From d35a46e2f33a204e2f66f946a8a9a725ba6564ec Mon Sep 17 00:00:00 2001
From: Owen Mansel-Chan <owen-mc@github.com>
Date: Fri, 26 Nov 2021 15:04:05 -0500
Subject: [PATCH 1/2] Always extract an empty interface type

---
 extractor/extractor.go | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/extractor/extractor.go b/extractor/extractor.go
index e90bfede7e1..d4cedcbc5dd 100644
--- a/extractor/extractor.go
+++ b/extractor/extractor.go
@@ -352,6 +352,9 @@ func extractUniverseScope() {
 	lbl := tw.Labeler.ScopeID(types.Universe, nil)
 	dbscheme.ScopesTable.Emit(tw, lbl, dbscheme.UniverseScopeType.Index())
 	extractObjects(tw, types.Universe, lbl)
+
+	// Always extract an empty interface type
+	extractType(tw, types.NewInterfaceType([]*types.Func{}, []types.Type{}))
 }
 
 // extractObjects extracts all objects declared in the given scope

From f9a3832aa275ee416a15c255213bfb429207fb7f Mon Sep 17 00:00:00 2001
From: Owen Mansel-Chan <owen-mc@github.com>
Date: Fri, 26 Nov 2021 15:12:39 -0500
Subject: [PATCH 2/2] Add extractor test that empty interface type exists

---
 ql/test/extractor-tests/empty-interface/tst.expected | 1 +
 ql/test/extractor-tests/empty-interface/tst.go       | 9 +++++++++
 ql/test/extractor-tests/empty-interface/tst.ql       | 4 ++++
 3 files changed, 14 insertions(+)
 create mode 100644 ql/test/extractor-tests/empty-interface/tst.expected
 create mode 100644 ql/test/extractor-tests/empty-interface/tst.go
 create mode 100644 ql/test/extractor-tests/empty-interface/tst.ql

diff --git a/ql/test/extractor-tests/empty-interface/tst.expected b/ql/test/extractor-tests/empty-interface/tst.expected
new file mode 100644
index 00000000000..cb2f8ad3b31
--- /dev/null
+++ b/ql/test/extractor-tests/empty-interface/tst.expected
@@ -0,0 +1 @@
+| success |
diff --git a/ql/test/extractor-tests/empty-interface/tst.go b/ql/test/extractor-tests/empty-interface/tst.go
new file mode 100644
index 00000000000..e5d8097fae4
--- /dev/null
+++ b/ql/test/extractor-tests/empty-interface/tst.go
@@ -0,0 +1,9 @@
+package main
+
+// This file tests that the extractor does not crash on files that do not
+// end in a newline, so it is important not to autoformat this file.
+
+// autoformat-ignore
+
+func main() {
+}
\ No newline at end of file
diff --git a/ql/test/extractor-tests/empty-interface/tst.ql b/ql/test/extractor-tests/empty-interface/tst.ql
new file mode 100644
index 00000000000..4cd2d43d823
--- /dev/null
+++ b/ql/test/extractor-tests/empty-interface/tst.ql
@@ -0,0 +1,4 @@
+import go
+
+where exists(InterfaceType empty | not empty.hasMethod(_, _))
+select "success"