Warn about misplaced or duplicated function/macro declarations

Doc strings, `declare` and `interactive` forms must appear in that
order and at most once each.  Complain if they don't, instead of
silently ignoring the problem (bug#55905).

* lisp/emacs-lisp/byte-run.el (byte-run--parse-body)
(byte-run--parse-declarations): New.
(defmacro, defun): Check for declaration well-formedness as
described above.  Clarify doc strings.  Refactor some common code.
* test/lisp/emacs-lisp/bytecomp-resources/fun-attr-warn.el:
* test/lisp/emacs-lisp/bytecomp-tests.el (bytecomp-fun-attr-warn):
New test.

1 files changed, 266 insertions, 0 deletions

diff --git a/test/lisp/emacs-lisp/bytecomp-resources/fun-attr-warn.el b/test/lisp/emacs-lisp/bytecomp-resources/fun-attr-warn.el
new file mode 100644
index 00000000000..be907b32f47
--- /dev/null
+++ b/test/lisp/emacs-lisp/bytecomp-resources/fun-attr-warn.el
@@ -0,0 +1,266 @@
+;;; -*- lexical-binding: t -*-
+
+;; Correct
+
+(defun faw-str-decl-code (x)
+  "something"
+  (declare (pure t))
+  (print x))
+
+(defun faw-doc-decl-code (x)
+  (:documentation "something")
+  (declare (pure t))
+  (print x))
+
+(defun faw-str-int-code (x)
+  "something"
+  (interactive "P")
+  (print x))
+
+(defun faw-doc-int-code (x)
+  (:documentation "something")
+  (interactive "P")
+  (print x))
+
+(defun faw-decl-int-code (x)
+  (declare (pure t))
+  (interactive "P")
+  (print x))
+
+(defun faw-str-decl-int-code (x)
+  "something"
+  (declare (pure t))
+  (interactive "P")
+  (print x))
+
+(defun faw-doc-decl-int-code (x)
+  (:documentation "something")
+  (declare (pure t))
+  (interactive "P")
+  (print x))
+
+
+;; Correct (last string is return value)
+
+(defun faw-str ()
+  "something")
+
+(defun faw-decl-str ()
+  (declare (pure t))
+  "something")
+
+(defun faw-decl-int-str ()
+  (declare (pure t))
+  (interactive)
+  "something")
+
+(defun faw-str-str ()
+  "something"
+  "something else")
+
+(defun faw-doc-str ()
+  (:documentation "something")
+  "something else")
+
+
+;; Incorrect (bad order)
+
+(defun faw-int-decl-code (x)
+  (interactive "P")
+  (declare (pure t))
+  (print x))
+
+(defun faw-int-str-code (x)
+  (interactive "P")
+  "something"
+  (print x))
+
+(defun faw-int-doc-code (x)
+  (interactive "P")
+  (:documentation "something")
+  (print x))
+
+(defun faw-decl-str-code (x)
+  (declare (pure t))
+  "something"
+  (print x))
+
+(defun faw-decl-doc-code (x)
+  (declare (pure t))
+  (:documentation "something")
+  (print x))
+
+(defun faw-str-int-decl-code (x)
+  "something"
+  (interactive "P")
+  (declare (pure t))
+  (print x))
+
+(defun faw-doc-int-decl-code (x)
+  (:documentation "something")
+  (interactive "P")
+  (declare (pure t))
+  (print x))
+
+(defun faw-int-str-decl-code (x)
+  (interactive "P")
+  "something"
+  (declare (pure t))
+  (print x))
+
+(defun faw-int-doc-decl-code (x)
+  (interactive "P")
+  (:documentation "something")
+  (declare (pure t))
+  (print x))
+
+(defun faw-int-decl-str-code (x)
+  (interactive "P")
+  (declare (pure t))
+  "something"
+  (print x))
+
+(defun faw-int-decl-doc-code (x)
+  (interactive "P")
+  (declare (pure t))
+  (:documentation "something")
+  (print x))
+
+(defun faw-decl-int-str-code (x)
+  (declare (pure t))
+  (interactive "P")
+  "something"
+  (print x))
+
+(defun faw-decl-int-doc-code (x)
+  (declare (pure t))
+  (interactive "P")
+  (:documentation "something")
+  (print x))
+
+(defun faw-decl-str-int-code (x)
+  (declare (pure t))
+  "something"
+  (interactive "P")
+  (print x))
+
+(defun faw-decl-doc-int-code (x)
+  (declare (pure t))
+  (:documentation "something")
+  (interactive "P")
+  (print x))
+
+
+;; Incorrect (duplication)
+
+(defun faw-str-str-decl-int-code (x)
+  "something"
+  "something else"
+  (declare (pure t))
+  (interactive "P")
+  (print x))
+
+(defun faw-str-doc-decl-int-code (x)
+  "something"
+  (:documentation "something else")
+  (declare (pure t))
+  (interactive "P")
+  (print x))
+
+(defun faw-doc-str-decl-int-code (x)
+  (:documentation "something")
+  "something else"
+  (declare (pure t))
+  (interactive "P")
+  (print x))
+
+(defun faw-doc-doc-decl-int-code (x)
+  (:documentation "something")
+  (:documentation "something else")
+  (declare (pure t))
+  (interactive "P")
+  (print x))
+
+(defun faw-str-decl-str-int-code (x)
+  "something"
+  (declare (pure t))
+  "something else"
+  (interactive "P")
+  (print x))
+
+(defun faw-doc-decl-str-int-code (x)
+  (:documentation "something")
+  (declare (pure t))
+  "something else"
+  (interactive "P")
+  (print x))
+
+(defun faw-str-decl-doc-int-code (x)
+  "something"
+  (declare (pure t))
+  (:documentation "something else")
+  (interactive "P")
+  (print x))
+
+(defun faw-doc-decl-doc-int-code (x)
+  (:documentation "something")
+  (declare (pure t))
+  (:documentation "something else")
+  (interactive "P")
+  (print x))
+
+(defun faw-str-decl-decl-int-code (x)
+  "something"
+  (declare (pure t))
+  (declare (indent 1))
+  (interactive "P")
+  (print x))
+
+(defun faw-doc-decl-decl-int-code (x)
+  (:documentation "something")
+  (declare (pure t))
+  (declare (indent 1))
+  (interactive "P")
+  (print x))
+
+(defun faw-str-decl-int-decl-code (x)
+  "something"
+  (declare (pure t))
+  (interactive "P")
+  (declare (indent 1))
+  (print x))
+
+(defun faw-doc-decl-int-decl-code (x)
+  (:documentation "something")
+  (declare (pure t))
+  (interactive "P")
+  (declare (indent 1))
+  (print x))
+
+(defun faw-str-decl-int-int-code (x)
+  "something"
+  (declare (pure t))
+  (interactive "P")
+  (interactive "p")
+  (print x))
+
+(defun faw-doc-decl-int-int-code (x)
+  (:documentation "something")
+  (declare (pure t))
+  (interactive "P")
+  (interactive "p")
+  (print x))
+
+(defun faw-str-int-decl-int-code (x)
+  "something"
+  (interactive "P")
+  (declare (pure t))
+  (interactive "p")
+  (print x))
+
+(defun faw-doc-int-decl-int-code (x)
+  (:documentation "something")
+  (interactive "P")
+  (declare (pure t))
+  (interactive "p")
+  (print x))