-use rustc::hir;
-use rustc::hir::intravisit;
-use rustc::lint::*;
-use rustc::ty;
-use utils::{higher, in_external_macro, span_lint};
+use clippy_utils::diagnostics::span_lint;
+use clippy_utils::higher;
+use rustc_hir as hir;
+use rustc_hir::intravisit;
+use rustc_lint::{LateContext, LateLintPass, LintContext};
+use rustc_middle::hir::map::Map;
+use rustc_middle::lint::in_external_macro;
+use rustc_middle::ty;
+use rustc_session::{declare_lint_pass, declare_tool_lint};
-/// **What it does:** Checks for instances of `mut mut` references.
-///
-/// **Why is this bad?** Multiple `mut`s don't add anything meaningful to the
-/// source. This is either a copy'n'paste error, or it shows a fundamental
-/// misunderstanding of references.
-///
-/// **Known problems:** None.
-///
-/// **Example:**
-/// ```rust
-/// let x = &mut &mut y;
-/// ```
-declare_lint! {
+declare_clippy_lint! {
+ /// ### What it does
+ /// Checks for instances of `mut mut` references.
+ ///
+ /// ### Why is this bad?
+ /// Multiple `mut`s don't add anything meaningful to the
+ /// source. This is either a copy'n'paste error, or it shows a fundamental
+ /// misunderstanding of references.
+ ///
+ /// ### Example
+ /// ```rust
+ /// # let mut y = 1;
+ /// let x = &mut &mut y;
+ /// ```
pub MUT_MUT,
- Allow,
- "usage of double-mut refs, e.g. `&mut &mut ...`"
+ pedantic,
+ "usage of double-mut refs, e.g., `&mut &mut ...`"
}
-#[derive(Copy,Clone)]
-pub struct MutMut;
+declare_lint_pass!(MutMut => [MUT_MUT]);
-impl LintPass for MutMut {
- fn get_lints(&self) -> LintArray {
- lint_array!(MUT_MUT)
- }
-}
-
-impl<'a, 'tcx> LateLintPass<'a, 'tcx> for MutMut {
- fn check_block(&mut self, cx: &LateContext<'a, 'tcx>, block: &'tcx hir::Block) {
- intravisit::walk_block(&mut MutVisitor { cx: cx }, block);
+impl<'tcx> LateLintPass<'tcx> for MutMut {
+ fn check_block(&mut self, cx: &LateContext<'tcx>, block: &'tcx hir::Block<'_>) {
+ intravisit::walk_block(&mut MutVisitor { cx }, block);
}
- fn check_ty(&mut self, cx: &LateContext<'a, 'tcx>, ty: &'tcx hir::Ty) {
- use rustc::hir::intravisit::Visitor;
+ fn check_ty(&mut self, cx: &LateContext<'tcx>, ty: &'tcx hir::Ty<'_>) {
+ use rustc_hir::intravisit::Visitor;
- MutVisitor { cx: cx }.visit_ty(ty);
+ MutVisitor { cx }.visit_ty(ty);
}
}
-pub struct MutVisitor<'a, 'tcx: 'a> {
- cx: &'a LateContext<'a, 'tcx>,
+pub struct MutVisitor<'a, 'tcx> {
+ cx: &'a LateContext<'tcx>,
}
impl<'a, 'tcx> intravisit::Visitor<'tcx> for MutVisitor<'a, 'tcx> {
- fn visit_expr(&mut self, expr: &'tcx hir::Expr) {
- if in_external_macro(self.cx, expr.span) {
+ type Map = Map<'tcx>;
+
+ fn visit_expr(&mut self, expr: &'tcx hir::Expr<'_>) {
+ if in_external_macro(self.cx.sess(), expr.span) {
return;
}
- if let Some((_, arg, body)) = higher::for_loop(expr) {
+ if let Some(higher::ForLoop { arg, body, .. }) = higher::ForLoop::hir(expr) {
// A `for` loop lowers to:
// ```rust
// match ::std::iter::Iterator::next(&mut iter) {
// Let's ignore the generated code.
intravisit::walk_expr(self, arg);
intravisit::walk_expr(self, body);
- } else if let hir::ExprAddrOf(hir::MutMutable, ref e) = expr.node {
- if let hir::ExprAddrOf(hir::MutMutable, _) = e.node {
- span_lint(self.cx,
- MUT_MUT,
- expr.span,
- "generally you want to avoid `&mut &mut _` if possible");
- } else if let ty::TyRef(_, ty::TypeAndMut { mutbl: hir::MutMutable, .. }) = self.cx.tables.expr_ty(e).sty {
- span_lint(self.cx,
- MUT_MUT,
- expr.span,
- "this expression mutably borrows a mutable reference. Consider reborrowing");
+ } else if let hir::ExprKind::AddrOf(hir::BorrowKind::Ref, hir::Mutability::Mut, e) = expr.kind {
+ if let hir::ExprKind::AddrOf(hir::BorrowKind::Ref, hir::Mutability::Mut, _) = e.kind {
+ span_lint(
+ self.cx,
+ MUT_MUT,
+ expr.span,
+ "generally you want to avoid `&mut &mut _` if possible",
+ );
+ } else if let ty::Ref(_, _, hir::Mutability::Mut) = self.cx.typeck_results().expr_ty(e).kind() {
+ span_lint(
+ self.cx,
+ MUT_MUT,
+ expr.span,
+ "this expression mutably borrows a mutable reference. Consider reborrowing",
+ );
}
}
}
- fn visit_ty(&mut self, ty: &'tcx hir::Ty) {
- if let hir::TyRptr(_, hir::MutTy { ty: ref pty, mutbl: hir::MutMutable }) = ty.node {
- if let hir::TyRptr(_, hir::MutTy { mutbl: hir::MutMutable, .. }) = pty.node {
- span_lint(self.cx,
- MUT_MUT,
- ty.span,
- "generally you want to avoid `&mut &mut _` if possible");
+ fn visit_ty(&mut self, ty: &'tcx hir::Ty<'_>) {
+ if let hir::TyKind::Rptr(
+ _,
+ hir::MutTy {
+ ty: pty,
+ mutbl: hir::Mutability::Mut,
+ },
+ ) = ty.kind
+ {
+ if let hir::TyKind::Rptr(
+ _,
+ hir::MutTy {
+ mutbl: hir::Mutability::Mut,
+ ..
+ },
+ ) = pty.kind
+ {
+ span_lint(
+ self.cx,
+ MUT_MUT,
+ ty.span,
+ "generally you want to avoid `&mut &mut _` if possible",
+ );
}
-
}
intravisit::walk_ty(self, ty);
}
- fn nested_visit_map<'this>(&'this mut self) -> intravisit::NestedVisitorMap<'this, 'tcx> {
+ fn nested_visit_map(&mut self) -> intravisit::NestedVisitorMap<Self::Map> {
intravisit::NestedVisitorMap::None
}
}