fix: Fix attributes on generic parameters colliding in item tree

crates/hir-ty/src/lower.rs

@@ -1056,23 +1056,7 @@ impl<'a> TyLoweringContext<'a> {
         let clause = match bound.as_ref() {
             TypeBound::Path(path, TraitBoundModifier::None) => {
                 trait_ref = self.lower_trait_ref_from_path(path, Some(self_ty));
-                trait_ref
-                    .clone()
-                    .filter(|tr| {
-                        // ignore `T: Drop` or `T: Destruct` bounds.
-                        // - `T: ~const Drop` has a special meaning in Rust 1.61 that we don't implement.
-                        //   (So ideally, we'd only ignore `~const Drop` here)
-                        // - `Destruct` impls are built-in in 1.62 (current nightly as of 08-04-2022), so until
-                        //   the builtin impls are supported by Chalk, we ignore them here.
-                        if let Some(lang) = self.db.lang_attr(tr.hir_trait_id().into()) {
-                            if matches!(lang, LangItem::Drop | LangItem::Destruct) {
-                                return false;
-                            }
-                        }
-                        true
-                    })
-                    .map(WhereClause::Implemented)
-                    .map(crate::wrap_empty_binders)
+                trait_ref.clone().map(WhereClause::Implemented).map(crate::wrap_empty_binders)
             }
             TypeBound::Path(path, TraitBoundModifier::Maybe) => {
                 let sized_trait = self

crates/hir-ty/src/tests/regression.rs

@@ -1599,85 +1599,6 @@ fn f(s: S) {
     );
 }
 
-#[test]
-fn rust_161_option_clone() {
-    check_types(
-        r#"
-//- minicore: option, drop
-
-fn test(o: &Option<i32>) {
-    o.my_clone();
-  //^^^^^^^^^^^^ Option<i32>
-}
-
-pub trait MyClone: Sized {
-    fn my_clone(&self) -> Self;
-}
-
-impl<T> const MyClone for Option<T>
-where
-    T: ~const MyClone + ~const Drop + ~const Destruct,
-{
-    fn my_clone(&self) -> Self {
-        match self {
-            Some(x) => Some(x.my_clone()),
-            None => None,
-        }
-    }
-}
-
-impl const MyClone for i32 {
-    fn my_clone(&self) -> Self {
-        *self
-    }
-}
-
-pub trait Destruct {}
-
-impl<T: ?Sized> const Destruct for T {}
-"#,
-    );
-}
-
-#[test]
-fn rust_162_option_clone() {
-    check_types(
-        r#"
-//- minicore: option, drop
-
-fn test(o: &Option<i32>) {
-    o.my_clone();
-  //^^^^^^^^^^^^ Option<i32>
-}
-
-pub trait MyClone: Sized {
-    fn my_clone(&self) -> Self;
-}
-
-impl<T> const MyClone for Option<T>
-where
-    T: ~const MyClone + ~const Destruct,
-{
-    fn my_clone(&self) -> Self {
-        match self {
-            Some(x) => Some(x.my_clone()),
-            None => None,
-        }
-    }
-}
-
-impl const MyClone for i32 {
-    fn my_clone(&self) -> Self {
-        *self
-    }
-}
-
-#[lang = "destruct"]
-pub trait Destruct {}
-"#,
-    );
-}
-
 #[test]
 fn tuple_struct_pattern_with_unmatched_args_crash() {
     check_infer(
@@ -2040,3 +1961,17 @@ fn main() {
 "#,
     )
 }
+
+#[test]
+fn cfg_first_trait_param_16141() {
+    check_no_mismatches(
+        r#"
+//- minicore: sized, coerce_unsized
+trait Bar {
+    fn bar(&self) {}
+}
+
+impl<#[cfg(feature = "a-feature")] A> Bar for (){}
+"#,
+    )
+}

crates/hir-ty/src/tests/traits.rs

@@ -238,6 +238,7 @@ fn infer_for_loop() {
 //- minicore: iterator
 //- /main.rs crate:main deps:alloc
 #![no_std]
+extern crate alloc;
 use alloc::collections::Vec;
 
 fn test() {