Warn when the return value of certain functions is unused. Previously
this was only done for side-effect-free functions, and for `mapcar`.
These are functions where the return value is important for correct
usage or where ignoring it is likely to indicate a mistake. The exact
set of functions is tentative and will be modified as we gain a better
understanding of which ones to include.
The current set comprises higher order functions such as `mapcar`
which are not primarily called for the effects of their function
arguments, and list-mutating functions like `nreverse` whose return
value is essential.
* lisp/emacs-lisp/bytecomp.el (byte-compile-form): Add list of
functions to warn about when their value is ignored.
* etc/NEWS: Announce.
Move the warning about unused return values from calls to
side-effect-free functions from the source-level optimiser to the code
generator, where it can be unified with the special-purpose warning
about unused values from `mapcar`. This change also cures spurious
duplicate warnings about the same code, makes the warnings amenable to
suppression through `with-suppressed-warnings`, and now warns about
some unused values that weren't caught before.
* lisp/emacs-lisp/byte-opt.el (byte-optimize-form-code-walker):
Move warning away from here.
* lisp/emacs-lisp/byte-run.el (with-suppressed-warnings):
* lisp/emacs-lisp/bytecomp.el (byte-compile-warnings):
Doc string updates.
(byte-compile-form): Put the new warnings here.
(byte-compile-normal-call): Move mapcar warning away from here.
* lisp/emacs-lisp/bytecomp.el (byte-compile-ignore):
Compile args to `ignore` for value to avoid unused-value warnings, and
then discard the generated values immediately thereafter. Mostly this
does not affect the generated code but in rare cases it might result
in slightly worse code.
* test/lisp/emacs-lisp/bytecomp-tests.el
(bytecomp-test--with-suppressed-warnings): Adapt test.
There is no particular requirement for safe-copy-tree so let's make it
internal for now. The new implementation is faster and more correct.
* doc/lispref/lists.texi (Building Lists):
* etc/NEWS: Remove doc and announcement.
* lisp/subr.el (safe-copy-tree--seen, safe-copy-tree--1)
(safe-copy-tree): Remove old version.
* lisp/emacs-lisp/bytecomp.el (bytecomp--copy-tree-seen)
(bytecomp--copy-tree-1, bytecomp--copy-tree): Add new version.
(byte-compile-initial-macro-environment): Use it.
* test/lisp/subr-tests.el (subr--safe-copy-tree):
* test/lisp/emacs-lisp/bytecomp-tests.el (bytecomp--copy-tree):
Move and improve tests.
This fixes bug #61962.
* lisp/subr.el (safe-copy-tree): New function.
* lisp/emacs-lisp/bytecomp.el (byte-compile-initial-macro-environment): Amend
the entry for eval-and-compile to use safe-copy-tree and
byte-run-strip-symbol-positions for the eval part.
* doc/lispref/lists.texi (Building Lists): Document safe-copy-tree.
* etc/NEWS: Note the new function safe-copy-tree.
This fixes a bug that miscompiled
(cond ... C S1...Sn)
where S1...Sn are switch clauses (that can be compiled into a switch
op) and C a non-switch clause, by tucking on an extra copy of C at the
end. This was a serious wrong-code bug when the condition of C had
side-effects; otherwise it was only a waste of time and space.
* lisp/emacs-lisp/bytecomp.el (byte-compile-cond): Fix.
* test/lisp/emacs-lisp/bytecomp-tests.el (bytecomp-tests--test-cases):
Add test case.
* lisp/emacs-lisp/bytecomp.el (byte-compile-file-form-defalias):
Be careful to propagate the for-effect mode through a
`with-suppressed-warnings` form when compiling, so that a form
inside isn't erroneously considered to have its value 'used'
by the surrounding warning suppression form itself.
* lisp/emacs-lisp/bytecomp.el (byte-compile-form):
* lisp/help-fns.el (help-fns--interactive-only): Fix obvious mistake.
Since `interactive-only` is not supposed to be anything other than
a symbol at these points it was not a very consequential bug.
Make `interactive-only` declarations apply to aliases of the same
function as well since this quality isn't in the name but in what
the function does.
* lisp/emacs-lisp/bytecomp.el (byte-compile-form):
* lisp/help-fns.el (help-fns--interactive-only):
Follow aliases when retrieving the `interactive-only` property.
This fixes bug #61579.
* lisp/emacs-lisp/bytecomp.el (byte-compile-initial-environment): Remove a
spurious `byte-run-strip-symbol-position' from the core form of the
eval-and-compile element.
* lisp/emacs-lisp/bytecomp.el (byte-compile-variadic-numeric):
Put a constant argument last for better LAP code opportunities.
This applies to commutative binary operations (+ and *).
`min` and `max` are not included being not quite commutative.
Transform n-ary comparisons to a chain of binary comparisons in the
Lisp optimiser instead of in codegen, to allow for subsequent
optimisations. This generalises the transform, so that
(< 1 X 10) -> (let ((x X)) (and (< 1 x) (< x 10)))
where (< 1 x) is then flipped to (> x 1) in codegen since it's
slightly more efficient to have the constant argument last. Arguments
that are neither constants nor variables are given temporary bindings.
This results in about 2× speedup for 3-ary comparisons of fixnums with
nontrivial arguments, and also improves the code slightly for binary
comparisons with a constant first argument.
* lisp/emacs-lisp/byte-opt.el (byte-opt--nary-comparison): New,
set as the `byte-optimizer` property for =, <, <=, >, and >=.
* lisp/emacs-lisp/bytecomp.el (byte-compile-and-folded):
Rename to...
(byte-compile-cmp): ...and rewrite.
cae528457c ; Add 2023 to copyright years.
b394359261 Improve documentation of 'isearch-open-overlay-temporary'
ab3210e709 Document 'use-package' in the 2 main manuals
# Conflicts:
# etc/refcards/ru-refcard.tex
# lib/explicit_bzero.c
# m4/explicit_bzero.m4
* lisp/emacs-lisp/byte-run.el (with-suppressed-warnings):
* lisp/emacs-lisp/bytecomp.el (bytecomp--warn-dodgy-eq-arg):
Suppress warning using (suspicious FUNCTION), where FUNCTION is
not always `eq`.
Warn about code like (when SOME-CONDITION) because these may indicate
bugs. Warnings currently apply to `when`, `unless`, `ignore-error`,
`with-suppressed-warnings` and (as before) `let` and `let*`.
* lisp/emacs-lisp/byte-run.el (with-suppressed-warnings):
Update doc string.
* lisp/emacs-lisp/bytecomp.el: (byte-compile-warning-types)
(byte-compile-warnings): Add empty-body.
(byte-compile-initial-macro-environment):
Add empty-body warning for with-suppressed-warnings.
* lisp/emacs-lisp/macroexp.el (macroexp--expand-all):
Use the empty-body category for let and let*.
* lisp/subr.el (when, unless, ignore-error): Add empty-body warning.
* test/lisp/emacs-lisp/bytecomp-tests.el
(bytecomp-test--with-suppressed-warnings): Add test cases.
Lambda expressions are not comparable; warn about calls such as
(eq x (lambda ...)) etc.
* lisp/emacs-lisp/bytecomp.el (bytecomp--dodgy-eq-arg): Rename to...
(bytecomp--dodgy-eq-arg-p): ...this. Use pcase. Add lambda checks.
(bytecomp--value-type-description, bytecomp--arg-type-description)
(bytecomp--check-eq-args, bytecomp--check-memq-args): Add function
checks. Update calls. Make compiler-macro arguments optional to
avoid crashes in malformed code.
* test/lisp/emacs-lisp/bytecomp-tests.el
(bytecomp--with-warning-test): Simplify argument. Run each
compilation with a fresh (empty) warning cache. Add ert-info for
easier debugging.
(bytecomp-warn-dodgy-args-eq, bytecomp-warn-dodgy-args-memq):
Add lambda tests.
Add a byte-compiler warning about attempts to compare literal values
with undefined identity relation to other values. For example:
(eq x 2.0)
(memq x '("a" (b) [c]))
Such incomparable values include all literal conses, strings, vectors,
records and (except for eql and memql) floats and bignums.
The warning currently applies to eq, eql, memq, memql, assq, rassq,
remq and delq.
* lisp/emacs-lisp/bytecomp.el (bytecomp--dodgy-eq-arg)
(bytecomp--value-type-description, bytecomp--arg-type-description)
(bytecomp--warn-dodgy-eq-arg, bytecomp--check-eq-args)
(bytecomp--check-memq-args): New.
(eq, eql, memq, memql, assq, rassq, remq, delq):
Set compiler-macro property.
* lisp/emacs-lisp/byte-run.el (with-suppressed-warnings):
Amend doc string.
* test/lisp/emacs-lisp/bytecomp-tests.el
(bytecomp--with-warning-test): Fix text-quoting-style and expand
re-warning so that it doesn't need to be a literal.
(bytecomp-warn-dodgy-args-eq, bytecomp-warn-dodgy-args-memq):
New tests.
Interpreted closures currently just grab a reference to the complete
lexical environment, so (lambda (x) (+ x y)) can end up looking like
(closure ((foo ...) (y 7) (bar ...) ...)
(x) (+ x y))
where the foo/bar/... bindings are not only useless but can prevent
the GC from collecting that memory (i.e. it's a representation that is
not "safe for space") and it can also make that closure "unwritable"
(or more specifically, it can cause the closure's print
representation to be u`read`able).
Compiled closures don't suffer from this problem because `cconv.el`
actually looks at the code and only stores in the compiled closure
those variables which are actually used.
So, we fix this discrepancy by letting the existing code in `cconv.el` tell
`Ffunction` which variables are actually used by the body of the
function such that it can filter out the irrelevant elements and
return a closure of the form:
(closure ((y 7)) (x) (+ x y))
* lisp/loadup.el: Preload `cconv` and set
`internal-filter-closure-env-function` once we have a usable `cconv-fv`.
* lisp/emacs-lisp/bytecomp.el (byte-compile-preprocess): Adjust to new
calling convention of `cconv-closure-convert`.
(byte-compile-not-lexical-var-p): Delete function, moved to `cconv.el`.
(byte-compile-bind): Use `cconv--not-lexical-var-p`.
* lisp/emacs-lisp/cconv.el (cconv--dynbound-variables): New var.
(cconv-closure-convert): New arg `dynbound-vars`
(cconv--warn-unused-msg): Remove special case for `ignored`,
so we don't get confused when a function uses an argument called
`ignored`, e.g. holding a list of things that it should ignore.
(cconv--not-lexical-var-p): New function, moved from `bytecomp.el`.
Don't special case keywords and `nil` and `t` since they are already
`special-variable-p`.
(cconv--analyze-function): Use `cconv--not-lexical-var-p`.
(cconv--dynbindings): New dynbound var.
(cconv-analyze-form): Use `cconv--not-lexical-var-p`.
Remember in `cconv--dynbindings` the vars for which we used
dynamic scoping.
(cconv-analyze-form): Use `cconv--dynbound-variables` rather than
`byte-compile-bound-variables`.
(cconv-fv): New function.
* src/eval.c (Fsetq, eval_sub): Remove optimization designed when
`lexical-binding == nil` was the common case.
(Ffunction): Use `internal-filter-closure-env-function` when available.
(eval_sub, Ffuncall): Improve error info for `excessive_lisp_nesting`.
(internal-filter-closure-env-function): New defvar.
* lisp/loadup.el (featurep): Define the hash table in nativecomp
builds (but not otherwise). A more natural place to define this
would be in comp.el, but comp.el isn't loaded yet when we load the
.elc file that updates comp--no-native-compile. We could change
the load order and move the definition to comp.el, though.
* lisp/emacs-lisp/bytecomp.el (byte-compile-from-buffer): Allow
inhibiting nativecomp earlier (bug#57627).
* lisp/emacs-lisp/comp.el (native-compile-async-skip-p): Use the data.
* lisp/emacs-lisp/cl-generic.el (cl-generic-define-method):
Preserve the `advertised-calling-convention`, if any (bug#58563).
* lisp/subr.el (declare): Warn when we hit this.
* lisp/emacs-lisp/byte-run.el (get-advertised-calling-convention): New fun.
* lisp/progmodes/elisp-mode.el (elisp-get-fnsym-args-string):
* lisp/help-fns.el (help-fns--signature):
* lisp/emacs-lisp/bytecomp.el (byte-compile-fdefinition): Use it.
* test/lisp/emacs-lisp/cl-generic-tests.el (cl-generic-tests--acc): New fun.
(cl-generic-tests--advertised-calling-convention-bug58563): New test.
* test/lisp/emacs-lisp/bytecomp-tests.el
("warn-wide-docstring-ignore-function-signature.el"): New test.
* lisp/emacs-lisp/bytecomp.el (byte-compile--wide-docstring-p):
Make regexp more allowing to silence warning.
* test/lisp/emacs-lisp/bytecomp-resources/warn-wide-docstring-ignore-function-signature.el:
New file.
* lisp/emacs-lisp/bytecomp.el (byte-compile-warn-obsolete):
Autoload so that the call here from gv.el (about obsolete
generalized variables) doesn't bug out (bug#57394).
* lisp/subr.el (point-at-eol, point-at-bol): Make XEmacs compat
aliases obsolete in favor of `pos-bol'/'line-beginning-position' or
'pos-eol'/'line-end-position'. Update callers.
Ref: https://lists.gnu.org/r/emacs-devel/2022-08/msg00853.html
* doc/lispref/variables.texi (Adding Generalized Variables):
Document it.
* lisp/emacs-lisp/bytecomp.el (byte-compile-warn-obsolete): Alter
the interface so that it can also be used by generalized variable
warnings.
(byte-compile-function-warn): Adjust caller.
(byte-compile-check-variable): Adjust caller.
* lisp/emacs-lisp/gv.el (gv-get): Warn about obsolete generalized
variables (bug#49730).
(make-obsolete-generalized-variable): New function.
'User variables' were made obsolete in Emacs 24 along with
user-variable-p; the sign of the position in (#$ . POS) hasn't
mattered since.
* lisp/emacs-lisp/bytecomp.el (byte-compile-output-docform):
Don't emit negative position when doc string starts with `*`.
* src/lread.c (get_lazy_string): Explain.
