-// Copyright 2014-2018 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-use crate::utils::{get_trait_def_id, higher, implements_trait, match_qpath, paths, span_lint};
-use rustc::hir::*;
-use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
-use rustc::{declare_tool_lint, lint_array};
-
-/// **What it does:** Checks for iteration that is guaranteed to be infinite.
-///
-/// **Why is this bad?** While there may be places where this is acceptable
-/// (e.g. in event streams), in most cases this is simply an error.
-///
-/// **Known problems:** None.
-///
-/// **Example:**
-/// ```rust
-/// repeat(1_u8).iter().collect::<Vec<_>>()
-/// ```
+use rustc_hir::{BorrowKind, Expr, ExprKind};
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_session::{declare_lint_pass, declare_tool_lint};
+
+use crate::utils::{get_trait_def_id, higher, implements_trait, match_qpath, match_type, paths, span_lint};
+
declare_clippy_lint! {
+ /// **What it does:** Checks for iteration that is guaranteed to be infinite.
+ ///
+ /// **Why is this bad?** While there may be places where this is acceptable
+ /// (e.g., in event streams), in most cases this is simply an error.
+ ///
+ /// **Known problems:** None.
+ ///
+ /// **Example:**
+ /// ```no_run
+ /// use std::iter;
+ ///
+ /// iter::repeat(1_u8).collect::<Vec<_>>();
+ /// ```
pub INFINITE_ITER,
correctness,
"infinite iteration"
}
-/// **What it does:** Checks for iteration that may be infinite.
-///
-/// **Why is this bad?** While there may be places where this is acceptable
-/// (e.g. in event streams), in most cases this is simply an error.
-///
-/// **Known problems:** The code may have a condition to stop iteration, but
-/// this lint is not clever enough to analyze it.
-///
-/// **Example:**
-/// ```rust
-/// [0..].iter().zip(infinite_iter.take_while(|x| x > 5))
-/// ```
declare_clippy_lint! {
+ /// **What it does:** Checks for iteration that may be infinite.
+ ///
+ /// **Why is this bad?** While there may be places where this is acceptable
+ /// (e.g., in event streams), in most cases this is simply an error.
+ ///
+ /// **Known problems:** The code may have a condition to stop iteration, but
+ /// this lint is not clever enough to analyze it.
+ ///
+ /// **Example:**
+ /// ```rust
+ /// let infinite_iter = 0..;
+ /// [0..].iter().zip(infinite_iter.take_while(|x| *x > 5));
+ /// ```
pub MAYBE_INFINITE_ITER,
pedantic,
"possible infinite iteration"
}
-#[derive(Copy, Clone)]
-pub struct Pass;
-
-impl LintPass for Pass {
- fn get_lints(&self) -> LintArray {
- lint_array!(INFINITE_ITER, MAYBE_INFINITE_ITER)
- }
-}
+declare_lint_pass!(InfiniteIter => [INFINITE_ITER, MAYBE_INFINITE_ITER]);
-impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Pass {
- fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr) {
+impl<'tcx> LateLintPass<'tcx> for InfiniteIter {
+ fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
let (lint, msg) = match complete_infinite_iter(cx, expr) {
Infinite => (INFINITE_ITER, "infinite iteration detected"),
MaybeInfinite => (MAYBE_INFINITE_ITER, "possible infinite iteration detected"),
use self::Finiteness::{Finite, Infinite, MaybeInfinite};
impl Finiteness {
+ #[must_use]
fn and(self, b: Self) -> Self {
match (self, b) {
(Finite, _) | (_, Finite) => Finite,
}
}
+ #[must_use]
fn or(self, b: Self) -> Self {
match (self, b) {
(Infinite, _) | (_, Infinite) => Infinite,
}
impl From<bool> for Finiteness {
+ #[must_use]
fn from(b: bool) -> Self {
if b {
Infinite
/// a slice of (method name, number of args, heuristic, bounds) tuples
/// that will be used to determine whether the method in question
/// returns an infinite or possibly infinite iterator. The finiteness
-/// is an upper bound, e.g. some methods can return a possibly
-/// infinite iterator at worst, e.g. `take_while`.
-static HEURISTICS: &[(&str, usize, Heuristic, Finiteness)] = &[
+/// is an upper bound, e.g., some methods can return a possibly
+/// infinite iterator at worst, e.g., `take_while`.
+const HEURISTICS: [(&str, usize, Heuristic, Finiteness); 19] = [
("zip", 2, All, Infinite),
("chain", 2, Any, Infinite),
("cycle", 1, Always, Infinite),
("scan", 3, First, MaybeInfinite),
];
-fn is_infinite(cx: &LateContext<'_, '_>, expr: &Expr) -> Finiteness {
- match expr.node {
- ExprKind::MethodCall(ref method, _, ref args) => {
- for &(name, len, heuristic, cap) in HEURISTICS.iter() {
- if method.ident.name == name && args.len() == len {
+fn is_infinite(cx: &LateContext<'_>, expr: &Expr<'_>) -> Finiteness {
+ match expr.kind {
+ ExprKind::MethodCall(ref method, _, ref args, _) => {
+ for &(name, len, heuristic, cap) in &HEURISTICS {
+ if method.ident.name.as_str() == name && args.len() == len {
return (match heuristic {
Always => Infinite,
First => is_infinite(cx, &args[0]),
.and(cap);
}
}
- if method.ident.name == "flat_map" && args.len() == 2 {
- if let ExprKind::Closure(_, _, body_id, _, _) = args[1].node {
+ if method.ident.name == sym!(flat_map) && args.len() == 2 {
+ if let ExprKind::Closure(_, _, body_id, _, _) = args[1].kind {
let body = cx.tcx.hir().body(body_id);
return is_infinite(cx, &body.value);
}
Finite
},
ExprKind::Block(ref block, _) => block.expr.as_ref().map_or(Finite, |e| is_infinite(cx, e)),
- ExprKind::Box(ref e) | ExprKind::AddrOf(_, ref e) => is_infinite(cx, e),
+ ExprKind::Box(ref e) | ExprKind::AddrOf(BorrowKind::Ref, _, ref e) => is_infinite(cx, e),
ExprKind::Call(ref path, _) => {
- if let ExprKind::Path(ref qpath) = path.node {
+ if let ExprKind::Path(ref qpath) = path.kind {
match_qpath(qpath, &paths::REPEAT).into()
} else {
Finite
}
},
- ExprKind::Struct(..) => higher::range(cx, expr).map_or(false, |r| r.end.is_none()).into(),
+ ExprKind::Struct(..) => higher::range(expr).map_or(false, |r| r.end.is_none()).into(),
_ => Finite,
}
}
/// the names and argument lengths of methods that *may* exhaust their
/// iterators
-static POSSIBLY_COMPLETING_METHODS: &[(&str, usize)] = &[
+const POSSIBLY_COMPLETING_METHODS: [(&str, usize); 6] = [
("find", 2),
("rfind", 2),
("position", 2),
/// the names and argument lengths of methods that *always* exhaust
/// their iterators
-static COMPLETING_METHODS: &[(&str, usize)] = &[
+const COMPLETING_METHODS: [(&str, usize); 12] = [
("count", 1),
- ("collect", 1),
("fold", 3),
("for_each", 2),
("partition", 2),
("product", 1),
];
-fn complete_infinite_iter(cx: &LateContext<'_, '_>, expr: &Expr) -> Finiteness {
- match expr.node {
- ExprKind::MethodCall(ref method, _, ref args) => {
- for &(name, len) in COMPLETING_METHODS.iter() {
- if method.ident.name == name && args.len() == len {
+/// the paths of types that are known to be infinitely allocating
+const INFINITE_COLLECTORS: [&[&str]; 8] = [
+ &paths::BINARY_HEAP,
+ &paths::BTREEMAP,
+ &paths::BTREESET,
+ &paths::HASHMAP,
+ &paths::HASHSET,
+ &paths::LINKED_LIST,
+ &paths::VEC,
+ &paths::VEC_DEQUE,
+];
+
+fn complete_infinite_iter(cx: &LateContext<'_>, expr: &Expr<'_>) -> Finiteness {
+ match expr.kind {
+ ExprKind::MethodCall(ref method, _, ref args, _) => {
+ for &(name, len) in &COMPLETING_METHODS {
+ if method.ident.name.as_str() == name && args.len() == len {
return is_infinite(cx, &args[0]);
}
}
- for &(name, len) in POSSIBLY_COMPLETING_METHODS.iter() {
- if method.ident.name == name && args.len() == len {
+ for &(name, len) in &POSSIBLY_COMPLETING_METHODS {
+ if method.ident.name.as_str() == name && args.len() == len {
return MaybeInfinite.and(is_infinite(cx, &args[0]));
}
}
- if method.ident.name == "last" && args.len() == 1 {
- let not_double_ended = get_trait_def_id(cx, &paths::DOUBLE_ENDED_ITERATOR)
- .map_or(false, |id| !implements_trait(cx, cx.tables.expr_ty(&args[0]), id, &[]));
+ if method.ident.name == sym!(last) && args.len() == 1 {
+ let not_double_ended = get_trait_def_id(cx, &paths::DOUBLE_ENDED_ITERATOR).map_or(false, |id| {
+ !implements_trait(cx, cx.typeck_results().expr_ty(&args[0]), id, &[])
+ });
if not_double_ended {
return is_infinite(cx, &args[0]);
}
+ } else if method.ident.name == sym!(collect) {
+ let ty = cx.typeck_results().expr_ty(expr);
+ if INFINITE_COLLECTORS.iter().any(|path| match_type(cx, ty, path)) {
+ return is_infinite(cx, &args[0]);
+ }
}
},
ExprKind::Binary(op, ref l, ref r) => {
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