Auto merge of rust-lang#10894 - Centri3:type_repetition_in_bounds, r=blyxyas,xFrednet

[`type_repetition_in_bounds`]: Don't lint on derived code

fixes rust-lang#10504.

changelog: [`type_repetition_in_bounds`]: Don't lint on derived code

Author: bors

clippy_lints/src/trait_bounds.rs

@@ -1,6 +1,6 @@
 use clippy_utils::diagnostics::{span_lint_and_help, span_lint_and_sugg};
 use clippy_utils::source::{snippet, snippet_opt, snippet_with_applicability};
-use clippy_utils::{SpanlessEq, SpanlessHash};
+use clippy_utils::{is_from_proc_macro, SpanlessEq, SpanlessHash};
 use core::hash::{Hash, Hasher};
 use if_chain::if_chain;
 use itertools::Itertools;
@@ -260,7 +260,7 @@ impl TraitBounds {
                     SpanlessTy { ty: p.bounded_ty, cx },
                     p.bounds.iter().collect::<Vec<_>>()
                 );
-
+                if !is_from_proc_macro(cx, p.bounded_ty);
                 then {
                     let trait_bounds = v
                         .iter()
@@ -342,7 +342,7 @@ fn check_trait_bound_duplication(cx: &LateContext<'_>, gen: &'_ Generics<'_>) {
                             "this trait bound is already specified in the where clause",
                             None,
                             "consider removing this trait bound",
-                            );
+                        );
                     }
                 }
             }

clippy_utils/src/check_proc_macro.rs

@@ -19,8 +19,8 @@ use rustc_ast::{
 };
 use rustc_hir::{
     intravisit::FnKind, Block, BlockCheckMode, Body, Closure, Destination, Expr, ExprKind, FieldDef, FnHeader, HirId,
-    Impl, ImplItem, ImplItemKind, IsAuto, Item, ItemKind, LoopSource, MatchSource, Node, QPath, TraitItem,
-    TraitItemKind, UnOp, UnsafeSource, Unsafety, Variant, VariantData, YieldSource,
+    Impl, ImplItem, ImplItemKind, IsAuto, Item, ItemKind, LoopSource, MatchSource, MutTy, Node, QPath, TraitItem,
+    TraitItemKind, Ty, TyKind, UnOp, UnsafeSource, Unsafety, Variant, VariantData, YieldSource,
 };
 use rustc_lint::{LateContext, LintContext};
 use rustc_middle::ty::TyCtxt;
@@ -319,6 +319,31 @@ fn attr_search_pat(attr: &Attribute) -> (Pat, Pat) {
     }
 }
 
+fn ty_search_pat(ty: &Ty<'_>) -> (Pat, Pat) {
+    match ty.kind {
+        TyKind::Slice(..) | TyKind::Array(..) => (Pat::Str("["), Pat::Str("]")),
+        TyKind::Ptr(MutTy { mutbl, ty }) => (
+            if mutbl.is_mut() {
+                Pat::Str("*const")
+            } else {
+                Pat::Str("*mut")
+            },
+            ty_search_pat(ty).1,
+        ),
+        TyKind::Ref(_, MutTy { ty, .. }) => (Pat::Str("&"), ty_search_pat(ty).1),
+        TyKind::BareFn(bare_fn) => (
+            Pat::OwnedStr(format!("{}{} fn", bare_fn.unsafety.prefix_str(), bare_fn.abi.name())),
+            ty_search_pat(ty).1,
+        ),
+        TyKind::Never => (Pat::Str("!"), Pat::Str("")),
+        TyKind::Tup(..) => (Pat::Str("("), Pat::Str(")")),
+        TyKind::OpaqueDef(..) => (Pat::Str("impl"), Pat::Str("")),
+        TyKind::Path(qpath) => qpath_search_pat(&qpath),
+        // NOTE: This is missing `TraitObject`. It always return true then.
+        _ => (Pat::Str(""), Pat::Str("")),
+    }
+}
+
 pub trait WithSearchPat {
     type Context: LintContext;
     fn search_pat(&self, cx: &Self::Context) -> (Pat, Pat);
@@ -345,6 +370,7 @@ impl_with_search_pat!(LateContext: TraitItem with trait_item_search_pat);
 impl_with_search_pat!(LateContext: ImplItem with impl_item_search_pat);
 impl_with_search_pat!(LateContext: FieldDef with field_def_search_pat);
 impl_with_search_pat!(LateContext: Variant with variant_search_pat);
+impl_with_search_pat!(LateContext: Ty with ty_search_pat);
 
 impl<'cx> WithSearchPat for (&FnKind<'cx>, &Body<'cx>, HirId, Span) {
     type Context = LateContext<'cx>;

tests/ui/type_repetition_in_bounds.rs

@@ -1,6 +1,7 @@
 #![deny(clippy::type_repetition_in_bounds)]
 #![allow(clippy::extra_unused_type_parameters)]
 
+use serde::Deserialize;
 use std::ops::{Add, AddAssign, Div, DivAssign, Mul, MulAssign, Sub, SubAssign};
 
 pub fn foo<T>(_t: T)
@@ -70,6 +71,20 @@ mod issue4326 {
     }
 }
 
+// Extern macros shouldn't lint, again (see #10504)
+mod issue10504 {
+    use serde::{Deserialize, Serialize};
+    use std::fmt::Debug;
+    use std::hash::Hash;
+
+    #[derive(Debug, Serialize, Deserialize)]
+    #[serde(bound(
+        serialize = "T: Serialize + Hash + Eq",
+        deserialize = "Box<T>: serde::de::DeserializeOwned + Hash + Eq"
+    ))]
+    struct OpaqueParams<T: ?Sized + Debug>(std::marker::PhantomData<T>);
+}
+
 // Issue #7360
 struct Foo<T, U>
 where

tests/ui/type_repetition_in_bounds.stderr

@@ -1,5 +1,5 @@
 error: this type has already been used as a bound predicate
-  --> $DIR/type_repetition_in_bounds.rs:9:5
+  --> $DIR/type_repetition_in_bounds.rs:10:5
    |
 LL |     T: Clone,
    |     ^^^^^^^^
@@ -12,23 +12,23 @@ LL | #![deny(clippy::type_repetition_in_bounds)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: this type has already been used as a bound predicate
-  --> $DIR/type_repetition_in_bounds.rs:26:5
+  --> $DIR/type_repetition_in_bounds.rs:27:5
    |
 LL |     Self: Copy + Default + Ord,
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = help: consider combining the bounds: `Self: Clone + Copy + Default + Ord`
 
 error: this type has already been used as a bound predicate
-  --> $DIR/type_repetition_in_bounds.rs:86:5
+  --> $DIR/type_repetition_in_bounds.rs:101:5
    |
 LL |     T: Clone,
    |     ^^^^^^^^
    |
    = help: consider combining the bounds: `T: ?Sized + Clone`
 
 error: this type has already been used as a bound predicate
-  --> $DIR/type_repetition_in_bounds.rs:91:5
+  --> $DIR/type_repetition_in_bounds.rs:106:5
    |
 LL |     T: ?Sized,
    |     ^^^^^^^^^