-use reexport::*;
-use rustc::hir::*;
-use rustc::hir::intravisit::FnKind;
-use rustc::lint::*;
-use rustc::middle::const_val::ConstVal;
-use rustc::ty;
-use rustc::ty::subst::Substs;
-use rustc_const_eval::ConstContext;
-use rustc_const_math::ConstFloat;
-use syntax::codemap::{ExpnFormat, Span};
-use 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};
-use utils::sugg::Sugg;
-use syntax::ast::{FloatTy, LitKind, CRATE_NODE_ID};
-use consts::constant;
-
-/// **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 { .. }
-/// ```
-declare_lint! {
+use clippy_utils::diagnostics::{span_lint, span_lint_and_sugg, span_lint_hir_and_then};
+use clippy_utils::source::{snippet, snippet_opt, snippet_with_context};
+use if_chain::if_chain;
+use rustc_errors::Applicability;
+use rustc_hir::intravisit::FnKind;
+use rustc_hir::{
+ self as hir, def, BinOpKind, BindingAnnotation, Body, ByRef, Expr, ExprKind, FnDecl, Mutability, PatKind, Stmt,
+ StmtKind, TyKind,
+};
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_middle::lint::in_external_macro;
+use rustc_session::{declare_tool_lint, impl_lint_pass};
+use rustc_span::def_id::LocalDefId;
+use rustc_span::hygiene::DesugaringKind;
+use rustc_span::source_map::{ExpnKind, Span};
+
+use clippy_utils::sugg::Sugg;
+use clippy_utils::{
+ get_parent_expr, in_constant, is_integer_literal, is_lint_allowed, is_no_std_crate, iter_input_pats,
+ last_path_segment, SpanlessEq,
+};
+
+use crate::ref_patterns::REF_PATTERNS;
+
+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) {}
+ /// ```
+ ///
+ /// Use instead:
+ /// ```rust
+ /// fn foo(_x: &u8) {}
+ /// ```
+ #[clippy::version = "pre 1.29.0"]
pub TOPLEVEL_REF_ARG,
- Warn,
+ 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_lint! {
- pub CMP_NAN,
- Deny,
- "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_lint! {
- pub FLOAT_CMP,
- Warn,
- "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_lint! {
- pub CMP_OWNED,
- Warn,
- "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_lint! {
- pub MODULO_ONE,
- Warn,
- "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_lint! {
- pub REDUNDANT_PATTERN,
- Warn,
- "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_lint! {
+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`
+ /// ```
+ #[clippy::version = "pre 1.29.0"]
pub USED_UNDERSCORE_BINDING,
- Allow,
+ 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_lint! {
+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.
+ ///
+ /// ### Example
+ /// ```rust,ignore
+ /// f() && g(); // We should write `if f() { g(); }`.
+ /// ```
+ #[clippy::version = "pre 1.29.0"]
pub SHORT_CIRCUIT_STATEMENT,
- Warn,
+ 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_lint! {
+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`}.
+ ///
+ /// ### Example
+ /// ```rust
+ /// let a = 0 as *const u32;
+ /// ```
+ ///
+ /// Use instead:
+ /// ```rust
+ /// let a = std::ptr::null::<u32>();
+ /// ```
+ #[clippy::version = "pre 1.29.0"]
pub ZERO_PTR,
- Warn,
- "using 0 as *{const, mut} T"
+ 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_restriction_lint! {
- pub FLOAT_CMP_CONST,
- "using `==` or `!=` on float constants instead of comparing difference with an epsilon"
+pub struct LintPass {
+ std_or_core: &'static str,
}
-
-#[derive(Copy, Clone)]
-pub struct Pass;
-
-impl LintPass for Pass {
- fn get_lints(&self) -> LintArray {
- lint_array!(
- TOPLEVEL_REF_ARG,
- CMP_NAN,
- FLOAT_CMP,
- CMP_OWNED,
- MODULO_ONE,
- REDUNDANT_PATTERN,
- USED_UNDERSCORE_BINDING,
- SHORT_CIRCUIT_STATEMENT,
- ZERO_PTR,
- FLOAT_CMP_CONST
- )
+impl Default for LintPass {
+ fn default() -> Self {
+ Self { std_or_core: "std" }
}
}
+impl_lint_pass!(LintPass => [
+ TOPLEVEL_REF_ARG,
+ USED_UNDERSCORE_BINDING,
+ SHORT_CIRCUIT_STATEMENT,
+ ZERO_PTR,
+]);
+
+impl<'tcx> LateLintPass<'tcx> for LintPass {
+ fn check_crate(&mut self, cx: &LateContext<'_>) {
+ if is_no_std_crate(cx) {
+ self.std_or_core = "core";
+ }
+ }
-impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Pass {
fn check_fn(
&mut self,
- cx: &LateContext<'a, 'tcx>,
+ cx: &LateContext<'tcx>,
k: FnKind<'tcx>,
- decl: &'tcx FnDecl,
- body: &'tcx Body,
- _: Span,
- _: NodeId,
+ decl: &'tcx FnDecl<'_>,
+ body: &'tcx Body<'_>,
+ span: Span,
+ _: LocalDefId,
) {
- 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) {
- match arg.pat.node {
- PatKind::Binding(BindingAnnotation::Ref, _, _, _) |
- PatKind::Binding(BindingAnnotation::RefMut, _, _, _) => {
- span_lint(
- cx,
- TOPLEVEL_REF_ARG,
- arg.pat.span,
- "`ref` directly on a function argument is ignored. Consider using a reference type \
- instead.",
- );
- },
- _ => {},
+ // Do not emit if clippy::ref_patterns is not allowed to avoid having two lints for the same issue.
+ if !is_lint_allowed(cx, REF_PATTERNS, arg.pat.hir_id) {
+ return;
+ }
+ if let PatKind::Binding(BindingAnnotation(ByRef::Yes, _), ..) = arg.pat.kind {
+ span_lint(
+ cx,
+ TOPLEVEL_REF_ARG,
+ arg.pat.span,
+ "`ref` directly on a function argument is ignored. \
+ Consider using a reference type instead",
+ );
}
}
}
- fn check_stmt(&mut self, cx: &LateContext<'a, 'tcx>, s: &'tcx Stmt) {
+ fn check_stmt(&mut self, cx: &LateContext<'tcx>, stmt: &'tcx Stmt<'_>) {
if_chain! {
- if let StmtDecl(ref d, _) = s.node;
- if let DeclLocal(ref l) = d.node;
- if let PatKind::Binding(an, _, i, None) = l.pat.node;
- if let Some(ref init) = l.init;
+ if !in_external_macro(cx.tcx.sess, stmt.span);
+ if let StmtKind::Local(local) = stmt.kind;
+ if let PatKind::Binding(BindingAnnotation(ByRef::Yes, mutabl), .., name, None) = local.pat.kind;
+ if let Some(init) = local.init;
+ // Do not emit if clippy::ref_patterns is not allowed to avoid having two lints for the same issue.
+ if is_lint_allowed(cx, REF_PATTERNS, local.pat.hir_id);
then {
- if an == BindingAnnotation::Ref || an == BindingAnnotation::RefMut {
- let init = Sugg::hir(cx, init, "..");
- let (mutopt,initref) = if an == BindingAnnotation::RefMut {
- ("mut ", init.mut_addr())
- } else {
- ("", init.addr())
- };
- let tyopt = if let Some(ref ty) = l.ty {
- format!(": &{mutopt}{ty}", mutopt=mutopt, ty=snippet(cx, ty.span, "_"))
- } else {
- "".to_owned()
- };
- span_lint_and_then(cx,
- TOPLEVEL_REF_ARG,
- l.pat.span,
- "`ref` on an entire `let` pattern is discouraged, take a reference with `&` instead",
- |db| {
- db.span_suggestion(s.span,
- "try",
- format!("let {name}{tyopt} = {initref};",
- name=snippet(cx, i.span, "_"),
- tyopt=tyopt,
- initref=initref));
- }
- );
- }
+ let ctxt = local.span.ctxt();
+ let mut app = Applicability::MachineApplicable;
+ let sugg_init = Sugg::hir_with_context(cx, init, ctxt, "..", &mut app);
+ let (mutopt, initref) = if mutabl == Mutability::Mut {
+ ("mut ", sugg_init.mut_addr())
+ } else {
+ ("", sugg_init.addr())
+ };
+ let tyopt = if let Some(ty) = local.ty {
+ let ty_snip = snippet_with_context(cx, ty.span, ctxt, "_", &mut app).0;
+ format!(": &{mutopt}{ty_snip}")
+ } 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, ".."),
+ ),
+ app,
+ );
+ }
+ );
}
};
if_chain! {
- if let StmtSemi(ref expr, _) = s.node;
- if let Expr_::ExprBinary(ref binop, ref a, ref b) = expr.node;
- if binop.node == BiAnd || binop.node == BiOr;
+ 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,
- s.span,
+ expr.hir_id,
+ stmt.span,
"boolean short circuit operator in statement may be clearer using an explicit test",
- |db| {
- let sugg = if binop.node == BiOr { !sugg } else { sugg };
- db.span_suggestion(s.span, "replace it with",
- format!("if {} {{ {}; }}", sugg, &snippet(cx, b.span, "..")));
+ |diag| {
+ let sugg = if binop.node == BinOpKind::Or { !sugg } else { sugg };
+ diag.span_suggestion(
+ stmt.span,
+ "replace it with",
+ format!(
+ "if {sugg} {{ {}; }}",
+ &snippet(cx, b.span, ".."),
+ ),
+ Applicability::MachineApplicable, // snippet
+ );
});
}
};
}
- fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr) {
- match expr.node {
- ExprCast(ref e, ref ty) => {
- check_cast(cx, expr.span, e, ty);
- return;
- },
- ExprBinary(ref cmp, ref left, ref right) => {
- let op = cmp.node;
- if op.is_comparison() {
- if let ExprPath(QPath::Resolved(_, ref path)) = left.node {
- check_nan(cx, path, expr);
- }
- if let ExprPath(QPath::Resolved(_, ref path)) = right.node {
- check_nan(cx, path, expr);
- }
- check_to_owned(cx, left, right);
- check_to_owned(cx, right, left);
- }
- if (op == BiEq || op == BiNe) && (is_float(cx, left) || is_float(cx, right)) {
- if is_allowed(cx, left) || is_allowed(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 (lint, msg) = if is_named_constant(cx, left) || is_named_constant(cx, right) {
- (FLOAT_CMP_CONST, "strict comparison of f32 or f64 constant")
- } else {
- (FLOAT_CMP, "strict comparison of f32 or f64")
- };
- span_lint_and_then(cx, lint, expr.span, msg, |db| {
- let lhs = Sugg::hir(cx, left, "..");
- let rhs = Sugg::hir(cx, right, "..");
-
- db.span_suggestion(
- expr.span,
- "consider comparing them within some error",
- format!("({}).abs() < error", lhs - rhs),
- );
- db.span_note(expr.span, "std::f32::EPSILON and std::f64::EPSILON are available.");
- });
- } else if op == BiRem && is_integer_literal(right, 1) {
- span_lint(cx, MODULO_ONE, expr.span, "any number modulo 1 will be 0");
- }
- },
- _ => {},
+ fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
+ if let ExprKind::Cast(e, ty) = expr.kind {
+ self.check_cast(cx, expr.span, e, ty);
+ return;
}
- if in_attributes_expansion(expr) {
- // Don't lint things expanded by #[derive(...)], etc
+ if in_attributes_expansion(expr) || expr.span.is_desugaring(DesugaringKind::Await) {
+ // Don't lint things expanded by #[derive(...)], etc or `await` desugaring
return;
}
- let binding = match expr.node {
- ExprPath(ref qpath) => {
- let binding = last_path_segment(qpath).name.as_str();
+ let sym;
+ let binding = match expr.kind {
+ 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("__") &&
binding != "_result" && // FIXME: #944
is_used(cx, expr) &&
// don't lint if the declaration is in a macro
- non_macro_local(cx, &cx.tables.qpath_def(qpath, expr.hir_id))
+ non_macro_local(cx, cx.qpath_res(qpath, expr.hir_id))
{
Some(binding)
} else {
None
}
},
- ExprField(_, spanned) => {
- let name = spanned.node.as_str();
+ ExprKind::Field(_, ident) => {
+ sym = ident.name;
+ let name = sym.as_str();
if name.starts_with('_') && !name.starts_with("__") {
Some(name)
} else {
USED_UNDERSCORE_BINDING,
expr.span,
&format!(
- "used binding `{}` which is prefixed with an underscore. A leading \
- underscore signals that a binding will not be used.",
- binding
+ "used binding `{binding}` which is prefixed with an underscore. A leading \
+ underscore signals that a binding will not be used"
),
);
}
}
-
- fn check_pat(&mut self, cx: &LateContext<'a, 'tcx>, pat: &'tcx Pat) {
- if let PatKind::Binding(_, _, ref ident, Some(ref right)) = pat.node {
- if right.node == PatKind::Wild {
- span_lint(
- cx,
- REDUNDANT_PATTERN,
- pat.span,
- &format!("the `{} @ _` pattern can be written as just `{}`", ident.node, ident.node),
- );
- }
- }
- }
}
-fn check_nan(cx: &LateContext, path: &Path, expr: &Expr) {
- if !in_constant(cx, expr.id) {
- path.segments.last().map(|seg| {
- if seg.name == "NAN" {
- span_lint(
- cx,
- CMP_NAN,
- expr.span,
- "doomed comparison with NAN, use `std::{f32,f64}::is_nan()` instead",
- );
- }
- });
- }
+/// 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 {
+ 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),
+ })
}
-fn is_named_constant<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr) -> bool {
- if let Some((_, res)) = constant(cx, expr) {
- res
+/// 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 {
+ use rustc_span::hygiene::MacroKind;
+ if expr.span.from_expansion() {
+ let data = expr.span.ctxt().outer_expn_data();
+ matches!(data.kind, ExpnKind::Macro(MacroKind::Attr | MacroKind::Derive, _))
} else {
- false
+ false
}
}
-fn is_allowed<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr) -> bool {
- let parent_item = cx.tcx.hir.get_parent(expr.id);
- let parent_def_id = cx.tcx.hir.local_def_id(parent_item);
- let substs = Substs::identity_for_item(cx.tcx, parent_def_id);
- let res = ConstContext::new(cx.tcx, cx.param_env.and(substs), cx.tables).eval(expr);
- if let Ok(&ty::Const {
- val: ConstVal::Float(val),
- ..
- }) = res
- {
- use std::cmp::Ordering;
- match val.ty {
- FloatTy::F32 => {
- let zero = ConstFloat {
- ty: FloatTy::F32,
- bits: u128::from(0.0_f32.to_bits()),
- };
-
- let infinity = ConstFloat {
- ty: FloatTy::F32,
- bits: u128::from(::std::f32::INFINITY.to_bits()),
- };
-
- let neg_infinity = ConstFloat {
- ty: FloatTy::F32,
- bits: u128::from(::std::f32::NEG_INFINITY.to_bits()),
- };
-
- val.try_cmp(zero) == Ok(Ordering::Equal) || val.try_cmp(infinity) == Ok(Ordering::Equal)
- || val.try_cmp(neg_infinity) == Ok(Ordering::Equal)
- },
- FloatTy::F64 => {
- let zero = ConstFloat {
- ty: FloatTy::F64,
- bits: u128::from(0.0_f64.to_bits()),
- };
-
- let infinity = ConstFloat {
- ty: FloatTy::F64,
- bits: u128::from(::std::f64::INFINITY.to_bits()),
- };
-
- let neg_infinity = ConstFloat {
- ty: FloatTy::F64,
- bits: u128::from(::std::f64::NEG_INFINITY.to_bits()),
- };
-
- val.try_cmp(zero) == Ok(Ordering::Equal) || val.try_cmp(infinity) == Ok(Ordering::Equal)
- || val.try_cmp(neg_infinity) == Ok(Ordering::Equal)
- },
- }
+/// Tests whether `res` is a variable defined outside a macro.
+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 {
false
}
}
-fn is_float(cx: &LateContext, expr: &Expr) -> bool {
- matches!(walk_ptrs_ty(cx.tables.expr_ty(expr)).sty, ty::TyFloat(_))
-}
-
-fn check_to_owned(cx: &LateContext, expr: &Expr, other: &Expr) {
- let (arg_ty, snip) = match expr.node {
- ExprMethodCall(.., 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;
- }
- },
- ExprCall(ref path, ref v) if v.len() == 1 => if let ExprPath(ref path) = path.node {
- if match_qpath(path, &["String", "from_str"]) || match_qpath(path, &["String", "from"]) {
- (cx.tables.expr_ty_adjusted(&v[0]), snippet(cx, v[0].span, ".."))
- } else {
- return;
- }
- } 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,
- };
-
- // *arg impls PartialEq<other>
- if !arg_ty
- .builtin_deref(true, ty::LvaluePreference::NoPreference)
- .map_or(false, |tam| implements_trait(cx, tam.ty, partial_eq_trait_id, &[other_ty]))
- // arg impls PartialEq<*other>
- && !other_ty
- .builtin_deref(true, ty::LvaluePreference::NoPreference)
- .map_or(false, |tam| implements_trait(cx, arg_ty, partial_eq_trait_id, &[tam.ty]))
- // arg impls PartialEq<other>
- && !implements_trait(cx, arg_ty, partial_eq_trait_id, &[other_ty])
- {
- return;
- }
+impl LintPass {
+ fn check_cast(&self, cx: &LateContext<'_>, span: Span, e: &Expr<'_>, ty: &hir::Ty<'_>) {
+ if_chain! {
+ if let TyKind::Ptr(ref mut_ty) = ty.kind;
+ if is_integer_literal(e, 0);
+ if !in_constant(cx, e.hir_id);
+ then {
+ let (msg, sugg_fn) = match mut_ty.mutbl {
+ Mutability::Mut => ("`0 as *mut _` detected", "ptr::null_mut"),
+ Mutability::Not => ("`0 as *const _` detected", "ptr::null"),
+ };
- span_lint_and_then(
- cx,
- CMP_OWNED,
- expr.span,
- "this creates an owned instance just for comparison",
- |db| {
- // this is as good as our recursion check can get, we can't prove that the
- // current function is
- // called by
- // PartialEq::eq, but we can at least ensure that this code is not part of it
- let parent_fn = cx.tcx.hir.get_parent(expr.id);
- let parent_impl = cx.tcx.hir.get_parent(parent_fn);
- if parent_impl != CRATE_NODE_ID {
- if let map::NodeItem(item) = cx.tcx.hir.get(parent_impl) {
- if let ItemImpl(.., Some(ref trait_ref), _, _) = item.node {
- if trait_ref.path.def.def_id() == partial_eq_trait_id {
- // we are implementing PartialEq, don't suggest not doing `to_owned`, otherwise
- // we go into
- // recursion
- db.span_label(expr.span, "try calling implementing the comparison without allocating");
- return;
- }
- }
- }
+ let (sugg, appl) = if let TyKind::Infer = mut_ty.ty.kind {
+ (format!("{}::{sugg_fn}()", self.std_or_core), Applicability::MachineApplicable)
+ } else if let Some(mut_ty_snip) = snippet_opt(cx, mut_ty.ty.span) {
+ (format!("{}::{sugg_fn}::<{mut_ty_snip}>()", self.std_or_core), Applicability::MachineApplicable)
+ } else {
+ // `MaybeIncorrect` as type inference may not work with the suggested code
+ (format!("{}::{sugg_fn}()", self.std_or_core), Applicability::MaybeIncorrect)
+ };
+ span_lint_and_sugg(cx, ZERO_PTR, span, msg, "try", sugg, appl);
}
- db.span_suggestion(expr.span, "try", snip.to_string());
- },
- );
-}
-
-/// 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.node {
- ExprAssign(_, ref rhs) | ExprAssignOp(_, _, ref rhs) => **rhs == *expr,
- _ => is_used(cx, parent),
- }
- } else {
- true
- }
-}
-
-/// Test 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()
- .outer()
- .expn_info()
- .map_or(false, |info| matches!(info.callee.format, ExpnFormat::MacroAttribute(_)))
-}
-
-/// Test 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)),
- _ => false,
- }
-}
-
-fn check_cast(cx: &LateContext, span: Span, e: &Expr, ty: &Ty) {
- if_chain! {
- if let TyPtr(MutTy { mutbl, .. }) = ty.node;
- if let ExprLit(ref lit) = e.node;
- if let LitKind::Int(value, ..) = lit.node;
- if value == 0;
- if !in_constant(cx, e.id);
- then {
- let msg = match mutbl {
- Mutability::MutMutable => "`0 as *mut _` detected. Consider using `ptr::null_mut()`",
- Mutability::MutImmutable => "`0 as *const _` detected. Consider using `ptr::null()`",
- };
- span_lint(cx, ZERO_PTR, span, msg);
}
}
}
projects / rustc.git / blobdiff