Merge pull request #75212 from kavon/6.0-handle-stdlib-with-no-files-129092011

[6.0🍒] NCGenerics: handle failure to load stdlib

Author: kavon

lib/AST/ASTContext.cpp

@@ -1255,6 +1255,14 @@ ASTContext::synthesizeInvertibleProtocolDecl(InvertibleProtocolKind ip) const {
     return proto;
 
   ModuleDecl *stdlib = getStdlibModule();
+  if (stdlib && stdlib->failedToLoad()) {
+    stdlib = nullptr; // Use the Builtin module instead.
+
+    // Ensure we emitted an error diagnostic!
+    if (!Diags.hadAnyError())
+      Diags.diagnose(SourceLoc(), diag::serialization_load_failed, "Swift");
+  }
+
   FileUnit *file = nullptr;
   if (stdlib) {
     file = &stdlib->getFiles()[0]->getOrCreateSynthesizedFile();