1 files changed, 24 insertions, 15 deletions

diff --git a/compiler/rustc_resolve/src/macros.rs b/compiler/rustc_resolve/src/macros.rs
index 6a5b675b4..90ae08ce3 100644
--- a/compiler/rustc_resolve/src/macros.rs
+++ b/compiler/rustc_resolve/src/macros.rs
@@ -2,12 +2,13 @@
 //! interface provided by `Resolver` to macro expander.
 
 use crate::errors::{
-    self, AddAsNonDerive, CannotFindIdentInThisScope, MacroExpectedFound, RemoveSurroundingDerive,
+    self, AddAsNonDerive, CannotDetermineMacroResolution, CannotFindIdentInThisScope,
+    MacroExpectedFound, RemoveSurroundingDerive,
 };
 use crate::Namespace::*;
 use crate::{BuiltinMacroState, Determinacy};
 use crate::{DeriveData, Finalize, ParentScope, ResolutionError, Resolver, ScopeSet};
-use crate::{ModuleKind, ModuleOrUniformRoot, NameBinding, PathResult, Segment};
+use crate::{ModuleKind, ModuleOrUniformRoot, NameBinding, PathResult, Segment, ToNameBinding};
 use rustc_ast::expand::StrippedCfgItem;
 use rustc_ast::{self as ast, attr, Crate, Inline, ItemKind, ModKind, NodeId};
 use rustc_ast_pretty::pprust;
@@ -20,12 +21,12 @@ use rustc_expand::base::{SyntaxExtension, SyntaxExtensionKind};
 use rustc_expand::compile_declarative_macro;
 use rustc_expand::expand::{AstFragment, Invocation, InvocationKind, SupportsMacroExpansion};
 use rustc_hir::def::{self, DefKind, NonMacroAttrKind};
-use rustc_hir::def_id::{CrateNum, LocalDefId};
+use rustc_hir::def_id::{CrateNum, DefId, LocalDefId};
 use rustc_middle::middle::stability;
 use rustc_middle::ty::RegisteredTools;
-use rustc_middle::ty::TyCtxt;
+use rustc_middle::ty::{TyCtxt, Visibility};
 use rustc_session::lint::builtin::{
-    LEGACY_DERIVE_HELPERS, SOFT_UNSTABLE, UNKNOWN_DIAGNOSTIC_ATTRIBUTES,
+    LEGACY_DERIVE_HELPERS, SOFT_UNSTABLE, UNKNOWN_OR_MALFORMED_DIAGNOSTIC_ATTRIBUTES,
 };
 use rustc_session::lint::builtin::{UNUSED_MACROS, UNUSED_MACRO_RULES};
 use rustc_session::lint::BuiltinLintDiagnostics;
@@ -401,8 +402,17 @@ impl<'a, 'tcx> ResolverExpand for Resolver<'a, 'tcx> {
         }
         // Sort helpers in a stable way independent from the derive resolution order.
         entry.helper_attrs.sort_by_key(|(i, _)| *i);
-        self.helper_attrs
-            .insert(expn_id, entry.helper_attrs.iter().map(|(_, ident)| *ident).collect());
+        let helper_attrs = entry
+            .helper_attrs
+            .iter()
+            .map(|(_, ident)| {
+                let res = Res::NonMacroAttr(NonMacroAttrKind::DeriveHelper);
+                let binding = (res, Visibility::<DefId>::Public, ident.span, expn_id)
+                    .to_name_binding(self.arenas);
+                (*ident, binding)
+            })
+            .collect();
+        self.helper_attrs.insert(expn_id, helper_attrs);
         // Mark this derive as having `Copy` either if it has `Copy` itself or if its parent derive
         // has `Copy`, to support cases like `#[derive(Clone, Copy)] #[derive(Debug)]`.
         if entry.has_derive_copy || self.has_derive_copy(parent_scope.expansion) {
@@ -600,9 +610,10 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
         if res == Res::NonMacroAttr(NonMacroAttrKind::Tool)
             && path.segments.len() >= 2
             && path.segments[0].ident.name == sym::diagnostic
+            && path.segments[1].ident.name != sym::on_unimplemented
         {
             self.tcx.sess.parse_sess.buffer_lint(
-                UNKNOWN_DIAGNOSTIC_ATTRIBUTES,
+                UNKNOWN_OR_MALFORMED_DIAGNOSTIC_ATTRIBUTES,
                 path.segments[1].span(),
                 node_id,
                 "unknown diagnostic attribute",
@@ -710,13 +721,11 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
                 // even if speculative `resolve_path` returned nothing previously, so we skip this
                 // less informative error if the privacy error is reported elsewhere.
                 if this.privacy_errors.is_empty() {
-                    let msg = format!(
-                        "cannot determine resolution for the {} `{}`",
-                        kind.descr(),
-                        Segment::names_to_string(path)
-                    );
-                    let msg_note = "import resolution is stuck, try simplifying macro imports";
-                    this.tcx.sess.struct_span_err(span, msg).note(msg_note).emit();
+                    this.tcx.sess.emit_err(CannotDetermineMacroResolution {
+                        span,
+                        kind: kind.descr(),
+                        path: Segment::names_to_string(path),
+                    });
                 }
             }
         };