Apply suggestions from code review

Co-authored-by: Oli Scherer <[email protected]>

Author: ZuseZ4

compiler/rustc_codegen_ssa/src/codegen_attrs.rs

@@ -875,11 +875,10 @@ fn autodiff_attrs(tcx: TyCtxt<'_>, id: DefId) -> AutoDiffAttrs {
     // There should only be one, since we generate a new placeholder per ad macro.
     // FIXME(ZuseZ4): re-enable this check. Currently we add multiple, which doesn't cause harm but
     // looks strange e.g. under cargo-expand.
-    let attr = match attrs.len() {
-        0 => return AutoDiffAttrs::error(),
-        1 => attrs.get(0).unwrap(),
+    let attr = match &attrs[..] {
+        [] => return AutoDiffAttrs::error(),
+        [attr] => attr,
         _ => {
-            attrs.get(0).unwrap()
             //FIXME(ZuseZ4): re-enable this check
             //span_bug!(attrs[1].span, "cg_ssa: rustc_autodiff should only exist once per source");
         }
@@ -908,7 +907,7 @@ fn autodiff_attrs(tcx: TyCtxt<'_>, id: DefId) -> AutoDiffAttrs {
         "ForwardFirst" => DiffMode::ForwardFirst,
         "ReverseFirst" => DiffMode::ReverseFirst,
         _ => {
-            span_bug!(attr.span, "rustc_autodiff attribute contains invalid mode");
+            span_bug!(mode.span, "rustc_autodiff attribute contains invalid mode");
         }
     };
 
@@ -921,7 +920,7 @@ fn autodiff_attrs(tcx: TyCtxt<'_>, id: DefId) -> AutoDiffAttrs {
 
     // Then parse it into an actual DiffActivity
     let Ok(ret_activity) = DiffActivity::from_str(ret_symbol.as_str()) else {
-        span_bug!(attr.span, "invalid return activity");
+        span_bug!(ret_symbol.span, "invalid return activity");
     };
 
     // Now parse all the intermediate (input) activities
@@ -932,19 +931,19 @@ fn autodiff_attrs(tcx: TyCtxt<'_>, id: DefId) -> AutoDiffAttrs {
                 Some(x) => x.ident,
                 None => {
                     span_bug!(
-                        attr.span,
+                        arg.span(),
                         "rustc_autodiff attribute must contain the input activity"
                     );
                 }
             }
         } else {
-            span_bug!(attr.span, "rustc_autodiff attribute must contain the input activity");
+            span_bug!(arg.span(), "rustc_autodiff attribute must contain the input activity");
         };
 
         match DiffActivity::from_str(arg_symbol.as_str()) {
             Ok(arg_activity) => arg_activities.push(arg_activity),
             Err(_) => {
-                span_bug!(attr.span, "invalid input activity");
+                span_bug!(arg_symbol.span, "invalid input activity");
             }
         }
     }

compiler/rustc_monomorphize/src/partitioning.rs

@@ -1146,7 +1146,7 @@ pub(crate) fn adjust_activity_to_abi<'tcx>(
     let mut new_activities = vec![];
     let mut new_positions = vec![];
     for (i, ty) in x.inputs().iter().enumerate() {
-        if ty.is_unsafe_ptr() || ty.is_ref() || ty.is_box() {
+        if let Some(inner_ty) = ty.builtin_deref(true).unwrap() {
             if ty.is_fn_ptr() {
                 unimplemented!("what to do whith fn ptr?");
             }