rust-clippy/clippy_lints/src/invalid_utf8_in_unchecked.rs

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2022-07-03 02:24:26 +00:00
use clippy_utils::diagnostics::span_lint;
use clippy_utils::{match_function_call, paths};
use rustc_ast::{BorrowKind, LitKind};
use rustc_hir::{Expr, ExprKind};
use rustc_lint::{LateContext, LateLintPass};
use rustc_session::{declare_lint_pass, declare_tool_lint};
use rustc_span::source_map::Spanned;
use rustc_span::Span;
declare_clippy_lint! {
/// ### What it does
/// Checks for `std::str::from_utf8_unchecked` with an invalid UTF-8 literal
///
/// ### Why is this bad?
/// Creating such a `str` would result in undefined behavior
///
/// ### Example
/// ```rust
/// # #[allow(unused)]
/// unsafe {
/// std::str::from_utf8_unchecked(b"cl\x82ippy");
/// }
/// ```
#[clippy::version = "1.64.0"]
pub INVALID_UTF8_IN_UNCHECKED,
correctness,
"using a non UTF-8 literal in `std::std::from_utf8_unchecked`"
}
declare_lint_pass!(InvalidUtf8InUnchecked => [INVALID_UTF8_IN_UNCHECKED]);
impl<'tcx> LateLintPass<'tcx> for InvalidUtf8InUnchecked {
fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) {
if let Some([arg]) = match_function_call(cx, expr, &paths::STR_FROM_UTF8_UNCHECKED) {
match &arg.kind {
ExprKind::Lit(Spanned { node: lit, .. }) => {
if let LitKind::ByteStr(bytes) = &lit
&& std::str::from_utf8(bytes).is_err()
{
lint(cx, expr.span);
}
},
ExprKind::AddrOf(BorrowKind::Ref, _, Expr { kind: ExprKind::Array(args), .. }) => {
let elements = args.iter().map(|e|{
match &e.kind {
ExprKind::Lit(Spanned { node: lit, .. }) => match lit {
LitKind::Byte(b) => Some(*b),
#[allow(clippy::cast_possible_truncation)]
LitKind::Int(b, _) => Some(*b as u8),
_ => None
}
_ => None
}
}).collect::<Option<Vec<_>>>();
if let Some(elements) = elements
&& std::str::from_utf8(&elements).is_err()
{
lint(cx, expr.span);
}
}
_ => {}
}
}
}
}
fn lint(cx: &LateContext<'_>, span: Span) {
span_lint(
cx,
INVALID_UTF8_IN_UNCHECKED,
span,
"non UTF-8 literal in `std::str::from_utf8_unchecked`",
);
}