Flymake: add new flymake-show-diagnostics-at-end-of-line option

Some editors have this.  Depending on your preference, this can either
be wildly distracting and easily confused with actual code, or a
significant early aid that relieves you from moving around or reaching
for the mouse to consult an error message.  To be safe, hide this
behind a customization variable and keep it disabled.

Personally, I find it less obstrusive and more helpful than expected.

* lisp/progmodes/flymake.el (flymake--delete-overlay): New helper.
(flymake--highlight-line): Handle flymake-show-diagnostics-at-end-of-line.
(flymake--clear-foreign-diags): Use flymake--delete-overlay.
(flymake--publish-diagnostics): Use flymake--delete-overlay.
(flymake-mode): Use flymake--delete-overlay.
(flymake-error-echo)
(flymake-warning-echo, flymake-note-echo): New faces.
(flymake-show-diagnostics-at-end-of-line): New option.
(Version): Bump to 1.3.4

* doc/misc/flymake.texi:
(Finding diagnostics): Mention flymake-show-diagnostics-at-end-of-line.
(Customizable variables): Mention
flymake-show-diagnostics-at-end-of-line and a few more relevant faces.

* etc/NEWS (Flymake): Mention flymake-show-diagnostics-at-end-of-line.

1 files changed, 24 insertions, 1 deletions

diff --git a/doc/misc/flymake.texi b/doc/misc/flymake.texi
index 13616f39f16..304a7d29ece 100644
--- a/doc/misc/flymake.texi
+++ b/doc/misc/flymake.texi
@@ -1,7 +1,7 @@
 \input texinfo   @c -*- mode: texinfo; coding: utf-8 -*-
 @comment %**start of header
 @setfilename ../../info/flymake.info
-@set VERSION 1.3.3
+@set VERSION 1.3.4
 @set UPDATED April 2023
 @settitle GNU Flymake @value{VERSION}
 @include docstyle.texi
@@ -142,6 +142,12 @@ highlighted regions to learn what the specific problem
 is.  Alternatively, place point on the highlighted regions and use the
 commands @code{eldoc} or @code{display-local-help}.
 
+Another easy way to get instant access to the diagnostic text is to
+set @code{flymake-show-diagnostics-at-end-of-line} to a non-@code{nil}
+value.  This makes the diagnostic messages appear at the end of the
+line where the regular annotation is located (@pxref{Customizable
+variables})
+
 @cindex next and previous diagnostic
 If the diagnostics are outside the visible region of the buffer,
 @code{flymake-goto-next-error} and @code{flymake-goto-prev-error} are
@@ -316,6 +322,23 @@ If non-@code{nil}, moving to errors with @code{flymake-goto-next-error} and
 @code{flymake-goto-prev-error} wraps around buffer boundaries.
 @end vtable
 
+@item flymake-show-diagnostics-at-end-of-line
+If non-@code{nil}, show summarized descriptions of diagnostics at the
+end of the line.  Depending on your preference, this can either be
+distracting and easily confused with actual code, or a significant
+early aid that relieves you from moving around or reaching for the
+mouse to consult an error message.
+
+@item flymake-error-eol
+A custom face for summarizing diagnostic error messages.
+
+@item flymake-warning-eol
+A custom face for summarizing diagnostic warning messages.
+
+@item flymake-note-eol
+A custom face for summarizing diagnostic notes.
+@end vtable
+
 @node Extending Flymake
 @chapter Extending Flymake
 @cindex extending flymake