Checker is defensive against unresolved redirecting constructor

pkg/analyzer/lib/src/task/strong/checker.dart

Index: pkg/analyzer/lib/src/task/strong/checker.dart
diff --git a/pkg/analyzer/lib/src/task/strong/checker.dart b/pkg/analyzer/lib/src/task/strong/checker.dart
index aadab6c32189de5b4fad1a41cd0aecef68ffd33d..dab56d1138878615b469613aef1e9a380a26a9d4 100644
--- a/pkg/analyzer/lib/src/task/strong/checker.dart
+++ b/pkg/analyzer/lib/src/task/strong/checker.dart
@@ -583,8 +583,13 @@ class CodeChecker extends RecursiveAstVisitor {
   @override
   void visitRedirectingConstructorInvocation(
       RedirectingConstructorInvocation node) {
-    var type = node.staticElement.type;
-    checkArgumentList(node.argumentList, type);
+    var type = node.staticElement?.type;
+    // TODO(leafp): There's a TODO in visitRedirectingConstructorInvocation
+    // in the element_resolver to handle the case that the element is null
+    // and emit an error.  In the meantime, just be defensive here.
+    if (type != null) {
+      checkArgumentList(node.argumentList, type);
+    }
     node.visitChildren(this);
   }