use rustc_session::{declare_lint_pass, declare_tool_lint};
use rustc_span::hygiene::DesugaringKind;
use rustc_span::source_map::{ExpnKind, Span};
+use rustc_span::symbol::sym;
use crate::consts::{constant, Constant};
use crate::utils::sugg::Sugg;
use crate::utils::{
- get_item_name, get_parent_expr, higher, implements_trait, in_constant, is_integer_const, iter_input_pats,
- last_path_segment, match_qpath, match_trait_method, paths, snippet, snippet_opt, span_lint, span_lint_and_sugg,
- span_lint_and_then, span_lint_hir_and_then, SpanlessEq,
+ get_item_name, get_parent_expr, higher, implements_trait, in_constant, is_diagnostic_assoc_item, is_integer_const,
+ iter_input_pats, last_path_segment, match_qpath, snippet, snippet_opt, span_lint, span_lint_and_sugg,
+ span_lint_and_then, span_lint_hir_and_then, unsext, SpanlessEq,
};
declare_clippy_lint! {
}
declare_clippy_lint! {
- /// **What it does:** Checks for getting the remainder of a division by one.
+ /// **What it does:** Checks for getting the remainder of a division by one or minus
+ /// one.
///
- /// **Why is this bad?** The result can only ever be zero. No one will write
- /// such code deliberately, unless trying to win an Underhanded Rust
- /// Contest. Even for that contest, it's probably a bad idea. Use something more
- /// underhanded.
+ /// **Why is this bad?** The result for a divisor of one can only ever be zero; for
+ /// minus one it can cause panic/overflow (if the left operand is the minimal value of
+ /// the respective integer type) or results in zero. No one will write such code
+ /// deliberately, unless trying to win an Underhanded Rust Contest. Even for that
+ /// contest, it's probably a bad idea. Use something more underhanded.
///
/// **Known problems:** None.
///
/// ```rust
/// # let x = 1;
/// let a = x % 1;
+ /// let a = x % -1;
/// ```
pub MODULO_ONE,
correctness,
- "taking a number modulo 1, which always returns 0"
+ "taking a number modulo +/-1, which can either panic/overflow or always returns 0"
}
declare_clippy_lint! {
span: Span,
_: HirId,
) {
- if let FnKind::Closure(_) = k {
+ if let FnKind::Closure = k {
// Does not apply to closures
return;
}
TOPLEVEL_REF_ARG,
arg.pat.span,
"`ref` directly on a function argument is ignored. \
- Consider using a reference type instead.",
+ Consider using a reference type instead",
);
}
}
return;
},
ExprKind::Binary(ref cmp, ref left, ref right) => {
- let op = cmp.node;
- if op.is_comparison() {
- check_nan(cx, left, expr);
- check_nan(cx, right, expr);
- check_to_owned(cx, left, right, true);
- check_to_owned(cx, right, left, false);
- }
- if (op == BinOpKind::Eq || op == BinOpKind::Ne) && (is_float(cx, left) || is_float(cx, right)) {
- if is_allowed(cx, left) || is_allowed(cx, right) {
- return;
- }
-
- // Allow comparing the results of signum()
- if is_signum(cx, left) && is_signum(cx, right) {
- return;
- }
-
- if let Some(name) = get_item_name(cx, expr) {
- let name = name.as_str();
- if name == "eq"
- || name == "ne"
- || name == "is_nan"
- || name.starts_with("eq_")
- || name.ends_with("_eq")
- {
- return;
- }
- }
- let is_comparing_arrays = is_array(cx, left) || is_array(cx, right);
- let (lint, msg) = get_lint_and_message(
- is_named_constant(cx, left) || is_named_constant(cx, right),
- is_comparing_arrays,
- );
- span_lint_and_then(cx, lint, expr.span, msg, |diag| {
- let lhs = Sugg::hir(cx, left, "..");
- let rhs = Sugg::hir(cx, right, "..");
-
- if !is_comparing_arrays {
- diag.span_suggestion(
- expr.span,
- "consider comparing them within some margin of error",
- format!(
- "({}).abs() {} error_margin",
- lhs - rhs,
- if op == BinOpKind::Eq { '<' } else { '>' }
- ),
- Applicability::HasPlaceholders, // snippet
- );
- }
- diag.note("`f32::EPSILON` and `f64::EPSILON` are available for the `error_margin`");
- });
- } else if op == BinOpKind::Rem && is_integer_const(cx, right, 1) {
- span_lint(cx, MODULO_ONE, expr.span, "any number modulo 1 will be 0");
- }
+ check_binary(cx, expr, cmp, left, right);
+ return;
},
_ => {},
}
expr.span,
&format!(
"used binding `{}` which is prefixed with an underscore. A leading \
- underscore signals that a binding will not be used.",
+ underscore signals that a binding will not be used",
binding
),
);
// Return true if `expr` is the result of `signum()` invoked on a float value.
fn is_signum(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
// The negation of a signum is still a signum
- if let ExprKind::Unary(UnOp::UnNeg, ref child_expr) = expr.kind {
+ if let ExprKind::Unary(UnOp::Neg, ref child_expr) = expr.kind {
return is_signum(cx, &child_expr);
}
let (arg_ty, snip) = match expr.kind {
ExprKind::MethodCall(.., ref args, _) if args.len() == 1 => {
- if match_trait_method(cx, expr, &paths::TO_STRING) || match_trait_method(cx, expr, &paths::TO_OWNED) {
- (cx.typeck_results().expr_ty(&args[0]), snippet(cx, args[0].span, ".."))
- } else {
- return;
- }
+ if_chain!(
+ if let Some(expr_def_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id);
+ if is_diagnostic_assoc_item(cx, expr_def_id, sym::ToString)
+ || is_diagnostic_assoc_item(cx, expr_def_id, sym::ToOwned);
+ then {
+ (cx.typeck_results().expr_ty(&args[0]), snippet(cx, args[0].span, ".."))
+ } else {
+ return;
+ }
+ )
},
ExprKind::Call(ref path, ref v) if v.len() == 1 => {
if let ExprKind::Path(ref path) = path.kind {
return;
}
- let other_gets_derefed = matches!(other.kind, ExprKind::Unary(UnOp::UnDeref, _));
+ let other_gets_derefed = matches!(other.kind, ExprKind::Unary(UnOp::Deref, _));
let lint_span = if other_gets_derefed {
expr.span.to(other.span)
}
}
}
+
+fn check_binary(
+ cx: &LateContext<'a>,
+ expr: &Expr<'_>,
+ cmp: &rustc_span::source_map::Spanned<rustc_hir::BinOpKind>,
+ left: &'a Expr<'_>,
+ right: &'a Expr<'_>,
+) {
+ let op = cmp.node;
+ if op.is_comparison() {
+ check_nan(cx, left, expr);
+ check_nan(cx, right, expr);
+ check_to_owned(cx, left, right, true);
+ check_to_owned(cx, right, left, false);
+ }
+ if (op == BinOpKind::Eq || op == BinOpKind::Ne) && (is_float(cx, left) || is_float(cx, right)) {
+ if is_allowed(cx, left) || is_allowed(cx, right) {
+ return;
+ }
+
+ // Allow comparing the results of signum()
+ if is_signum(cx, left) && is_signum(cx, right) {
+ return;
+ }
+
+ if let Some(name) = get_item_name(cx, expr) {
+ let name = name.as_str();
+ if name == "eq" || name == "ne" || name == "is_nan" || name.starts_with("eq_") || name.ends_with("_eq") {
+ return;
+ }
+ }
+ let is_comparing_arrays = is_array(cx, left) || is_array(cx, right);
+ let (lint, msg) = get_lint_and_message(
+ is_named_constant(cx, left) || is_named_constant(cx, right),
+ is_comparing_arrays,
+ );
+ span_lint_and_then(cx, lint, expr.span, msg, |diag| {
+ let lhs = Sugg::hir(cx, left, "..");
+ let rhs = Sugg::hir(cx, right, "..");
+
+ if !is_comparing_arrays {
+ diag.span_suggestion(
+ expr.span,
+ "consider comparing them within some margin of error",
+ format!(
+ "({}).abs() {} error_margin",
+ lhs - rhs,
+ if op == BinOpKind::Eq { '<' } else { '>' }
+ ),
+ Applicability::HasPlaceholders, // snippet
+ );
+ }
+ diag.note("`f32::EPSILON` and `f64::EPSILON` are available for the `error_margin`");
+ });
+ } else if op == BinOpKind::Rem {
+ if is_integer_const(cx, right, 1) {
+ span_lint(cx, MODULO_ONE, expr.span, "any number modulo 1 will be 0");
+ }
+
+ if let ty::Int(ity) = cx.typeck_results().expr_ty(right).kind() {
+ if is_integer_const(cx, right, unsext(cx.tcx, -1, *ity)) {
+ span_lint(
+ cx,
+ MODULO_ONE,
+ expr.span,
+ "any number modulo -1 will panic/overflow or result in 0",
+ );
+ }
+ };
+ }
+}
projects / rust.git / blobdiff