3 files changed, 48 insertions, 16 deletions

diff --git a/crates/hir_def/src/nameres/collector.rs b/crates/hir_def/src/nameres/collector.rs
index d9d6c91a8..50b2b0af4 100644
--- a/crates/hir_def/src/nameres/collector.rs
+++ b/crates/hir_def/src/nameres/collector.rs
@@ -1679,14 +1679,22 @@ impl ModCollector<'_, '_> {
                 None => &mac.name,
             };
             let krate = self.def_collector.def_map.krate;
-            if let Some(macro_id) = find_builtin_macro(name, krate, ast_id) {
-                self.def_collector.define_macro_rules(
-                    self.module_id,
-                    mac.name.clone(),
-                    macro_id,
-                    is_export,
-                );
-                return;
+            match find_builtin_macro(name, krate, ast_id) {
+                Some(macro_id) => {
+                    self.def_collector.define_macro_rules(
+                        self.module_id,
+                        mac.name.clone(),
+                        macro_id,
+                        is_export,
+                    );
+                    return;
+                }
+                None => {
+                    self.def_collector
+                        .def_map
+                        .diagnostics
+                        .push(DefDiagnostic::unimplemented_builtin_macro(self.module_id, ast_id));
+                }
             }
         }
 
@@ -1715,15 +1723,23 @@ impl ModCollector<'_, '_> {
             let macro_id = find_builtin_macro(&mac.name, krate, ast_id)
                 .or_else(|| find_builtin_derive(&mac.name, krate, ast_id));
 
-            if let Some(macro_id) = macro_id {
-                self.def_collector.define_macro_def(
-                    self.module_id,
-                    mac.name.clone(),
-                    macro_id,
-                    &self.item_tree[mac.visibility],
-                );
+            match macro_id {
+                Some(macro_id) => {
+                    self.def_collector.define_macro_def(
+                        self.module_id,
+                        mac.name.clone(),
+                        macro_id,
+                        &self.item_tree[mac.visibility],
+                    );
+                    return;
+                }
+                None => {
+                    self.def_collector
+                        .def_map
+                        .diagnostics
+                        .push(DefDiagnostic::unimplemented_builtin_macro(self.module_id, ast_id));
+                }
             }
-            return;
         }
 
         // Case 2: normal `macro`
diff --git a/crates/hir_def/src/nameres/diagnostics.rs b/crates/hir_def/src/nameres/diagnostics.rs
index 57c36c3c6..95061f601 100644
--- a/crates/hir_def/src/nameres/diagnostics.rs
+++ b/crates/hir_def/src/nameres/diagnostics.rs
@@ -27,6 +27,8 @@ pub enum DefDiagnosticKind {
     UnresolvedMacroCall { ast: AstId<ast::MacroCall>, path: ModPath },
 
     MacroError { ast: MacroCallKind, message: String },
+
+    UnimplementedBuiltinMacro { ast: AstId<ast::Macro> },
 }
 
 #[derive(Debug, PartialEq, Eq)]
@@ -93,4 +95,11 @@ impl DefDiagnostic {
     ) -> Self {
         Self { in_module: container, kind: DefDiagnosticKind::UnresolvedMacroCall { ast, path } }
     }
+
+    pub(super) fn unimplemented_builtin_macro(
+        container: LocalModuleId,
+        ast: AstId<ast::Macro>,
+    ) -> Self {
+        Self { in_module: container, kind: DefDiagnosticKind::UnimplementedBuiltinMacro { ast } }
+    }
 }
diff --git a/crates/hir_def/src/test_db.rs b/crates/hir_def/src/test_db.rs
index a9c1e13e2..e840fe5e8 100644
--- a/crates/hir_def/src/test_db.rs
+++ b/crates/hir_def/src/test_db.rs
@@ -298,6 +298,13 @@ impl TestDB {
                     DefDiagnosticKind::MacroError { ast, message } => {
                         (ast.to_node(self.upcast()), message.as_str())
                     }
+                    DefDiagnosticKind::UnimplementedBuiltinMacro { ast } => {
+                        let node = ast.to_node(self.upcast());
+                        (
+                            InFile::new(ast.file_id, node.syntax().clone()),
+                            "UnimplementedBuiltinMacro",
+                        )
+                    }
                 };
 
                 let frange = node.as_ref().original_file_range(self);