Rollup of 5 pull requests

compiler/rustc_lint/src/types.rs

@@ -1634,6 +1634,9 @@ impl ImproperCTypesDefinitions {
             return true;
         } else if let Adt(adt_def, _) = ty.kind()
             && adt_def.is_struct()
+            && adt_def.repr().c()
+            && !adt_def.repr().packed()
+            && adt_def.repr().align.is_none()
         {
             let struct_variant = adt_def.variant(VariantIdx::ZERO);
             // Within a nested struct, all fields are examined to correctly
@@ -1655,8 +1658,11 @@ impl ImproperCTypesDefinitions {
         item: &'tcx hir::Item<'tcx>,
     ) {
         let adt_def = cx.tcx.adt_def(item.owner_id.to_def_id());
+        // repr(C) structs also with packed or aligned representation
+        // should be ignored.
         if adt_def.repr().c()
             && !adt_def.repr().packed()
+            && adt_def.repr().align.is_none()
             && cx.tcx.sess.target.os == "aix"
             && !adt_def.all_fields().next().is_none()
         {

tests/ui/layout/reprc-power-alignment.rs

@@ -148,5 +148,29 @@ pub struct I {
     d: f32,
     e: f64,
 }
-
+#[repr(C)]
+pub struct J {
+    a: u8,
+    b: I,
+}
+// The lint also ignores diagnosing #[repr(align(n))].
+#[repr(C, align(8))]
+pub struct K {
+    a: u8,
+    b: u8,
+    c: f64,
+    d: f32,
+    e: f64,
+}
+#[repr(C)]
+pub struct L {
+    a: u8,
+    b: K,
+}
+#[repr(C, align(8))]
+pub struct M {
+    a: u8,
+    b: K,
+    c: L,
+}
 fn main() { }