diff options
Diffstat (limited to 'compiler/rustc_lint/src/invalid_from_utf8.rs')
-rw-r--r-- | compiler/rustc_lint/src/invalid_from_utf8.rs | 118 |
1 files changed, 118 insertions, 0 deletions
diff --git a/compiler/rustc_lint/src/invalid_from_utf8.rs b/compiler/rustc_lint/src/invalid_from_utf8.rs new file mode 100644 index 000000000..3291286ad --- /dev/null +++ b/compiler/rustc_lint/src/invalid_from_utf8.rs @@ -0,0 +1,118 @@ +use std::str::Utf8Error; + +use rustc_ast::{BorrowKind, LitKind}; +use rustc_hir::{Expr, ExprKind}; +use rustc_span::source_map::Spanned; +use rustc_span::sym; + +use crate::lints::InvalidFromUtf8Diag; +use crate::{LateContext, LateLintPass, LintContext}; + +declare_lint! { + /// The `invalid_from_utf8_unchecked` lint checks for calls to + /// `std::str::from_utf8_unchecked` and `std::str::from_utf8_unchecked_mut` + /// with an invalid UTF-8 literal. + /// + /// ### Example + /// + /// ```rust,compile_fail + /// # #[allow(unused)] + /// unsafe { + /// std::str::from_utf8_unchecked(b"Ru\x82st"); + /// } + /// ``` + /// + /// {{produces}} + /// + /// ### Explanation + /// + /// Creating such a `str` would result in undefined behavior as per documentation + /// for `std::str::from_utf8_unchecked` and `std::str::from_utf8_unchecked_mut`. + pub INVALID_FROM_UTF8_UNCHECKED, + Deny, + "using a non UTF-8 literal in `std::str::from_utf8_unchecked`" +} + +declare_lint! { + /// The `invalid_from_utf8` lint checks for calls to + /// `std::str::from_utf8` and `std::str::from_utf8_mut` + /// with an invalid UTF-8 literal. + /// + /// ### Example + /// + /// ```rust + /// # #[allow(unused)] + /// std::str::from_utf8(b"Ru\x82st"); + /// ``` + /// + /// {{produces}} + /// + /// ### Explanation + /// + /// Trying to create such a `str` would always return an error as per documentation + /// for `std::str::from_utf8` and `std::str::from_utf8_mut`. + pub INVALID_FROM_UTF8, + Warn, + "using a non UTF-8 literal in `std::str::from_utf8`" +} + +declare_lint_pass!(InvalidFromUtf8 => [INVALID_FROM_UTF8_UNCHECKED, INVALID_FROM_UTF8]); + +impl<'tcx> LateLintPass<'tcx> for InvalidFromUtf8 { + fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) { + if let ExprKind::Call(path, [arg]) = expr.kind + && let ExprKind::Path(ref qpath) = path.kind + && let Some(def_id) = cx.qpath_res(qpath, path.hir_id).opt_def_id() + && let Some(diag_item) = cx.tcx.get_diagnostic_name(def_id) + && [sym::str_from_utf8, sym::str_from_utf8_mut, + sym::str_from_utf8_unchecked, sym::str_from_utf8_unchecked_mut].contains(&diag_item) + { + let lint = |utf8_error: Utf8Error| { + let label = arg.span; + let method = diag_item.as_str().strip_prefix("str_").unwrap(); + let method = format!("std::str::{method}"); + let valid_up_to = utf8_error.valid_up_to(); + let is_unchecked_variant = diag_item.as_str().contains("unchecked"); + + cx.emit_spanned_lint( + if is_unchecked_variant { INVALID_FROM_UTF8_UNCHECKED } else { INVALID_FROM_UTF8 }, + expr.span, + if is_unchecked_variant { + InvalidFromUtf8Diag::Unchecked { method, valid_up_to, label } + } else { + InvalidFromUtf8Diag::Checked { method, valid_up_to, label } + } + ) + }; + + match &arg.kind { + ExprKind::Lit(Spanned { node: lit, .. }) => { + if let LitKind::ByteStr(bytes, _) = &lit + && let Err(utf8_error) = std::str::from_utf8(bytes) + { + lint(utf8_error); + } + }, + 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), + LitKind::Int(b, _) => Some(*b as u8), + _ => None + } + _ => None + } + }).collect::<Option<Vec<_>>>(); + + if let Some(elements) = elements + && let Err(utf8_error) = std::str::from_utf8(&elements) + { + lint(utf8_error); + } + } + _ => {} + } + } + } +} |