Check for nullptr inside NominalTypeDecl::isResilient

rdar://58049956

Author: nkcsgexi

lib/AST/Decl.cpp

@@ -3533,6 +3533,14 @@ bool NominalTypeDecl::isResilient() const {
   return getModuleContext()->isResilient();
 }
 
+static bool isOriginallyDefinedIn(const Decl *D, const ModuleDecl* MD) {
+  if (!MD)
+    return false;
+  if (D->getAlternateModuleName().empty())
+    return false;
+  return D->getAlternateModuleName() == MD->getName().str();
+}
+
 bool NominalTypeDecl::isResilient(ModuleDecl *M,
                                   ResilienceExpansion expansion) const {
   switch (expansion) {
@@ -3542,8 +3550,8 @@ bool NominalTypeDecl::isResilient(ModuleDecl *M,
     // We consider this decl belongs to the module either it's currently
     // defined in this module or it's originally defined in this module, which
     // is specified by @_originallyDefinedIn
-    return M != getModuleContext() &&
-      M->getName().str() != getAlternateModuleName() && isResilient();
+    return M != getModuleContext() && !isOriginallyDefinedIn(this, M) &&
+      isResilient();
   }
   llvm_unreachable("bad resilience expansion");
 }