (defun idris-warning-overlay (warning)
@@ -103,23 +97,21 @@ is mostly the same as (startline startcolumn)"
             (save-restriction
               (widen) ;; Show errors at the proper location in narrowed buffers
               (goto-char (point-min))
-              (cl-multiple-value-bind (startp endp) (idris-get-line-region startline)
-                (goto-char startp)
-                (let ((start (+ startp startcol))
-                      (end (if (and (= startline endline) (= startcol endcol))
-                               ;; this is a hack to have warnings reported which point to empty lines
-                               (if (= startp endp)
-                                   (progn (insert " ")
-                                          (1+ endp))
-                                 endp)
-                             (+ (save-excursion
-                                  (goto-char (point-min))
-                                  (line-beginning-position endline))
-                                endcol)))
-                      (overlay (idris-warning-overlay-at-point)))
-                  (if overlay
-                      (idris-warning-merge-overlays overlay message)
-                    (idris-warning-create-overlay start end message)))))))))))
+              (let* ((startp (line-beginning-position startline))
+                     (endp (line-end-position startline))
+                     (start (+ startp startcol))
+                     (end (if (and (= startline endline) (= startcol endcol))
+                              ;; this is a hack to have warnings reported which point to empty lines
+                              (if (= startp endp)
+                                  (progn (goto-char startp)
+                                         (insert " ")
+                                         (1+ endp))
+                                endp)
+                            (+ (line-beginning-position endline) endcol)))
+                     (overlay (idris-warning-overlay-at-point startp)))
+                (if overlay
+                    (idris-warning-merge-overlays overlay message)
+                  (idris-warning-create-overlay start end message))))))))))
 
 (defun idris-warning-merge-overlays (overlay message)
   (overlay-put overlay 'help-echo