anchor.diff:        // Since it compiled successfully from source, the bootstrap-from-Dill
         // should also succeed without errors.
         assert(errors.isEmpty);
  +
  +      IncrementalCompiler? dillCompilerNoNNBD;
  +      if (context.fuzz) {
  +        dillCompilerNoNNBD = new IncrementalCompiler(
  +            context.compilerContextNoNNBD, dillFileNoNNBDUri);
  +        IncrementalCompilerResult dillCompilerNoNNBDResult =
  +            await dillCompilerNoNNBD
  +                .computeDelta(entryPoints: [test.entryPoint]);
  +        Component componentNoNNBD = dillCompilerNoNNBDResult.component;
  +        componentNoNNBD.computeCanonicalNames();
  +        context.takeErrors();
  +      }
  +
         context.fuzzedLibraries.clear();
         context.fuzzedLibraries.addAll(beforeFuzzedLibraries);
  -      await compileExpression(test, dillCompiler, dillCompilerResult, context);
  +      await compileExpression(
  +          test, dillCompiler, dillCompilerNoNNBD, dillCompilerResult, context);
       }
       return new Result.pass(tests);
     }
  
positive.code:   final Set<Uri> fuzzedLibraries = {};
    int fuzzCompiles = 0;
  
    Context(this.compilerContext, this.errors, bool updateExpectations, this.fuzz)
        : steps = <Step>[
            const ReadTest(),
            const CompileExpression(),
  
negative.code: 
    // Compile [test.expression], update [test.errors] with results.
    // As a side effect - verify that generated procedure can be serialized.
    Future<void> compileExpression(
        TestCase test,
        IncrementalCompiler compiler,
        IncrementalCompiler? compilerNoNNBD,
        IncrementalCompilerResult compilerResult,
        Context context) async {
      Map<String, DartType>? definitions = createDefinitionsWithTypes(
          compilerResult.classHierarchy?.knownLibraries,
          test.definitionTypes,
  