Store macro parent module in ExpnData.

compiler/rustc_expand/src/base.rs

@@ -809,6 +809,7 @@ impl SyntaxExtension {
         call_site: Span,
         descr: Symbol,
         macro_def_id: Option<DefId>,
+        parent_module: Option<DefId>,
     ) -> ExpnData {
         use SyntaxExtensionKind::*;
         let proc_macro = match self.kind {
@@ -828,6 +829,7 @@ impl SyntaxExtension {
             self.local_inner_macros,
             self.edition,
             macro_def_id,
+            parent_module,
         )
     }
 }