List all errors

You can see all errors in the current buffer in Flycheck’s error list:

The key C-c ! l pops up the error list:

C-c ! l

M-x flycheck-list-errors

M-x list-flycheck-errors

Pop up a list of errors in the current buffer.

The error list automatically updates itself after every syntax check and follows the current buffer: If you switch to different buffer or window it automatically shows the errors of the now current buffer. The buffer whose errors are shown in the error list is the source buffer.

Whenever the point is on an error in the source buffer the error list highlights these errors—the green line in the screenshot above.

Within the error list the following key bindings are available:

RET	Go to the current error in the source buffer
n	Jump to the next error
p	Jump to the previous error
e	Explain the error
j	Visit a related location of the error, if it has one
x	Apply the error’s fix, if it has one
X	Apply every fix in the source buffer
f	Filter the error list by level
F	Remove the filter
S	Sort the error list by the column at point
g	Check the source buffer and update the error list
P	Toggle between buffer and whole-project scope
M-1	Show a flat list, without grouping
M-2	Toggle grouping the errors by file
M-3	Toggle grouping the errors by checker
M-4	Toggle grouping the errors by level
TAB	Collapse or expand the group at point
q	Quit the error list and hide its window

When you jump to an error from the error list with RET, Flycheck runs flycheck-error-list-after-jump-hook in the source buffer. This is useful for post-jump actions like recentering:

defcustom flycheck-error-list-after-jump-hook

Functions to run after jumping to an error from the error list. For example, to recenter the window on the error location:

(add-hook 'flycheck-error-list-after-jump-hook #'recenter)

See the whole project

Press P to switch the error list between the current buffer and the whole project. In project scope the list aggregates the diagnostics of every open Flycheck buffer in the source buffer’s project, together with the cross-file errors your checkers report but the per-buffer view discards. A checker like tsc, cargo check or mypy that checks a whole package reports errors for files other than the one you are editing; Flycheck normally drops those from the buffer (see flycheck-relevant-error-other-file-show), but in project scope it keeps them, so you see the whole picture in one place. Press RET on an error in another file to jump straight to it.

Note

Flycheck does not run checkers on files you haven’t opened; project scope surfaces the diagnostics it already has, from open buffers and from the cross-file output of the checks you run. It does not turn Flycheck into a background whole-project linter. A cross-file error therefore reflects the last check that reported it: it stays until the buffer that produced it is checked again, since Flycheck cannot tell that another file changed without re-running a check.

The project of a buffer is Emacs’ project (see project-current) when one is found, and the checker’s working directory otherwise. The current scope is shown as [project] in the error list’s mode line.

Group the errors under a header per file, syntax checker or level with M-2, M-3 and M-4; M-1 switches back to a flat list. Grouping makes a project-wide list much easier to scan. The keys toggle each dimension, so you can combine them: with both M-2 and M-3 the errors nest by checker within each file. Combined dimensions always nest in the file, checker, level order. The available groupings and the active ones are shown in a strip at the top of the error list. Press TAB (or RET on a header) to collapse or expand the group at point. You can also click a grouping in the strip to toggle it, or a group header to collapse or expand it.

Filter the list

By default the error list shows all errors but sometimes you’d like to narrow it down. The error list supports three filters, which combine and stay in effect as long as the error list buffer stays alive, until you reset them all with F:

• f prompts for an error level and hides all errors of lower levels.

• c prompts for a syntax checker and shows only its errors, e.g. only the type errors from your type checker while ignoring stylistic complaints.

• / prompts for a regular expression and shows only errors whose message or ID matches it.

The active filters are shown in the error list’s mode line.

Sort the list

You can press S or click on the column headings to sort the error list by any of the following columns:

• Line

• Level

• ID

• Message and checker

Click twice or press S repeatedly to flip the sort order from ascending to descending or vice versa.

Tune error list display

By default the error list pops up in a side window at the bottom of the frame, a quarter of the frame tall, like similar lists in contemporary IDEs. Side windows are not affected by C-x 1 (delete-other-windows); dismiss the error list with q in its window instead. You can change or disable this behavior:

defcustom flycheck-error-list-display-buffer-action

The display-buffer action used to display the error list. Set to nil to fall back to the default behavior of display-buffer, where the error list pops up at an arbitrary place wherever Emacs finds a window for it.

Entries in the built-in option display-buffer-alist matching the error list buffer take precedence over this action, so any existing window-management configuration keeps working. For example, to display the error list at the bottom with a third of the frame height instead:

(add-to-list 'display-buffer-alist
             `(,(rx bos "*Flycheck errors*" eos)
              (display-buffer-reuse-window
               display-buffer-in-side-window)
              (side            . bottom)
              (reusable-frames . visible)
              (window-height   . 0.33)))

See also

Shackle

An Emacs package which provides an alternative way to control buffer display