Diagnose unimplemented built-in macros

crates/hir/src/diagnostics.rs

@@ -227,3 +227,27 @@ impl Diagnostic for MacroError {
         true
     }
 }
+
+#[derive(Debug)]
+pub struct UnimplementedBuiltinMacro {
+    pub file: HirFileId,
+    pub node: SyntaxNodePtr,
+}
+
+impl Diagnostic for UnimplementedBuiltinMacro {
+    fn code(&self) -> DiagnosticCode {
+        DiagnosticCode("unimplemented-builtin-macro")
+    }
+
+    fn message(&self) -> String {
+        "unimplemented built-in macro".to_string()
+    }
+
+    fn display_source(&self) -> InFile<SyntaxNodePtr> {
+        InFile::new(self.file, self.node.clone())
+    }
+
+    fn as_any(&self) -> &(dyn Any + Send + 'static) {
+        self
+    }
+}

crates/hir/src/lib.rs

@@ -36,8 +36,8 @@ use std::{iter, sync::Arc};
 use arrayvec::ArrayVec;
 use base_db::{CrateDisplayName, CrateId, Edition, FileId};
 use diagnostics::{
-    InactiveCode, MacroError, UnresolvedExternCrate, UnresolvedImport, UnresolvedMacroCall,
-    UnresolvedModule, UnresolvedProcMacro,
+    InactiveCode, MacroError, UnimplementedBuiltinMacro, UnresolvedExternCrate, UnresolvedImport,
+    UnresolvedMacroCall, UnresolvedModule, UnresolvedProcMacro,
 };
 use either::Either;
 use hir_def::{
@@ -565,6 +565,14 @@ impl Module {
                     };
                     sink.push(MacroError { file, node: ast, message: message.clone() });
                 }
+
+                DefDiagnosticKind::UnimplementedBuiltinMacro { ast } => {
+                    let node = ast.to_node(db.upcast());
+                    // Must have a name, otherwise we wouldn't emit it.
+                    let name = node.name().expect("unimplemented builtin macro with no name");
+                    let ptr = SyntaxNodePtr::from(AstPtr::new(&name));
+                    sink.push(UnimplementedBuiltinMacro { file: ast.file_id, node: ptr });
+                }
             }
         }
         for decl in self.declarations(db) {