The top level message shouldn't be too long; the
replaced-by-coercion/temporary-variable advice can live in a note. Also,
don't mention type ascription when it's not actually available as a real
thing. (The current state of discussion on the type ascription tracking
issue #23416 makes one rather suspect it will never be a stable thing in
its current form, but that's not for us to adjudicate in this commit.)
While we're here, yank out the differentiating parts of the
numeric/other conditional and only have one codepath emitting the
diagnostic.
Rollup of 8 pull requests
Successful merges:
- #50531 (Cleanup uses of TypeIdHasher and replace them with StableHasher)
- #50819 (Fix potential divide by zero)
- #50827 (Update LLVM to 56c931901cfb85cd6f7ed44c7d7520a8de1edf97)
- #50829 (CheckLoopVisitor: also visit break expressions)
- #50854 (in which the unused shorthand field pattern debacle/saga continues)
- #50858 (Reorder description for snippets in rustdoc documentation)
- #50883 (Fix warning when building stage0 libcore)
- #50889 (Update clippy)
Failed merges:
In e4b1a79 (#47922), we corrected erroneous suggestions for unused
shorthand field pattern bindings, suggesting `field: _` where the
previous suggestion of `_field` wouldn't even have compiled
(#47390). Soon, it was revealed that this was insufficient (#50303), and
the fix was extended to references, slices, &c. (#50327) But even this
proved inadequate, as the erroneous suggestions were still being issued
for patterns in local (`let`) bindings (#50804). Here, we yank the
shorthand-detection and variable/node registration code into a new
common function that can be called while visiting both match arms and
`let` bindings.
Resolves#50804.
The Higher Intermediate Representation doesn't have spans for visibility
keywords, so we were assuming that the first whitespace-delimited token
in the item span was the `pub` to be weakened. This doesn't work for
brace-grouped `use`s, which get lowered as if they were several
individual `use` statements, but with spans that only cover the braced
path-segments. Constructing a correct suggestion here presents some
challenges—until someone works those out, we can at least protect the
dignity of our compiler marking the suggestion for `use` items as
potentially incorrect.
This resolves#50455 (but again, it would be desirable in the future to
make a correct suggestion instead of copping out like this).
decline to lint technically-unnecessary parens in function or method arguments inside of nested macros
In #46980 ("in which the unused-parens lint..." (14982db2d6)), the
unused-parens lint was made to check function and method arguments,
which it previously did not (seemingly due to oversight rather than
willful design). However, in #47775 and discussion thereon,
user–developers of Geal/nom and graphql-rust/juniper reported that the
lint was seemingly erroneously triggering on certain complex macros in
those projects. While this doesn't seem like a bug in the lint in the
particular strict sense that the expanded code would, in fact, contain
unncecessary parentheses, it also doesn't seem like the sort of thing
macro authors should have to think about: the spirit of the
unused-parens lint is to prevent needless clutter in code, not to give
macro authors extra heartache in the handling of token trees.
We propose the expediency of declining to lint unused parentheses in
function or method args inside of nested expansions: we believe that
this should eliminate the petty, troublesome lint warnings reported
in the issue, without forgoing the benefits of the lint in simpler
macros.
It seemed like too much duplicated code for the `Call` and `MethodCall`
match arms to duplicate the nested-macro check in addition to each
having their own `for` loop, so this occasioned a slight refactor so
that the function and method cases could share code—hopefully the
overall intent is at least no less clear to the gentle reader.
This is concerning #47775.
Previously, unused variables would get a note that the warning could be
silenced by prefixing the variable with an underscore, but that doesn't
work for field shorthand patterns, which the liveness analysis didn't
know about.
The "to avoid this warning" verbiage seemed unnecessary.
Resolves#47390.
In #46980 ("in which the unused-parens lint..." (14982db2d6)), the
unused-parens lint was made to check function and method arguments,
which it previously did not (seemingly due to oversight rather than
willful design). However, in #47775 and discussion thereon,
user–developers of Geal/nom and graphql-rust/juniper reported that the
lint was seemingly erroneously triggering on certain complex macros in
those projects. While this doesn't seem like a bug in the lint in the
particular strict sense that the expanded code would, in fact, contain
unncecessary parentheses, it also doesn't seem like the sort of thing
macro authors should have to think about: the spirit of the
unused-parens lint is to prevent needless clutter in code, not to give
macro authors extra heartache in the handling of token trees.
We propose the expediency of declining to lint unused parentheses in
function or method args inside of nested expansions: we believe that
this should eliminate the petty, troublesome lint warnings reported
in the issue, without forgoing the benefits of the lint in simpler
macros.
It seemed like too much duplicated code for the `Call` and `MethodCall`
match arms to duplicate the nested-macro check in addition to each
having their own `for` loop, so this occasioned a slight refactor so
that the function and method cases could share code—hopefully the
overall intent is at least no less clear to the gentle reader.
This is concerning #47775.
