patch 8.1.0022: repeating put from expression register fails

Problem:    Repeating put from expression register fails.
Solution:   Re-evaluate the expression register. (Andy Massimino,
            closes #2945)

src/getchar.c

@@ -844,6 +844,14 @@ start_redo(long count, int old_redo)
 	if (c >= '1' && c < '9')
 	    ++c;
 	add_char_buff(&readbuf2, c);
+
+	/* the expression register should be re-evaluated */
+	if (c == '=')
+	{
+	    add_char_buff(&readbuf2, CAR);
+	    cmd_silent = TRUE;
+	}
+
 	c = read_redo(FALSE, old_redo);
     }
 

src/testdir/test_put.vim

@@ -45,3 +45,16 @@ func Test_put_lines()
   bw!
   call setreg('a', a[0], a[1])
 endfunc
+
+func Test_put_expr()
+  new
+  call setline(1, repeat(['A'], 6))
+  exec "1norm! \"=line('.')\<cr>p"
+  norm! j0.
+  norm! j0.
+  exec "4norm! \"=\<cr>P"
+  norm! j0.
+  norm! j0.
+  call assert_equal(['A1','A2','A3','4A','5A','6A'], getline(1,'$'))
+  bw!
+endfunc

src/version.c

@@ -761,6 +761,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    22,
 /**/
     21,
 /**/