[clang] [clang][ASTImporter] Fix of unchecked Error object (NFC) (PR #112688)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: Balázs Kéri (balazske)

<details>
<summary>Changes</summary>

After a previous fix and commit 30a9cac error handling in function 'importTemplateParameterDefaultArgument' was not correct because std::move was removed from return of an Error object and this caused crash "Error value was Success" in some cases.

---
Full diff: https://github.com/llvm/llvm-project/pull/112688.diff


1 Files Affected:

- (modified) clang/lib/AST/ASTImporter.cpp (+13-13) 


``````````diff
diff --git a/clang/lib/AST/ASTImporter.cpp b/clang/lib/AST/ASTImporter.cpp
index 020a2f396b5aa0..e7a6509167f0a0 100644
--- a/clang/lib/AST/ASTImporter.cpp
+++ b/clang/lib/AST/ASTImporter.cpp
@@ -362,24 +362,24 @@ namespace clang {
     template <typename TemplateParmDeclT>
     Error importTemplateParameterDefaultArgument(const TemplateParmDeclT *D,
                                                  TemplateParmDeclT *ToD) {
-      Error Err = Error::success();
       if (D->hasDefaultArgument()) {
         if (D->defaultArgumentWasInherited()) {
-          auto *ToInheritedFrom = const_cast<TemplateParmDeclT *>(
-              importChecked(Err, D->getDefaultArgStorage().getInheritedFrom()));
-          if (Err)
-            return Err;
+          Expected<TemplateParmDeclT *> ToInheritedFromOrErr =
+              import(D->getDefaultArgStorage().getInheritedFrom());
+          if (!ToInheritedFromOrErr)
+            return ToInheritedFromOrErr.takeError();
+          TemplateParmDeclT *ToInheritedFrom = *ToInheritedFromOrErr;
           if (!ToInheritedFrom->hasDefaultArgument()) {
             // Resolve possible circular dependency between default value of the
             // template argument and the template declaration.
-            const auto ToInheritedDefaultArg =
-                importChecked(Err, D->getDefaultArgStorage()
-                                       .getInheritedFrom()
-                                       ->getDefaultArgument());
-            if (Err)
-              return Err;
+            Expected<TemplateArgumentLoc> ToInheritedDefaultArgOrErr =
+                import(D->getDefaultArgStorage()
+                           .getInheritedFrom()
+                           ->getDefaultArgument());
+            if (!ToInheritedDefaultArgOrErr)
+              return ToInheritedDefaultArgOrErr.takeError();
             ToInheritedFrom->setDefaultArgument(Importer.getToContext(),
-                                                ToInheritedDefaultArg);
+                                                *ToInheritedDefaultArgOrErr);
           }
           ToD->setInheritedDefaultArgument(ToD->getASTContext(),
                                            ToInheritedFrom);
@@ -395,7 +395,7 @@ namespace clang {
                                     *ToDefaultArgOrErr);
         }
       }
-      return Err;
+      return Error::success();
     }
 
   public:

``````````

</details>


https://github.com/llvm/llvm-project/pull/112688