Abbreviations and "mappings!" suddenly stop working

[bohrshaw]

• nvim --version: v0.2.1-dev (20170522)
• Vim (version: ) behaves differently? Unknown
• Operating system/version: Ubuntu VM 16.04
• Terminal name/version: mintty(https://github.com/mintty/wsltty) (Nvim inside of Tmux)
• $TERM: screen-256color

Actual behaviour

Abbreviations especially cabbreviations are suddenly not triggered.

All Alt/Meta-based mappings like M-v in Command Line or Insert Mode suddenly take effect by inserting a character: v in case of M-v.

While a custom mapping like C-d in Insert Mode simply takes no effect, or fall back to the stock behavior in case of C-a.

Normal and Visual Mode mappings behaves correctly.

Steps to reproduce

Happened 3 times, especially after extensive long-time usages.

[justinmk]

Does it happen without mosh?

[bohrshaw]

Yes. This Nvim instance is inside of Tmux. Thus I have tried attaching Tmux via SSH and Native. But both make no difference.
However, I'm not sure what triggered this malfunctioning state.

[d3adb5]

Of my Alt bindings, one still works: M-n. M-Right and M-Left have stopped working on all modes they're set in.

[bohrshaw]

This just happened again when I <S-Insert> in Neovim(Insert Mode) in Tmux connected through Mosh.
And I have to restart Neovim to get back to normal.

[justinmk]

Ah, sounds like the bracketedpaste paste bug. To get back to normal:

:set nopaste

[bohrshaw]

I will try this if it happens again.

[justinmk]

see #7994