patch 8.0.0542: getpos() can return a negative line number commit https://github.com/vim/vim/commit/a1d5fa65bc7e8a548858e9c295a192b63dcd011b Author: Bram Moolenaar <Bram@vim.org> Date: Mon Apr 3 22:02:55 2017 +0200 patch 8.0.0542: getpos() can return a negative line number Problem: getpos() can return a negative line number. (haya14busa) Solution: Handle a zero topline and botline. (closes https://github.com/vim/vim/issues/1613)

is<F4>foo
{'silent': 0, 'noremap': 0, 'lhs': 'foo<C-V>', 'mode': ' ', 'nowait': 0, 'expr': 0, 'sid': 0, 'rhs': 'is<F4>foo', 'buffer': 0}
{'silent': 1, 'noremap': 1, 'lhs': 'bar', 'mode': 'v', 'nowait': 0, 'expr': 1, 'sid': 0, 'rhs': 'isbar', 'buffer': 1}
{'silent': 0, 'noremap': 0, 'lhs': 'foo', 'mode': ' ', 'nowait': 1, 'expr': 0, 'sid': 0, 'rhs': 'bar', 'buffer': 1}
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