rust/clippy_lints/src/invalid_ref.rs
2019-06-21 14:17:59 +02:00

56 lines
2.0 KiB
Rust

use crate::utils::{match_def_path, paths, span_help_and_lint};
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};
declare_clippy_lint! {
/// **What it does:** Checks for creation of references to zeroed or uninitialized memory.
///
/// **Why is this bad?** Creation of null references is undefined behavior.
///
/// **Known problems:** None.
///
/// **Example:**
/// ```no_run
/// let bad_ref: &usize = unsafe { std::mem::zeroed() };
/// ```
pub INVALID_REF,
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";
declare_lint_pass!(InvalidRef => [INVALID_REF]);
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for InvalidRef {
fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr) {
if_chain! {
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) = cx.tables.qpath_res(qpath, path.hir_id).opt_def_id();
then {
let msg = if match_def_path(cx, def_id, &paths::MEM_ZEROED) |
match_def_path(cx, def_id, &paths::INIT)
{
ZERO_REF_SUMMARY
} else if match_def_path(cx, def_id, &paths::MEM_UNINIT) |
match_def_path(cx, def_id, &paths::UNINIT)
{
UNINIT_REF_SUMMARY
} else {
return;
};
span_help_and_lint(cx, INVALID_REF, expr.span, msg, HELP);
}
}
}
}