1 files changed, 10 insertions, 4 deletions
diff --git a/clang/lib/Sema/SemaTemplateDeduction.cpp b/clang/lib/Sema/SemaTemplateDeduction.cpp
index 0b090c8ff7e..b101a16f5c8 100644
--- a/clang/lib/Sema/SemaTemplateDeduction.cpp
+++ b/clang/lib/Sema/SemaTemplateDeduction.cpp
@@ -2552,6 +2552,8 @@ Sema::SubstituteExplicitTemplateArguments(
   // Isolate our substituted parameters from our caller.
   LocalInstantiationScope InstScope(*this, /*MergeWithOuterScope*/true);
 
+  ExtParameterInfoBuilder ExtParamInfos;
+
   // Instantiate the types of each of the function parameters given the
   // explicitly-specified template arguments. If the function has a trailing
   // return type, substitute it after the arguments to ensure we substitute
@@ -2559,8 +2561,9 @@ Sema::SubstituteExplicitTemplateArguments(
   if (Proto->hasTrailingReturn()) {
     if (SubstParmTypes(Function->getLocation(),
                        Function->param_begin(), Function->getNumParams(),
+                       Proto->getExtParameterInfosOrNull(),
                        MultiLevelTemplateArgumentList(*ExplicitArgumentList),
-                       ParamTypes))
+                       ParamTypes, /*params*/ nullptr, ExtParamInfos))
       return TDK_SubstitutionFailure;
   }
   
@@ -2590,21 +2593,24 @@ Sema::SubstituteExplicitTemplateArguments(
     if (ResultType.isNull() || Trap.hasErrorOccurred())
       return TDK_SubstitutionFailure;
   }
-  
+
   // Instantiate the types of each of the function parameters given the
   // explicitly-specified template arguments if we didn't do so earlier.
   if (!Proto->hasTrailingReturn() &&
       SubstParmTypes(Function->getLocation(),
                      Function->param_begin(), Function->getNumParams(),
+                     Proto->getExtParameterInfosOrNull(),
                      MultiLevelTemplateArgumentList(*ExplicitArgumentList),
-                     ParamTypes))
+                     ParamTypes, /*params*/ nullptr, ExtParamInfos))
     return TDK_SubstitutionFailure;
 
   if (FunctionType) {
+    auto EPI = Proto->getExtProtoInfo();
+    EPI.ExtParameterInfos = ExtParamInfos.getPointerOrNull(ParamTypes.size());
     *FunctionType = BuildFunctionType(ResultType, ParamTypes,
                                       Function->getLocation(),
                                       Function->getDeclName(),
-                                      Proto->getExtProtoInfo());
+                                      EPI);
     if (FunctionType->isNull() || Trap.hasErrorOccurred())
       return TDK_SubstitutionFailure;
   }