[ASTImporter] Import TemplateParameterLists in function templates.

Summary: Correct missing import of TemplateParameterList in function decl.

Reviewers: martong, a.sidorin, shafik

Reviewed By: martong

Subscribers: rnkovacs, dkrupp, Szelethus, gamesh411, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D60461

llvm-svn: 360132
diff --git a/clang/lib/AST/ASTImporter.cpp b/clang/lib/AST/ASTImporter.cpp
index 1ac4870..da0d689 100644
--- a/clang/lib/AST/ASTImporter.cpp
+++ b/clang/lib/AST/ASTImporter.cpp
@@ -419,6 +419,8 @@
     Expected<FunctionTemplateAndArgsTy>
     ImportFunctionTemplateWithTemplateArgsFromSpecialization(
         FunctionDecl *FromFD);
+    Error ImportTemplateParameterLists(const DeclaratorDecl *FromD,
+                                       DeclaratorDecl *ToD);
 
     Error ImportTemplateInformation(FunctionDecl *FromFD, FunctionDecl *ToFD);
 
@@ -2780,6 +2782,22 @@
   return ToEnumerator;
 }
 
+Error ASTNodeImporter::ImportTemplateParameterLists(const DeclaratorDecl *FromD,
+                                                    DeclaratorDecl *ToD) {
+  unsigned int Num = FromD->getNumTemplateParameterLists();
+  if (Num == 0)
+    return Error::success();
+  SmallVector<TemplateParameterList *, 2> ToTPLists(Num);
+  for (unsigned int I = 0; I < Num; ++I)
+    if (Expected<TemplateParameterList *> ToTPListOrErr =
+            import(FromD->getTemplateParameterList(I)))
+      ToTPLists[I] = *ToTPListOrErr;
+    else
+      return ToTPListOrErr.takeError();
+  ToD->setTemplateParameterListsInfo(Importer.ToContext, ToTPLists);
+  return Error::success();
+}
+
 Error ASTNodeImporter::ImportTemplateInformation(
     FunctionDecl *FromFD, FunctionDecl *ToFD) {
   switch (FromFD->getTemplatedKind()) {
@@ -2826,6 +2844,9 @@
     if (!POIOrErr)
       return POIOrErr.takeError();
 
+    if (Error Err = ImportTemplateParameterLists(FromFD, ToFD))
+      return Err;
+
     TemplateSpecializationKind TSK = FTSInfo->getTemplateSpecializationKind();
     ToFD->setFunctionTemplateSpecialization(
         std::get<0>(*FunctionAndArgsOrErr), ToTAList, /* InsertPos= */ nullptr,