-use crate::utils::{in_macro, snippet_with_applicability, span_lint_and_sugg};
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::source::{snippet_opt, snippet_with_applicability};
use if_chain::if_chain;
-use rustc_ast::ast::{Expr, ExprKind, UnOp};
+use rustc_ast::ast::{Expr, ExprKind, Mutability, UnOp};
use rustc_errors::Applicability;
use rustc_lint::{EarlyContext, EarlyLintPass};
use rustc_session::{declare_lint_pass, declare_tool_lint};
+use rustc_span::BytePos;
declare_clippy_lint! {
- /// **What it does:** Checks for usage of `*&` and `*&mut` in expressions.
+ /// ### What it does
+ /// Checks for usage of `*&` and `*&mut` in expressions.
///
- /// **Why is this bad?** Immediately dereferencing a reference is no-op and
+ /// ### Why is this bad?
+ /// Immediately dereferencing a reference is no-op and
/// makes the code less clear.
///
- /// **Known problems:** Multiple dereference/addrof pairs are not handled so
+ /// ### Known problems
+ /// Multiple dereference/addrof pairs are not handled so
/// the suggested fix for `x = **&&y` is `x = *&y`, which is still incorrect.
///
- /// **Example:**
+ /// ### Example
/// ```rust,ignore
/// let a = f(*&mut b);
/// let c = *&d;
/// ```
+ ///
+ /// Use instead:
+ /// ```rust,ignore
+ /// let a = f(b);
+ /// let c = d;
+ /// ```
+ #[clippy::version = "pre 1.29.0"]
pub DEREF_ADDROF,
complexity,
"use of `*&` or `*&mut` in an expression"
fn check_expr(&mut self, cx: &EarlyContext<'_>, e: &Expr) {
if_chain! {
if let ExprKind::Unary(UnOp::Deref, ref deref_target) = e.kind;
- if let ExprKind::AddrOf(_, _, ref addrof_target) = without_parens(deref_target).kind;
- if !in_macro(addrof_target.span);
+ if let ExprKind::AddrOf(_, ref mutability, ref addrof_target) = without_parens(deref_target).kind;
+ if deref_target.span.ctxt() == e.span.ctxt();
+ if !addrof_target.span.from_expansion();
then {
let mut applicability = Applicability::MachineApplicable;
- span_lint_and_sugg(
- cx,
- DEREF_ADDROF,
- e.span,
- "immediately dereferencing a reference",
- "try this",
- format!("{}", snippet_with_applicability(cx, addrof_target.span, "_", &mut applicability)),
- applicability,
- );
- }
- }
- }
-}
-
-declare_clippy_lint! {
- /// **What it does:** Checks for references in expressions that use
- /// auto dereference.
- ///
- /// **Why is this bad?** The reference is a no-op and is automatically
- /// dereferenced by the compiler and makes the code less clear.
- ///
- /// **Example:**
- /// ```rust
- /// struct Point(u32, u32);
- /// let point = Point(30, 20);
- /// let x = (&point).0;
- /// ```
- pub REF_IN_DEREF,
- complexity,
- "Use of reference in auto dereference expression."
-}
+ let sugg = if e.span.from_expansion() {
+ if let Some(macro_source) = snippet_opt(cx, e.span) {
+ // Remove leading whitespace from the given span
+ // e.g: ` $visitor` turns into `$visitor`
+ let trim_leading_whitespaces = |span| {
+ snippet_opt(cx, span).and_then(|snip| {
+ #[expect(clippy::cast_possible_truncation)]
+ snip.find(|c: char| !c.is_whitespace()).map(|pos| {
+ span.lo() + BytePos(pos as u32)
+ })
+ }).map_or(span, |start_no_whitespace| e.span.with_lo(start_no_whitespace))
+ };
-declare_lint_pass!(RefInDeref => [REF_IN_DEREF]);
+ let mut generate_snippet = |pattern: &str| {
+ #[expect(clippy::cast_possible_truncation)]
+ macro_source.rfind(pattern).map(|pattern_pos| {
+ let rpos = pattern_pos + pattern.len();
+ let span_after_ref = e.span.with_lo(BytePos(e.span.lo().0 + rpos as u32));
+ let span = trim_leading_whitespaces(span_after_ref);
+ snippet_with_applicability(cx, span, "_", &mut applicability)
+ })
+ };
-impl EarlyLintPass for RefInDeref {
- fn check_expr(&mut self, cx: &EarlyContext<'_>, e: &Expr) {
- if_chain! {
- if let ExprKind::Field(ref object, _) = e.kind;
- if let ExprKind::Paren(ref parened) = object.kind;
- if let ExprKind::AddrOf(_, _, ref inner) = parened.kind;
- then {
- let mut applicability = Applicability::MachineApplicable;
- span_lint_and_sugg(
- cx,
- REF_IN_DEREF,
- object.span,
- "Creating a reference that is immediately dereferenced.",
- "try this",
- snippet_with_applicability(cx, inner.span, "_", &mut applicability).to_string(),
- applicability,
- );
+ if *mutability == Mutability::Mut {
+ generate_snippet("mut")
+ } else {
+ generate_snippet("&")
+ }
+ } else {
+ Some(snippet_with_applicability(cx, e.span, "_", &mut applicability))
+ }
+ } else {
+ Some(snippet_with_applicability(cx, addrof_target.span, "_", &mut applicability))
+ };
+ if let Some(sugg) = sugg {
+ span_lint_and_sugg(
+ cx,
+ DEREF_ADDROF,
+ e.span,
+ "immediately dereferencing a reference",
+ "try this",
+ sugg.to_string(),
+ applicability,
+ );
+ }
}
}
}
projects / rust.git / blobdiff