[clang] NFCI: use TemplateArgumentLoc for type-param DefaultArgument (#92854)

This is an enabler for a future patch.

This allows an type-parameter default argument to be set as an arbitrary
TemplateArgument, not just a type.
This allows template parameter packs to have default arguments in the
AST, even though the language proper doesn't support the syntax for it.

This will be used in a later patch which synthesizes template parameter
lists with arbitrary default arguments taken from template
specializations.

There are a few places we used SubsType, because we only had a type, now
we use SubstTemplateArgument.
SubstTemplateArgument was missing arguments for setting Instantiation
location and entity names.
Adding those is needed so we don't regress in diagnostics.

1 files changed, 5 insertions, 3 deletions

diff --git a/clang-tools-extra/clang-tidy/modernize/UseConstraintsCheck.cpp b/clang-tools-extra/clang-tidy/modernize/UseConstraintsCheck.cpp
index 7a021fe..ea4d995 100644
--- a/clang-tools-extra/clang-tidy/modernize/UseConstraintsCheck.cpp
+++ b/clang-tools-extra/clang-tidy/modernize/UseConstraintsCheck.cpp
@@ -177,9 +177,11 @@ matchTrailingTemplateParam(const FunctionTemplateDecl *FunctionTemplate) {
           dyn_cast<TemplateTypeParmDecl>(LastParam)) {
     if (LastTemplateParam->hasDefaultArgument() &&
         LastTemplateParam->getIdentifier() == nullptr) {
-      return {matchEnableIfSpecialization(
-                  LastTemplateParam->getDefaultArgumentInfo()->getTypeLoc()),
-              LastTemplateParam};
+      return {
+          matchEnableIfSpecialization(LastTemplateParam->getDefaultArgument()
+                                          .getTypeSourceInfo()
+                                          ->getTypeLoc()),
+          LastTemplateParam};
     }
   }
   return {};