diff --git a/ql/test/library-tests/semmle/go/Types/SignatureType_getNumParameter.expected b/ql/test/library-tests/semmle/go/Types/SignatureType_getNumParameter.expected
index 1e7e4fd9cb5..6f7f3920bdf 100644
--- a/ql/test/library-tests/semmle/go/Types/SignatureType_getNumParameter.expected
+++ b/ql/test/library-tests/semmle/go/Types/SignatureType_getNumParameter.expected
@@ -4,3 +4,4 @@
 | pkg1/tst.go:33:1:35:1 | function declaration | 0 |
 | pkg1/tst.go:37:1:37:26 | function declaration | 1 |
 | pkg1/tst.go:39:1:57:1 | function declaration | 2 |
+| unknownFunction.go:8:1:12:1 | function declaration | 0 |
diff --git a/ql/test/library-tests/semmle/go/Types/SignatureType_getNumResult.expected b/ql/test/library-tests/semmle/go/Types/SignatureType_getNumResult.expected
index d38ddcce152..3b37704f7b3 100644
--- a/ql/test/library-tests/semmle/go/Types/SignatureType_getNumResult.expected
+++ b/ql/test/library-tests/semmle/go/Types/SignatureType_getNumResult.expected
@@ -4,3 +4,4 @@
 | pkg1/tst.go:33:1:35:1 | function declaration | 1 |
 | pkg1/tst.go:37:1:37:26 | function declaration | 0 |
 | pkg1/tst.go:39:1:57:1 | function declaration | 0 |
+| unknownFunction.go:8:1:12:1 | function declaration | 0 |
diff --git a/ql/test/library-tests/semmle/go/Types/notype.expected b/ql/test/library-tests/semmle/go/Types/notype.expected
new file mode 100644
index 00000000000..669165864d4
--- /dev/null
+++ b/ql/test/library-tests/semmle/go/Types/notype.expected
@@ -0,0 +1,3 @@
+| unknownFunction.go:9:7:9:21 | unknownFunction | invalid type |
+| unknownFunction.go:9:7:9:23 | call to unknownFunction | invalid type |
+| unknownFunction.go:10:7:10:15 | ...+... | invalid type |
diff --git a/ql/test/library-tests/semmle/go/Types/notype.ql b/ql/test/library-tests/semmle/go/Types/notype.ql
new file mode 100644
index 00000000000..9c781d2bff2
--- /dev/null
+++ b/ql/test/library-tests/semmle/go/Types/notype.ql
@@ -0,0 +1,8 @@
+import go
+
+from Expr e
+where
+  // filter out expressions that don't have any semantics
+  exists(DataFlow::exprNode(e)) and
+  not type_of(e, _)
+select e, e.getType()
diff --git a/ql/test/library-tests/semmle/go/Types/unknownFunction.go b/ql/test/library-tests/semmle/go/Types/unknownFunction.go
new file mode 100644
index 00000000000..5af16d4b13f
--- /dev/null
+++ b/ql/test/library-tests/semmle/go/Types/unknownFunction.go
@@ -0,0 +1,12 @@
+package main
+
+// This file tests type inference for expressions referencing undeclared entities.
+// It is therefore expected to produce extractor warnings.
+
+import "fmt"
+
+func unknownFunctionTest() {
+	e := unknownFunction()
+	f := "hi " + e
+	fmt.Println(e, f)
+}