use rustc::ty;
use rustc_const_eval::EvalHint::ExprTypeChecked;
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, is_integer_literal, match_path, snippet,
- span_lint, span_lint_and_then, walk_ptrs_ty
+ 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, last_path_segment
};
+use utils::sugg::Sugg;
-/// **What it does:** This lint checks for function arguments and let bindings denoted as `ref`.
+/// **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.
+/// **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.
+/// 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.
+/// **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:** `fn foo(ref x: u8) -> bool { .. }`
+/// **Example:**
+/// ```rust
+/// fn foo(ref x: u8) -> bool { .. }
+/// ```
+declare_lint! {
+ pub TOPLEVEL_REF_ARG,
+ Warn,
+ "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 TOPLEVEL_REF_ARG, Warn,
- "An entire binding was declared as `ref`, in a function argument (`fn foo(ref x: Bar)`), \
- or a `let` statement (`let ref x = foo()`). In such cases, it is preferred to take \
- references with `&`."
+ pub REDUNDANT_PATTERN,
+ Warn,
+ "using `name @ _` in a pattern"
}
-#[allow(missing_copy_implementations)]
-pub struct TopLevelRefPass;
+/// **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"
+}
-impl LintPass for TopLevelRefPass {
+#[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 ref arg in &decl.inputs {
- if let PatKind::Binding(BindByRef(_), _, _) = arg.pat.node {
+ for arg in &decl.inputs {
+ 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) {
- if_let_chain! {
- [
+
+ 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(_), i, None) = l.pat.node,
+ let PatKind::Binding(BindByRef(mt), _, i, None) = l.pat.node,
let Some(ref init) = l.init
- ], {
- let tyopt = if let Some(ref ty) = l.ty {
- format!(": {}", 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 {}{} = &{};",
- snippet(cx, i.span, "_"),
- tyopt,
- snippet(cx, init.span, "_")));
- }
- );
- }
- };
- }
-}
-
-/// **What it does:** This lint 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:** `x == NAN`
-declare_lint!(pub CMP_NAN, Deny,
- "comparisons to NAN (which will always return false, which is probably not intended)");
-
-#[derive(Copy,Clone)]
-pub struct CmpNan;
-
-impl LintPass for CmpNan {
- fn get_lints(&self) -> LintArray {
- lint_array!(CMP_NAN)
+ ], {
+ let init = Sugg::hir(cx, init, "..");
+ let (mutopt,initref) = if mt == Mutability::MutMutable {
+ ("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));
+ }
+ );
+ }}
}
-}
-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:** This lint 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:** `y == 1.23f64`
-declare_lint!(pub FLOAT_CMP, Warn,
- "using `==` or `!=` on float values (as floating-point operations \
- usually involve rounding errors, it is always better to check for approximate \
- equality within small bounds)");
-
-#[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;
}
}
+ span_lint_and_then(cx,
+ FLOAT_CMP,
+ expr.span,
+ "strict comparison of f32 or f64",
+ |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");
+ }
+ }
+ 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));
+ }
+ }
+
+ 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,
- FLOAT_CMP,
- expr.span,
- &format!("{}-comparison of f32 or f64 detected. Consider changing this to `({} - {}).abs() < \
- epsilon` for some suitable value of epsilon. \
- std::f32::EPSILON and std::f64::EPSILON are available.",
- op.as_str(),
- snippet(cx, left.span, ".."),
- snippet(cx, right.span, "..")));
+ 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 {
- val == 0.0 || val == ::std::f64::INFINITY || val == ::std::f64::NEG_INFINITY
- } else {
- false
- }
-}
+ use std::cmp::Ordering;
-fn is_float(cx: &LateContext, expr: &Expr) -> bool {
- if let ty::TyFloat(_) = walk_ptrs_ty(cx.tcx.expr_ty(expr)).sty {
- true
- } else {
- false
- }
-}
+ let zero = ConstFloat::FInfer {
+ f32: 0.0,
+ f64: 0.0,
+ };
-/// **What it does:** This lint 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:** `x.to_owned() == y`
-declare_lint!(pub CMP_OWNED, Warn,
- "creating owned instances for comparing with others, e.g. `x == \"foo\".to_string()`");
+ let infinity = ConstFloat::FInfer {
+ f32: ::std::f32::INFINITY,
+ f64: ::std::f64::INFINITY,
+ };
-#[derive(Copy,Clone)]
-pub struct CmpOwned;
+ let neg_infinity = ConstFloat::FInfer {
+ f32: ::std::f32::NEG_INFINITY,
+ f64: ::std::f64::NEG_INFINITY,
+ };
-impl LintPass for CmpOwned {
- fn get_lints(&self) -> LintArray {
- lint_array!(CMP_OWNED)
+ val.try_cmp(zero) == Ok(Ordering::Equal)
+ || val.try_cmp(infinity) == Ok(Ordering::Equal)
+ || val.try_cmp(neg_infinity) == Ok(Ordering::Equal)
+ } else {
+ false
}
}
-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)
- }
- }
- }
+fn is_float(cx: &LateContext, expr: &Expr) -> bool {
+ 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 &&
- if let ty::TyStr = walk_ptrs_ty(cx.tcx.expr_ty(&args[0])).sty {
- true
- } else {
- false
- }
-}
-
-/// **What it does:** This lint 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:** `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:** This lint 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**:
-/// ```
-/// 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:** This lint 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**:
-/// ```
-/// 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 segment = path.segments
- .last()
- .expect("path should always have at least one segment")
- .name;
- if segment.as_str().starts_with('_') &&
- !segment.as_str().starts_with("__") &&
- segment != segment.unhygienize() && // not in bang macro
- is_used(cx, expr) {
- Some(segment.as_str())
- } 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 {
- if binding != "_result" { // FIXME: #944
- 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
/// of what it means for an expression to be "used".
fn is_used(cx: &LateContext, expr: &Expr) -> bool {
- if let Some(ref parent) = get_parent_expr(cx, expr) {
+ if let Some(parent) = get_parent_expr(cx, expr) {
match parent.node {
ExprAssign(_, ref rhs) |
ExprAssignOp(_, _, ref rhs) => **rhs == *expr,
fn in_attributes_expansion(cx: &LateContext, expr: &Expr) -> bool {
cx.sess().codemap().with_expn_info(expr.span.expn_id, |info_opt| {
info_opt.map_or(false, |info| {
- match info.callee.format {
- ExpnFormat::MacroAttribute(_) => true,
- _ => false,
- }
+ 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, _, _) => {
+ if let Some(span) = cx.tcx.map.span_if_local(id) {
+ !in_macro(cx, span)
+ } else {
+ true
+ }
+ }
+ _ => false,
+ }
+}
projects / rust.git / blobdiff