Auto merge of #84401 - crlf0710:impl_main_by_path, r=petrochenkov

[rust.git] / clippy_lints / src / escape.rs

diff --git a/clippy_lints/src/escape.rs b/clippy_lints/src/escape.rs
index eebf4a81a8716377b339a217cce7019f31f7ecc3..3581ab41906f414f26e97311c5d8360c2c855f21 100644 (file)
--- a/clippy_lints/src/escape.rs
+++ b/clippy_lints/src/escape.rs
@@ -1,16 +1,18 @@
+use clippy_utils::diagnostics::span_lint;
+use clippy_utils::ty::contains_ty;
 use rustc_hir::intravisit;
-use rustc_hir::{self, Body, FnDecl, HirId, HirIdSet, ItemKind, Node};
+use rustc_hir::{self, AssocItemKind, Body, FnDecl, HirId, HirIdSet, Impl, ItemKind, Node};
 use rustc_infer::infer::TyCtxtInferExt;
 use rustc_lint::{LateContext, LateLintPass};
-use rustc_middle::ty::{self, Ty};
+use rustc_middle::mir::FakeReadCause;
+use rustc_middle::ty::{self, TraitRef, Ty};
 use rustc_session::{declare_tool_lint, impl_lint_pass};
 use rustc_span::source_map::Span;
+use rustc_span::symbol::kw;
 use rustc_target::abi::LayoutOf;
 use rustc_target::spec::abi::Abi;
 use rustc_typeck::expr_use_visitor::{ConsumeMode, Delegate, ExprUseVisitor, PlaceBase, PlaceWithHirId};
 
-use crate::utils::span_lint;
-
 #[derive(Copy, Clone)]
 pub struct BoxedLocal {
     pub too_large_for_stack: u64,
@@ -29,7 +31,6 @@ pub struct BoxedLocal {
     /// **Example:**
     /// ```rust
     /// # fn foo(bar: usize) {}
-    ///
     /// // Bad
     /// let x = Box::new(1);
     /// foo(*x);
@@ -52,6 +53,7 @@ fn is_non_trait_box(ty: Ty<'_>) -> bool {
 struct EscapeDelegate<'a, 'tcx> {
     cx: &'a LateContext<'tcx>,
     set: HirIdSet,
+    trait_self_ty: Option<Ty<'a>>,
     too_large_for_stack: u64,
 }
 
@@ -73,19 +75,34 @@ fn check_fn(
             }
         }
 
-        // If the method is an impl for a trait, don't warn.
         let parent_id = cx.tcx.hir().get_parent_item(hir_id);
         let parent_node = cx.tcx.hir().find(parent_id);
 
+        let mut trait_self_ty = None;
         if let Some(Node::Item(item)) = parent_node {
-            if let ItemKind::Impl { of_trait: Some(_), .. } = item.kind {
+            // If the method is an impl for a trait, don't warn.
+            if let ItemKind::Impl(Impl { of_trait: Some(_), .. }) = item.kind {
                 return;
             }
+
+            // find `self` ty for this trait if relevant
+            if let ItemKind::Trait(_, _, _, _, items) = item.kind {
+                for trait_item in items {
+                    if trait_item.id.hir_id() == hir_id {
+                        // be sure we have `self` parameter in this function
+                        if let AssocItemKind::Fn { has_self: true } = trait_item.kind {
+                            trait_self_ty =
+                                Some(TraitRef::identity(cx.tcx, trait_item.id.def_id.to_def_id()).self_ty());
+                        }
+                    }
+                }
+            }
         }
 
         let mut v = EscapeDelegate {
             cx,
             set: HirIdSet::default(),
+            trait_self_ty,
             too_large_for_stack: self.too_large_for_stack,
         };
 
@@ -154,13 +171,22 @@ fn mutate(&mut self, cmt: &PlaceWithHirId<'tcx>, _: HirId) {
                     return;
                 }
 
+                // skip if there is a `self` parameter binding to a type
+                // that contains `Self` (i.e.: `self: Box<Self>`), see #4804
+                if let Some(trait_self_ty) = self.trait_self_ty {
+                    if map.name(cmt.hir_id) == kw::SelfLower && contains_ty(cmt.place.ty(), trait_self_ty) {
+                        return;
+                    }
+                }
+
                 if is_non_trait_box(cmt.place.ty()) && !self.is_large_box(cmt.place.ty()) {
                     self.set.insert(cmt.hir_id);
                 }
-                return;
             }
         }
     }
+
+    fn fake_read(&mut self, _: rustc_typeck::expr_use_visitor::Place<'tcx>, _: FakeReadCause, _: HirId) {}
 }
 
 impl<'a, 'tcx> EscapeDelegate<'a, 'tcx> {