-use consts::{constant_simple, Constant, FloatWidth};
+use crate::consts::{constant_simple, Constant};
use rustc::lint::*;
+use rustc::{declare_lint, lint_array};
+use if_chain::if_chain;
use rustc::hir::*;
-use utils::span_help_and_lint;
+use crate::utils::span_help_and_lint;
/// **What it does:** Checks for `0.0 / 0.0`.
///
/// ```rust
/// 0.0f32 / 0.0
/// ```
-declare_lint! {
+declare_clippy_lint! {
pub ZERO_DIVIDED_BY_ZERO,
- Warn,
+ complexity,
"usage of `0.0 / 0.0` to obtain NaN instead of std::f32::NaN or std::f64::NaN"
}
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Pass {
fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr) {
// check for instances of 0.0/0.0
- if_let_chain! {[
- let ExprBinary(ref op, ref left, ref right) = expr.node,
- let BinOp_::BiDiv = op.node,
+ if_chain! {
+ if let ExprKind::Binary(ref op, ref left, ref right) = expr.node;
+ if let BinOpKind::Div = op.node;
// TODO - constant_simple does not fold many operations involving floats.
// That's probably fine for this lint - it's pretty unlikely that someone would
// do something like 0.0/(2.0 - 2.0), but it would be nice to warn on that case too.
- let Some(Constant::Float(ref lhs_value, lhs_width)) = constant_simple(cx, left),
- let Some(Constant::Float(ref rhs_value, rhs_width)) = constant_simple(cx, right),
- Ok(0.0) == lhs_value.parse(),
- Ok(0.0) == rhs_value.parse()
- ], {
- // since we're about to suggest a use of std::f32::NaN or std::f64::NaN,
- // match the precision of the literals that are given.
- let float_type = match (lhs_width, rhs_width) {
- (FloatWidth::F64, _)
- | (_, FloatWidth::F64) => "f64",
- _ => "f32"
- };
- span_help_and_lint(cx, ZERO_DIVIDED_BY_ZERO, expr.span,
- "constant division of 0.0 with 0.0 will always result in NaN",
- &format!("Consider using `std::{}::NAN` if you would like a constant representing NaN", float_type));
- }}
+ if let Some(lhs_value) = constant_simple(cx, cx.tables, left);
+ if let Some(rhs_value) = constant_simple(cx, cx.tables, right);
+ if Constant::F32(0.0) == lhs_value || Constant::F64(0.0) == lhs_value;
+ if Constant::F32(0.0) == rhs_value || Constant::F64(0.0) == rhs_value;
+ then {
+ // since we're about to suggest a use of std::f32::NaN or std::f64::NaN,
+ // match the precision of the literals that are given.
+ let float_type = match (lhs_value, rhs_value) {
+ (Constant::F64(_), _)
+ | (_, Constant::F64(_)) => "f64",
+ _ => "f32"
+ };
+ span_help_and_lint(
+ cx,
+ ZERO_DIVIDED_BY_ZERO,
+ expr.span,
+ "constant division of 0.0 with 0.0 will always result in NaN",
+ &format!(
+ "Consider using `std::{}::NAN` if you would like a constant representing NaN",
+ float_type,
+ ),
+ );
+ }
+ }
}
}