+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_hir::intravisit::FnKind;
use rustc_hir::{
- def, BinOpKind, BindingAnnotation, Body, Expr, ExprKind, FnDecl, HirId, Mutability, PatKind, Stmt, StmtKind, Ty,
- TyKind, UnOp,
+ self as hir, def, BinOpKind, BindingAnnotation, Body, Expr, ExprKind, FnDecl, HirId, Mutability, PatKind, Stmt,
+ StmtKind, TyKind, UnOp,
};
use rustc_lint::{LateContext, LateLintPass};
-use rustc_middle::ty;
+use rustc_middle::lint::in_external_macro;
+use rustc_middle::ty::{self, Ty};
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, walk_ptrs_ty, SpanlessEq,
+use clippy_utils::consts::{constant, Constant};
+use clippy_utils::sugg::Sugg;
+use clippy_utils::{
+ get_item_name, get_parent_expr, in_constant, is_diag_trait_item, is_integer_const, iter_input_pats,
+ last_path_segment, match_any_def_paths, path_def_id, paths, unsext, SpanlessEq,
};
declare_clippy_lint! {
- /// **What it does:** Checks for function arguments and let bindings denoted as
+ /// ### What it does
+ /// Checks for function arguments and let bindings denoted as
/// `ref`.
///
- /// **Why is this bad?** The `ref` declaration makes the function take an owned
+ /// ### Why is this bad?
+ /// The `ref` declaration makes the function take an owned
/// value, but turns the argument into a reference (which means that the value
/// is destroyed when exiting the function). This adds not much value: either
/// take a reference type, or take an owned value and create references in the
/// For let bindings, `let x = &foo;` is preferred over `let ref x = foo`. The
/// type of `x` is more obvious with the former.
///
- /// **Known problems:** If the argument is dereferenced within the function,
+ /// ### Known problems
+ /// If the argument is dereferenced within the function,
/// removing the `ref` will lead to errors. This can be fixed by removing the
/// dereferences, e.g., changing `*x` to `x` within the function.
///
- /// **Example:**
+ /// ### Example
/// ```rust,ignore
/// // Bad
/// fn foo(ref x: u8) -> bool {
/// true
/// }
/// ```
+ #[clippy::version = "pre 1.29.0"]
pub TOPLEVEL_REF_ARG,
style,
"an entire binding declared as `ref`, in a function argument or a `let` statement"
}
declare_clippy_lint! {
- /// **What it does:** Checks for comparisons to NaN.
+ /// ### What it does
+ /// Checks for comparisons to NaN.
///
- /// **Why is this bad?** NaN does not compare meaningfully to anything – not
+ /// ### Why is this bad?
+ /// NaN does not compare meaningfully to anything – not
/// even itself – so those comparisons are simply wrong.
///
- /// **Known problems:** None.
- ///
- /// **Example:**
+ /// ### Example
/// ```rust
/// # let x = 1.0;
///
/// // Good
/// if x.is_nan() { }
/// ```
+ #[clippy::version = "pre 1.29.0"]
pub CMP_NAN,
correctness,
"comparisons to `NAN`, which will always return false, probably not intended"
}
declare_clippy_lint! {
- /// **What it does:** Checks for (in-)equality comparisons on floating-point
+ /// ### What it does
+ /// Checks for (in-)equality comparisons on floating-point
/// values (apart from zero), except in functions called `*eq*` (which probably
/// implement equality for a type involving floats).
///
- /// **Why is this bad?** Floating point calculations are usually imprecise, so
+ /// ### Why is this bad?
+ /// Floating point calculations are usually imprecise, so
/// asking if two values are *exactly* equal is asking for trouble. For a good
/// guide on what to do, see [the floating point
/// guide](http://www.floating-point-gui.de/errors/comparison).
///
- /// **Known problems:** None.
- ///
- /// **Example:**
+ /// ### Example
/// ```rust
/// let x = 1.2331f64;
/// let y = 1.2332f64;
/// if y != x {} // where both are floats
///
/// // Good
- /// let error = 0.01f64; // Use an epsilon for comparison
- /// if (y - 1.23f64).abs() < error { }
- /// if (y - x).abs() > error { }
+ /// let error_margin = f64::EPSILON; // Use an epsilon for comparison
+ /// // Or, if Rust <= 1.42, use `std::f64::EPSILON` constant instead.
+ /// // let error_margin = std::f64::EPSILON;
+ /// if (y - 1.23f64).abs() < error_margin { }
+ /// if (y - x).abs() > error_margin { }
/// ```
+ #[clippy::version = "pre 1.29.0"]
pub FLOAT_CMP,
- correctness,
+ pedantic,
"using `==` or `!=` on float values instead of comparing difference with an epsilon"
}
declare_clippy_lint! {
- /// **What it does:** Checks for conversions to owned values just for the sake
+ /// ### What it does
+ /// Checks for conversions to owned values just for the sake
/// of a comparison.
///
- /// **Why is this bad?** The comparison can operate on a reference, so creating
+ /// ### Why is this bad?
+ /// The comparison can operate on a reference, so creating
/// an owned value effectively throws it away directly afterwards, which is
/// needlessly consuming code and heap space.
///
- /// **Known problems:** None.
- ///
- /// **Example:**
+ /// ### Example
/// ```rust
/// # let x = "foo";
/// # let y = String::from("foo");
/// # let y = String::from("foo");
/// if x == y {}
/// ```
+ #[clippy::version = "pre 1.29.0"]
pub CMP_OWNED,
perf,
"creating owned instances for comparing with others, e.g., `x == \"foo\".to_string()`"
}
declare_clippy_lint! {
- /// **What it does:** Checks for getting the remainder of a division by 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.
- ///
- /// **Known problems:** None.
- ///
- /// **Example:**
+ /// ### What it does
+ /// Checks for getting the remainder of a division by one or minus
+ /// one.
+ ///
+ /// ### 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.
+ ///
+ /// ### Example
/// ```rust
/// # let x = 1;
/// let a = x % 1;
+ /// let a = x % -1;
/// ```
+ #[clippy::version = "pre 1.29.0"]
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! {
- /// **What it does:** Checks for the use of bindings with a single leading
+ /// ### What it does
+ /// Checks for the use of bindings with a single leading
/// underscore.
///
- /// **Why is this bad?** A single leading underscore is usually used to indicate
+ /// ### Why is this bad?
+ /// A single leading underscore is usually used to indicate
/// that a binding will not be used. Using such a binding breaks this
/// expectation.
///
- /// **Known problems:** The lint does not work properly with desugaring and
+ /// ### Known problems
+ /// The lint does not work properly with desugaring and
/// macro, it has been allowed in the mean time.
///
- /// **Example:**
+ /// ### Example
/// ```rust
/// let _x = 0;
/// let y = _x + 1; // Here we are using `_x`, even though it has a leading
/// // underscore. We should rename `_x` to `x`
/// ```
+ #[clippy::version = "pre 1.29.0"]
pub USED_UNDERSCORE_BINDING,
pedantic,
"using a binding which is prefixed with an underscore"
}
declare_clippy_lint! {
- /// **What it does:** Checks for the use of short circuit boolean conditions as
+ /// ### What it does
+ /// Checks for the use of short circuit boolean conditions as
/// a
/// statement.
///
- /// **Why is this bad?** Using a short circuit boolean condition as a statement
+ /// ### Why is this bad?
+ /// Using a short circuit boolean condition as a statement
/// may hide the fact that the second part is executed or not depending on the
/// outcome of the first part.
///
- /// **Known problems:** None.
- ///
- /// **Example:**
+ /// ### Example
/// ```rust,ignore
/// f() && g(); // We should write `if f() { g(); }`.
/// ```
+ #[clippy::version = "pre 1.29.0"]
pub SHORT_CIRCUIT_STATEMENT,
complexity,
"using a short circuit boolean condition as a statement"
}
declare_clippy_lint! {
- /// **What it does:** Catch casts from `0` to some pointer type
+ /// ### What it does
+ /// Catch casts from `0` to some pointer type
///
- /// **Why is this bad?** This generally means `null` and is better expressed as
+ /// ### Why is this bad?
+ /// This generally means `null` and is better expressed as
/// {`std`, `core`}`::ptr::`{`null`, `null_mut`}.
///
- /// **Known problems:** None.
- ///
- /// **Example:**
- ///
+ /// ### Example
/// ```rust
/// // Bad
/// let a = 0 as *const u32;
/// // Good
/// let a = std::ptr::null::<u32>();
/// ```
+ #[clippy::version = "pre 1.29.0"]
pub ZERO_PTR,
style,
"using `0 as *{const, mut} T`"
}
declare_clippy_lint! {
- /// **What it does:** Checks for (in-)equality comparisons on floating-point
+ /// ### What it does
+ /// Checks for (in-)equality comparisons on floating-point
/// value and constant, except in functions called `*eq*` (which probably
/// implement equality for a type involving floats).
///
- /// **Why is this bad?** Floating point calculations are usually imprecise, so
+ /// ### Why is this bad?
+ /// Floating point calculations are usually imprecise, so
/// asking if two values are *exactly* equal is asking for trouble. For a good
/// guide on what to do, see [the floating point
/// guide](http://www.floating-point-gui.de/errors/comparison).
///
- /// **Known problems:** None.
- ///
- /// **Example:**
+ /// ### Example
/// ```rust
/// let x: f64 = 1.0;
/// const ONE: f64 = 1.00;
///
/// // Bad
- /// if x == ONE { } // where both are floats
+ /// if x == ONE { } // where both are floats
///
/// // Good
- /// let error = 0.1f64; // Use an epsilon for comparison
- /// if (x - ONE).abs() < error { }
+ /// let error_margin = f64::EPSILON; // Use an epsilon for comparison
+ /// // Or, if Rust <= 1.42, use `std::f64::EPSILON` constant instead.
+ /// // let error_margin = std::f64::EPSILON;
+ /// if (x - ONE).abs() < error_margin { }
/// ```
+ #[clippy::version = "pre 1.29.0"]
pub FLOAT_CMP_CONST,
restriction,
"using `==` or `!=` on float constants instead of comparing difference with an epsilon"
FLOAT_CMP_CONST
]);
-impl<'a, 'tcx> LateLintPass<'a, 'tcx> for MiscLints {
+impl<'tcx> LateLintPass<'tcx> for MiscLints {
fn check_fn(
&mut self,
- cx: &LateContext<'a, 'tcx>,
+ cx: &LateContext<'tcx>,
k: FnKind<'tcx>,
decl: &'tcx FnDecl<'_>,
body: &'tcx Body<'_>,
- _: Span,
+ span: Span,
_: HirId,
) {
- if let FnKind::Closure(_) = k {
+ if let FnKind::Closure = k {
// Does not apply to closures
return;
}
+ if in_external_macro(cx.tcx.sess, span) {
+ return;
+ }
for arg in iter_input_pats(decl, body) {
if let PatKind::Binding(BindingAnnotation::Ref | BindingAnnotation::RefMut, ..) = arg.pat.kind {
span_lint(
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<'a, 'tcx>, stmt: &'tcx Stmt<'_>) {
+ fn check_stmt(&mut self, cx: &LateContext<'tcx>, stmt: &'tcx Stmt<'_>) {
if_chain! {
- if let StmtKind::Local(ref local) = stmt.kind;
+ if !in_external_macro(cx.tcx.sess, stmt.span);
+ 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 !higher::is_from_for_desugar(local);
+ if let Some(init) = local.init;
+ if an == BindingAnnotation::Ref || an == BindingAnnotation::RefMut;
then {
- if an == BindingAnnotation::Ref || an == BindingAnnotation::RefMut {
- let sugg_init = if init.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 {
- span_lint_and_then(cx,
+ span_lint_hir_and_then(
+ cx,
SHORT_CIRCUIT_STATEMENT,
+ expr.hir_id,
stmt.span,
"boolean short circuit operator in statement may be clearer using an explicit test",
|diag| {
};
}
- fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr<'_>) {
+ 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);
- check_to_owned(cx, right, left);
- }
- 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 error",
- format!(
- "({}).abs() {} error",
- lhs - rhs,
- if op == BinOpKind::Eq { '<' } else { '>' }
- ),
- Applicability::HasPlaceholders, // snippet
- );
- }
- diag.note("`f32::EPSILON` and `f64::EPSILON` are available for the `error`");
- });
- } 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;
},
_ => {},
}
// Don't lint things expanded by #[derive(...)], etc or `await` desugaring
return;
}
+ let sym;
let binding = match expr.kind {
- ExprKind::Path(ref qpath) => {
+ ExprKind::Path(ref qpath) if !matches!(qpath, hir::QPath::LangItem(..)) => {
let binding = last_path_segment(qpath).ident.as_str();
if binding.starts_with('_') &&
!binding.starts_with("__") &&
}
},
ExprKind::Field(_, ident) => {
- let name = ident.as_str();
+ sym = ident.name;
+ let name = sym.as_str();
if name.starts_with('_') && !name.starts_with("__") {
Some(name)
} else {
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
),
);
}
}
-fn check_nan(cx: &LateContext<'_, '_>, expr: &Expr<'_>, cmp_expr: &Expr<'_>) {
+fn check_nan(cx: &LateContext<'_>, expr: &Expr<'_>, cmp_expr: &Expr<'_>) {
if_chain! {
if !in_constant(cx, cmp_expr.hir_id);
- if let Some((value, _)) = constant(cx, cx.tables(), expr);
+ 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",
+ );
}
}
}
-fn is_named_constant<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr<'_>) -> bool {
- if let Some((_, res)) = constant(cx, cx.tables(), expr) {
+fn is_named_constant<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> bool {
+ if let Some((_, res)) = constant(cx, cx.typeck_results(), expr) {
res
} else {
false
}
}
-fn is_allowed<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr<'_>) -> bool {
- match constant(cx, cx.tables(), expr) {
+fn is_allowed<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> bool {
+ match constant(cx, cx.typeck_results(), expr) {
Some((Constant::F32(f), _)) => f == 0.0 || f.is_infinite(),
Some((Constant::F64(f), _)) => f == 0.0 || f.is_infinite(),
Some((Constant::Vec(vec), _)) => vec.iter().all(|f| match f {
}
// Return true if `expr` is the result of `signum()` invoked on a float value.
-fn is_signum(cx: &LateContext<'_, '_>, expr: &Expr<'_>) -> bool {
+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, [ref self_arg, ..], _) = 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)
then {
- return is_float(cx, &expressions[0]);
+ return is_float(cx, self_arg);
}
}
false
}
-fn is_float(cx: &LateContext<'_, '_>, expr: &Expr<'_>) -> bool {
- let value = &walk_ptrs_ty(cx.tables().expr_ty(expr)).kind;
+fn is_float(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
+ let value = &cx.typeck_results().expr_ty(expr).peel_refs().kind();
if let ty::Array(arr_ty, _) = value {
- return matches!(arr_ty.kind, ty::Float(_));
+ return matches!(arr_ty.kind(), ty::Float(_));
};
matches!(value, ty::Float(_))
}
-fn is_array(cx: &LateContext<'_, '_>, expr: &Expr<'_>) -> bool {
- matches!(&walk_ptrs_ty(cx.tables().expr_ty(expr)).kind, ty::Array(_, _))
+fn is_array(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
+ matches!(&cx.typeck_results().expr_ty(expr).peel_refs().kind(), ty::Array(_, _))
}
-fn check_to_owned(cx: &LateContext<'_, '_>, expr: &Expr<'_>, other: &Expr<'_>) {
+#[allow(clippy::too_many_lines)]
+fn check_to_owned(cx: &LateContext<'_>, expr: &Expr<'_>, other: &Expr<'_>, left: bool) {
+ #[derive(Default)]
+ struct EqImpl {
+ ty_eq_other: bool,
+ other_eq_ty: bool,
+ }
+
+ impl EqImpl {
+ fn is_implemented(&self) -> bool {
+ self.ty_eq_other || self.other_eq_ty
+ }
+ }
+
+ fn symmetric_partial_eq<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>, other: Ty<'tcx>) -> Option<EqImpl> {
+ cx.tcx.lang_items().eq_trait().map(|def_id| EqImpl {
+ ty_eq_other: implements_trait(cx, ty, def_id, &[other.into()]),
+ other_eq_ty: implements_trait(cx, other, def_id, &[ty.into()]),
+ })
+ }
+
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.tables().expr_ty_adjusted(&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 {
- if match_qpath(path, &["String", "from_str"]) || match_qpath(path, &["String", "from"]) {
- (cx.tables().expr_ty_adjusted(&v[0]), snippet(cx, v[0].span, ".."))
+ 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(path, [arg]) => {
+ if path_def_id(cx, path)
+ .and_then(|id| match_any_def_paths(cx, id, &[&paths::FROM_STR_METHOD, &paths::FROM_FROM]))
+ .is_some()
+ {
+ (cx.typeck_results().expr_ty(arg), snippet(cx, arg.span, ".."))
} else {
return;
}
_ => return,
};
- let other_ty = cx.tables().expr_ty_adjusted(other);
- let partial_eq_trait_id = match cx.tcx.lang_items().eq_trait() {
- Some(id) => id,
- None => return,
- };
+ let other_ty = cx.typeck_results().expr_ty(other);
- let deref_arg_impl_partial_eq_other = arg_ty.builtin_deref(true).map_or(false, |tam| {
- implements_trait(cx, tam.ty, partial_eq_trait_id, &[other_ty.into()])
- });
- let arg_impl_partial_eq_deref_other = other_ty.builtin_deref(true).map_or(false, |tam| {
- implements_trait(cx, arg_ty, partial_eq_trait_id, &[tam.ty.into()])
- });
- let arg_impl_partial_eq_other = implements_trait(cx, arg_ty, partial_eq_trait_id, &[other_ty.into()]);
+ let without_deref = symmetric_partial_eq(cx, arg_ty, other_ty).unwrap_or_default();
+ let with_deref = arg_ty
+ .builtin_deref(true)
+ .and_then(|tam| symmetric_partial_eq(cx, tam.ty, other_ty))
+ .unwrap_or_default();
- if !deref_arg_impl_partial_eq_other && !arg_impl_partial_eq_deref_other && !arg_impl_partial_eq_other {
+ if !with_deref.is_implemented() && !without_deref.is_implemented() {
return;
}
- let other_gets_derefed = match other.kind {
- ExprKind::Unary(UnOp::UnDeref, _) => true,
- _ => false,
- };
+ let other_gets_derefed = matches!(other.kind, ExprKind::Unary(UnOp::Deref, _));
let lint_span = if other_gets_derefed {
expr.span.to(other.span)
return;
}
- let try_hint = if deref_arg_impl_partial_eq_other {
- // suggest deref on the left
- format!("*{}", snip)
+ let expr_snip;
+ let eq_impl;
+ if with_deref.is_implemented() {
+ expr_snip = format!("*{}", snip);
+ eq_impl = with_deref;
} else {
- // suggest dropping the to_owned on the left
- snip.to_string()
+ expr_snip = snip.to_string();
+ eq_impl = without_deref;
};
+ let span;
+ let hint;
+ if (eq_impl.ty_eq_other && left) || (eq_impl.other_eq_ty && !left) {
+ span = expr.span;
+ hint = expr_snip;
+ } else {
+ span = expr.span.to(other.span);
+
+ let cmp_span = if other.span < expr.span {
+ other.span.between(expr.span)
+ } else {
+ expr.span.between(other.span)
+ };
+ if eq_impl.ty_eq_other {
+ hint = format!(
+ "{}{}{}",
+ expr_snip,
+ snippet(cx, cmp_span, ".."),
+ snippet(cx, other.span, "..")
+ );
+ } else {
+ hint = format!(
+ "{}{}{}",
+ snippet(cx, other.span, ".."),
+ snippet(cx, cmp_span, ".."),
+ expr_snip
+ );
+ }
+ }
+
diag.span_suggestion(
- lint_span,
+ span,
"try",
- try_hint,
+ hint,
Applicability::MachineApplicable, // snippet
);
},
/// Heuristic to see if an expression is used. Should be compatible with
/// `unused_variables`'s idea
/// of what it means for an expression to be "used".
-fn is_used(cx: &LateContext<'_, '_>, expr: &Expr<'_>) -> bool {
- if let Some(parent) = get_parent_expr(cx, expr) {
- match parent.kind {
- ExprKind::Assign(_, ref rhs, _) | ExprKind::AssignOp(_, _, ref rhs) => {
- SpanlessEq::new(cx).eq_expr(rhs, expr)
- },
- _ => is_used(cx, parent),
- }
- } else {
- true
- }
+fn is_used(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
+ get_parent_expr(cx, expr).map_or(true, |parent| match parent.kind {
+ ExprKind::Assign(_, rhs, _) | ExprKind::AssignOp(_, _, rhs) => SpanlessEq::new(cx).eq_expr(rhs, expr),
+ _ => is_used(cx, parent),
+ })
}
/// Tests whether an expression is in a macro expansion (e.g., something
use rustc_span::hygiene::MacroKind;
if expr.span.from_expansion() {
let data = expr.span.ctxt().outer_expn_data();
-
- if let ExpnKind::Macro(MacroKind::Attr, _) = data.kind {
- true
- } else {
- false
- }
+ matches!(data.kind, ExpnKind::Macro(MacroKind::Attr, _))
} else {
false
}
}
/// Tests whether `res` is a variable defined outside a macro.
-fn non_macro_local(cx: &LateContext<'_, '_>, res: def::Res) -> bool {
+fn non_macro_local(cx: &LateContext<'_>, res: def::Res) -> bool {
if let def::Res::Local(id) = res {
!cx.tcx.hir().span(id).from_expansion()
} else {
}
}
-fn check_cast(cx: &LateContext<'_, '_>, span: Span, e: &Expr<'_>, ty: &Ty<'_>) {
+fn check_cast(cx: &LateContext<'_>, span: Span, e: &Expr<'_>, ty: &hir::Ty<'_>) {
if_chain! {
if let TyKind::Ptr(ref mut_ty) = ty.kind;
if let ExprKind::Lit(ref lit) = e.kind;
}
}
}
+
+fn check_binary<'a>(
+ 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