anchor.diff:      }
   
       for (LibraryBuilder builder in _builders.values) {
  -      if (builder.loader != this) {
  +      if (builder.importUri.isScheme("dart") && !builder.isSynthetic) {
  +        // Assume the platform is precompiled.
           addPrecompiledLibrary(builder.importUri);
  -      } else if (precompiledMacroLibraries.contains(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 "
  
positive.code:                       .macroDeclarations[libraryUri] ??= [])
                    .add(builder.name);
              }
            } else {
              precompiledMacroLibraries.add(libraryUri);
            }
          }
        }
  
negative.code:     /// [ClassBuilder]s for the macro classes.
      Map<Uri, List<ClassBuilder>> macroLibraries = {};
  
      Map<Uri, Uri> precompiledMacroUris =
          target.context.options.precompiledMacroUris;
  
  