Rollup merge of #132388 - frank-king:feature/where-cfg, r=petrochenkov

Implement `#[cfg]` in `where` clauses

This PR implements #115590, which supports `#[cfg]` attributes in `where` clauses.

The biggest change is, that it adds `AttrsVec` and  `NodeId` to the `ast::WherePredicate` and `HirId` to the `hir::WherePredicate`.

1 files changed, 116 insertions, 0 deletions

diff --git a/src/tools/rustfmt/tests/target/cfg_attribute_in_where.rs b/src/tools/rustfmt/tests/target/cfg_attribute_in_where.rs
new file mode 100644
index 00000000000..11f495b1629
--- /dev/null
+++ b/src/tools/rustfmt/tests/target/cfg_attribute_in_where.rs
@@ -0,0 +1,116 @@
+// rustfmt-inline_attribute_width: 40
+
+#![crate_type = "lib"]
+#![feature(cfg_attribute_in_where)]
+use std::marker::PhantomData;
+
+#[cfg(a)]
+trait TraitA {}
+
+#[cfg(b)]
+trait TraitB {}
+
+trait A<T>
+where
+    #[cfg = a_very_long_attribute_name]
+    T: TraitA,
+    #[cfg = another_very_long_attribute_name]
+    T: TraitB,
+{
+    type B<U>
+    where
+        #[cfg = a]
+        // line comment after the attribute
+        U: TraitA,
+        #[cfg = b]
+        /* block comment after the attribute */
+        U: TraitB,
+        #[cfg = a] // short
+        U: TraitA,
+        #[cfg = b] /* short */ U: TraitB;
+
+    fn foo<U>(&self)
+    where
+        /// line doc comment before the attribute
+        U: TraitA,
+        /** line doc block comment before the attribute */
+        U: TraitB;
+}
+
+impl<T> A<T> for T
+where
+    #[doc = "line doc before the attribute"]
+    T: TraitA,
+    /** short doc */
+    T: TraitB,
+{
+    type B<U>
+        = ()
+    where
+        #[doc = "short"] U: TraitA,
+        #[doc = "short"]
+        #[cfg = a]
+        U: TraitB;
+
+    fn foo<U>(&self)
+    where
+        #[cfg = a]
+        #[cfg = b]
+        U: TraitA,
+        /// line doc
+        #[cfg = c]
+        U: TraitB,
+    {
+    }
+}
+
+struct C<T>
+where
+    #[cfg = a] T: TraitA,
+    #[cfg = b] T: TraitB,
+{
+    _t: PhantomData<T>,
+}
+
+union D<T>
+where
+    #[cfg = a] T: TraitA,
+    #[cfg = b] T: TraitB,
+{
+    _t: PhantomData<T>,
+}
+
+enum E<T>
+where
+    #[cfg = a] T: TraitA,
+    #[cfg = b] T: TraitB,
+{
+    E(PhantomData<T>),
+}
+
+#[allow(type_alias_bounds)]
+type F<T>
+where
+    #[cfg = a] T: TraitA,
+    #[cfg = b] T: TraitB,
+= T;
+
+impl<T> C<T>
+where
+    #[cfg = a] T: TraitA,
+    #[cfg = b] T: TraitB,
+{
+    fn new<U>()
+    where
+        #[cfg = a] U: TraitA,
+        #[cfg = b] U: TraitB,
+    {
+    }
+}
+
+fn foo<T>()
+where
+    #[cfg = a] T: TraitA,
+    #[cfg = b] T: TraitB,
+{
+}