[clang] [AST] Print the "aggregate" for aggregate deduction guide decl. (PR #84018)

[Haojian Wu via cfe-commits]

https://github.com/hokein created https://github.com/llvm/llvm-project/pull/84018

I found this is useful for debugging purpose to identify different kind of deduction guide decl.

>From 63e1f39e9580f4b33fcd86572aea70bf46edb264 Mon Sep 17 00:00:00 2001
From: Haojian Wu <hokein.wu at gmail.com>
Date: Tue, 5 Mar 2024 14:50:23 +0100
Subject: [PATCH] [AST] Print the "aggregate" kind for aggregate deduction
 guide decl.

I found this is useful for debugging purpose to identify different kind of deduction guide decl.
---
 clang/include/clang/AST/TextNodeDumper.h    |  1 +
 clang/lib/AST/TextNodeDumper.cpp            | 12 ++++++++++++
 clang/test/SemaTemplate/deduction-guide.cpp |  9 +++++++++
 3 files changed, 22 insertions(+)

diff --git a/clang/include/clang/AST/TextNodeDumper.h b/clang/include/clang/AST/TextNodeDumper.h
index de67f0b5714846..efb5bfe7f83d40 100644
--- a/clang/include/clang/AST/TextNodeDumper.h
+++ b/clang/include/clang/AST/TextNodeDumper.h
@@ -352,6 +352,7 @@ class TextNodeDumper
   void VisitEnumConstantDecl(const EnumConstantDecl *D);
   void VisitIndirectFieldDecl(const IndirectFieldDecl *D);
   void VisitFunctionDecl(const FunctionDecl *D);
+  void VisitCXXDeductionGuideDecl(const CXXDeductionGuideDecl *D);
   void VisitFieldDecl(const FieldDecl *D);
   void VisitVarDecl(const VarDecl *D);
   void VisitBindingDecl(const BindingDecl *D);
diff --git a/clang/lib/AST/TextNodeDumper.cpp b/clang/lib/AST/TextNodeDumper.cpp
index b683eb1edd8f13..347a1ede3d1123 100644
--- a/clang/lib/AST/TextNodeDumper.cpp
+++ b/clang/lib/AST/TextNodeDumper.cpp
@@ -1990,6 +1990,18 @@ void TextNodeDumper::VisitFunctionDecl(const FunctionDecl *D) {
   }
 }
 
+void TextNodeDumper::VisitCXXDeductionGuideDecl(const CXXDeductionGuideDecl *D) {
+  VisitFunctionDecl(D);
+  switch (D->getDeductionCandidateKind()) {
+  case DeductionCandidate::Normal:
+  case DeductionCandidate::Copy:
+    return;
+  case DeductionCandidate::Aggregate:
+    OS << " aggregate ";
+    break;
+  }
+}
+
 void TextNodeDumper::VisitLifetimeExtendedTemporaryDecl(
     const LifetimeExtendedTemporaryDecl *D) {
   OS << " extended by ";
diff --git a/clang/test/SemaTemplate/deduction-guide.cpp b/clang/test/SemaTemplate/deduction-guide.cpp
index 16c7083df29d0c..0caef78fedbfd9 100644
--- a/clang/test/SemaTemplate/deduction-guide.cpp
+++ b/clang/test/SemaTemplate/deduction-guide.cpp
@@ -239,3 +239,12 @@ F s(0);
 // CHECK: |-InjectedClassNameType {{.*}} 'F<>' dependent
 // CHECK: | `-CXXRecord {{.*}} 'F'
 // CHECK: `-TemplateTypeParmType {{.*}} 'type-parameter-0-1' dependent depth 0 index 1
+
+template<typename T>
+struct G { T t; };
+
+G g = {1};
+// CHECK-LABEL: Dumping <deduction guide for G>:
+// CHECK: FunctionTemplateDecl
+// CHECK: |-CXXDeductionGuideDecl {{.*}} implicit <deduction guide for G> 'auto (T) -> G<T>' aggregate
+// CHECK: `-CXXDeductionGuideDecl {{.*}} implicit used <deduction guide for G> 'auto (int) -> G<int>' implicit_instantiation aggregate