fix(screenpos, float): add top and left border adjustment

(cherry picked from commit ffe3003e02)

src/nvim/move.c

@@ -1011,7 +1011,7 @@ void textpos2screenpos(win_T *wp, pos_T *pos, int *rowp, int *scolp, int *ccolp,
     col -= wp->w_leftcol;
 
     if (col >= 0 && col < wp->w_width) {
-      coloff = col - scol + (local ? 0 : wp->w_wincol) + 1;
+      coloff = col - scol + (local ? 0 : wp->w_wincol + wp->w_border_adj[3]) + 1;
     } else {
       scol = ccol = ecol = 0;
       // character is left or right of the window
@@ -1022,7 +1022,7 @@ void textpos2screenpos(win_T *wp, pos_T *pos, int *rowp, int *scolp, int *ccolp,
       }
     }
   }
-  *rowp = (local ? 0 : wp->w_winrow) + row + rowoff;
+  *rowp = (local ? 0 : wp->w_winrow + wp->w_border_adj[0]) + row + rowoff;
   *scolp = scol + coloff;
   *ccolp = ccol + coloff;
   *ecolp = ecol + coloff;

test/functional/vimscript/screenpos_spec.lua

@@ -0,0 +1,51 @@
+local helpers = require('test.functional.helpers')(after_each)
+local clear, eq, meths = helpers.clear, helpers.eq, helpers.meths
+local command, funcs = helpers.command, helpers.funcs
+
+before_each(clear)
+
+describe('screenpos() function', function()
+  it('works in floating window with border', function()
+    local bufnr = meths.create_buf(false, true)
+    local opts = {
+      relative='editor',
+      height=8,
+      width=12,
+      row=6,
+      col=8,
+      anchor='NW',
+      style='minimal',
+      border='none',
+      focusable=1
+    }
+    local float = meths.open_win(bufnr, false, opts)
+    command('redraw')
+    local pos = funcs.screenpos(bufnr, 1, 1)
+    eq(7, pos.row)
+    eq(9, pos.col)
+
+    -- only left border
+    opts.border = {'', '', '', '', '', '', '', '|'}
+    meths.win_set_config(float, opts)
+    command('redraw')
+    pos = funcs.screenpos(bufnr, 1, 1)
+    eq(7, pos.row)
+    eq(10, pos.col)
+
+    -- only top border
+    opts.border = {'', '_', '', '', '', '', '', ''}
+    meths.win_set_config(float, opts)
+    command('redraw')
+    pos = funcs.screenpos(bufnr, 1, 1)
+    eq(8, pos.row)
+    eq(9, pos.col)
+
+    -- both left and top border
+    opts.border = 'single'
+    meths.win_set_config(float, opts)
+    command('redraw')
+    pos = funcs.screenpos(bufnr, 1, 1)
+    eq(8, pos.row)
+    eq(10, pos.col)
+  end)
+end)