//!
//! This lint is **warn** by default
-use crate::utils::{in_macro, snippet, span_lint_and_then};
+use crate::utils::{snippet_with_applicability, span_lint_and_then};
use if_chain::if_chain;
-use rustc::hir::{BindingAnnotation, MutImmutable, Pat, PatKind};
+use rustc::declare_lint_pass;
+use rustc::hir::{BindingAnnotation, Mutability, Node, Pat, PatKind};
use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
-use rustc::{declare_lint_pass, declare_tool_lint};
use rustc_errors::Applicability;
+use rustc_session::declare_tool_lint;
declare_clippy_lint! {
/// **What it does:** Checks for useless borrowed references.
///
/// **Known problems:** It seems that the `&ref` pattern is sometimes useful.
/// For instance in the following snippet:
- /// ```rust
+ /// ```rust,ignore
/// enum Animal {
/// Cat(u64),
/// Dog(u64),
///
/// fn foo(a: &Animal, b: &Animal) {
/// match (a, b) {
- /// (&Animal::Cat(v), k) | (k, &Animal::Cat(v)) => (), // lifetime
- /// mismatch error
+ /// (&Animal::Cat(v), k) | (k, &Animal::Cat(v)) => (), // lifetime mismatch error
/// (&Animal::Dog(ref c), &Animal::Dog(_)) => ()
/// }
/// }
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for NeedlessBorrowedRef {
fn check_pat(&mut self, cx: &LateContext<'a, 'tcx>, pat: &'tcx Pat) {
- if in_macro(pat.span) {
+ if pat.span.from_expansion() {
// OK, simple enough, lints doesn't check in macro.
return;
}
if_chain! {
// Only lint immutable refs, because `&mut ref T` may be useful.
- if let PatKind::Ref(ref sub_pat, MutImmutable) = pat.node;
+ if let PatKind::Ref(ref sub_pat, Mutability::Immutable) = pat.kind;
// Check sub_pat got a `ref` keyword (excluding `ref mut`).
- if let PatKind::Binding(BindingAnnotation::Ref, .., spanned_name, _) = sub_pat.node;
+ if let PatKind::Binding(BindingAnnotation::Ref, .., spanned_name, _) = sub_pat.kind;
+ let parent_id = cx.tcx.hir().get_parent_node(pat.hir_id);
+ if let Some(parent_node) = cx.tcx.hir().find(parent_id);
then {
+ // do not recurse within patterns, as they may have other references
+ // XXXManishearth we can relax this constraint if we only check patterns
+ // with a single ref pattern inside them
+ if let Node::Pat(_) = parent_node {
+ return;
+ }
+ let mut applicability = Applicability::MachineApplicable;
span_lint_and_then(cx, NEEDLESS_BORROWED_REFERENCE, pat.span,
"this pattern takes a reference on something that is being de-referenced",
|db| {
- let hint = snippet(cx, spanned_name.span, "..").into_owned();
+ let hint = snippet_with_applicability(cx, spanned_name.span, "..", &mut applicability).into_owned();
db.span_suggestion(
pat.span,
"try removing the `&ref` part and just keep",
hint,
- Applicability::MachineApplicable, // snippet
+ applicability,
);
});
}