Merge pull request #75211 from kavon/handle-stdlib-with-no-files-129092011

NCGenerics: handle failure to load stdlib

Author: kavon

include/swift/AST/Module.h

@@ -25,6 +25,7 @@
 #include "swift/AST/Import.h"
 #include "swift/AST/LookupKinds.h"
 #include "swift/AST/Type.h"
+#include "swift/Basic/Assertions.h"
 #include "swift/Basic/BasicSourceInfo.h"
 #include "swift/Basic/Compiler.h"
 #include "swift/Basic/Debug.h"
@@ -388,7 +389,7 @@ class ModuleDecl
   void setBypassResilience() { BypassResilience = true; }
 
   ArrayRef<FileUnit *> getFiles() {
-    assert(!Files.empty() || failedToLoad());
+    ASSERT(!Files.empty() || failedToLoad());
     return Files;
   }
   ArrayRef<const FileUnit *> getFiles() const {

lib/AST/ASTContext.cpp

@@ -1313,6 +1313,14 @@ 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();