rustc_pass_by_value lint: add test on custom types

2 files changed, 4 insertions, 8 deletions

diff --git a/compiler/rustc_lint/src/pass_by_value.rs b/compiler/rustc_lint/src/pass_by_value.rs
index 0bfa2a673c2..0847f600f9d 100644
--- a/compiler/rustc_lint/src/pass_by_value.rs
+++ b/compiler/rustc_lint/src/pass_by_value.rs
@@ -11,6 +11,7 @@ declare_tool_lint! {
     /// The `rustc_pass_by_value` lint marks a type with `#[rustc_pass_by_value]` requiring it to always be passed by value.
     /// This is usually used for types that are thin wrappers around references, so there is no benefit to an extra
     /// layer of indirection. (Example: `Ty` which is a reference to a `TyS`)
+    /// This lint relies on `#[rustc_diagnostic_item]` being available for the target.
     pub rustc::PASS_BY_VALUE,
     Warn,
     "pass by reference of a type flagged as `#[rustc_pass_by_value]`",
diff --git a/compiler/rustc_passes/src/check_attr.rs b/compiler/rustc_passes/src/check_attr.rs
index 2febb2e56ec..e700a61ce48 100644
--- a/compiler/rustc_passes/src/check_attr.rs
+++ b/compiler/rustc_passes/src/check_attr.rs
@@ -1070,20 +1070,15 @@ impl CheckAttrVisitor<'_> {
     /// Warns against some misuses of `#[pass_by_value]`
     fn check_pass_by_value(&self, attr: &Attribute, span: &Span, target: Target) -> bool {
         match target {
-            Target::Struct
-            | Target::Enum
-            | Target::Union
-            | Target::Trait
-            | Target::TraitAlias
-            | Target::TyAlias => true,
+            Target::Struct | Target::Enum | Target::TyAlias => true,
             _ => {
                 self.tcx
                     .sess
                     .struct_span_err(
                         attr.span,
-                        "`pass_by_value` attribute should be applied to a struct, enum, trait or type alias.",
+                        "`pass_by_value` attribute should be applied to a struct, enum or type alias.",
                     )
-                    .span_label(*span, "is not a struct, enum, trait or type alias")
+                    .span_label(*span, "is not a struct, enum or type alias")
                     .emit();
                 false
             }