guard against null staticInvokeType

pkg/analyzer/lib/src/generated/element_resolver.dart

Index: pkg/analyzer/lib/src/generated/element_resolver.dart
diff --git a/pkg/analyzer/lib/src/generated/element_resolver.dart b/pkg/analyzer/lib/src/generated/element_resolver.dart
index 59285f21720d6e70d491dd16cca9f4ed8b19b249..57b8060e5a88a58076ae9e7d7b372c382969978a 100644
--- a/pkg/analyzer/lib/src/generated/element_resolver.dart
+++ b/pkg/analyzer/lib/src/generated/element_resolver.dart
@@ -653,7 +653,8 @@ class ElementResolver extends SimpleAstVisitor<Object> {
 
     node.staticInvokeType = staticInvokeType;
     if (propagatedInvokeType != null &&
-        propagatedInvokeType.isMoreSpecificThan(staticInvokeType)) {
+        (staticInvokeType == null ||
+            propagatedInvokeType.isMoreSpecificThan(staticInvokeType))) {
       // Don't store the propagated invoke type unless it's more specific than
       // the static type. We still need to record the propagated parameter
       // elements however, as that is used for the propagatedType downwards