Fix new_return_no_self with recursive bounds

rust-lang · Dec 31, 2022 · 67745d4 · 67745d4
1 parent 6b1892c
commit 67745d4
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Showing 3 changed files with 105 additions and 50 deletions.
diff --git a/src/tools/clippy/clippy_utils/src/ty.rs b/src/tools/clippy/clippy_utils/src/ty.rs
@@ -69,50 +69,66 @@ pub fn contains_adt_constructor<'tcx>(ty: Ty<'tcx>, adt: AdtDef<'tcx>) -> bool {
 /// This method also recurses into opaque type predicates, so call it with `impl Trait<U>` and `U`
 /// will also return `true`.
 pub fn contains_ty_adt_constructor_opaque<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>, needle: Ty<'tcx>) -> bool {
-    ty.walk().any(|inner| match inner.unpack() {
-        GenericArgKind::Type(inner_ty) => {
-            if inner_ty == needle {
-                return true;
-            }
+    fn contains_ty_adt_constructor_opaque_inner<'tcx>(
+        cx: &LateContext<'tcx>,
+        ty: Ty<'tcx>,
+        needle: Ty<'tcx>,
+        seen: &mut FxHashSet<DefId>,
+    ) -> bool {
+        ty.walk().any(|inner| match inner.unpack() {
+            GenericArgKind::Type(inner_ty) => {
+                if inner_ty == needle {
+                    return true;
+                }
 
-            if inner_ty.ty_adt_def() == needle.ty_adt_def() {
-                return true;
-            }
+                if inner_ty.ty_adt_def() == needle.ty_adt_def() {
+                    return true;
+                }
+
+                if let ty::Opaque(def_id, _) = *inner_ty.kind() {
+                    if !seen.insert(def_id) {
+                        return false;
+                    }
 
-            if let ty::Opaque(def_id, _) = *inner_ty.kind() {
-                for &(predicate, _span) in cx.tcx.explicit_item_bounds(def_id) {
-                    match predicate.kind().skip_binder() {
-                        // For `impl Trait<U>`, it will register a predicate of `T: Trait<U>`, so we go through
-                        // and check substituions to find `U`.
-                        ty::PredicateKind::Clause(ty::Clause::Trait(trait_predicate)) => {
-                            if trait_predicate
-                                .trait_ref
-                                .substs
-                                .types()
-                                .skip(1) // Skip the implicit `Self` generic parameter
-                                .any(|ty| contains_ty_adt_constructor_opaque(cx, ty, needle))
-                            {
-                                return true;
-                            }
-                        },
-                        // For `impl Trait<Assoc=U>`, it will register a predicate of `<T as Trait>::Assoc = U`,
-                        // so we check the term for `U`.
-                        ty::PredicateKind::Clause(ty::Clause::Projection(projection_predicate)) => {
-                            if let ty::TermKind::Ty(ty) = projection_predicate.term.unpack() {
-                                if contains_ty_adt_constructor_opaque(cx, ty, needle) {
+                    for &(predicate, _span) in cx.tcx.explicit_item_bounds(def_id) {
+                        match predicate.kind().skip_binder() {
+                            // For `impl Trait<U>`, it will register a predicate of `T: Trait<U>`, so we go through
+                            // and check substituions to find `U`.
+                            ty::PredicateKind::Clause(ty::Clause::Trait(trait_predicate)) => {
+                                if trait_predicate
+                                    .trait_ref
+                                    .substs
+                                    .types()
+                                    .skip(1) // Skip the implicit `Self` generic parameter
+                                    .any(|ty| contains_ty_adt_constructor_opaque_inner(cx, ty, needle, seen))
+                                {
                                     return true;
                                 }
-                            };
-                        },
-                        _ => (),
+                            },
+                            // For `impl Trait<Assoc=U>`, it will register a predicate of `<T as Trait>::Assoc = U`,
+                            // so we check the term for `U`.
+                            ty::PredicateKind::Clause(ty::Clause::Projection(projection_predicate)) => {
+                                if let ty::TermKind::Ty(ty) = projection_predicate.term.unpack() {
+                                    if contains_ty_adt_constructor_opaque_inner(cx, ty, needle, seen) {
+                                        return true;
+                                    }
+                                };
+                            },
+                            _ => (),
+                        }
                     }
                 }
-            }
 
-            false
-        },
-        GenericArgKind::Lifetime(_) | GenericArgKind::Const(_) => false,
-    })
+                false
+            },
+            GenericArgKind::Lifetime(_) | GenericArgKind::Const(_) => false,
+        })
+    }
+
+    // A hash set to ensure that the same opaque type (`impl Trait` in RPIT or TAIT) is not
+    // visited twice.
+    let mut seen = FxHashSet::default();
+    contains_ty_adt_constructor_opaque_inner(cx, ty, needle, &mut seen)
 }
 
 /// Resolves `<T as Iterator>::Item` for `T`

diff --git a/src/tools/clippy/tests/ui/new_ret_no_self.rs b/src/tools/clippy/tests/ui/new_ret_no_self.rs
@@ -1,3 +1,4 @@
+#![feature(type_alias_impl_trait)]
 #![warn(clippy::new_ret_no_self)]
 #![allow(dead_code)]
 
@@ -400,3 +401,25 @@ mod issue7344 {
         }
     }
 }
+
+mod issue10041 {
+    struct Bomb;
+
+    impl Bomb {
+        // Hidden <Rhs = Self> default generic paramter.
+        pub fn new() -> impl PartialOrd {
+            0i32
+        }
+    }
+
+    // TAIT with self-referencing bounds
+    type X = impl std::ops::Add<Output = X>;
+
+    struct Bomb2;
+
+    impl Bomb2 {
+        pub fn new() -> X {
+            0i32
+        }
+    }
+}
diff --git a/src/tools/clippy/tests/ui/new_ret_no_self.stderr b/src/tools/clippy/tests/ui/new_ret_no_self.stderr
@@ -1,5 +1,5 @@
 error: methods called `new` usually return `Self`
-  --> $DIR/new_ret_no_self.rs:49:5
+  --> $DIR/new_ret_no_self.rs:50:5
    |
 LL | /     pub fn new(_: String) -> impl R<Item = u32> {
 LL | |         S3
@@ -9,88 +9,104 @@ LL | |     }
    = note: `-D clippy::new-ret-no-self` implied by `-D warnings`
 
 error: methods called `new` usually return `Self`
-  --> $DIR/new_ret_no_self.rs:81:5
+  --> $DIR/new_ret_no_self.rs:82:5
    |
 LL | /     pub fn new() -> u32 {
 LL | |         unimplemented!();
 LL | |     }
    | |_____^
 
 error: methods called `new` usually return `Self`
-  --> $DIR/new_ret_no_self.rs:90:5
+  --> $DIR/new_ret_no_self.rs:91:5
    |
 LL | /     pub fn new(_: String) -> u32 {
 LL | |         unimplemented!();
 LL | |     }
    | |_____^
 
 error: methods called `new` usually return `Self`
-  --> $DIR/new_ret_no_self.rs:126:5
+  --> $DIR/new_ret_no_self.rs:127:5
    |
 LL | /     pub fn new() -> (u32, u32) {
 LL | |         unimplemented!();
 LL | |     }
    | |_____^
 
 error: methods called `new` usually return `Self`
-  --> $DIR/new_ret_no_self.rs:153:5
+  --> $DIR/new_ret_no_self.rs:154:5
    |
 LL | /     pub fn new() -> *mut V {
 LL | |         unimplemented!();
 LL | |     }
    | |_____^
 
 error: methods called `new` usually return `Self`
-  --> $DIR/new_ret_no_self.rs:171:5
+  --> $DIR/new_ret_no_self.rs:172:5
    |
 LL | /     pub fn new() -> Option<u32> {
 LL | |         unimplemented!();
 LL | |     }
    | |_____^
 
 error: methods called `new` usually return `Self`
-  --> $DIR/new_ret_no_self.rs:224:9
+  --> $DIR/new_ret_no_self.rs:225:9
    |
 LL |         fn new() -> String;
    |         ^^^^^^^^^^^^^^^^^^^
 
 error: methods called `new` usually return `Self`
-  --> $DIR/new_ret_no_self.rs:236:9
+  --> $DIR/new_ret_no_self.rs:237:9
    |
 LL |         fn new(_: String) -> String;
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: methods called `new` usually return `Self`
-  --> $DIR/new_ret_no_self.rs:271:9
+  --> $DIR/new_ret_no_self.rs:272:9
    |
 LL | /         fn new() -> (u32, u32) {
 LL | |             unimplemented!();
 LL | |         }
    | |_________^
 
 error: methods called `new` usually return `Self`
-  --> $DIR/new_ret_no_self.rs:298:9
+  --> $DIR/new_ret_no_self.rs:299:9
    |
 LL | /         fn new() -> *mut V {
 LL | |             unimplemented!();
 LL | |         }
    | |_________^
 
 error: methods called `new` usually return `Self`
-  --> $DIR/new_ret_no_self.rs:368:9
+  --> $DIR/new_ret_no_self.rs:369:9
    |
 LL | /         fn new(t: T) -> impl Into<i32> {
 LL | |             1
 LL | |         }
    | |_________^
 
 error: methods called `new` usually return `Self`
-  --> $DIR/new_ret_no_self.rs:389:9
+  --> $DIR/new_ret_no_self.rs:390:9
    |
 LL | /         fn new(t: T) -> impl Trait2<(), i32> {
 LL | |             unimplemented!()
 LL | |         }
    | |_________^
 
-error: aborting due to 12 previous errors
+error: methods called `new` usually return `Self`
+  --> $DIR/new_ret_no_self.rs:410:9
+   |
+LL | /         pub fn new() -> impl PartialOrd {
+LL | |             0i32
+LL | |         }
+   | |_________^
+
+error: methods called `new` usually return `Self`
+  --> $DIR/new_ret_no_self.rs:421:9
+   |
+LL | /         pub fn new() -> X {
+LL | |             0i32
+LL | |         }
+   | |_________^
+
+error: aborting due to 14 previous errors