anchor.diff:                        .macroDeclarations[libraryUri] ??= [])
                     .add(builder.name);
               }
  -          } else {
  -            precompiledMacroLibraries.add(libraryUri);
             }
           }
         }
  
positive.code:     /// [ClassBuilder]s for the macro classes.
      Map<Uri, List<ClassBuilder>> macroLibraries = {};
  
      /// Libraries containing precompiled macro classes.
      Set<Uri> precompiledMacroLibraries = {};
  
      Map<Uri, Uri> precompiledMacroUris =
          target.context.options.precompiledMacroUris;
  
  
negative.code:     }
  
      for (LibraryBuilder builder in _builders.values) {
        if (builder.importUri.isScheme("dart") && !builder.isSynthetic) {
          // Assume the platform is precompiled.
          addPrecompiledLibrary(builder.importUri);
        } else if (precompiledMacroUris.containsKey(builder.importUri)) {
          // The precompiled macros given are also precompiled.
          assert(
              !macroLibraries.containsKey(builder.importUri),
              "Macro library ${builder.importUri} is only partially "
  