commit https://github.com/vim/vim/commit/a742e084b677f76c67e9e52c4f9fb9ab24002e20 Author: Bram Moolenaar <Bram@vim.org> Date: Tue Apr 5 21:10:38 2016 +0200 patch 7.4.1711 Problem: When using try/catch in 'statusline' it is still considered an error and the status line will be disabled. Solution: Check did_emsg instead of called_emsg. (haya14busa, closes https://github.com/vim/vim/issues/729)

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}
xrx
yRy
abcd