-use rustc::hir::*;
-use rustc::lint::*;
-use rustc::{declare_lint, lint_array};
+use crate::utils::{
+ contains_name, get_pat_name, match_type, paths, single_segment_path, snippet_with_applicability,
+ span_lint_and_sugg, walk_ptrs_ty,
+};
use if_chain::if_chain;
+use rustc::hir::*;
+use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
use rustc::ty;
+use rustc::{declare_lint_pass, declare_tool_lint};
+use rustc_errors::Applicability;
use syntax::ast::{Name, UintTy};
-use crate::utils::{contains_name, get_pat_name, match_type, paths, single_segment_path, snippet, span_lint_and_sugg,
- walk_ptrs_ty};
-/// **What it does:** Checks for naive byte counts
-///
-/// **Why is this bad?** The [`bytecount`](https://crates.io/crates/bytecount)
-/// crate has methods to count your bytes faster, especially for large slices.
-///
-/// **Known problems:** If you have predominantly small slices, the
-/// `bytecount::count(..)` method may actually be slower. However, if you can
-/// ensure that less than 2³²-1 matches arise, the `naive_count_32(..)` can be
-/// faster in those cases.
-///
-/// **Example:**
-///
-/// ```rust
-/// &my_data.filter(|&x| x == 0u8).count() // use bytecount::count instead
-/// ```
declare_clippy_lint! {
+ /// **What it does:** Checks for naive byte counts
+ ///
+ /// **Why is this bad?** The [`bytecount`](https://crates.io/crates/bytecount)
+ /// crate has methods to count your bytes faster, especially for large slices.
+ ///
+ /// **Known problems:** If you have predominantly small slices, the
+ /// `bytecount::count(..)` method may actually be slower. However, if you can
+ /// ensure that less than 2³²-1 matches arise, the `naive_count_32(..)` can be
+ /// faster in those cases.
+ ///
+ /// **Example:**
+ ///
+ /// ```rust
+ /// # let vec = vec![1_u8];
+ /// &vec.iter().filter(|x| **x == 0u8).count(); // use bytecount::count instead
+ /// ```
pub NAIVE_BYTECOUNT,
perf,
"use of naive `<slice>.filter(|&x| x == y).count()` to count byte values"
}
-#[derive(Copy, Clone)]
-pub struct ByteCount;
-
-impl LintPass for ByteCount {
- fn get_lints(&self) -> LintArray {
- lint_array!(NAIVE_BYTECOUNT)
- }
-}
+declare_lint_pass!(ByteCount => [NAIVE_BYTECOUNT]);
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for ByteCount {
fn check_expr(&mut self, cx: &LateContext<'_, '_>, expr: &Expr) {
if_chain! {
if let ExprKind::MethodCall(ref count, _, ref count_args) = expr.node;
- if count.ident.name == "count";
+ if count.ident.name == sym!(count);
if count_args.len() == 1;
if let ExprKind::MethodCall(ref filter, _, ref filter_args) = count_args[0].node;
- if filter.ident.name == "filter";
+ if filter.ident.name == sym!(filter);
if filter_args.len() == 2;
if let ExprKind::Closure(_, _, body_id, _, _) = filter_args[1].node;
then {
- let body = cx.tcx.hir.body(body_id);
+ let body = cx.tcx.hir().body(body_id);
if_chain! {
- if body.arguments.len() == 1;
- if let Some(argname) = get_pat_name(&body.arguments[0].pat);
+ if body.params.len() == 1;
+ if let Some(argname) = get_pat_name(&body.params[0].pat);
if let ExprKind::Binary(ref op, ref l, ref r) = body.value.node;
if op.node == BinOpKind::Eq;
if match_type(cx,
_ => { return; }
}
};
- if ty::TyUint(UintTy::U8) != walk_ptrs_ty(cx.tables.expr_ty(needle)).sty {
+ if ty::Uint(UintTy::U8) != walk_ptrs_ty(cx.tables.expr_ty(needle)).sty {
return;
}
let haystack = if let ExprKind::MethodCall(ref path, _, ref args) =
filter_args[0].node {
let p = path.ident.name;
- if (p == "iter" || p == "iter_mut") && args.len() == 1 {
+ if (p == sym!(iter) || p == sym!(iter_mut)) && args.len() == 1 {
&args[0]
} else {
&filter_args[0]
} else {
&filter_args[0]
};
- span_lint_and_sugg(cx,
- NAIVE_BYTECOUNT,
- expr.span,
- "You appear to be counting bytes the naive way",
- "Consider using the bytecount crate",
- format!("bytecount::count({}, {})",
- snippet(cx, haystack.span, ".."),
- snippet(cx, needle.span, "..")));
+ let mut applicability = Applicability::MaybeIncorrect;
+ span_lint_and_sugg(
+ cx,
+ NAIVE_BYTECOUNT,
+ expr.span,
+ "You appear to be counting bytes the naive way",
+ "Consider using the bytecount crate",
+ format!("bytecount::count({}, {})",
+ snippet_with_applicability(cx, haystack.span, "..", &mut applicability),
+ snippet_with_applicability(cx, needle.span, "..", &mut applicability)),
+ applicability,
+ );
}
};
}
fn get_path_name(expr: &Expr) -> Option<Name> {
match expr.node {
ExprKind::Box(ref e) | ExprKind::AddrOf(_, ref e) | ExprKind::Unary(UnOp::UnDeref, ref e) => get_path_name(e),
- ExprKind::Block(ref b, _) => if b.stmts.is_empty() {
- b.expr.as_ref().and_then(|p| get_path_name(p))
- } else {
- None
+ ExprKind::Block(ref b, _) => {
+ if b.stmts.is_empty() {
+ b.expr.as_ref().and_then(|p| get_path_name(p))
+ } else {
+ None
+ }
},
ExprKind::Path(ref qpath) => single_segment_path(qpath).map(|ps| ps.ident.name),
_ => None,
projects / rust.git / blobdiff