How does Ctrl+C differ from Escape when exiting insert mode, and why does it matter?

Explanation

<C-c> exits insert mode immediately but silently skips two important side effects that <Esc> (and its equivalent <C-[>) always trigger: abbreviation expansion and InsertLeave autocommands.

How it works

Example

If you have an abbreviation and an autocommand:

iabbrev teh the
autocmd InsertLeave * echo 'left insert'

Type: teh<Esc>   → expands to "the", echo fires
Type: teh<C-c>   → stays as "teh", echo does NOT fire

Tips

• If you remap <C-c> to <Esc> (:inoremap <C-c> <Esc>) you get full <Esc> behaviour including autocommand firing
• Plugin authors rely on InsertLeave for features like auto-formatting on save, LSP signature hiding, and copilot dismissal — using <C-c> to exit insert will bypass these
• Use <Esc> or <C-[> for clean insert-mode exits; reserve <C-c> for interrupting a runaway operation