* Improve `comp-async-report-warnings-errors' docstring

	* lisp/emacs-lisp/comp.el (comp-async-report-warnings-errors):
	Improve docstring.

diff --git a/lisp/emacs-lisp/comp.el b/lisp/emacs-lisp/comp.el
index c242c5c871ec26008fd948f5ccfb0d65a5bbcd27..184aef489dcaefa38fc2d30e3e8b7db26ecc2d7b 100644 (file)
--- a/lisp/emacs-lisp/comp.el
+++ b/lisp/emacs-lisp/comp.el
@@ -124,7 +124,18 @@ Usable to modify the compiler environment."
   :type 'list)
 
 (defcustom comp-async-report-warnings-errors t
-  "Whether to report warnings and errors from asynchronous native compilation."
+  "Whether to report warnings and errors from asynchronous native compilation.
+
+When native compilation happens asynchronously this can produce
+warnings and errors, some of these diagnostic messages might not be
+emitted by the first synchronous byte-compilation.  The typical case
+for that is byte-compiling a file that is missing to require a
+necessary feature while having it already loaded into the environment.
+
+As asynchronous native compilation always starts from a fresh
+environment it is more sensitive into highlighting issues about non
+consistent source files and might not be able to compile correctly
+these."
   :type 'boolean)
 
 (defcustom comp-async-query-on-exit nil