More generic function type cases working

pkg/analyzer/lib/src/summary/summarize_ast.dart

Index: pkg/analyzer/lib/src/summary/summarize_ast.dart
diff --git a/pkg/analyzer/lib/src/summary/summarize_ast.dart b/pkg/analyzer/lib/src/summary/summarize_ast.dart
index 60b4d96cb9285f1dae63fb597109fdcd57fc506f..321e9aa10bbec70655c19a433663c3fb31aa8538 100644
--- a/pkg/analyzer/lib/src/summary/summarize_ast.dart
+++ b/pkg/analyzer/lib/src/summary/summarize_ast.dart
@@ -1342,8 +1342,10 @@ class _SummarizeAstVisitor extends RecursiveAstVisitor {
     b.nameOffset = node.name.offset;
     b.typeParameters =
         serializeTypeParameters(node.typeParameters, typeParameterScope);
-    EntityRefBuilder serializedType =
-        serializeGenericFunctionType(node.functionType);
+    GenericFunctionType functionType = node.functionType;
+    EntityRefBuilder serializedType = functionType == null
+        ? null
+        : serializeGenericFunctionType(functionType);
     if (serializedType != null) {
       b.returnType = serializedType;
     }