49 lines
1.4 KiB
Rust
49 lines
1.4 KiB
Rust
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use rustc::hir::*;
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use rustc::lint::*;
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use utils::{span_lint_and_then, snippet};
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/// **What it does:** Checks for usage of `*&` and `*&mut` in expressions.
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///
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/// **Why is this bad?** Immediately dereferencing a reference is no-op and
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/// makes the code less clear.
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///
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/// **Known problems:** Multiple dereference/addrof pairs are not handled so
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/// the suggested fix for `x = **&&y` is `x = *&y`, which is still incorrect.
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///
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/// **Example:**
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/// ```rust
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/// let a = f(*&mut b);
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/// let c = *&d;
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/// ```
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declare_lint! {
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pub DEREF_ADDROF,
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Warn,
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"use of `*&` or `*&mut` in an expression"
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}
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pub struct Pass;
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impl LintPass for Pass {
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fn get_lints(&self) -> LintArray {
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lint_array!(DEREF_ADDROF)
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}
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}
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impl LateLintPass for Pass {
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fn check_expr(&mut self, cx: &LateContext, e: &Expr) {
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if let ExprUnary(UnDeref, ref deref_target) = e.node {
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if let ExprAddrOf(_, ref addrof_target) = deref_target.node {
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span_lint_and_then(
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cx,
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DEREF_ADDROF,
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e.span,
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"immediately dereferencing a reference",
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|db| {
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db.span_suggestion(e.span, "try this",
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format!("{}", snippet(cx, addrof_target.span, "_")));
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});
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}
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}
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}
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}
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