diff --git a/src/librustc_save_analysis/data.rs b/src/librustc_save_analysis/data.rs
index d4ded71a333..cac1a2e3c5a 100644
--- a/src/librustc_save_analysis/data.rs
+++ b/src/librustc_save_analysis/data.rs
@@ -267,7 +267,7 @@ pub struct ModData {
     pub items: Vec<NodeId>,
     pub visibility: Visibility,
     pub docs: String,
-    pub sig: Signature,
+    pub sig: Option<Signature>,
     pub attributes: Vec<Attribute>,
 }
 
diff --git a/src/librustc_save_analysis/dump_visitor.rs b/src/librustc_save_analysis/dump_visitor.rs
index 763414c1a55..dd022dee78c 100644
--- a/src/librustc_save_analysis/dump_visitor.rs
+++ b/src/librustc_save_analysis/dump_visitor.rs
@@ -1211,6 +1211,33 @@ impl<'l, 'tcx: 'l, 'll, D: Dump + 'll> DumpVisitor<'l, 'tcx, 'll, D> {
 }
 
 impl<'l, 'tcx: 'l, 'll, D: Dump +'ll> Visitor<'l> for DumpVisitor<'l, 'tcx, 'll, D> {
+    fn visit_mod(&mut self, m: &'l ast::Mod, span: Span, id: NodeId) {
+        // Since we handle explicit modules ourselves in visit_item, this should
+        // only get called for the root module of a crate.
+        assert_eq!(id, ast::CRATE_NODE_ID);
+
+        let qualname = format!("::{}", self.tcx.node_path_str(id));
+
+        let cm = self.tcx.sess.codemap();
+        let filename = cm.span_to_filename(span);
+        self.dumper.mod_data(ModData {
+            id: id,
+            name: String::new(),
+            qualname: qualname,
+            span: span,
+            scope: id,
+            filename: filename,
+            items: m.items.iter().map(|i| i.id).collect(),
+            visibility: Visibility::Public,
+            // TODO Visitor doesn't pass us the attibutes.
+            docs: String::new(),
+            sig: None,
+            // TODO Visitor doesn't pass us the attibutes.
+            attributes: vec![],
+        }.lower(self.tcx));
+        self.nest_scope(id, |v| visit::walk_mod(v, m));
+    }
+
     fn visit_item(&mut self, item: &'l ast::Item) {
         use syntax::ast::ItemKind::*;
         self.process_macro_use(item.span, item.id);
diff --git a/src/librustc_save_analysis/external_data.rs b/src/librustc_save_analysis/external_data.rs
index 6fd2de97767..02441a0587e 100644
--- a/src/librustc_save_analysis/external_data.rs
+++ b/src/librustc_save_analysis/external_data.rs
@@ -392,7 +392,7 @@ pub struct ModData {
     pub items: Vec<DefId>,
     pub visibility: Visibility,
     pub docs: String,
-    pub sig: Signature,
+    pub sig: Option<Signature>,
     pub attributes: Vec<Attribute>,
 }
 
@@ -410,7 +410,7 @@ impl Lower for data::ModData {
             items: self.items.into_iter().map(|id| make_def_id(id, &tcx.hir)).collect(),
             visibility: self.visibility,
             docs: self.docs,
-            sig: self.sig.lower(tcx),
+            sig: self.sig.map(|s| s.lower(tcx)),
             attributes: self.attributes.lower(tcx),
         }
     }
diff --git a/src/librustc_save_analysis/json_api_dumper.rs b/src/librustc_save_analysis/json_api_dumper.rs
index 41221ad9863..49b14f5eca0 100644
--- a/src/librustc_save_analysis/json_api_dumper.rs
+++ b/src/librustc_save_analysis/json_api_dumper.rs
@@ -293,7 +293,7 @@ impl Into<Option<Def>> for ModData {
                 parent: None,
                 decl_id: None,
                 docs: self.docs,
-                sig: Some(self.sig.into()),
+                sig: self.sig.map(|s| s.into()),
                 attributes: vec![],
             }),
             _ => None,
diff --git a/src/librustc_save_analysis/json_dumper.rs b/src/librustc_save_analysis/json_dumper.rs
index 2d1e12bf0a1..eaa0c0825f0 100644
--- a/src/librustc_save_analysis/json_dumper.rs
+++ b/src/librustc_save_analysis/json_dumper.rs
@@ -121,7 +121,7 @@ impl<'b, O: DumpOutput + 'b> Dump for JsonDumper<O> {
             children: data.items.into_iter().map(|id| id_from_def_id(id)).collect(),
             decl_id: None,
             docs: data.docs,
-            sig: Some(data.sig.into()),
+            sig: data.sig.map(|s| s.into()),
             attributes: data.attributes.into_iter().map(|a| a.into()).collect(),
         };
         if def.span.file_name.to_str().unwrap() != def.value {
diff --git a/src/librustc_save_analysis/lib.rs b/src/librustc_save_analysis/lib.rs
index fd6898d19d8..9283c6d7b53 100644
--- a/src/librustc_save_analysis/lib.rs
+++ b/src/librustc_save_analysis/lib.rs
@@ -257,7 +257,7 @@ impl<'l, 'tcx: 'l> SaveContext<'l, 'tcx> {
                     items: m.items.iter().map(|i| i.id).collect(),
                     visibility: From::from(&item.vis),
                     docs: docs_for_attrs(&item.attrs),
-                    sig: self.sig_base(item),
+                    sig: Some(self.sig_base(item)),
                     attributes: item.attrs.clone(),
                 }))
             }