## Summary The line-editor used in GHCi is unusably broken. ## Steps to reproduce Run GHCi, then type `abc` and press Ctrl+A (or the Home key). The visible cursor will now be over the `c`. Pressing the right arrow key three times moves the visible cursor far beyond the visible text. Repeating this process will continually shift rightward the position that the line-editor sees as the beginning of the line. The cursor location and the visible text are out of sync. ## Expected behavior The press of Ctrl+A should result in the cursor moving to the beginning of the line, rather than just one character to the left of where it was. ## Environment * GHC version used: 8.10.5 Optional: * Operating System: macOS 11.3 * System Architecture: arm64