136 lines
4.1 KiB
Rust
136 lines
4.1 KiB
Rust
use rustc::lint::*;
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use rustc::hir::*;
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use syntax::ast::{LitKind, NodeId};
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use syntax::codemap::Span;
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use unicode_normalization::UnicodeNormalization;
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use utils::{snippet, span_help_and_lint, is_allowed};
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/// **What it does:** Checks for the Unicode zero-width space in the code.
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///
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/// **Why is this bad?** Having an invisible character in the code makes for all
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/// sorts of April fools, but otherwise is very much frowned upon.
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///
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/// **Known problems:** None.
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///
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/// **Example:** You don't see it, but there may be a zero-width space
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/// somewhere in this text.
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declare_lint! {
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pub ZERO_WIDTH_SPACE,
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Deny,
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"using a zero-width space in a string literal, which is confusing"
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}
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/// **What it does:** Checks for non-ASCII characters in string literals.
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///
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/// **Why is this bad?** Yeah, we know, the 90's called and wanted their charset
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/// back. Even so, there still are editors and other programs out there that
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/// don't work well with Unicode. So if the code is meant to be used
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/// internationally, on multiple operating systems, or has other portability
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/// requirements, activating this lint could be useful.
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///
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/// **Known problems:** None.
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///
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/// **Example:**
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/// ```rust
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/// let x = "Hä?"
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/// ```
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declare_lint! {
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pub NON_ASCII_LITERAL,
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Allow,
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"using any literal non-ASCII chars in a string literal instead of \
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using the `\\u` escape"
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}
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/// **What it does:** Checks for string literals that contain Unicode in a form
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/// that is not equal to its
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/// [NFC-recomposition](http://www.unicode.org/reports/tr15/#Norm_Forms).
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///
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/// **Why is this bad?** If such a string is compared to another, the results
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/// may be surprising.
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///
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/// **Known problems** None.
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///
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/// **Example:** You may not see it, but “à” and “à” aren't the same string. The
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/// former when escaped is actually `"a\u{300}"` while the latter is `"\u{e0}"`.
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declare_lint! {
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pub UNICODE_NOT_NFC,
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Allow,
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"using a unicode literal not in NFC normal form (see \
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[unicode tr15](http://www.unicode.org/reports/tr15/) for further information)"
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}
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#[derive(Copy, Clone)]
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pub struct Unicode;
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impl LintPass for Unicode {
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fn get_lints(&self) -> LintArray {
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lint_array!(ZERO_WIDTH_SPACE, NON_ASCII_LITERAL, UNICODE_NOT_NFC)
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}
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}
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impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Unicode {
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fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr) {
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if let ExprLit(ref lit) = expr.node {
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if let LitKind::Str(_, _) = lit.node {
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check_str(cx, lit.span, expr.id)
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}
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}
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}
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}
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fn escape<T: Iterator<Item = char>>(s: T) -> String {
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let mut result = String::new();
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for c in s {
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if c as u32 > 0x7F {
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for d in c.escape_unicode() {
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result.push(d)
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}
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} else {
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result.push(c);
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}
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}
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result
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}
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fn check_str(cx: &LateContext, span: Span, id: NodeId) {
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let string = snippet(cx, span, "");
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if string.contains('\u{200B}') {
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span_help_and_lint(
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cx,
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ZERO_WIDTH_SPACE,
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span,
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"zero-width space detected",
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&format!(
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"Consider replacing the string with:\n\"{}\"",
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string.replace("\u{200B}", "\\u{200B}")
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),
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);
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}
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if string.chars().any(|c| c as u32 > 0x7F) {
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span_help_and_lint(
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cx,
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NON_ASCII_LITERAL,
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span,
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"literal non-ASCII character detected",
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&format!(
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"Consider replacing the string with:\n\"{}\"",
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if is_allowed(cx, UNICODE_NOT_NFC, id) {
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escape(string.chars())
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} else {
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escape(string.nfc())
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}
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),
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);
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}
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if is_allowed(cx, NON_ASCII_LITERAL, id) && string.chars().zip(string.nfc()).any(|(a, b)| a != b) {
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span_help_and_lint(
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cx,
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UNICODE_NOT_NFC,
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span,
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"non-nfc unicode sequence detected",
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&format!("Consider replacing the string with:\n\"{}\"", string.nfc().collect::<String>()),
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);
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}
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}
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