-use crate::consts::{constant, Constant};
-use crate::utils::sugg::Sugg;
-use crate::utils::{
- get_item_name, get_parent_expr, implements_trait, in_constant, in_macro, is_integer_literal, iter_input_pats,
- last_path_segment, match_qpath, match_trait_method, paths, snippet, span_lint, span_lint_and_then, walk_ptrs_ty,
- SpanlessEq,
-};
use if_chain::if_chain;
use matches::matches;
use rustc::hir::intravisit::FnKind;
use syntax::ast::LitKind;
use syntax::source_map::{ExpnFormat, Span};
-/// **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
-/// 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
-/// body.
-///
-/// 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,
-/// 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:**
-/// ```rust
-/// fn foo(ref x: u8) -> bool {
-/// ..
-/// }
-/// ```
+use crate::consts::{constant, Constant};
+use crate::utils::sugg::Sugg;
+use crate::utils::{
+ get_item_name, get_parent_expr, implements_trait, in_constant, in_macro, is_integer_literal, iter_input_pats,
+ last_path_segment, match_qpath, match_trait_method, paths, snippet, span_lint, span_lint_and_then, walk_ptrs_ty,
+ SpanlessEq,
+};
+
declare_clippy_lint! {
+ /// **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
+ /// 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
+ /// body.
+ ///
+ /// 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,
+ /// 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:**
+ /// ```rust
+ /// fn foo(ref x: u8) -> bool {
+ /// ..
+ /// }
+ /// ```
pub TOPLEVEL_REF_ARG,
style,
"an entire binding declared as `ref`, in a function argument or a `let` statement"
}
-/// **What it does:** Checks for comparisons to NaN.
-///
-/// **Why is this bad?** NaN does not compare meaningfully to anything – not
-/// even itself – so those comparisons are simply wrong.
-///
-/// **Known problems:** None.
-///
-/// **Example:**
-/// ```rust
-/// x == NAN
-/// ```
declare_clippy_lint! {
+ /// **What it does:** Checks for comparisons to NaN.
+ ///
+ /// **Why is this bad?** NaN does not compare meaningfully to anything – not
+ /// even itself – so those comparisons are simply wrong.
+ ///
+ /// **Known problems:** None.
+ ///
+ /// **Example:**
+ /// ```ignore
+ /// x == NAN
+ /// ```
pub CMP_NAN,
correctness,
"comparisons to NAN, which will always return false, probably not intended"
}
-/// **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
-/// 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:**
-/// ```rust
-/// y == 1.23f64
-/// y != x // where both are floats
-/// ```
declare_clippy_lint! {
+ /// **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
+ /// 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:**
+ /// ```ignore
+ /// y == 1.23f64
+ /// y != x // where both are floats
+ /// ```
pub FLOAT_CMP,
correctness,
"using `==` or `!=` on float values instead of comparing difference with an epsilon"
}
-/// **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
-/// an owned value effectively throws it away directly afterwards, which is
-/// needlessly consuming code and heap space.
-///
-/// **Known problems:** None.
-///
-/// **Example:**
-/// ```rust
-/// x.to_owned() == y
-/// ```
declare_clippy_lint! {
+ /// **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
+ /// an owned value effectively throws it away directly afterwards, which is
+ /// needlessly consuming code and heap space.
+ ///
+ /// **Known problems:** None.
+ ///
+ /// **Example:**
+ /// ```rust
+ /// x.to_owned() == y
+ /// ```
pub CMP_OWNED,
perf,
- "creating owned instances for comparing with others, e.g. `x == \"foo\".to_string()`"
+ "creating owned instances for comparing with others, e.g., `x == \"foo\".to_string()`"
}
-/// **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:**
-/// ```rust
-/// x % 1
-/// ```
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:**
+ /// ```ignore
+ /// x % 1
+ /// ```
pub MODULO_ONE,
correctness,
"taking a number modulo 1, which always returns 0"
}
-/// **What it does:** Checks for patterns in the form `name @ _`.
-///
-/// **Why is this bad?** It's almost always more readable to just use direct
-/// bindings.
-///
-/// **Known problems:** None.
-///
-/// **Example:**
-/// ```rust
-/// match v {
-/// Some(x) => (),
-/// y @ _ => (), // easier written as `y`,
-/// }
-/// ```
declare_clippy_lint! {
+ /// **What it does:** Checks for patterns in the form `name @ _`.
+ ///
+ /// **Why is this bad?** It's almost always more readable to just use direct
+ /// bindings.
+ ///
+ /// **Known problems:** None.
+ ///
+ /// **Example:**
+ /// ```ignore
+ /// match v {
+ /// Some(x) => (),
+ /// y @ _ => (), // easier written as `y`,
+ /// }
+ /// ```
pub REDUNDANT_PATTERN,
style,
"using `name @ _` in a pattern"
}
-/// **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
-/// 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
-/// macro, it has been allowed in the mean time.
-///
-/// **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`
-/// ```
declare_clippy_lint! {
+ /// **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
+ /// 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
+ /// macro, it has been allowed in the mean time.
+ ///
+ /// **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`
+ /// ```
pub USED_UNDERSCORE_BINDING,
pedantic,
"using a binding which is prefixed with an underscore"
}
-/// **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
-/// may hide the fact that the second part is executed or not depending on the
-/// outcome of the first part.
-///
-/// **Known problems:** None.
-///
-/// **Example:**
-/// ```rust
-/// f() && g(); // We should write `if f() { g(); }`.
-/// ```
declare_clippy_lint! {
+ /// **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
+ /// may hide the fact that the second part is executed or not depending on the
+ /// outcome of the first part.
+ ///
+ /// **Known problems:** None.
+ ///
+ /// **Example:**
+ /// ```rust
+ /// f() && g(); // We should write `if f() { g(); }`.
+ /// ```
pub SHORT_CIRCUIT_STATEMENT,
complexity,
"using a short circuit boolean condition as a statement"
}
-/// **What it does:** Catch casts from `0` to some pointer type
-///
-/// **Why is this bad?** This generally means `null` and is better expressed as
-/// {`std`, `core`}`::ptr::`{`null`, `null_mut`}.
-///
-/// **Known problems:** None.
-///
-/// **Example:**
-///
-/// ```rust
-/// 0 as *const u32
-/// ```
declare_clippy_lint! {
+ /// **What it does:** Catch casts from `0` to some pointer type
+ ///
+ /// **Why is this bad?** This generally means `null` and is better expressed as
+ /// {`std`, `core`}`::ptr::`{`null`, `null_mut`}.
+ ///
+ /// **Known problems:** None.
+ ///
+ /// **Example:**
+ ///
+ /// ```ignore
+ /// 0 as *const u32
+ /// ```
pub ZERO_PTR,
style,
"using 0 as *{const, mut} T"
}
-/// **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
-/// 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:**
-/// ```rust
-/// const ONE = 1.00f64;
-/// x == ONE // where both are floats
-/// ```
declare_clippy_lint! {
+ /// **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
+ /// 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:**
+ /// ```rust
+ /// const ONE = 1.00f64;
+ /// x == ONE // where both are floats
+ /// ```
pub FLOAT_CMP_CONST,
restriction,
"using `==` or `!=` on float constants instead of comparing difference with an epsilon"
}
fn check_nan(cx: &LateContext<'_, '_>, path: &Path, expr: &Expr) {
- if !in_constant(cx, expr.id) {
+ if !in_constant(cx, expr.hir_id) {
if let Some(seg) = path.segments.last() {
if seg.ident.name == "NAN" {
span_lint(
lint_span,
"this creates an owned instance just for comparison",
|db| {
- // this also catches PartialEq implementations that call to_owned
+ // This also catches `PartialEq` implementations that call `to_owned`.
if other_gets_derefed {
db.span_label(lint_span, "try implementing the comparison without allocating");
return;
}
}
-/// Test whether an expression is in a macro expansion (e.g. something
-/// generated by
-/// `#[derive(...)`] or the like).
+/// Tests whether an expression is in a macro expansion (e.g., something
+/// generated by `#[derive(...)]` or the like).
fn in_attributes_expansion(expr: &Expr) -> bool {
expr.span
.ctxt()
.map_or(false, |info| matches!(info.format, ExpnFormat::MacroAttribute(_)))
}
-/// Test whether `def` is a variable defined outside a macro.
+/// Tests whether `def` is a variable defined outside a macro.
fn non_macro_local(cx: &LateContext<'_, '_>, def: &def::Def) -> bool {
match *def {
def::Def::Local(id) | def::Def::Upvar(id, _, _) => !in_macro(cx.tcx.hir().span(id)),
if let ExprKind::Lit(ref lit) = e.node;
if let LitKind::Int(value, ..) = lit.node;
if value == 0;
- if !in_constant(cx, e.id);
+ if !in_constant(cx, e.hir_id);
then {
let msg = match mutbl {
Mutability::MutMutable => "`0 as *mut _` detected. Consider using `ptr::null_mut()`",
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