#![feature(iter_zip)]
#![feature(rustc_private)]
#![recursion_limit = "512"]
+#![cfg_attr(feature = "deny-warnings", deny(warnings))]
#![allow(clippy::missing_errors_doc, clippy::missing_panics_doc, clippy::must_use_candidate)]
+// warn on the same lints as `clippy_lints`
+#![warn(trivial_casts, trivial_numeric_casts)]
+// warn on lints, that are included in `rust-lang/rust`s bootstrap
+#![warn(rust_2018_idioms, unused_lifetimes)]
+// warn on rustc internal lints
+#![warn(rustc::internal)]
// FIXME: switch to something more ergonomic here, once available.
// (Currently there is no way to opt into sysroot crates without `extern crate`.)
extern crate rustc_data_structures;
extern crate rustc_errors;
extern crate rustc_hir;
-extern crate rustc_hir_pretty;
extern crate rustc_infer;
extern crate rustc_lexer;
extern crate rustc_lint;
pub mod eager_or_lazy;
pub mod higher;
mod hir_utils;
+pub mod msrvs;
pub mod numeric_literal;
pub mod paths;
pub mod ptr;
use if_chain::if_chain;
use rustc_ast::ast::{self, Attribute, BorrowKind, LitKind};
-use rustc_data_structures::fx::FxHashMap;
+use rustc_data_structures::unhash::UnhashMap;
use rustc_hir as hir;
use rustc_hir::def::{DefKind, Res};
-use rustc_hir::def_id::{DefId, LOCAL_CRATE};
-use rustc_hir::intravisit::{self, NestedVisitorMap, Visitor};
+use rustc_hir::def_id::DefId;
+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, Expr, ExprKind, FnDecl, GenericArgs, HirId, Impl, ImplItem,
- ImplItemKind, Item, ItemKind, LangItem, MatchSource, Node, Param, Pat, PatKind, Path, PathSegment, QPath,
- TraitItem, TraitItemKind, TraitRef, TyKind,
+ 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,
};
use rustc_lint::{LateContext, Level, Lint, LintContext};
use rustc_middle::hir::exports::Export;
use rustc_target::abi::Integer;
use crate::consts::{constant, Constant};
-use crate::ty::is_recursively_primitive_type;
+use crate::ty::{can_partially_move_ty, 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 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 ExprKind::Path(QPath::Resolved(None, path)) = expr.kind {
if let [p] = path.segments {
return p.ident.name == var;
}
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, resolve it. Otherwise, return `Res::Err`.
+pub fn expr_path_res(cx: &LateContext<'_>, expr: &Expr<'_>) -> Res {
+ if let ExprKind::Path(p) = &expr.kind {
+ cx.qpath_res(p, expr.hir_id)
+ } else {
+ Res::Err
+ }
+}
+
+/// Resolves the path to a `DefId` and checks if it matches the given path.
+pub fn is_qpath_def_path(cx: &LateContext<'_>, path: &QPath<'_>, hir_id: HirId, segments: &[&str]) -> bool {
+ cx.qpath_res(path, hir_id)
+ .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 path.
+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))
+}
+
/// 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()`.
.all(|(a, b)| a.ident.name.as_str() == *b)
}
-/// Matches a `Path` against a slice of segment string literals, e.g.
-///
-/// # Examples
-/// ```rust,ignore
-/// match_path_ast(path, &["std", "rt", "begin_unwind"])
-/// ```
-pub fn match_path_ast(path: &ast::Path, segments: &[&str]) -> bool {
- path.segments
- .iter()
- .rev()
- .zip(segments.iter().rev())
- .all(|(a, b)| a.ident.name.as_str() == *b)
-}
-
/// 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);
}
None
}
+/// 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 {
+ match expr.kind {
+ ExprKind::Break(Destination { target_id: Ok(id), .. }, _)
+ | ExprKind::Continue(Destination { target_id: Ok(id), .. })
+ if jump_targets.contains(&id) =>
+ {
+ true
+ },
+ ExprKind::Break(..)
+ | ExprKind::Continue(_)
+ | ExprKind::Ret(_)
+ | ExprKind::Yield(..)
+ | ExprKind::InlineAsm(_)
+ | 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)) =>
+ {
+ // 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 {
+ struct V<'cx, 'tcx> {
+ cx: &'cx LateContext<'tcx>,
+ loops: Vec<HirId>,
+ allow_closure: bool,
+ }
+ impl Visitor<'tcx> for V<'_, 'tcx> {
+ type Map = ErasedMap<'tcx>;
+ fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
+ NestedVisitorMap::None
+ }
+
+ fn visit_expr(&mut self, e: &'tcx Expr<'_>) {
+ 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);
+ }
+ }
+ }
+
+ let mut v = V {
+ cx,
+ allow_closure: true,
+ loops: Vec::new(),
+ };
+ v.visit_expr(expr);
+ v.allow_closure
+}
+
/// Returns the method names and argument list of nested method call expressions that make up
/// `expr`. method/span lists are sorted with the most recent call first.
pub fn method_calls<'tcx>(
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;
}
/// Returns `true` if the provided `def_id` is an entrypoint to a program.
pub fn is_entrypoint_fn(cx: &LateContext<'_>, def_id: DefId) -> bool {
cx.tcx
- .entry_fn(LOCAL_CRATE)
- .map_or(false, |(entry_fn_def_id, _)| def_id == entry_fn_def_id.to_def_id())
+ .entry_fn(())
+ .map_or(false, |(entry_fn_def_id, _)| def_id == entry_fn_def_id)
}
/// Returns `true` if the expression is in the program's `#[panic_handler]`.
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),
+ PatKind::Box(p) | PatKind::Ref(p, _) => get_pat_name(&*p),
_ => None,
}
}
/// Gets the parent expression, if any –- this is useful to constrain a lint.
pub fn get_parent_expr<'tcx>(cx: &LateContext<'tcx>, e: &Expr<'_>) -> Option<&'tcx Expr<'tcx>> {
- match get_parent_node(cx.tcx, e.hir_id) {
+ get_parent_expr_for_hir(cx, e.hir_id)
+}
+
+/// This retrieves the parent for the given `HirId` if it's an expression. This is useful for
+/// constraint lints
+pub fn get_parent_expr_for_hir<'tcx>(cx: &LateContext<'tcx>, hir_id: hir::HirId) -> Option<&'tcx Expr<'tcx>> {
+ match get_parent_node(cx.tcx, hir_id) {
Some(Node::Expr(parent)) => Some(parent),
_ => None,
}
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>> {
+ let map = tcx.hir();
+ for (_, node) in map.parent_iter(expr.hir_id) {
+ match node {
+ Node::Expr(
+ e @ Expr {
+ kind: ExprKind::Loop(..),
+ ..
+ },
+ ) => return Some(e),
+ Node::Expr(_) | Node::Stmt(_) | Node::Block(_) | Node::Local(_) | Node::Arm(_) => (),
+ _ => break,
+ }
+ }
+ None
+}
+
/// Gets the parent node if it's an impl block.
pub fn get_parent_as_impl(tcx: TyCtxt<'_>, id: HirId) -> Option<&Impl<'_>> {
let map = tcx.hir();
let data = span.ctxt().outer_expn_data();
let new_span = data.call_site;
- if let ExpnKind::Macro(MacroKind::Bang, mac_name) = data.kind {
+ if let ExpnKind::Macro {
+ kind: MacroKind::Bang,
+ name: mac_name,
+ proc_macro: _,
+ } = 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(MacroKind::Bang, mac_name) = data.kind {
+ if let ExpnKind::Macro {
+ kind: MacroKind::Bang,
+ name: mac_name,
+ proc_macro: _,
+ } = 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 {
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))
},
- 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.iter().map(|pat| &**pat)),
+ 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, _) => {
+ PatKind::TupleStruct(ref qpath, 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::Slice(head, ref middle, tail) => {
match &cx.typeck_results().node_type(pat.hir_id).kind() {
rustc_ty::Slice(..) => {
// [..] is the only irrefutable slice pattern.
/// 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().cloned().for_each(f)
+ pats.iter().copied().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);
path: &[&str],
) -> Option<&'tcx [Expr<'tcx>]> {
if_chain! {
- if let ExprKind::Call(ref fun, ref 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);
then {
- return Some(&args)
+ return Some(args)
}
};
None
}
+/// Checks if the given `DefId` matches any of the paths. Returns the index of matching path, if
+/// any.
+pub fn match_any_def_paths(cx: &LateContext<'_>, did: DefId, paths: &[&[&str]]) -> Option<usize> {
+ let search_path = cx.get_def_path(did);
+ paths
+ .iter()
+ .position(|p| p.iter().map(|x| Symbol::intern(x)).eq(search_path.iter().copied()))
+}
+
+/// Checks if the given `DefId` matches the path.
pub fn match_def_path<'tcx>(cx: &LateContext<'tcx>, did: DefId, syms: &[&str]) -> bool {
- // We have to convert `syms` to `&[Symbol]` here because rustc's `match_def_path`
- // accepts only that. We should probably move to Symbols in Clippy as well.
- let syms = syms.iter().map(|p| Symbol::intern(p)).collect::<Vec<Symbol>>();
- cx.match_def_path(did, &syms)
+ // We should probably move to Symbols in Clippy as well rather than interning every time.
+ let path = cx.get_def_path(did);
+ syms.iter().map(|x| Symbol::intern(x)).eq(path.iter().copied())
}
-pub fn match_panic_call<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> Option<&'tcx [Expr<'tcx>]> {
- match_function_call(cx, expr, &paths::BEGIN_PANIC)
- .or_else(|| match_function_call(cx, expr, &paths::BEGIN_PANIC_FMT))
- .or_else(|| match_function_call(cx, expr, &paths::PANIC_ANY))
- .or_else(|| match_function_call(cx, expr, &paths::PANICKING_PANIC))
- .or_else(|| match_function_call(cx, expr, &paths::PANICKING_PANIC_FMT))
- .or_else(|| match_function_call(cx, expr, &paths::PANICKING_PANIC_STR))
+pub fn match_panic_call(cx: &LateContext<'_>, expr: &'tcx Expr<'_>) -> Option<&'tcx Expr<'tcx>> {
+ if let ExprKind::Call(func, [arg]) = expr.kind {
+ expr_path_res(cx, func)
+ .opt_def_id()
+ .map_or(false, |id| match_panic_def_id(cx, id))
+ .then(|| arg)
+ } else {
+ None
+ }
}
pub fn match_panic_def_id(cx: &LateContext<'_>, did: DefId) -> bool {
- match_def_path(cx, did, &paths::BEGIN_PANIC)
- || match_def_path(cx, did, &paths::BEGIN_PANIC_FMT)
- || match_def_path(cx, did, &paths::PANIC_ANY)
- || match_def_path(cx, did, &paths::PANICKING_PANIC)
- || match_def_path(cx, did, &paths::PANICKING_PANIC_FMT)
- || match_def_path(cx, did, &paths::PANICKING_PANIC_STR)
+ match_any_def_paths(
+ cx,
+ did,
+ &[
+ &paths::BEGIN_PANIC,
+ &paths::BEGIN_PANIC_FMT,
+ &paths::PANIC_ANY,
+ &paths::PANICKING_PANIC,
+ &paths::PANICKING_PANIC_FMT,
+ &paths::PANICKING_PANIC_STR,
+ ],
+ )
+ .is_some()
}
/// Returns the list of condition expressions and the list of blocks in a
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);
}
}
(conds, blocks)
}
-/// This function returns true if the given expression is the `else` or `if else` part of an if
-/// statement
-pub fn parent_node_is_if_expr(expr: &Expr<'_>, cx: &LateContext<'_>) -> bool {
- let map = cx.tcx.hir();
- let parent_id = map.get_parent_node(expr.hir_id);
- let parent_node = map.get(parent_id);
- matches!(
- parent_node,
- Node::Expr(Expr {
- kind: ExprKind::If(_, _, _),
+/// Checks if the given function kind is an async function.
+pub fn is_async_fn(kind: FnKind<'_>) -> bool {
+ matches!(kind, FnKind::ItemFn(_, _, header, _) if header.asyncness == IsAsync::Async)
+}
+
+/// Peels away all the compiler generated code surrounding the body of an async function,
+pub fn get_async_fn_body(tcx: TyCtxt<'tcx>, body: &Body<'_>) -> Option<&'tcx Expr<'tcx>> {
+ if let ExprKind::Call(
+ _,
+ &[Expr {
+ kind: ExprKind::Closure(_, _, body, _, _),
..
- })
- )
+ }],
+ ) = body.value.kind
+ {
+ if let ExprKind::Block(
+ Block {
+ stmts: [],
+ expr:
+ Some(Expr {
+ kind: ExprKind::DropTemps(expr),
+ ..
+ }),
+ ..
+ },
+ _,
+ ) = tcx.hir().body(body).value.kind
+ {
+ return Some(expr);
+ }
+ };
+ None
}
// Finds the `#[must_use]` attribute, if any
// 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())
+}
+
+/// Gets the node where an expression is either used, or it's type is unified with another branch.
+pub fn get_expr_use_or_unification_node(tcx: TyCtxt<'tcx>, expr: &Expr<'_>) -> Option<Node<'tcx>> {
+ let map = tcx.hir();
+ let mut child_id = expr.hir_id;
+ let mut iter = map.parent_iter(child_id);
+ loop {
+ match iter.next() {
+ None => break None,
+ Some((id, Node::Block(_))) => child_id = id,
+ Some((id, Node::Arm(arm))) if arm.body.hir_id == child_id => child_id = id,
+ Some((_, Node::Expr(expr))) => match expr.kind {
+ ExprKind::Match(_, [arm], _) if arm.hir_id == child_id => child_id = expr.hir_id,
+ ExprKind::Block(..) | ExprKind::DropTemps(_) => child_id = expr.hir_id,
+ ExprKind::If(_, then_expr, None) if then_expr.hir_id == child_id => break None,
+ _ => break Some(Node::Expr(expr)),
+ },
+ Some((_, node)) => break Some(node),
+ }
+ }
+}
+
+/// Checks if the result of an expression is used, or it's type is unified with another branch.
+pub fn is_expr_used_or_unified(tcx: TyCtxt<'_>, expr: &Expr<'_>) -> bool {
+ !matches!(
+ get_expr_use_or_unification_node(tcx, expr),
+ None | Some(Node::Stmt(Stmt {
+ kind: StmtKind::Expr(_)
+ | StmtKind::Semi(_)
+ | StmtKind::Local(Local {
+ pat: Pat {
+ kind: PatKind::Wild,
+ ..
+ },
+ ..
+ }),
+ ..
+ }))
+ )
+}
+
+/// Checks if the expression is the final expression returned from a block.
+pub fn is_expr_final_block_expr(tcx: TyCtxt<'_>, expr: &Expr<'_>) -> bool {
+ matches!(get_parent_node(tcx, expr.hir_id), Some(Node::Block(..)))
}
pub fn is_no_std_crate(cx: &LateContext<'_>) -> bool {
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)) {
peel(pat, 0)
}
+/// Peels of expressions while the given closure returns `Some`.
+pub fn peel_hir_expr_while<'tcx>(
+ mut expr: &'tcx Expr<'tcx>,
+ mut f: impl FnMut(&'tcx Expr<'tcx>) -> Option<&'tcx Expr<'tcx>>,
+) -> &'tcx Expr<'tcx> {
+ while let Some(e) = f(expr) {
+ expr = e;
+ }
+ expr
+}
+
/// Peels off up to the given number of references on the expression. Returns the underlying
/// expression and the number of references removed.
pub fn peel_n_hir_expr_refs(expr: &'a Expr<'a>, count: usize) -> (&'a Expr<'a>, usize) {
- fn f(expr: &'a Expr<'a>, count: usize, target: usize) -> (&'a Expr<'a>, usize) {
- match expr.kind {
- ExprKind::AddrOf(_, _, expr) if count != target => f(expr, count + 1, target),
- _ => (expr, count),
- }
- }
- f(expr, 0, count)
+ let mut remaining = count;
+ let e = peel_hir_expr_while(expr, |e| match e.kind {
+ ExprKind::AddrOf(BorrowKind::Ref, _, e) if remaining != 0 => {
+ remaining -= 1;
+ Some(e)
+ },
+ _ => None,
+ });
+ (e, count - remaining)
}
/// Peels off all references on the expression. Returns the underlying expression and the number of
/// references removed.
pub fn peel_hir_expr_refs(expr: &'a Expr<'a>) -> (&'a Expr<'a>, usize) {
- fn f(expr: &'a Expr<'a>, count: usize) -> (&'a Expr<'a>, usize) {
- match expr.kind {
- ExprKind::AddrOf(BorrowKind::Ref, _, expr) => f(expr, count + 1),
- _ => (expr, count),
- }
- }
- f(expr, 0)
+ let mut count = 0;
+ let e = peel_hir_expr_while(expr, |e| match e.kind {
+ ExprKind::AddrOf(BorrowKind::Ref, _, e) => {
+ count += 1;
+ Some(e)
+ },
+ _ => None,
+ });
+ (e, count)
}
#[macro_export]