[clang] [clang] [ASTDump] Add support for structural value template arguments in TextNodeDumper (PR #126341)

[via cfe-commits]

https://github.com/sakria9 created https://github.com/llvm/llvm-project/pull/126341

Dump structural value in AST.

Example code

```cpp
template<_Complex int x>
struct E;
template<>
struct E<{1, 2}>;
```

Command `clang++ -Xclang -ast-dump usr.cpp -fsyntax-only -std=c++23`

Current AST dump result

```
|-ClassTemplateDecl 0x61a3b52364e8 <usr.cpp:172:1, line:173:8> col:8 E
| |-NonTypeTemplateParmDecl 0x61a3b52363b8 <line:172:10, col:23> col:23 '_Complex int' depth 0 index 0 x
| |-CXXRecordDecl 0x61a3b5236438 <line:173:1, col:8> col:8 struct E
| `-ClassTemplateSpecialization 0x61a3b5236918 'E'
`-ClassTemplateSpecializationDecl 0x61a3b5236918 <line:174:1, line:175:16> col:8 struct E explicit_specialization
  `-TemplateArgument
```

After apply this fix

```
|-ClassTemplateDecl 0x7ce2a834fd60 <usr.cpp:172:1, line:173:8> col:8 E
| |-NonTypeTemplateParmDecl 0x7ce2a834fc10 <line:172:10, col:23> col:23 '_Complex int' depth 0 index 0 x
| |-CXXRecordDecl 0x7ce2a834fca0 <line:173:1, col:8> col:8 struct E
| `-ClassTemplateSpecialization 0x7ce2a8350218 'E'
`-ClassTemplateSpecializationDecl 0x7ce2a8350218 <line:174:1, line:175:16> col:8 struct E explicit_specialization
  `-TemplateArgument structural value '1+2i'
```

>From a382aa9de206a194397f9424150f170d35101b42 Mon Sep 17 00:00:00 2001
From: sakria9 <i at sustech.moe>
Date: Sat, 8 Feb 2025 04:00:08 +0000
Subject: [PATCH] [ASTDump] Add support for structural value template arguments
 in TextNodeDumper

---
 clang/include/clang/AST/TextNodeDumper.h | 1 +
 clang/lib/AST/TextNodeDumper.cpp         | 5 +++++
 2 files changed, 6 insertions(+)

diff --git a/clang/include/clang/AST/TextNodeDumper.h b/clang/include/clang/AST/TextNodeDumper.h
index bfd205ffb0d99ad..4b5ad2b5fa74c04 100644
--- a/clang/include/clang/AST/TextNodeDumper.h
+++ b/clang/include/clang/AST/TextNodeDumper.h
@@ -249,6 +249,7 @@ class TextNodeDumper
   void VisitDeclarationTemplateArgument(const TemplateArgument &TA);
   void VisitNullPtrTemplateArgument(const TemplateArgument &TA);
   void VisitIntegralTemplateArgument(const TemplateArgument &TA);
+  void VisitStructuralValueTemplateArgument(const TemplateArgument &TA);
   void VisitTemplateTemplateArgument(const TemplateArgument &TA);
   void VisitTemplateExpansionTemplateArgument(const TemplateArgument &TA);
   void VisitExpressionTemplateArgument(const TemplateArgument &TA);
diff --git a/clang/lib/AST/TextNodeDumper.cpp b/clang/lib/AST/TextNodeDumper.cpp
index 6da1f776b4b6357..cb0c742177d2c7f 100644
--- a/clang/lib/AST/TextNodeDumper.cpp
+++ b/clang/lib/AST/TextNodeDumper.cpp
@@ -1226,6 +1226,11 @@ void TextNodeDumper::VisitIntegralTemplateArgument(const TemplateArgument &TA) {
   dumpTemplateArgument(TA);
 }
 
+void TextNodeDumper::VisitStructuralValueTemplateArgument(const TemplateArgument &TA) {
+  OS << " structural value";
+  dumpTemplateArgument(TA);
+}
+
 void TextNodeDumper::dumpTemplateName(TemplateName TN, StringRef Label) {
   AddChild(Label, [=] {
     {