[clang] [clang] Improve ast-dumper text printing of TemplateArgument (PR #93431)

[via cfe-commits]

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@@ -1086,45 +1106,100 @@ void TextNodeDumper::VisitNullTemplateArgument(const TemplateArgument &) {
 
 void TextNodeDumper::VisitTypeTemplateArgument(const TemplateArgument &TA) {
   OS << " type";
-  dumpType(TA.getAsType());
+  dumpTemplateArgument(TA);
 }
 
 void TextNodeDumper::VisitDeclarationTemplateArgument(
     const TemplateArgument &TA) {
   OS << " decl";
+  dumpTemplateArgument(TA);
   dumpDeclRef(TA.getAsDecl());
 }
 
-void TextNodeDumper::VisitNullPtrTemplateArgument(const TemplateArgument &) {
+void TextNodeDumper::VisitNullPtrTemplateArgument(const TemplateArgument &TA) {
   OS << " nullptr";
+  dumpTemplateArgument(TA);
 }
 
 void TextNodeDumper::VisitIntegralTemplateArgument(const TemplateArgument &TA) {
-  OS << " integral " << TA.getAsIntegral();
+  OS << " integral";
+  dumpTemplateArgument(TA);
+}
+
+void TextNodeDumper::dumpTemplateName(TemplateName TN) {
+  switch (TN.getKind()) {
+  case TemplateName::Template:
+    AddChild([=] { Visit(TN.getAsTemplateDecl()); });
+    return;
+  case TemplateName::UsingTemplate: {
+    const UsingShadowDecl *USD = TN.getAsUsingShadowDecl();
+    AddChild([=] { Visit(USD); });
+    AddChild("target", [=] { Visit(USD->getTargetDecl()); });
+    return;
+  }
+  case TemplateName::QualifiedTemplate: {
+    OS << " qualified";
+    const QualifiedTemplateName *QTN = TN.getAsQualifiedTemplateName();
+    if (QTN->hasTemplateKeyword())
+      OS << " keyword";
+    dumpNestedNameSpecifier(QTN->getQualifier());
+    dumpTemplateName(QTN->getUnderlyingTemplate());
+    return;
+  }
+  case TemplateName::DependentTemplate: {
+    OS << " dependent";
+    const DependentTemplateName *DTN = TN.getAsDependentTemplateName();
+    dumpNestedNameSpecifier(DTN->getQualifier());
+    return;
+  }
+  case TemplateName::SubstTemplateTemplateParm: {
+    const SubstTemplateTemplateParmStorage *STS =
+        TN.getAsSubstTemplateTemplateParm();
+    OS << " subst index " << STS->getIndex();
+    if (std::optional<unsigned int> PackIndex = STS->getPackIndex())
+      OS << " pack_index " << *PackIndex;
----------------
cor3ntin wrote:

if we decide individual properties have no space (which is reasonable), them "subst index" should be renamed.
IE, as long as we are consistent I'm happy

@AaronBallman 

https://github.com/llvm/llvm-project/pull/93431