rust/clippy_lints/src/neg_multiply.rs
xFrednet d647696c1f
Added clippy::version attribute to all normal lints
So, some context for this, well, more a story. I'm not used to scripting, I've never really scripted anything, even if it's a valuable skill. I just never really needed it. Now, `@flip1995` correctly suggested using a script for this in `rust-clippy#7813`...

And I decided to write a script using nushell because why not? This was a mistake... I spend way more time on this than I would like to admit. It has definitely been more than 4 hours. It shouldn't take that long, but me being new to scripting and nushell just wasn't a good mixture... Anyway, here is the script that creates another script which adds the versions. Fun...

Just execute this on the `gh-pages` branch and the resulting `replacer.sh` in `clippy_lints` and it should all work.

```nu
mv v0.0.212 rust-1.00.0;
mv beta rust-1.57.0;
mv master rust-1.58.0;

let paths = (open ./rust-1.58.0/lints.json | select id id_span | flatten | select id path);
let versions = (
    ls | where name =~ "rust-" | select name | format {name}/lints.json |
    each { open $it | select id | insert version $it | str substring "5,11" version} |
    group-by id | rotate counter-clockwise id version |
    update version {get version | first 1} | flatten | select id version);
$paths | each { |row|
    let version = ($versions | where id == ($row.id) | format {version})
    let idu = ($row.id | str upcase)
    $"sed -i '0,/($idu),/{s/pub ($idu),/#[clippy::version = "($version)"]\n    pub ($idu),/}' ($row.path)"
} | str collect ";" | str find-replace --all '1.00.0' 'pre 1.29.0' | save "replacer.sh";
```

And this still has some problems, but at this point I just want to be done -.-
2021-11-10 19:48:31 +01:00

57 lines
1.8 KiB
Rust

use clippy_utils::consts::{self, Constant};
use clippy_utils::diagnostics::span_lint;
use if_chain::if_chain;
use rustc_hir::{BinOpKind, Expr, ExprKind, UnOp};
use rustc_lint::{LateContext, LateLintPass};
use rustc_session::{declare_lint_pass, declare_tool_lint};
use rustc_span::source_map::Span;
declare_clippy_lint! {
/// ### What it does
/// Checks for multiplication by -1 as a form of negation.
///
/// ### Why is this bad?
/// It's more readable to just negate.
///
/// ### Known problems
/// This only catches integers (for now).
///
/// ### Example
/// ```ignore
/// x * -1
/// ```
#[clippy::version = "pre 1.29.0"]
pub NEG_MULTIPLY,
style,
"multiplying integers with `-1`"
}
declare_lint_pass!(NegMultiply => [NEG_MULTIPLY]);
#[allow(clippy::match_same_arms)]
impl<'tcx> LateLintPass<'tcx> for NegMultiply {
fn check_expr(&mut self, cx: &LateContext<'tcx>, e: &'tcx Expr<'_>) {
if let ExprKind::Binary(ref op, left, right) = e.kind {
if BinOpKind::Mul == op.node {
match (&left.kind, &right.kind) {
(&ExprKind::Unary(..), &ExprKind::Unary(..)) => {},
(&ExprKind::Unary(UnOp::Neg, lit), _) => check_mul(cx, e.span, lit, right),
(_, &ExprKind::Unary(UnOp::Neg, lit)) => check_mul(cx, e.span, lit, left),
_ => {},
}
}
}
}
}
fn check_mul(cx: &LateContext<'_>, span: Span, lit: &Expr<'_>, exp: &Expr<'_>) {
if_chain! {
if let ExprKind::Lit(ref l) = lit.kind;
if consts::lit_to_constant(&l.node, cx.typeck_results().expr_ty_opt(lit)) == Constant::Int(1);
if cx.typeck_results().expr_ty(exp).is_integral();
then {
span_lint(cx, NEG_MULTIPLY, span, "negation by multiplying with `-1`");
}
}
}