use std::hash::BuildHasherDefault;
use if_chain::if_chain;
-use rustc_ast::ast::{self, Attribute, BorrowKind, LitKind};
-use rustc_data_structures::fx::FxHashMap;
+use rustc_ast::ast::{self, Attribute, LitKind};
+use rustc_data_structures::unhash::UnhashMap;
use rustc_hir as hir;
use rustc_hir::def::{DefKind, Res};
use rustc_hir::def_id::DefId;
+use rustc_hir::hir_id::{HirIdMap, HirIdSet};
use rustc_hir::intravisit::{self, walk_expr, ErasedMap, FnKind, NestedVisitorMap, Visitor};
use rustc_hir::LangItem::{ResultErr, ResultOk};
use rustc_hir::{
def, Arm, BindingAnnotation, Block, Body, Constness, Destination, Expr, ExprKind, FnDecl, GenericArgs, HirId, Impl,
- ImplItem, ImplItemKind, IsAsync, Item, ItemKind, LangItem, Local, MatchSource, Node, Param, Pat, PatKind, Path,
- PathSegment, QPath, Stmt, StmtKind, TraitItem, TraitItemKind, TraitRef, TyKind,
+ ImplItem, ImplItemKind, IsAsync, Item, ItemKind, LangItem, Local, MatchSource, Mutability, Node, Param, Pat,
+ PatKind, Path, PathSegment, PrimTy, QPath, Stmt, StmtKind, TraitItem, TraitItemKind, TraitRef, TyKind, UnOp,
};
use rustc_lint::{LateContext, Level, Lint, LintContext};
use rustc_middle::hir::exports::Export;
use rustc_middle::hir::map::Map;
+use rustc_middle::hir::place::PlaceBase;
use rustc_middle::ty as rustc_ty;
-use rustc_middle::ty::{layout::IntegerExt, DefIdTree, Ty, TyCtxt, TypeFoldable};
+use rustc_middle::ty::adjustment::{Adjust, Adjustment, AutoBorrow};
+use rustc_middle::ty::binding::BindingMode;
+use rustc_middle::ty::{layout::IntegerExt, BorrowKind, DefIdTree, Ty, TyCtxt, TypeAndMut, TypeFoldable, UpvarCapture};
use rustc_semver::RustcVersion;
use rustc_session::Session;
use rustc_span::hygiene::{ExpnKind, MacroKind};
use rustc_target::abi::Integer;
use crate::consts::{constant, Constant};
-use crate::ty::{can_partially_move_ty, is_recursively_primitive_type};
+use crate::ty::{can_partially_move_ty, is_copy, is_recursively_primitive_type};
pub fn parse_msrv(msrv: &str, sess: Option<&Session>, span: Option<Span>) -> Option<RustcVersion> {
if let Ok(version) = RustcVersion::parse(msrv) {
}
/// Checks if given pattern is a wildcard (`_`)
-pub fn is_wild<'tcx>(pat: &impl std::ops::Deref<Target = Pat<'tcx>>) -> bool {
+pub fn is_wild(pat: &Pat<'_>) -> bool {
matches!(pat.kind, PatKind::Wild)
}
.map_or(false, |did| is_diag_trait_item(cx, did, diag_item))
}
-/// Checks if an expression references a variable of the given name.
-pub fn match_var(expr: &Expr<'_>, var: Symbol) -> bool {
- if let ExprKind::Path(QPath::Resolved(None, ref path)) = expr.kind {
- if let [p] = path.segments {
- return p.ident.name == var;
- }
+/// Checks if the given expression is a path referring an item on the trait
+/// that is marked with the given diagnostic item.
+///
+/// For checking method call expressions instead of path expressions, use
+/// [`is_trait_method`].
+///
+/// For example, this can be used to find if an expression like `u64::default`
+/// refers to an item of the trait `Default`, which is associated with the
+/// `diag_item` of `sym::Default`.
+pub fn is_trait_item(cx: &LateContext<'_>, expr: &Expr<'_>, diag_item: Symbol) -> bool {
+ if let hir::ExprKind::Path(ref qpath) = expr.kind {
+ cx.qpath_res(qpath, expr.hir_id)
+ .opt_def_id()
+ .map_or(false, |def_id| is_diag_trait_item(cx, def_id, diag_item))
+ } else {
+ false
}
- false
}
pub fn last_path_segment<'tcx>(path: &QPath<'tcx>) -> &'tcx PathSegment<'tcx> {
match *path {
- QPath::Resolved(_, ref path) => path.segments.last().expect("A path must have at least one segment"),
- QPath::TypeRelative(_, ref seg) => seg,
+ QPath::Resolved(_, path) => path.segments.last().expect("A path must have at least one segment"),
+ QPath::TypeRelative(_, seg) => seg,
QPath::LangItem(..) => panic!("last_path_segment: lang item has no path segments"),
}
}
pub fn single_segment_path<'tcx>(path: &QPath<'tcx>) -> Option<&'tcx PathSegment<'tcx>> {
match *path {
- QPath::Resolved(_, ref path) => path.segments.get(0),
- QPath::TypeRelative(_, ref seg) => Some(seg),
+ QPath::Resolved(_, path) => path.segments.get(0),
+ QPath::TypeRelative(_, seg) => Some(seg),
QPath::LangItem(..) => None,
}
}
/// ```
pub fn match_qpath(path: &QPath<'_>, segments: &[&str]) -> bool {
match *path {
- QPath::Resolved(_, ref path) => match_path(path, segments),
- QPath::TypeRelative(ref ty, ref segment) => match ty.kind {
+ QPath::Resolved(_, path) => match_path(path, segments),
+ QPath::TypeRelative(ty, segment) => match ty.kind {
TyKind::Path(ref inner_path) => {
if let [prefix @ .., end] = segments {
if match_qpath(inner_path, prefix) {
}
/// If the expression is a path, resolves it to a `DefId` and checks if it matches the given path.
+///
+/// Please use `is_expr_diagnostic_item` if the target is a diagnostic item.
pub fn is_expr_path_def_path(cx: &LateContext<'_>, expr: &Expr<'_>, segments: &[&str]) -> bool {
expr_path_res(cx, expr)
.opt_def_id()
.map_or(false, |id| match_def_path(cx, id, segments))
}
+/// If the expression is a path, resolves it to a `DefId` and checks if it matches the given
+/// diagnostic item.
+pub fn is_expr_diagnostic_item(cx: &LateContext<'_>, expr: &Expr<'_>, diag_item: Symbol) -> bool {
+ expr_path_res(cx, expr)
+ .opt_def_id()
+ .map_or(false, |id| cx.tcx.is_diagnostic_item(diag_item, id))
+}
+
/// THIS METHOD IS DEPRECATED and will eventually be removed since it does not match against the
/// entire path or resolved `DefId`. Prefer using `match_def_path`. Consider getting a `DefId` from
/// `QPath::Resolved.1.res.opt_def_id()`.
/// If the expression is a path to a local, returns the canonical `HirId` of the local.
pub fn path_to_local(expr: &Expr<'_>) -> Option<HirId> {
- if let ExprKind::Path(QPath::Resolved(None, ref path)) = expr.kind {
+ if let ExprKind::Path(QPath::Resolved(None, path)) = expr.kind {
if let Res::Local(id) = path.res {
return Some(id);
}
let (krate, first, path) = match *path {
[krate, first, ref path @ ..] => (krate, first, path),
+ [primitive] => {
+ return PrimTy::from_name(Symbol::intern(primitive)).map_or(Res::Err, Res::PrimTy);
+ },
_ => return Res::Err,
};
let tcx = cx.tcx;
- let crates = tcx.crates();
+ let crates = tcx.crates(());
let krate = try_res!(crates.iter().find(|&&num| tcx.crate_name(num).as_str() == krate));
let first = try_res!(item_child_by_name(tcx, krate.as_def_id(), first));
let last = path
None
}
+/// This method will return tuple of projection stack and root of the expression,
+/// used in `can_mut_borrow_both`.
+///
+/// For example, if `e` represents the `v[0].a.b[x]`
+/// this method will return a tuple, composed of a `Vec`
+/// containing the `Expr`s for `v[0], v[0].a, v[0].a.b, v[0].a.b[x]`
+/// and a `Expr` for root of them, `v`
+fn projection_stack<'a, 'hir>(mut e: &'a Expr<'hir>) -> (Vec<&'a Expr<'hir>>, &'a Expr<'hir>) {
+ let mut result = vec![];
+ let root = loop {
+ match e.kind {
+ ExprKind::Index(ep, _) | ExprKind::Field(ep, _) => {
+ result.push(e);
+ e = ep;
+ },
+ _ => break e,
+ };
+ };
+ result.reverse();
+ (result, root)
+}
+
+/// Checks if two expressions can be mutably borrowed simultaneously
+/// and they aren't dependent on borrowing same thing twice
+pub fn can_mut_borrow_both(cx: &LateContext<'_>, e1: &Expr<'_>, e2: &Expr<'_>) -> bool {
+ let (s1, r1) = projection_stack(e1);
+ let (s2, r2) = projection_stack(e2);
+ if !eq_expr_value(cx, r1, r2) {
+ return true;
+ }
+ for (x1, x2) in s1.iter().zip(s2.iter()) {
+ match (&x1.kind, &x2.kind) {
+ (ExprKind::Field(_, i1), ExprKind::Field(_, i2)) => {
+ if i1 != i2 {
+ return true;
+ }
+ },
+ (ExprKind::Index(_, i1), ExprKind::Index(_, i2)) => {
+ if !eq_expr_value(cx, i1, i2) {
+ return false;
+ }
+ },
+ _ => return false,
+ }
+ }
+ false
+}
+
/// Checks if the top level expression can be moved into a closure as is.
-pub fn can_move_expr_to_closure_no_visit(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, jump_targets: &[HirId]) -> bool {
+/// Currently checks for:
+/// * Break/Continue outside the given loop HIR ids.
+/// * Yield/Return statments.
+/// * Inline assembly.
+/// * Usages of a field of a local where the type of the local can be partially moved.
+///
+/// For example, given the following function:
+///
+/// ```
+/// fn f<'a>(iter: &mut impl Iterator<Item = (usize, &'a mut String)>) {
+/// for item in iter {
+/// let s = item.1;
+/// if item.0 > 10 {
+/// continue;
+/// } else {
+/// s.clear();
+/// }
+/// }
+/// }
+/// ```
+///
+/// When called on the expression `item.0` this will return false unless the local `item` is in the
+/// `ignore_locals` set. The type `(usize, &mut String)` can have the second element moved, so it
+/// isn't always safe to move into a closure when only a single field is needed.
+///
+/// When called on the `continue` expression this will return false unless the outer loop expression
+/// is in the `loop_ids` set.
+///
+/// Note that this check is not recursive, so passing the `if` expression will always return true
+/// even though sub-expressions might return false.
+pub fn can_move_expr_to_closure_no_visit(
+ cx: &LateContext<'tcx>,
+ expr: &'tcx Expr<'_>,
+ loop_ids: &[HirId],
+ ignore_locals: &HirIdSet,
+) -> bool {
match expr.kind {
ExprKind::Break(Destination { target_id: Ok(id), .. }, _)
| ExprKind::Continue(Destination { target_id: Ok(id), .. })
- if jump_targets.contains(&id) =>
+ if loop_ids.contains(&id) =>
{
true
},
| ExprKind::LlvmInlineAsm(_) => false,
// Accessing a field of a local value can only be done if the type isn't
// partially moved.
- ExprKind::Field(base_expr, _)
- if matches!(
- base_expr.kind,
- ExprKind::Path(QPath::Resolved(_, Path { res: Res::Local(_), .. }))
- ) && can_partially_move_ty(cx, cx.typeck_results().expr_ty(base_expr)) =>
- {
+ ExprKind::Field(
+ &Expr {
+ hir_id,
+ kind:
+ ExprKind::Path(QPath::Resolved(
+ _,
+ Path {
+ res: Res::Local(local_id),
+ ..
+ },
+ )),
+ ..
+ },
+ _,
+ ) if !ignore_locals.contains(local_id) && can_partially_move_ty(cx, cx.typeck_results().node_type(hir_id)) => {
// TODO: check if the local has been partially moved. Assume it has for now.
false
- }
+ },
_ => true,
}
}
-/// Checks if the expression can be moved into a closure as is.
-pub fn can_move_expr_to_closure(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> bool {
+/// How a local is captured by a closure
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum CaptureKind {
+ Value,
+ Ref(Mutability),
+}
+impl std::ops::BitOr for CaptureKind {
+ type Output = Self;
+ fn bitor(self, rhs: Self) -> Self::Output {
+ match (self, rhs) {
+ (CaptureKind::Value, _) | (_, CaptureKind::Value) => CaptureKind::Value,
+ (CaptureKind::Ref(Mutability::Mut), CaptureKind::Ref(_))
+ | (CaptureKind::Ref(_), CaptureKind::Ref(Mutability::Mut)) => CaptureKind::Ref(Mutability::Mut),
+ (CaptureKind::Ref(Mutability::Not), CaptureKind::Ref(Mutability::Not)) => CaptureKind::Ref(Mutability::Not),
+ }
+ }
+}
+impl std::ops::BitOrAssign for CaptureKind {
+ fn bitor_assign(&mut self, rhs: Self) {
+ *self = *self | rhs;
+ }
+}
+
+/// Given an expression referencing a local, determines how it would be captured in a closure.
+/// Note as this will walk up to parent expressions until the capture can be determined it should
+/// only be used while making a closure somewhere a value is consumed. e.g. a block, match arm, or
+/// function argument (other than a receiver).
+pub fn capture_local_usage(cx: &LateContext<'tcx>, e: &Expr<'_>) -> CaptureKind {
+ fn pat_capture_kind(cx: &LateContext<'_>, pat: &Pat<'_>) -> CaptureKind {
+ let mut capture = CaptureKind::Ref(Mutability::Not);
+ pat.each_binding(|_, id, span, _| {
+ match cx.typeck_results().extract_binding_mode(cx.sess(), id, span).unwrap() {
+ BindingMode::BindByValue(_) if !is_copy(cx, cx.typeck_results().node_type(id)) => {
+ capture = CaptureKind::Value;
+ },
+ BindingMode::BindByReference(Mutability::Mut) if capture != CaptureKind::Value => {
+ capture = CaptureKind::Ref(Mutability::Mut);
+ },
+ _ => (),
+ }
+ });
+ capture
+ }
+
+ debug_assert!(matches!(
+ e.kind,
+ ExprKind::Path(QPath::Resolved(None, Path { res: Res::Local(_), .. }))
+ ));
+
+ let map = cx.tcx.hir();
+ let mut child_id = e.hir_id;
+ let mut capture = CaptureKind::Value;
+ let mut capture_expr_ty = e;
+
+ for (parent_id, parent) in map.parent_iter(e.hir_id) {
+ if let [Adjustment {
+ kind: Adjust::Deref(_) | Adjust::Borrow(AutoBorrow::Ref(..)),
+ target,
+ }, ref adjust @ ..] = *cx
+ .typeck_results()
+ .adjustments()
+ .get(child_id)
+ .map_or(&[][..], |x| &**x)
+ {
+ if let rustc_ty::RawPtr(TypeAndMut { mutbl: mutability, .. }) | rustc_ty::Ref(_, _, mutability) =
+ *adjust.last().map_or(target, |a| a.target).kind()
+ {
+ return CaptureKind::Ref(mutability);
+ }
+ }
+
+ match parent {
+ Node::Expr(e) => match e.kind {
+ ExprKind::AddrOf(_, mutability, _) => return CaptureKind::Ref(mutability),
+ ExprKind::Index(..) | ExprKind::Unary(UnOp::Deref, _) => capture = CaptureKind::Ref(Mutability::Not),
+ ExprKind::Assign(lhs, ..) | ExprKind::Assign(_, lhs, _) if lhs.hir_id == child_id => {
+ return CaptureKind::Ref(Mutability::Mut);
+ },
+ ExprKind::Field(..) => {
+ if capture == CaptureKind::Value {
+ capture_expr_ty = e;
+ }
+ },
+ ExprKind::Match(_, arms, _) => {
+ let mut mutability = Mutability::Not;
+ for capture in arms.iter().map(|arm| pat_capture_kind(cx, arm.pat)) {
+ match capture {
+ CaptureKind::Value => break,
+ CaptureKind::Ref(Mutability::Mut) => mutability = Mutability::Mut,
+ CaptureKind::Ref(Mutability::Not) => (),
+ }
+ }
+ return CaptureKind::Ref(mutability);
+ },
+ _ => break,
+ },
+ Node::Local(l) => match pat_capture_kind(cx, l.pat) {
+ CaptureKind::Value => break,
+ capture @ CaptureKind::Ref(_) => return capture,
+ },
+ _ => break,
+ }
+
+ child_id = parent_id;
+ }
+
+ if capture == CaptureKind::Value && is_copy(cx, cx.typeck_results().expr_ty(capture_expr_ty)) {
+ // Copy types are never automatically captured by value.
+ CaptureKind::Ref(Mutability::Not)
+ } else {
+ capture
+ }
+}
+
+/// Checks if the expression can be moved into a closure as is. This will return a list of captures
+/// if so, otherwise, `None`.
+pub fn can_move_expr_to_closure(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> Option<HirIdMap<CaptureKind>> {
struct V<'cx, 'tcx> {
cx: &'cx LateContext<'tcx>,
+ // Stack of potential break targets contained in the expression.
loops: Vec<HirId>,
+ /// Local variables created in the expression. These don't need to be captured.
+ locals: HirIdSet,
+ /// Whether this expression can be turned into a closure.
allow_closure: bool,
+ /// Locals which need to be captured, and whether they need to be by value, reference, or
+ /// mutable reference.
+ captures: HirIdMap<CaptureKind>,
}
impl Visitor<'tcx> for V<'_, 'tcx> {
type Map = ErasedMap<'tcx>;
if !self.allow_closure {
return;
}
- if let ExprKind::Loop(b, ..) = e.kind {
- self.loops.push(e.hir_id);
- self.visit_block(b);
- self.loops.pop();
- } else {
- self.allow_closure &= can_move_expr_to_closure_no_visit(self.cx, e, &self.loops);
- walk_expr(self, e);
+
+ match e.kind {
+ ExprKind::Path(QPath::Resolved(None, &Path { res: Res::Local(l), .. })) => {
+ if !self.locals.contains(&l) {
+ let cap = capture_local_usage(self.cx, e);
+ self.captures.entry(l).and_modify(|e| *e |= cap).or_insert(cap);
+ }
+ },
+ ExprKind::Closure(..) => {
+ let closure_id = self.cx.tcx.hir().local_def_id(e.hir_id).to_def_id();
+ for capture in self.cx.typeck_results().closure_min_captures_flattened(closure_id) {
+ let local_id = match capture.place.base {
+ PlaceBase::Local(id) => id,
+ PlaceBase::Upvar(var) => var.var_path.hir_id,
+ _ => continue,
+ };
+ if !self.locals.contains(&local_id) {
+ let capture = match capture.info.capture_kind {
+ UpvarCapture::ByValue(_) => CaptureKind::Value,
+ UpvarCapture::ByRef(borrow) => match borrow.kind {
+ BorrowKind::ImmBorrow => CaptureKind::Ref(Mutability::Not),
+ BorrowKind::UniqueImmBorrow | BorrowKind::MutBorrow => {
+ CaptureKind::Ref(Mutability::Mut)
+ },
+ },
+ };
+ self.captures
+ .entry(local_id)
+ .and_modify(|e| *e |= capture)
+ .or_insert(capture);
+ }
+ }
+ },
+ ExprKind::Loop(b, ..) => {
+ self.loops.push(e.hir_id);
+ self.visit_block(b);
+ self.loops.pop();
+ },
+ _ => {
+ self.allow_closure &= can_move_expr_to_closure_no_visit(self.cx, e, &self.loops, &self.locals);
+ walk_expr(self, e);
+ },
}
}
+
+ fn visit_pat(&mut self, p: &'tcx Pat<'tcx>) {
+ p.each_binding_or_first(&mut |_, id, _, _| {
+ self.locals.insert(id);
+ });
+ }
}
let mut v = V {
cx,
allow_closure: true,
loops: Vec::new(),
+ locals: HirIdSet::default(),
+ captures: HirIdMap::default(),
};
v.visit_expr(expr);
- v.allow_closure
+ v.allow_closure.then(|| v.captures)
}
/// Returns the method names and argument list of nested method call expressions that make up
let mut matched = Vec::with_capacity(methods.len());
for method_name in methods.iter().rev() {
// method chains are stored last -> first
- if let ExprKind::MethodCall(ref path, _, ref args, _) = current.kind {
+ if let ExprKind::MethodCall(path, _, args, _) = current.kind {
if path.ident.name.as_str() == *method_name {
if args.iter().any(|e| e.span.from_expansion()) {
return None;
}
- matched.push(&**args); // build up `matched` backwards
- current = &args[0] // go to parent expression
+ matched.push(args); // build up `matched` backwards
+ current = &args[0]; // go to parent expression
} else {
return None;
}
}
}
-/// Gets the name of a `Pat`, if any.
-pub fn get_pat_name(pat: &Pat<'_>) -> Option<Symbol> {
- match pat.kind {
- PatKind::Binding(.., ref spname, _) => Some(spname.name),
- PatKind::Path(ref qpath) => single_segment_path(qpath).map(|ps| ps.ident.name),
- PatKind::Box(ref p) | PatKind::Ref(ref p, _) => get_pat_name(&*p),
- _ => None,
- }
-}
-
pub struct ContainsName {
pub name: Symbol,
pub result: bool,
kind: ImplItemKind::Fn(_, eid),
..
}) => match cx.tcx.hir().body(eid).value.kind {
- ExprKind::Block(ref block, _) => Some(block),
+ ExprKind::Block(block, _) => Some(block),
_ => None,
},
_ => None,
})
}
-/// Gets the loop enclosing the given expression, if any.
-pub fn get_enclosing_loop(tcx: TyCtxt<'tcx>, expr: &Expr<'_>) -> Option<&'tcx Expr<'tcx>> {
+/// Gets the loop or closure enclosing the given expression, if any.
+pub fn get_enclosing_loop_or_closure(tcx: TyCtxt<'tcx>, expr: &Expr<'_>) -> Option<&'tcx Expr<'tcx>> {
let map = tcx.hir();
for (_, node) in map.parent_iter(expr.hir_id) {
match node {
Node::Expr(
- e @ Expr {
- kind: ExprKind::Loop(..),
+ e
+ @
+ Expr {
+ kind: ExprKind::Loop(..) | ExprKind::Closure(..),
..
},
) => return Some(e),
if is_integer_literal(e, value) {
return true;
}
- let map = cx.tcx.hir();
- let parent_item = map.get_parent_item(e.hir_id);
- if let Some((Constant::Int(v), _)) = map
- .maybe_body_owned_by(parent_item)
- .and_then(|body_id| constant(cx, cx.tcx.typeck_body(body_id), e))
- {
+ let enclosing_body = cx.tcx.hir().local_def_id(cx.tcx.hir().enclosing_body_owner(e.hir_id));
+ if let Some((Constant::Int(v), _)) = constant(cx, cx.tcx.typeck(enclosing_body), e) {
value == v
} else {
false
let data = span.ctxt().outer_expn_data();
let new_span = data.call_site;
- if let ExpnKind::Macro {
- kind: MacroKind::Bang,
- name: mac_name,
- proc_macro: _,
- } = data.kind
- {
+ if let ExpnKind::Macro(MacroKind::Bang, mac_name) = data.kind {
if mac_name.as_str() == name {
return Some(new_span);
}
let data = span.ctxt().outer_expn_data();
let new_span = data.call_site;
- if let ExpnKind::Macro {
- kind: MacroKind::Bang,
- name: mac_name,
- proc_macro: _,
- } = data.kind
- {
+ if let ExpnKind::Macro(MacroKind::Bang, mac_name) = data.kind {
if mac_name.as_str() == name {
return Some(new_span);
}
/// Checks if an expression is constructing a tuple-like enum variant or struct
pub fn is_ctor_or_promotable_const_function(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
- if let ExprKind::Call(ref fun, _) = expr.kind {
+ if let ExprKind::Call(fun, _) = expr.kind {
if let ExprKind::Path(ref qp) = fun.kind {
let res = cx.qpath_res(qp, fun.hir_id);
return match res {
)
}
- fn are_refutable<'a, I: Iterator<Item = &'a Pat<'a>>>(cx: &LateContext<'_>, mut i: I) -> bool {
- i.any(|pat| is_refutable(cx, pat))
+ fn are_refutable<'a, I: IntoIterator<Item = &'a Pat<'a>>>(cx: &LateContext<'_>, i: I) -> bool {
+ i.into_iter().any(|pat| is_refutable(cx, pat))
}
match pat.kind {
PatKind::Wild => false,
PatKind::Binding(_, _, _, pat) => pat.map_or(false, |pat| is_refutable(cx, pat)),
- PatKind::Box(ref pat) | PatKind::Ref(ref pat, _) => is_refutable(cx, pat),
+ PatKind::Box(pat) | PatKind::Ref(pat, _) => is_refutable(cx, pat),
PatKind::Lit(..) | PatKind::Range(..) => true,
PatKind::Path(ref qpath) => is_enum_variant(cx, qpath, pat.hir_id),
- PatKind::Or(ref pats) => {
+ PatKind::Or(pats) => {
// TODO: should be the honest check, that pats is exhaustive set
- are_refutable(cx, pats.iter().map(|pat| &**pat))
+ are_refutable(cx, pats)
},
- PatKind::Tuple(ref pats, _) => are_refutable(cx, pats.iter().map(|pat| &**pat)),
- PatKind::Struct(ref qpath, ref fields, _) => {
+ PatKind::Tuple(pats, _) => are_refutable(cx, pats),
+ PatKind::Struct(ref qpath, fields, _) => {
is_enum_variant(cx, qpath, pat.hir_id) || are_refutable(cx, fields.iter().map(|field| &*field.pat))
},
- PatKind::TupleStruct(ref qpath, ref pats, _) => {
- is_enum_variant(cx, qpath, pat.hir_id) || are_refutable(cx, pats.iter().map(|pat| &**pat))
- },
- PatKind::Slice(ref head, ref middle, ref tail) => {
+ PatKind::TupleStruct(ref qpath, pats, _) => is_enum_variant(cx, qpath, pat.hir_id) || are_refutable(cx, pats),
+ PatKind::Slice(head, middle, tail) => {
match &cx.typeck_results().node_type(pat.hir_id).kind() {
rustc_ty::Slice(..) => {
// [..] is the only irrefutable slice pattern.
!head.is_empty() || middle.is_none() || !tail.is_empty()
},
- rustc_ty::Array(..) => {
- are_refutable(cx, head.iter().chain(middle).chain(tail.iter()).map(|pat| &**pat))
- },
+ rustc_ty::Array(..) => are_refutable(cx, head.iter().chain(middle).chain(tail.iter())),
_ => {
// unreachable!()
true
/// the function once on the given pattern.
pub fn recurse_or_patterns<'tcx, F: FnMut(&'tcx Pat<'tcx>)>(pat: &'tcx Pat<'tcx>, mut f: F) {
if let PatKind::Or(pats) = pat.kind {
- pats.iter().copied().for_each(f)
+ pats.iter().for_each(f);
} else {
- f(pat)
+ f(pat);
}
}
/// Ie. `x`, `{ x }` and `{{{{ x }}}}` all give `x`. `{ x; y }` and `{}` return
/// themselves.
pub fn remove_blocks<'tcx>(mut expr: &'tcx Expr<'tcx>) -> &'tcx Expr<'tcx> {
- while let ExprKind::Block(ref block, ..) = expr.kind {
+ while let ExprKind::Block(block, ..) = expr.kind {
match (block.stmts.is_empty(), block.expr.as_ref()) {
(true, Some(e)) => expr = e,
_ => break,
pub fn is_self_ty(slf: &hir::Ty<'_>) -> bool {
if_chain! {
- if let TyKind::Path(QPath::Resolved(None, ref path)) = slf.kind;
+ if let TyKind::Path(QPath::Resolved(None, path)) = slf.kind;
if let Res::SelfTy(..) = path.res;
then {
return true
pub fn is_try<'tcx>(cx: &LateContext<'_>, expr: &'tcx Expr<'tcx>) -> Option<&'tcx Expr<'tcx>> {
fn is_ok(cx: &LateContext<'_>, arm: &Arm<'_>) -> bool {
if_chain! {
- if let PatKind::TupleStruct(ref path, ref pat, None) = arm.pat.kind;
+ if let PatKind::TupleStruct(ref path, pat, None) = arm.pat.kind;
if is_lang_ctor(cx, path, ResultOk);
if let PatKind::Binding(_, hir_id, _, None) = pat[0].kind;
if path_to_local_id(arm.body, hir_id);
}
}
- if let ExprKind::Match(_, ref arms, ref source) = expr.kind {
+ if let ExprKind::Match(_, arms, ref source) = expr.kind {
// desugared from a `?` operator
if let MatchSource::TryDesugar = *source {
return Some(expr);
/// Returns `true` if the lint is allowed in the current context
///
/// Useful for skipping long running code when it's unnecessary
-pub fn is_allowed(cx: &LateContext<'_>, lint: &'static Lint, id: HirId) -> bool {
+pub fn is_lint_allowed(cx: &LateContext<'_>, lint: &'static Lint, id: HirId) -> bool {
cx.tcx.lint_level_at_node(lint, id).0 == Level::Allow
}
path: &[&str],
) -> Option<&'tcx [Expr<'tcx>]> {
if_chain! {
- if let ExprKind::Call(ref fun, args) = expr.kind;
+ if let ExprKind::Call(fun, args) = expr.kind;
if let ExprKind::Path(ref qpath) = fun.kind;
if let Some(fun_def_id) = cx.qpath_res(qpath, fun.hir_id).opt_def_id();
if match_def_path(cx, fun_def_id, path);
/// Checks if the given `DefId` matches any of the paths. Returns the index of matching path, if
/// any.
+///
+/// Please use `match_any_diagnostic_items` if the targets are all diagnostic items.
pub fn match_any_def_paths(cx: &LateContext<'_>, did: DefId, paths: &[&[&str]]) -> Option<usize> {
let search_path = cx.get_def_path(did);
paths
.position(|p| p.iter().map(|x| Symbol::intern(x)).eq(search_path.iter().copied()))
}
+/// Checks if the given `DefId` matches any of provided diagnostic items. Returns the index of
+/// matching path, if any.
+pub fn match_any_diagnostic_items(cx: &LateContext<'_>, def_id: DefId, diag_items: &[Symbol]) -> Option<usize> {
+ diag_items
+ .iter()
+ .position(|item| cx.tcx.is_diagnostic_item(*item, def_id))
+}
+
/// Checks if the given `DefId` matches the path.
pub fn match_def_path<'tcx>(cx: &LateContext<'tcx>, did: DefId, syms: &[&str]) -> bool {
// We should probably move to Symbols in Clippy as well rather than interning every time.
let mut conds = Vec::new();
let mut blocks: Vec<&Block<'_>> = Vec::new();
- while let ExprKind::If(ref cond, ref then_expr, ref else_expr) = expr.kind {
- conds.push(&**cond);
- if let ExprKind::Block(ref block, _) = then_expr.kind {
+ while let ExprKind::If(cond, then_expr, ref else_expr) = expr.kind {
+ conds.push(cond);
+ if let ExprKind::Block(block, _) = then_expr.kind {
blocks.push(block);
} else {
panic!("ExprKind::If node is not an ExprKind::Block");
}
- if let Some(ref else_expr) = *else_expr {
+ if let Some(else_expr) = *else_expr {
expr = else_expr;
} else {
break;
// final `else {..}`
if !blocks.is_empty() {
- if let ExprKind::Block(ref block, _) = expr.kind {
- blocks.push(&**block);
+ if let ExprKind::Block(block, _) = expr.kind {
+ blocks.push(block);
}
}
// check if expr is calling method or function with #[must_use] attribute
pub fn is_must_use_func_call(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
let did = match expr.kind {
- ExprKind::Call(ref path, _) => if_chain! {
+ ExprKind::Call(path, _) => if_chain! {
if let ExprKind::Path(ref qpath) = path.kind;
if let def::Res::Def(_, did) = cx.qpath_res(qpath, path.hir_id);
then {
_ => None,
};
- did.map_or(false, |did| must_use_attr(&cx.tcx.get_attrs(did)).is_some())
+ did.map_or(false, |did| must_use_attr(cx.tcx.get_attrs(did)).is_some())
+}
+
+/// Checks if an expression represents the identity function
+/// Only examines closures and `std::convert::identity`
+pub fn is_expr_identity_function(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
+ /// Checks if a function's body represents the identity function. Looks for bodies of the form:
+ /// * `|x| x`
+ /// * `|x| return x`
+ /// * `|x| { return x }`
+ /// * `|x| { return x; }`
+ fn is_body_identity_function(cx: &LateContext<'_>, func: &Body<'_>) -> bool {
+ let id = if_chain! {
+ if let [param] = func.params;
+ if let PatKind::Binding(_, id, _, _) = param.pat.kind;
+ then {
+ id
+ } else {
+ return false;
+ }
+ };
+
+ let mut expr = &func.value;
+ loop {
+ match expr.kind {
+ #[rustfmt::skip]
+ ExprKind::Block(&Block { stmts: [], expr: Some(e), .. }, _, )
+ | ExprKind::Ret(Some(e)) => expr = e,
+ #[rustfmt::skip]
+ ExprKind::Block(&Block { stmts: [stmt], expr: None, .. }, _) => {
+ if_chain! {
+ if let StmtKind::Semi(e) | StmtKind::Expr(e) = stmt.kind;
+ if let ExprKind::Ret(Some(ret_val)) = e.kind;
+ then {
+ expr = ret_val;
+ } else {
+ return false;
+ }
+ }
+ },
+ _ => return path_to_local_id(expr, id) && cx.typeck_results().expr_adjustments(expr).is_empty(),
+ }
+ }
+ }
+
+ match expr.kind {
+ ExprKind::Closure(_, _, body_id, _, _) => is_body_identity_function(cx, cx.tcx.hir().body(body_id)),
+ ExprKind::Path(ref path) => is_qpath_def_path(cx, path, expr.hir_id, &paths::CONVERT_IDENTITY),
+ _ => false,
+ }
}
/// Gets the node where an expression is either used, or it's type is unified with another branch.
}
}
-/// This function checks if any of the lints in the slice is enabled for the provided `HirId`.
-/// A lint counts as enabled with any of the levels: `Level::Forbid` | `Level::Deny` | `Level::Warn`
-///
-/// ```ignore
-/// #[deny(clippy::YOUR_AWESOME_LINT)]
-/// println!("Hello, World!"); // <- Clippy code: run_lints(cx, &[YOUR_AWESOME_LINT], id) == true
-///
-/// #[allow(clippy::YOUR_AWESOME_LINT)]
-/// println!("See you soon!"); // <- Clippy code: run_lints(cx, &[YOUR_AWESOME_LINT], id) == false
-/// ```
-pub fn run_lints(cx: &LateContext<'_>, lints: &[&'static Lint], id: HirId) -> bool {
- lints.iter().any(|lint| {
- matches!(
- cx.tcx.lint_level_at_node(lint, id),
- (Level::Forbid | Level::Deny | Level::Warn, _)
- )
- })
-}
-
/// Returns Option<String> where String is a textual representation of the type encapsulated in the
/// slice iff the given expression is a slice of primitives (as defined in the
/// `is_recursively_primitive_type` function) and None otherwise.
Hash: Fn(&T) -> u64,
Eq: Fn(&T, &T) -> bool,
{
- if exprs.len() == 2 && eq(&exprs[0], &exprs[1]) {
- return vec![(&exprs[0], &exprs[1])];
+ match exprs {
+ [a, b] if eq(a, b) => return vec![(a, b)],
+ _ if exprs.len() <= 2 => return vec![],
+ _ => {},
}
let mut match_expr_list: Vec<(&T, &T)> = Vec::new();
- let mut map: FxHashMap<_, Vec<&_>> =
- FxHashMap::with_capacity_and_hasher(exprs.len(), BuildHasherDefault::default());
+ let mut map: UnhashMap<u64, Vec<&_>> =
+ UnhashMap::with_capacity_and_hasher(exprs.len(), BuildHasherDefault::default());
for expr in exprs {
match map.entry(hash(expr)) {
pub fn peel_n_hir_expr_refs(expr: &'a Expr<'a>, count: usize) -> (&'a Expr<'a>, usize) {
let mut remaining = count;
let e = peel_hir_expr_while(expr, |e| match e.kind {
- ExprKind::AddrOf(BorrowKind::Ref, _, e) if remaining != 0 => {
+ ExprKind::AddrOf(ast::BorrowKind::Ref, _, e) if remaining != 0 => {
remaining -= 1;
Some(e)
},
pub fn peel_hir_expr_refs(expr: &'a Expr<'a>) -> (&'a Expr<'a>, usize) {
let mut count = 0;
let e = peel_hir_expr_while(expr, |e| match e.kind {
- ExprKind::AddrOf(BorrowKind::Ref, _, e) => {
+ ExprKind::AddrOf(ast::BorrowKind::Ref, _, e) => {
count += 1;
Some(e)
},
(e, count)
}
+/// Removes `AddrOf` operators (`&`) or deref operators (`*`), but only if a reference type is
+/// dereferenced. An overloaded deref such as `Vec` to slice would not be removed.
+pub fn peel_ref_operators<'hir>(cx: &LateContext<'_>, mut expr: &'hir Expr<'hir>) -> &'hir Expr<'hir> {
+ loop {
+ match expr.kind {
+ ExprKind::AddrOf(_, _, e) => expr = e,
+ ExprKind::Unary(UnOp::Deref, e) if cx.typeck_results().expr_ty(e).is_ref() => expr = e,
+ _ => break,
+ }
+ }
+ expr
+}
+
#[macro_export]
macro_rules! unwrap_cargo_metadata {
($cx: ident, $lint: ident, $deps: expr) => {{
}
}
}
+
+/// Checks whether item either has `test` attribute applied, or
+/// is a module with `test` in its name.
+pub fn is_test_module_or_function(tcx: TyCtxt<'_>, item: &Item<'_>) -> bool {
+ if let Some(def_id) = tcx.hir().opt_local_def_id(item.hir_id()) {
+ if tcx.has_attr(def_id.to_def_id(), sym::test) {
+ return true;
+ }
+ }
+
+ matches!(item.kind, ItemKind::Mod(..)) && item.ident.name.as_str().contains("test")
+}
+
+macro_rules! op_utils {
+ ($($name:ident $assign:ident)*) => {
+ /// Binary operation traits like `LangItem::Add`
+ pub static BINOP_TRAITS: &[LangItem] = &[$(LangItem::$name,)*];
+
+ /// Operator-Assign traits like `LangItem::AddAssign`
+ pub static OP_ASSIGN_TRAITS: &[LangItem] = &[$(LangItem::$assign,)*];
+
+ /// Converts `BinOpKind::Add` to `(LangItem::Add, LangItem::AddAssign)`, for example
+ pub fn binop_traits(kind: hir::BinOpKind) -> Option<(LangItem, LangItem)> {
+ match kind {
+ $(hir::BinOpKind::$name => Some((LangItem::$name, LangItem::$assign)),)*
+ _ => None,
+ }
+ }
+ };
+}
+
+op_utils! {
+ Add AddAssign
+ Sub SubAssign
+ Mul MulAssign
+ Div DivAssign
+ Rem RemAssign
+ BitXor BitXorAssign
+ BitAnd BitAndAssign
+ BitOr BitOrAssign
+ Shl ShlAssign
+ Shr ShrAssign
+}