patch 8.0.1416: crash when searching for a sentence

Problem:    Crash when searching for a sentence.
Solution:   Return NUL when getting character at MAXCOL. (closes #2468)

src/ex_docmd.c

@@ -4521,13 +4521,14 @@ get_address(
 		    if (lnum != MAXLNUM)
 			curwin->w_cursor.lnum = lnum;
 		    /*
-		     * Start a forward search at the end of the line.
+		     * Start a forward search at the end of the line (unless
+		     * before the first line).
 		     * Start a backward search at the start of the line.
 		     * This makes sure we never match in the current
 		     * line, and can match anywhere in the
 		     * next/previous line.
 		     */
-		    if (c == '/')
+		    if (c == '/' && curwin->w_cursor.lnum > 0)
 			curwin->w_cursor.col = MAXCOL;
 		    else
 			curwin->w_cursor.col = 0;

src/misc1.c

@@ -2650,8 +2650,12 @@ del_lines(
     int
 gchar_pos(pos_T *pos)
 {
-    char_u	*ptr = ml_get_pos(pos);
+    char_u	*ptr;
 
+    /* When searching columns is sometimes put at the end of a line. */
+    if (pos->col == MAXCOL)
+	return NUL;
+    ptr = ml_get_pos(pos);
 #ifdef FEAT_MBYTE
     if (has_mbyte)
 	return (*mb_ptr2char)(ptr);

src/misc2.c

@@ -348,8 +348,12 @@ inc_cursor(void)
     int
 inc(pos_T *lp)
 {
-    char_u  *p = ml_get_pos(lp);
+    char_u  *p;
 
+    /* when searching position may be set to end of a line */
+    if (lp->col != MAXCOL)
+    {
+	p = ml_get_pos(lp);
 	if (*p != NUL)	/* still within line, move to next char (may be NUL) */
 	{
 #ifdef FEAT_MBYTE
@@ -367,6 +371,7 @@ inc(pos_T *lp)
 #endif
 	    return ((p[1] != NUL) ? 0 : 2);
 	}
+    }
     if (lp->lnum != curbuf->b_ml.ml_line_count)     /* there is a next line */
     {
 	lp->col = 0;

src/testdir/test_search.vim

@@ -729,3 +729,10 @@ func Test_look_behind()
   call search(getline("."))
   bwipe!
 endfunc
+
+func Test_search_sentence()
+  new
+  " this used to cause a crash
+  call assert_fails("/\\%'", 'E486')
+  call assert_fails("/", 'E486')
+endfunc

src/version.c

@@ -771,6 +771,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1416,
 /**/
     1415,
 /**/