use rustc_const_eval::eval_const_expr_partial;
use rustc_const_math::ConstFloat;
use syntax::codemap::{Span, Spanned, ExpnFormat};
-use syntax::ptr::P;
use utils::{
get_item_name, get_parent_expr, implements_trait, in_macro, is_integer_literal, match_path,
- snippet, span_lint, span_lint_and_then, walk_ptrs_ty
+ snippet, span_lint, span_lint_and_then, walk_ptrs_ty, last_path_segment
};
use utils::sugg::Sugg;
"an entire binding declared as `ref`, in a function argument or a `let` statement"
}
-#[allow(missing_copy_implementations)]
-pub struct TopLevelRefPass;
+/// **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"
+}
-impl LintPass for TopLevelRefPass {
+/// **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! {
+ pub USED_UNDERSCORE_BINDING,
+ Allow,
+ "using a binding which is prefixed with an underscore"
+}
+
+#[derive(Copy, Clone)]
+pub struct Pass;
+
+impl LintPass for Pass {
fn get_lints(&self) -> LintArray {
- lint_array!(TOPLEVEL_REF_ARG)
+ lint_array!(TOPLEVEL_REF_ARG, CMP_NAN, FLOAT_CMP, CMP_OWNED, MODULO_ONE, REDUNDANT_PATTERN,
+ USED_UNDERSCORE_BINDING)
}
}
-impl LateLintPass for TopLevelRefPass {
- fn check_fn(&mut self, cx: &LateContext, k: FnKind, decl: &FnDecl, _: &Block, _: Span, _: NodeId) {
+impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Pass {
+ fn check_fn(&mut self, cx: &LateContext<'a, 'tcx>, k: FnKind<'tcx>, decl: &'tcx FnDecl, _: &'tcx Expr, _: Span, _: NodeId) {
if let FnKind::Closure(_) = k {
// Does not apply to closures
return;
}
for arg in &decl.inputs {
- if let PatKind::Binding(BindByRef(_), _, _) = arg.pat.node {
+ if let PatKind::Binding(BindByRef(_), _, _, _) = arg.pat.node {
span_lint(cx,
TOPLEVEL_REF_ARG,
arg.pat.span,
}
}
}
- fn check_stmt(&mut self, cx: &LateContext, s: &Stmt) {
+
+ fn check_stmt(&mut self, cx: &LateContext<'a, 'tcx>, s: &'tcx Stmt) {
if_let_chain! {[
let StmtDecl(ref d, _) = s.node,
let DeclLocal(ref l) = d.node,
- let PatKind::Binding(BindByRef(mt), i, None) = l.pat.node,
+ let PatKind::Binding(BindByRef(mt), _, i, None) = l.pat.node,
let Some(ref init) = l.init
], {
let init = Sugg::hir(cx, init, "..");
);
}}
}
-}
-/// **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"
-}
-
-#[derive(Copy,Clone)]
-pub struct CmpNan;
-
-impl LintPass for CmpNan {
- fn get_lints(&self) -> LintArray {
- lint_array!(CMP_NAN)
- }
-}
-
-impl LateLintPass for CmpNan {
- fn check_expr(&mut self, cx: &LateContext, expr: &Expr) {
+ fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr) {
if let ExprBinary(ref cmp, ref left, ref right) = expr.node {
- if cmp.node.is_comparison() {
- if let ExprPath(_, ref path) = left.node {
+ let op = cmp.node;
+ if op.is_comparison() {
+ if let ExprPath(QPath::Resolved(_, ref path)) = left.node {
check_nan(cx, path, expr.span);
}
- if let ExprPath(_, ref path) = right.node {
+ if let ExprPath(QPath::Resolved(_, ref path)) = right.node {
check_nan(cx, path, expr.span);
}
+ check_to_owned(cx, left, right, true, cmp.span);
+ check_to_owned(cx, right, left, false, cmp.span)
}
- }
- }
-}
-
-fn check_nan(cx: &LateContext, path: &Path, span: Span) {
- path.segments.last().map(|seg| {
- if seg.name.as_str() == "NAN" {
- span_lint(cx,
- CMP_NAN,
- span,
- "doomed comparison with NAN, use `std::{f32,f64}::is_nan()` instead");
- }
- });
-}
-
-/// **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"
-}
-
-#[derive(Copy,Clone)]
-pub struct FloatCmp;
-
-impl LintPass for FloatCmp {
- fn get_lints(&self) -> LintArray {
- lint_array!(FLOAT_CMP)
- }
-}
-
-impl LateLintPass for FloatCmp {
- fn check_expr(&mut self, cx: &LateContext, expr: &Expr) {
- if let ExprBinary(ref cmp, ref left, ref right) = expr.node {
- let op = cmp.node;
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();
+ let name = &*name.as_str();
if name == "eq" || name == "ne" || name == "is_nan" || name.starts_with("eq_") ||
- name.ends_with("_eq") {
+ name.ends_with("_eq") {
return;
}
}
expr.span,
"strict comparison of f32 or f64",
|db| {
- let lhs = Sugg::hir(cx, left, "..");
- let rhs = Sugg::hir(cx, right, "..");
+ 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");
+ }
+ }
+ if in_attributes_expansion(cx, expr) {
+ // Don't lint things expanded by #[derive(...)], etc
+ return;
+ }
+ let binding = match expr.node {
+ ExprPath(ref qpath) => {
+ let binding = last_path_segment(qpath).name.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.tcx.tables().qpath_def(qpath, expr.id)) {
+ Some(binding)
+ } else {
+ None
+ }
+ }
+ ExprField(_, spanned) => {
+ let name = spanned.node.as_str();
+ if name.starts_with('_') && !name.starts_with("__") {
+ Some(name)
+ } else {
+ None
+ }
+ }
+ _ => None,
+ };
+ if let Some(binding) = binding {
+ span_lint(cx,
+ 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));
+ }
+ }
- 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.");
- });
+ 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, span: Span) {
+ path.segments.last().map(|seg| {
+ if &*seg.name.as_str() == "NAN" {
+ span_lint(cx,
+ CMP_NAN,
+ span,
+ "doomed comparison with NAN, use `std::{f32,f64}::is_nan()` instead");
+ }
+ });
+}
+
fn is_allowed(cx: &LateContext, expr: &Expr) -> bool {
let res = eval_const_expr_partial(cx.tcx, expr, ExprTypeChecked, None);
if let Ok(ConstVal::Float(val)) = res {
}
fn is_float(cx: &LateContext, expr: &Expr) -> bool {
- matches!(walk_ptrs_ty(cx.tcx.expr_ty(expr)).sty, ty::TyFloat(_))
-}
-
-/// **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()`"
-}
-
-#[derive(Copy,Clone)]
-pub struct CmpOwned;
-
-impl LintPass for CmpOwned {
- fn get_lints(&self) -> LintArray {
- lint_array!(CMP_OWNED)
- }
-}
-
-impl LateLintPass for CmpOwned {
- fn check_expr(&mut self, cx: &LateContext, expr: &Expr) {
- if let ExprBinary(ref cmp, ref left, ref right) = expr.node {
- if cmp.node.is_comparison() {
- check_to_owned(cx, left, right, true, cmp.span);
- check_to_owned(cx, right, left, false, cmp.span)
- }
- }
- }
+ matches!(walk_ptrs_ty(cx.tcx.tables().expr_ty(expr)).sty, ty::TyFloat(_))
}
fn check_to_owned(cx: &LateContext, expr: &Expr, other: &Expr, left: bool, op: Span) {
let (arg_ty, snip) = match expr.node {
ExprMethodCall(Spanned { node: ref name, .. }, _, ref args) if args.len() == 1 => {
- if name.as_str() == "to_string" || name.as_str() == "to_owned" && is_str_arg(cx, args) {
- (cx.tcx.expr_ty(&args[0]), snippet(cx, args[0].span, ".."))
+ let name = &*name.as_str();
+ if name == "to_string" || name == "to_owned" && is_str_arg(cx, args) {
+ (cx.tcx.tables().expr_ty(&args[0]), snippet(cx, args[0].span, ".."))
} else {
return;
}
}
ExprCall(ref path, ref v) if v.len() == 1 => {
- if let ExprPath(None, ref path) = path.node {
+ if let ExprPath(ref path) = path.node {
if match_path(path, &["String", "from_str"]) || match_path(path, &["String", "from"]) {
- (cx.tcx.expr_ty(&v[0]), snippet(cx, v[0].span, ".."))
+ (cx.tcx.tables().expr_ty(&v[0]), snippet(cx, v[0].span, ".."))
} else {
return;
}
_ => return,
};
- let other_ty = cx.tcx.expr_ty(other);
+ let other_ty = cx.tcx.tables().expr_ty(other);
let partial_eq_trait_id = match cx.tcx.lang_items.eq_trait() {
Some(id) => id,
None => return,
}
-fn is_str_arg(cx: &LateContext, args: &[P<Expr>]) -> bool {
+fn is_str_arg(cx: &LateContext, args: &[Expr]) -> bool {
args.len() == 1 &&
- matches!(walk_ptrs_ty(cx.tcx.expr_ty(&args[0])).sty, ty::TyStr)
-}
-
-/// **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"
-}
-
-#[derive(Copy,Clone)]
-pub struct ModuloOne;
-
-impl LintPass for ModuloOne {
- fn get_lints(&self) -> LintArray {
- lint_array!(MODULO_ONE)
- }
-}
-
-impl LateLintPass for ModuloOne {
- fn check_expr(&mut self, cx: &LateContext, expr: &Expr) {
- if let ExprBinary(ref cmp, _, ref right) = expr.node {
- if let Spanned { node: BinOp_::BiRem, .. } = *cmp {
- if is_integer_literal(right, 1) {
- span_lint(cx, MODULO_ONE, expr.span, "any number modulo 1 will be 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"
-}
-
-#[derive(Copy,Clone)]
-pub struct PatternPass;
-
-impl LintPass for PatternPass {
- fn get_lints(&self) -> LintArray {
- lint_array!(REDUNDANT_PATTERN)
- }
-}
-
-impl LateLintPass for PatternPass {
- fn check_pat(&mut self, cx: &LateContext, pat: &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));
- }
- }
- }
-}
-
-
-/// **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! {
- pub USED_UNDERSCORE_BINDING,
- Allow,
- "using a binding which is prefixed with an underscore"
-}
-
-#[derive(Copy, Clone)]
-pub struct UsedUnderscoreBinding;
-
-impl LintPass for UsedUnderscoreBinding {
- fn get_lints(&self) -> LintArray {
- lint_array!(USED_UNDERSCORE_BINDING)
- }
-}
-
-impl LateLintPass for UsedUnderscoreBinding {
- #[cfg_attr(rustfmt, rustfmt_skip)]
- fn check_expr(&mut self, cx: &LateContext, expr: &Expr) {
- if in_attributes_expansion(cx, expr) {
- // Don't lint things expanded by #[derive(...)], etc
- return;
- }
- let binding = match expr.node {
- ExprPath(_, ref path) => {
- let binding = path.segments
- .last()
- .expect("path should always have at least one segment")
- .name
- .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.tcx.expect_def(expr.id)) {
- Some(binding)
- } else {
- None
- }
- }
- ExprField(_, spanned) => {
- let name = spanned.node.as_str();
- if name.starts_with('_') && !name.starts_with("__") {
- Some(name)
- } else {
- None
- }
- }
- _ => None,
- };
- if let Some(binding) = binding {
- span_lint(cx,
- 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));
- }
- }
+ matches!(walk_ptrs_ty(cx.tcx.tables().expr_ty(&args[0])).sty, ty::TyStr)
}
/// Heuristic to see if an expression is used. Should be compatible with `unused_variables`'s idea
/// 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, _, _) => {
- if let Some(span) = cx.tcx.map.opt_span(id) {
+ def::Def::Local(id) | def::Def::Upvar(id, _, _) => {
+ if let Some(span) = cx.tcx.map.span_if_local(id) {
!in_macro(cx, span)
} else {
true
projects / rust.git / blobdiff