rust-clippy/clippy_lints/src/invalid_ref.rs

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// 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.
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use crate::rustc::hir::*;
use crate::rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
use crate::rustc::ty;
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use crate::rustc::{declare_tool_lint, lint_array};
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use crate::utils::{match_def_path, opt_def_id, paths, span_help_and_lint};
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use if_chain::if_chain;
/// **What it does:** Checks for creation of references to zeroed or uninitialized memory.
///
/// **Why is this bad?** Creation of null references is undefined behavior.
///
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/// **Known problems:** None.
///
/// **Example:**
/// ```rust
/// let bad_ref: &usize = std::mem::zeroed();
/// ```
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declare_clippy_lint! {
pub INVALID_REF,
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correctness,
"creation of invalid reference"
}
const ZERO_REF_SUMMARY: &str = "reference to zeroed memory";
const UNINIT_REF_SUMMARY: &str = "reference to uninitialized memory";
const HELP: &str = "Creation of a null reference is undefined behavior; \
see https://doc.rust-lang.org/reference/behavior-considered-undefined.html";
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pub struct InvalidRef;
impl LintPass for InvalidRef {
fn get_lints(&self) -> LintArray {
lint_array!(INVALID_REF)
}
}
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for InvalidRef {
fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr) {
if_chain! {
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if let ExprKind::Call(ref path, ref args) = expr.node;
if let ExprKind::Path(ref qpath) = path.node;
if args.len() == 0;
if let ty::Ref(..) = cx.tables.expr_ty(expr).sty;
if let Some(def_id) = opt_def_id(cx.tables.qpath_def(qpath, path.hir_id));
then {
let msg = if match_def_path(cx.tcx, def_id, &paths::MEM_ZEROED) |
match_def_path(cx.tcx, def_id, &paths::INIT)
{
ZERO_REF_SUMMARY
} else if match_def_path(cx.tcx, def_id, &paths::MEM_UNINIT) |
match_def_path(cx.tcx, def_id, &paths::UNINIT)
{
UNINIT_REF_SUMMARY
} else {
return;
};
span_help_and_lint(cx, INVALID_REF, expr.span, msg, HELP);
}
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}
return;
}
}