allow `#[rustc_align_static(N)]` on `static`s

We need a different attribute than `rustc_align` because unstable attributes are
tied to their feature (we can't have two unstable features use the same
unstable attribute). Otherwise this uses all of the same infrastructure
as `#[rustc_align]`.

2 files changed, 16 insertions, 1 deletions

diff --git a/compiler/rustc_passes/src/check_attr.rs b/compiler/rustc_passes/src/check_attr.rs
index 2cd4830b5d9..10585e7b920 100644
--- a/compiler/rustc_passes/src/check_attr.rs
+++ b/compiler/rustc_passes/src/check_attr.rs
@@ -1602,12 +1602,18 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                 ReprAttr::ReprAlign(align) => {
                     match target {
                         Target::Struct | Target::Union | Target::Enum => {}
-                        Target::Fn | Target::Method(_) => {
+                        Target::Fn | Target::Method(_) if self.tcx.features().fn_align() => {
                             self.dcx().emit_err(errors::ReprAlignShouldBeAlign {
                                 span: *repr_span,
                                 item: target.plural_name(),
                             });
                         }
+                        Target::Static if self.tcx.features().static_align() => {
+                            self.dcx().emit_err(errors::ReprAlignShouldBeAlignStatic {
+                                span: *repr_span,
+                                item: target.plural_name(),
+                            });
+                        }
                         _ => {
                             self.dcx().emit_err(errors::AttrApplication::StructEnumUnion {
                                 hint_span: *repr_span,
diff --git a/compiler/rustc_passes/src/errors.rs b/compiler/rustc_passes/src/errors.rs
index 23dcabef1a1..2da4b6f52cf 100644
--- a/compiler/rustc_passes/src/errors.rs
+++ b/compiler/rustc_passes/src/errors.rs
@@ -1610,6 +1610,15 @@ pub(crate) struct ReprAlignShouldBeAlign {
 }
 
 #[derive(Diagnostic)]
+#[diag(passes_repr_align_should_be_align_static)]
+pub(crate) struct ReprAlignShouldBeAlignStatic {
+    #[primary_span]
+    #[help]
+    pub span: Span,
+    pub item: &'static str,
+}
+
+#[derive(Diagnostic)]
 #[diag(passes_custom_mir_phase_requires_dialect)]
 pub(crate) struct CustomMirPhaseRequiresDialect {
     #[primary_span]