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use clippy_utils::{numeric_literal::NumericLiteral, source::snippet_with_context};
use rustc_errors::Applicability;
use rustc_hir::{BinOpKind, Expr, ExprKind};
use rustc_lint::{LateContext, LateLintPass, LintContext};
use rustc_middle::lint::in_external_macro;
use rustc_session::{declare_lint_pass, declare_tool_lint};
declare_clippy_lint! {
/// ### What it does
/// Warns for a Bitwise XOR (`^`) operator being probably confused as a powering. It will not trigger if any of the numbers are not in decimal.
/// ### Why is this bad?
/// It's most probably a typo and may lead to unexpected behaviours.
/// ### Example
/// ```rust
/// let x = 3_i32 ^ 4_i32;
/// ```
/// Use instead:
/// ```rust
/// let x = 3_i32.pow(4);
/// ```
#[clippy::version = "1.66.0"]
pub SUSPICIOUS_XOR_USED_AS_POW,
restriction,
"XOR (`^`) operator possibly used as exponentiation operator"
}
declare_lint_pass!(ConfusingXorAndPow => [SUSPICIOUS_XOR_USED_AS_POW]);
impl LateLintPass<'_> for ConfusingXorAndPow {
fn check_expr(&mut self, cx: &LateContext<'_>, expr: &Expr<'_>) {
if !in_external_macro(cx.sess(), expr.span) &&
let ExprKind::Binary(op, left, right) = &expr.kind &&
op.node == BinOpKind::BitXor &&
left.span.ctxt() == right.span.ctxt() &&
let ExprKind::Lit(lit_left) = &left.kind &&
let ExprKind::Lit(lit_right) = &right.kind &&
let snip_left = snippet_with_context(cx, lit_left.span, lit_left.span.ctxt(), "..", &mut Applicability::MaybeIncorrect) &&
let snip_right = snippet_with_context(cx, lit_right.span, lit_right.span.ctxt(), "..", &mut Applicability::MaybeIncorrect) &&
let Some(left_val) = NumericLiteral::from_lit_kind(&snip_left.0, &lit_left.node) &&
let Some(right_val) = NumericLiteral::from_lit_kind(&snip_right.0, &lit_right.node) &&
left_val.is_decimal() &&
right_val.is_decimal() {
clippy_utils::diagnostics::span_lint_and_sugg(
cx,
SUSPICIOUS_XOR_USED_AS_POW,
expr.span,
"`^` is not the exponentiation operator",
"did you mean to write",
format!("{}.pow({})", left_val.format(), right_val.format()),
Applicability::MaybeIncorrect,
);
}
}
}
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