+use rustc::front::map::Node::{NodeExpr, NodeStmt};
use rustc::lint::*;
-use rustc_front::hir::*;
-use rustc_front::intravisit as visit;
-use rustc::front::map::Node;
-use rustc::middle::ty;
-use rustc::middle::ty::adjustment::AutoAdjustment;
use rustc::middle::expr_use_visitor::*;
-use rustc::middle::infer;
+use rustc::infer;
use rustc::middle::mem_categorization::{cmt, Categorization};
+use rustc::traits::ProjectionMode;
+use rustc::ty::adjustment::AutoAdjustment;
+use rustc::ty;
use rustc::util::nodemap::NodeSet;
+use rustc_front::hir::*;
+use rustc_front::intravisit as visit;
use syntax::ast::NodeId;
use syntax::codemap::Span;
use utils::span_lint;
pub struct EscapePass;
-/// **What it does:** This lint checks for usage of `Box<T>` where an unboxed `T` would work fine
+/// **What it does:** This lint checks for usage of `Box<T>` where an unboxed `T` would work fine.
///
-/// **Why is this bad?** This is an unnecessary allocation, and bad for performance
+/// **Why is this bad?** This is an unnecessary allocation, and bad for performance. It is only necessary to allocate if you wish to move the box into something.
///
-/// It is only necessary to allocate if you wish to move the box into something.
+/// **Known problems:** None
///
/// **Example:**
///
/// foo(*x);
/// println!("{}", *x);
/// }
-declare_lint!(pub BOXED_LOCAL, Warn, "using Box<T> where unnecessary");
+/// ```
+declare_lint! {
+ pub BOXED_LOCAL, Warn, "using Box<T> where unnecessary"
+}
+
+fn is_non_trait_box(ty: ty::Ty) -> bool {
+ match ty.sty {
+ ty::TyBox(ref inner) => !inner.is_trait(),
+ _ => false,
+ }
+}
struct EscapeDelegate<'a, 'tcx: 'a> {
cx: &'a LateContext<'a, 'tcx>,
}
impl LateLintPass for EscapePass {
- fn check_fn(&mut self,
- cx: &LateContext,
- _: visit::FnKind,
- decl: &FnDecl,
- body: &Block,
- _: Span,
- id: NodeId) {
+ fn check_fn(&mut self, cx: &LateContext, _: visit::FnKind, decl: &FnDecl, body: &Block, _: Span, id: NodeId) {
let param_env = ty::ParameterEnvironment::for_item(cx.tcx, id);
- let infcx = infer::new_infer_ctxt(cx.tcx, &cx.tcx.tables, Some(param_env), false);
+ let infcx = infer::new_infer_ctxt(cx.tcx, &cx.tcx.tables, Some(param_env), ProjectionMode::Any);
let mut v = EscapeDelegate {
cx: cx,
set: NodeSet(),
}
impl<'a, 'tcx: 'a> Delegate<'tcx> for EscapeDelegate<'a, 'tcx> {
- fn consume(&mut self,
- _: NodeId,
- _: Span,
- cmt: cmt<'tcx>,
- mode: ConsumeMode) {
+ fn consume(&mut self, _: NodeId, _: Span, cmt: cmt<'tcx>, mode: ConsumeMode) {
if let Categorization::Local(lid) = cmt.cat {
if self.set.contains(&lid) {
}
fn matched_pat(&mut self, _: &Pat, _: cmt<'tcx>, _: MatchMode) {}
fn consume_pat(&mut self, consume_pat: &Pat, cmt: cmt<'tcx>, _: ConsumeMode) {
+ let map = &self.cx.tcx.map;
+ if map.is_argument(consume_pat.id) {
+ // Skip closure arguments
+ if let Some(NodeExpr(..)) = map.find(map.get_parent_node(consume_pat.id)) {
+ return;
+ }
+ if is_non_trait_box(cmt.ty) {
+ self.set.insert(consume_pat.id);
+ }
+ return;
+ }
if let Categorization::Rvalue(..) = cmt.cat {
- if let Some(Node::NodeStmt(st)) = self.cx
- .tcx
- .map
- .find(self.cx.tcx.map.get_parent_node(cmt.id)) {
+ if let Some(NodeStmt(st)) = map.find(map.get_parent_node(cmt.id)) {
if let StmtDecl(ref decl, _) = st.node {
if let DeclLocal(ref loc) = decl.node {
if let Some(ref ex) = loc.init {
if let ExprBox(..) = ex.node {
- if let ty::TyBox(..) = cmt.ty.sty {
+ if is_non_trait_box(cmt.ty) {
// let x = box (...)
self.set.insert(consume_pat.id);
}
}
}
- fn borrow(&mut self,
- borrow_id: NodeId,
- _: Span,
- cmt: cmt<'tcx>,
- _: ty::Region,
- _: ty::BorrowKind,
+ fn borrow(&mut self, borrow_id: NodeId, _: Span, cmt: cmt<'tcx>, _: ty::Region, _: ty::BorrowKind,
loan_cause: LoanCause) {
if let Categorization::Local(lid) = cmt.cat {
.get(&borrow_id) {
if LoanCause::AutoRef == loan_cause {
// x.foo()
- if adj.autoderefs <= 0 {
+ if adj.autoderefs == 0 {
self.set.remove(&lid); // Used without autodereffing (i.e. x.clone())
}
} else {
- self.cx.sess().span_bug(cmt.span, "Unknown adjusted AutoRef");
+ span_bug!(cmt.span, "Unknown adjusted AutoRef");
}
} else if LoanCause::AddrOf == loan_cause {
// &x
- if let Some(&AutoAdjustment::AdjustDerefRef(adj)) =
- self.cx.tcx.tables.borrow().adjustments
- .get(&self.cx.tcx.map.get_parent_node(borrow_id)) {
+ if let Some(&AutoAdjustment::AdjustDerefRef(adj)) = self.cx
+ .tcx
+ .tables
+ .borrow()
+ .adjustments
+ .get(&self.cx
+ .tcx
+ .map
+ .get_parent_node(borrow_id)) {
if adj.autoderefs <= 1 {
// foo(&x) where no extra autoreffing is happening
self.set.remove(&lid);
}
}
fn decl_without_init(&mut self, _: NodeId, _: Span) {}
- fn mutate(&mut self,
- _: NodeId,
- _: Span,
- _: cmt<'tcx>,
- _: MutateMode) {
- }
+ fn mutate(&mut self, _: NodeId, _: Span, _: cmt<'tcx>, _: MutateMode) {}
}