+use clippy_utils::diagnostics::{span_lint, span_lint_and_sugg, span_lint_and_then, span_lint_hir_and_then};
+use clippy_utils::source::{snippet, snippet_opt};
+use clippy_utils::ty::implements_trait;
use if_chain::if_chain;
use rustc_ast::ast::LitKind;
use rustc_errors::Applicability;
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,
+use clippy_utils::sugg::Sugg;
+use clippy_utils::{
+ get_item_name, get_parent_expr, higher, in_constant, is_diag_trait_item, is_integer_const, iter_input_pats,
+ last_path_segment, match_qpath, 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",
);
}
}
fn check_stmt(&mut self, cx: &LateContext<'tcx>, stmt: &'tcx Stmt<'_>) {
if_chain! {
if !in_external_macro(cx.tcx.sess, stmt.span);
- if let StmtKind::Local(ref local) = stmt.kind;
+ if let StmtKind::Local(local) = stmt.kind;
if let PatKind::Binding(an, .., name, None) = local.pat.kind;
- if let Some(ref init) = local.init;
+ if let Some(init) = local.init;
if !higher::is_from_for_desugar(local);
+ if an == BindingAnnotation::Ref || an == BindingAnnotation::RefMut;
then {
- if an == BindingAnnotation::Ref || an == BindingAnnotation::RefMut {
- // use the macro callsite when the init span (but not the whole local span)
- // comes from an expansion like `vec![1, 2, 3]` in `let ref _ = vec![1, 2, 3];`
- let sugg_init = if init.span.from_expansion() && !local.span.from_expansion() {
- Sugg::hir_with_macro_callsite(cx, init, "..")
- } else {
- Sugg::hir(cx, init, "..")
- };
- let (mutopt, initref) = if an == BindingAnnotation::RefMut {
- ("mut ", sugg_init.mut_addr())
- } else {
- ("", sugg_init.addr())
- };
- let tyopt = if let Some(ref ty) = local.ty {
- format!(": &{mutopt}{ty}", mutopt=mutopt, ty=snippet(cx, ty.span, ".."))
- } else {
- String::new()
- };
- span_lint_hir_and_then(
- cx,
- TOPLEVEL_REF_ARG,
- init.hir_id,
- local.pat.span,
- "`ref` on an entire `let` pattern is discouraged, take a reference with `&` instead",
- |diag| {
- diag.span_suggestion(
- stmt.span,
- "try",
- format!(
- "let {name}{tyopt} = {initref};",
- name=snippet(cx, name.span, ".."),
- tyopt=tyopt,
- initref=initref,
- ),
- Applicability::MachineApplicable,
- );
- }
- );
- }
+ // use the macro callsite when the init span (but not the whole local span)
+ // comes from an expansion like `vec![1, 2, 3]` in `let ref _ = vec![1, 2, 3];`
+ let sugg_init = if init.span.from_expansion() && !local.span.from_expansion() {
+ Sugg::hir_with_macro_callsite(cx, init, "..")
+ } else {
+ Sugg::hir(cx, init, "..")
+ };
+ let (mutopt, initref) = if an == BindingAnnotation::RefMut {
+ ("mut ", sugg_init.mut_addr())
+ } else {
+ ("", sugg_init.addr())
+ };
+ let tyopt = if let Some(ty) = local.ty {
+ format!(": &{mutopt}{ty}", mutopt=mutopt, ty=snippet(cx, ty.span, ".."))
+ } else {
+ String::new()
+ };
+ span_lint_hir_and_then(
+ cx,
+ TOPLEVEL_REF_ARG,
+ init.hir_id,
+ local.pat.span,
+ "`ref` on an entire `let` pattern is discouraged, take a reference with `&` instead",
+ |diag| {
+ diag.span_suggestion(
+ stmt.span,
+ "try",
+ format!(
+ "let {name}{tyopt} = {initref};",
+ name=snippet(cx, name.span, ".."),
+ tyopt=tyopt,
+ initref=initref,
+ ),
+ Applicability::MachineApplicable,
+ );
+ }
+ );
}
};
if_chain! {
- if let StmtKind::Semi(ref expr) = stmt.kind;
- if let ExprKind::Binary(ref binop, ref a, ref b) = expr.kind;
+ if let StmtKind::Semi(expr) = stmt.kind;
+ if let ExprKind::Binary(ref binop, a, b) = expr.kind;
if binop.node == BinOpKind::And || binop.node == BinOpKind::Or;
if let Some(sugg) = Sugg::hir_opt(cx, a);
then {
fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
match expr.kind {
- ExprKind::Cast(ref e, ref ty) => {
+ ExprKind::Cast(e, ty) => {
check_cast(cx, expr.span, e, ty);
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");
- }
+ ExprKind::Binary(ref cmp, left, right) => {
+ 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
),
);
if_chain! {
if !in_constant(cx, cmp_expr.hir_id);
if let Some((value, _)) = constant(cx, cx.typeck_results(), expr);
+ if match value {
+ Constant::F32(num) => num.is_nan(),
+ Constant::F64(num) => num.is_nan(),
+ _ => false,
+ };
then {
- let needs_lint = match value {
- Constant::F32(num) => num.is_nan(),
- Constant::F64(num) => num.is_nan(),
- _ => false,
- };
-
- if needs_lint {
- span_lint(
- cx,
- CMP_NAN,
- cmp_expr.span,
- "doomed comparison with `NAN`, use `{f32,f64}::is_nan()` instead",
- );
- }
+ span_lint(
+ cx,
+ CMP_NAN,
+ cmp_expr.span,
+ "doomed comparison with `NAN`, use `{f32,f64}::is_nan()` instead",
+ );
}
}
}
// 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 {
- return is_signum(cx, &child_expr);
+ if let ExprKind::Unary(UnOp::Neg, child_expr) = expr.kind {
+ return is_signum(cx, child_expr);
}
if_chain! {
- if let ExprKind::MethodCall(ref method_name, _, ref expressions, _) = expr.kind;
+ if let ExprKind::MethodCall(method_name, _, expressions, _) = expr.kind;
if sym!(signum) == method_name.ident.name;
// Check that the receiver of the signum() is a float (expressions[0] is the receiver of
// the method call)
}
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;
- }
+ ExprKind::MethodCall(.., args, _) if args.len() == 1 => {
+ if_chain!(
+ if let Some(expr_def_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id);
+ if is_diag_trait_item(cx, expr_def_id, sym::ToString)
+ || is_diag_trait_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 => {
+ ExprKind::Call(path, v) if v.len() == 1 => {
if let ExprKind::Path(ref path) = path.kind {
if match_qpath(path, &["String", "from_str"]) || match_qpath(path, &["String", "from"]) {
(cx.typeck_results().expr_ty(&v[0]), snippet(cx, v[0].span, ".."))
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)
/// of what it means for an expression to be "used".
fn is_used(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
get_parent_expr(cx, expr).map_or(true, |parent| match parent.kind {
- ExprKind::Assign(_, ref rhs, _) | ExprKind::AssignOp(_, _, ref rhs) => SpanlessEq::new(cx).eq_expr(rhs, expr),
+ ExprKind::Assign(_, rhs, _) | ExprKind::AssignOp(_, _, rhs) => SpanlessEq::new(cx).eq_expr(rhs, expr),
_ => is_used(cx, parent),
})
}
}
}
}
+
+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