[clang] Fix incorrect partial ordering context setting (#108491)

Author: mizvekov

clang/lib/Sema/SemaTemplateDeduction.cpp

@@ -3411,7 +3411,7 @@ DeduceTemplateArguments(Sema &S, T *Partial,
   if (TemplateDeductionResult Result = ::DeduceTemplateArguments(
           S, Partial->getTemplateParameters(),
           Partial->getTemplateArgs().asArray(), TemplateArgs, Info, Deduced,
-          /*NumberOfArgumentsMustMatch=*/false, /*PartialOrdering=*/true,
+          /*NumberOfArgumentsMustMatch=*/false, /*PartialOrdering=*/false,
           PackFold::ParameterToArgument,
           /*HasDeducedAnyParam=*/nullptr);
       Result != TemplateDeductionResult::Success)

clang/test/SemaTemplate/cwg2398.cpp

@@ -379,3 +379,13 @@ namespace regression1 {
     bar(input);
   }
 } // namespace regression1
+
+namespace regression2 {
+  template <class> struct D {};
+
+  template <class ET, template <class> class VT>
+  struct D<VT<ET>>;
+
+  template <typename, int> struct Matrix;
+  template struct D<Matrix<double, 3>>;
+} // namespace regression2