Throw NSM on unresolved factory redirection.

pkg/front_end/lib/src/fasta/kernel/body_builder.dart

Index: pkg/front_end/lib/src/fasta/kernel/body_builder.dart
diff --git a/pkg/front_end/lib/src/fasta/kernel/body_builder.dart b/pkg/front_end/lib/src/fasta/kernel/body_builder.dart
index 59578cedf592ed68c0ea720ce38745bfcbb6d7c6..d0970fa01290df1405f4ab3b91221e2d39c0cbcb 100644
--- a/pkg/front_end/lib/src/fasta/kernel/body_builder.dart
+++ b/pkg/front_end/lib/src/fasta/kernel/body_builder.dart
@@ -64,7 +64,11 @@ import '../quote.dart'
 
 import '../modifier.dart' show Modifier, constMask, finalMask;
 
-import 'redirecting_factory_body.dart' show getRedirectionTarget;
+import 'redirecting_factory_body.dart'
+    show
+        RedirectingFactoryBody,
+        getRedirectingFactoryBody,
+        getRedirectionTarget;
 
 import 'kernel_builder.dart';
 
@@ -2173,6 +2177,15 @@ class BodyBuilder extends ScopeListener<JumpTarget> implements BuilderHelper {
                 nameToken.charOffset));
             return;
           }
+          RedirectingFactoryBody body = getRedirectingFactoryBody(target);
+          if (body != null) {
+            // If the redirection target is itself a redirecting factory, it
+            // means that it is unresolved. So we set target to null so we
+            // can generate a no-such-method error below.
+            assert(body.isUnresolved);
+            target = null;
+            errorName = body.unresolvedName;
+          }
         }
         if (target is Constructor ||
             (target is Procedure && target.kind == ProcedureKind.Factory)) {
@@ -2182,7 +2195,7 @@ class BodyBuilder extends ScopeListener<JumpTarget> implements BuilderHelper {
               initialTarget: initialTarget));
           return;
         } else {
-          errorName = debugName(type.name, name);
+          errorName ??= debugName(type.name, name);
         }
       } else {
         errorName = debugName(getNodeName(type), name);