-// 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::consts::{constant, Constant};
-use crate::rustc::hir::*;
-use crate::rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
-use crate::rustc::{declare_tool_lint, lint_array};
-use crate::rustc_errors::Applicability;
-use crate::syntax::ast::LitKind;
-use crate::syntax::source_map::Span;
use crate::utils::sugg::Sugg;
use crate::utils::{span_lint, span_lint_and_then};
use if_chain::if_chain;
+use rustc::hir::*;
+use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
+use rustc::{declare_tool_lint, lint_array};
+use rustc_errors::Applicability;
+use syntax::ast::LitKind;
+use syntax::source_map::Span;
-/// **What it does:** Checks for incompatible bit masks in comparisons.
-///
-/// The formula for detecting if an expression of the type `_ <bit_op> m
-/// <cmp_op> c` (where `<bit_op>` is one of {`&`, `|`} and `<cmp_op>` is one of
-/// {`!=`, `>=`, `>`, `!=`, `>=`, `>`}) can be determined from the following
-/// table:
-///
-/// |Comparison |Bit Op|Example |is always|Formula |
-/// |------------|------|------------|---------|----------------------|
-/// |`==` or `!=`| `&` |`x & 2 == 3`|`false` |`c & m != c` |
-/// |`<` or `>=`| `&` |`x & 2 < 3` |`true` |`m < c` |
-/// |`>` or `<=`| `&` |`x & 1 > 1` |`false` |`m <= c` |
-/// |`==` or `!=`| `|` |`x | 1 == 0`|`false` |`c | m != c` |
-/// |`<` or `>=`| `|` |`x | 1 < 1` |`false` |`m >= c` |
-/// |`<=` or `>` | `|` |`x | 1 > 0` |`true` |`m > c` |
-///
-/// **Why is this bad?** If the bits that the comparison cares about are always
-/// set to zero or one by the bit mask, the comparison is constant `true` or
-/// `false` (depending on mask, compared value, and operators).
-///
-/// So the code is actively misleading, and the only reason someone would write
-/// this intentionally is to win an underhanded Rust contest or create a
-/// test-case for this lint.
-///
-/// **Known problems:** None.
-///
-/// **Example:**
-/// ```rust
-/// if (x & 1 == 2) { … }
-/// ```
declare_clippy_lint! {
+ /// **What it does:** Checks for incompatible bit masks in comparisons.
+ ///
+ /// The formula for detecting if an expression of the type `_ <bit_op> m
+ /// <cmp_op> c` (where `<bit_op>` is one of {`&`, `|`} and `<cmp_op>` is one of
+ /// {`!=`, `>=`, `>`, `!=`, `>=`, `>`}) can be determined from the following
+ /// table:
+ ///
+ /// |Comparison |Bit Op|Example |is always|Formula |
+ /// |------------|------|------------|---------|----------------------|
+ /// |`==` or `!=`| `&` |`x & 2 == 3`|`false` |`c & m != c` |
+ /// |`<` or `>=`| `&` |`x & 2 < 3` |`true` |`m < c` |
+ /// |`>` or `<=`| `&` |`x & 1 > 1` |`false` |`m <= c` |
+ /// |`==` or `!=`| `|` |`x | 1 == 0`|`false` |`c | m != c` |
+ /// |`<` or `>=`| `|` |`x | 1 < 1` |`false` |`m >= c` |
+ /// |`<=` or `>` | `|` |`x | 1 > 0` |`true` |`m > c` |
+ ///
+ /// **Why is this bad?** If the bits that the comparison cares about are always
+ /// set to zero or one by the bit mask, the comparison is constant `true` or
+ /// `false` (depending on mask, compared value, and operators).
+ ///
+ /// So the code is actively misleading, and the only reason someone would write
+ /// this intentionally is to win an underhanded Rust contest or create a
+ /// test-case for this lint.
+ ///
+ /// **Known problems:** None.
+ ///
+ /// **Example:**
+ /// ```rust
+ /// # let x = 1;
+ /// if (x & 1 == 2) { }
+ /// ```
pub BAD_BIT_MASK,
correctness,
"expressions of the form `_ & mask == select` that will only ever return `true` or `false`"
}
-/// **What it does:** Checks for bit masks in comparisons which can be removed
-/// without changing the outcome. The basic structure can be seen in the
-/// following table:
-///
-/// |Comparison| Bit Op |Example |equals |
-/// |----------|---------|-----------|-------|
-/// |`>` / `<=`|`|` / `^`|`x | 2 > 3`|`x > 3`|
-/// |`<` / `>=`|`|` / `^`|`x ^ 1 < 4`|`x < 4`|
-///
-/// **Why is this bad?** Not equally evil as [`bad_bit_mask`](#bad_bit_mask),
-/// but still a bit misleading, because the bit mask is ineffective.
-///
-/// **Known problems:** False negatives: This lint will only match instances
-/// where we have figured out the math (which is for a power-of-two compared
-/// value). This means things like `x | 1 >= 7` (which would be better written
-/// as `x >= 6`) will not be reported (but bit masks like this are fairly
-/// uncommon).
-///
-/// **Example:**
-/// ```rust
-/// if (x | 1 > 3) { … }
-/// ```
declare_clippy_lint! {
+ /// **What it does:** Checks for bit masks in comparisons which can be removed
+ /// without changing the outcome. The basic structure can be seen in the
+ /// following table:
+ ///
+ /// |Comparison| Bit Op |Example |equals |
+ /// |----------|---------|-----------|-------|
+ /// |`>` / `<=`|`|` / `^`|`x | 2 > 3`|`x > 3`|
+ /// |`<` / `>=`|`|` / `^`|`x ^ 1 < 4`|`x < 4`|
+ ///
+ /// **Why is this bad?** Not equally evil as [`bad_bit_mask`](#bad_bit_mask),
+ /// but still a bit misleading, because the bit mask is ineffective.
+ ///
+ /// **Known problems:** False negatives: This lint will only match instances
+ /// where we have figured out the math (which is for a power-of-two compared
+ /// value). This means things like `x | 1 >= 7` (which would be better written
+ /// as `x >= 6`) will not be reported (but bit masks like this are fairly
+ /// uncommon).
+ ///
+ /// **Example:**
+ /// ```rust
+ /// # let x = 1;
+ /// if (x | 1 > 3) { }
+ /// ```
pub INEFFECTIVE_BIT_MASK,
correctness,
- "expressions where a bit mask will be rendered useless by a comparison, e.g. `(x | 1) > 2`"
+ "expressions where a bit mask will be rendered useless by a comparison, e.g., `(x | 1) > 2`"
}
-/// **What it does:** Checks for bit masks that can be replaced by a call
-/// to `trailing_zeros`
-///
-/// **Why is this bad?** `x.trailing_zeros() > 4` is much clearer than `x & 15
-/// == 0`
-///
-/// **Known problems:** llvm generates better code for `x & 15 == 0` on x86
-///
-/// **Example:**
-/// ```rust
-/// x & 0x1111 == 0
-/// ```
declare_clippy_lint! {
+ /// **What it does:** Checks for bit masks that can be replaced by a call
+ /// to `trailing_zeros`
+ ///
+ /// **Why is this bad?** `x.trailing_zeros() > 4` is much clearer than `x & 15
+ /// == 0`
+ ///
+ /// **Known problems:** llvm generates better code for `x & 15 == 0` on x86
+ ///
+ /// **Example:**
+ /// ```rust
+ /// # let x = 1;
+ /// if x & 0x1111 == 0 { }
+ /// ```
pub VERBOSE_BIT_MASK,
style,
"expressions where a bit mask is less readable than the corresponding method call"
fn get_lints(&self) -> LintArray {
lint_array!(BAD_BIT_MASK, INEFFECTIVE_BIT_MASK, VERBOSE_BIT_MASK)
}
+ fn name(&self) -> &'static str {
+ "BitMask"
+ }
}
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for BitMask {
fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, e: &'tcx Expr) {
- if let ExprKind::Binary(ref cmp, ref left, ref right) = e.node {
+ if let ExprKind::Binary(cmp, left, right) = &e.node {
if cmp.node.is_comparison() {
if let Some(cmp_opt) = fetch_int_literal(cx, right) {
check_compare(cx, left, cmp.node, cmp_opt, e.span)
}
}
if_chain! {
- if let ExprKind::Binary(ref op, ref left, ref right) = e.node;
+ if let ExprKind::Binary(op, left, right) = &e.node;
if BinOpKind::Eq == op.node;
- if let ExprKind::Binary(ref op1, ref left1, ref right1) = left.node;
+ if let ExprKind::Binary(op1, left1, right1) = &left.node;
if BinOpKind::BitAnd == op1.node;
- if let ExprKind::Lit(ref lit) = right1.node;
+ if let ExprKind::Lit(lit) = &right1.node;
if let LitKind::Int(n, _) = lit.node;
- if let ExprKind::Lit(ref lit1) = right.node;
+ if let ExprKind::Lit(lit1) = &right.node;
if let LitKind::Int(0, _) = lit1.node;
if n.leading_zeros() == n.count_zeros();
if n > u128::from(self.verbose_bit_mask_threshold);
"bit mask could be simplified with a call to `trailing_zeros`",
|db| {
let sugg = Sugg::hir(cx, left1, "...").maybe_par();
- db.span_suggestion_with_applicability(
+ db.span_suggestion(
e.span,
"try",
format!("{}.trailing_zeros() >= {}", sugg, n.count_ones()),
}
fn check_compare(cx: &LateContext<'_, '_>, bit_op: &Expr, cmp_op: BinOpKind, cmp_value: u128, span: Span) {
- if let ExprKind::Binary(ref op, ref left, ref right) = bit_op.node {
+ if let ExprKind::Binary(op, left, right) = &bit_op.node {
if op.node != BinOpKind::BitAnd && op.node != BinOpKind::BitOr {
return;
}
}
}
+#[allow(clippy::too_many_lines)]
fn check_bit_mask(
cx: &LateContext<'_, '_>,
bit_op: BinOpKind,
projects / rust.git / blobdiff