diff --git a/src/go/doc/example.go b/src/go/doc/example.go
index 125fd530b1..274000cecb 100644
--- a/src/go/doc/example.go
+++ b/src/go/doc/example.go
@@ -237,7 +237,10 @@ func playExample(file *ast.File, f *ast.FuncDecl) *ast.File {
 				}
 			}
 
-			ast.Inspect(d.Body, inspectFunc)
+			// Functions might not have a body. See #42706.
+			if d.Body != nil {
+				ast.Inspect(d.Body, inspectFunc)
+			}
 		case *ast.GenDecl:
 			for _, spec := range d.Specs {
 				switch s := spec.(type) {
diff --git a/src/go/doc/example_test.go b/src/go/doc/example_test.go
index 7c96f0300a..cf1b702549 100644
--- a/src/go/doc/example_test.go
+++ b/src/go/doc/example_test.go
@@ -352,6 +352,25 @@ func main() {
 }
 `
 
+const exampleWholeFileExternalFunction = `package foo_test
+
+func foo(int)
+
+func Example() {
+	foo(42)
+	// Output:
+}
+`
+
+const exampleWholeFileExternalFunctionOutput = `package main
+
+func foo(int)
+
+func main() {
+	foo(42)
+}
+`
+
 var exampleWholeFileTestCases = []struct {
 	Title, Source, Play, Output string
 }{
@@ -367,6 +386,12 @@ var exampleWholeFileTestCases = []struct {
 		exampleWholeFileFunctionOutput,
 		"Hello, world!\n",
 	},
+	{
+		"ExternalFunction",
+		exampleWholeFileExternalFunction,
+		exampleWholeFileExternalFunctionOutput,
+		"",
+	},
 }
 
 func TestExamplesWholeFile(t *testing.T) {