[clang] -ast-dump-decl-types crashes on codes involving concepts #94928 (PR #108142)

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https://github.com/ofAlpaca created https://github.com/llvm/llvm-project/pull/108142

Resolve #94928

Hi @zyn0217
This PR adds `if (TD->getTemplateDecl())` to prevent `InnerD` becoming `nullptr`, suggested by @firstmoonlight.
I also add `-ast-dump-decl-types` option and declare type `CHECK` to the testcase `clang/test/AST/ast-dump-concepts.cpp`.
Could you kindly review this commit?


>From efcf875af403831bbd4d472a9a3a9fbff4438753 Mon Sep 17 00:00:00 2001
From: ofAlpaca <frank70199 at gmail.com>
Date: Wed, 11 Sep 2024 11:24:55 +0800
Subject: [PATCH] [clang] Fix TemplatedDecl being nullptr and cause crash

---
 clang/lib/Frontend/ASTConsumers.cpp  |  3 ++-
 clang/test/AST/ast-dump-concepts.cpp | 19 ++++++++++++++++---
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/clang/lib/Frontend/ASTConsumers.cpp b/clang/lib/Frontend/ASTConsumers.cpp
index 7b58eaa04df95a..8a2e3b032ace28 100644
--- a/clang/lib/Frontend/ASTConsumers.cpp
+++ b/clang/lib/Frontend/ASTConsumers.cpp
@@ -101,7 +101,8 @@ namespace {
       if (DumpDeclTypes) {
         Decl *InnerD = D;
         if (auto *TD = dyn_cast<TemplateDecl>(D))
-          InnerD = TD->getTemplatedDecl();
+          if (TD->getTemplatedDecl())
+            InnerD = TD->getTemplatedDecl();
 
         // FIXME: Support OutputFormat in type dumping.
         // FIXME: Support combining -ast-dump-decl-types with -ast-dump-lookups.
diff --git a/clang/test/AST/ast-dump-concepts.cpp b/clang/test/AST/ast-dump-concepts.cpp
index a5e0673c241ef4..84d981d2ab8dec 100644
--- a/clang/test/AST/ast-dump-concepts.cpp
+++ b/clang/test/AST/ast-dump-concepts.cpp
@@ -1,9 +1,9 @@
-// RUN: %clang_cc1 -triple x86_64-unknown-unknown -std=c++2a -ast-dump -ast-dump-filter Foo %s | FileCheck -strict-whitespace %s
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown -std=c++2a -ast-dump -ast-dump-decl-types -ast-dump-filter Foo %s | FileCheck -strict-whitespace %s
 
 // Test with serialization:
 // RUN: %clang_cc1 -std=c++20 -triple x86_64-unknown-unknown -emit-pch -o %t %s
 // RUN: %clang_cc1 -x c++ -std=c++20 -triple x86_64-unknown-unknown -include-pch %t \
-// RUN: -ast-dump-all -ast-dump-filter Foo /dev/null \
+// RUN: -ast-dump-all -ast-dump-decl-types -ast-dump-filter Foo /dev/null \
 // RUN: | FileCheck --strict-whitespace %s
 
 template <typename T>
@@ -56,6 +56,9 @@ struct Foo {
   // CHECK: CXXFoldExpr {{.*}} <col:13, col:34>
   template <variadic_concept<int>... Ts>
   Foo();
+  
+  // CHECK:InjectedClassNameType
+  // CHECK-NEXT: CXXRecord {{.*}} 'Foo'
 };
 
 namespace GH82628 {
@@ -75,20 +78,28 @@ template <typename T>
 concept Foo = C<T>;
 
 // CHECK: TemplateTypeParmDecl {{.*}} Concept {{.*}} 'C' (UsingShadow {{.*}} 'C')
+// CHECK: QualType
+// CHECK-NEXT: `-BuiltinType {{.*}} 'bool'
 template <C T>
 constexpr bool FooVar = false;
 
 // CHECK: ConceptSpecializationExpr {{.*}} UsingShadow {{.*}} 'C'
+// CHECK: QualType
+// CHECK-NEXT: `-BuiltinType {{.*}} 'bool'
 template <typename T> requires C<T>
 constexpr bool FooVar2 = true;
 
 // CHECK: SimpleRequirement
 // CHECK-NEXT: `-ConceptSpecializationExpr {{.*}} UsingShadow {{.*}} 'C'
+// CHECK: QualType
+// CHECK-NEXT: `-BuiltinType {{.*}} 'bool'
 template <typename T> requires requires (T) { C<T>; }
 constexpr bool FooVar3 = true;
 
 // CHECK: NonTypeTemplateParmDecl
 // CHECK-NEXT: `-ConceptSpecializationExpr {{.*}} UsingShadow {{.*}} 'C'
+// CHECK: QualType
+// CHECK-NEXT: `-BuiltinType {{.*}} 'bool'
 template <C auto T>
 constexpr bool FooVar4 = bool(T());
 
@@ -97,7 +108,9 @@ constexpr bool FooVar4 = bool(T());
 // CHECK: NonTypeTemplateParmDecl {{.*}} depth 0 index 1 U
 // CHECK-NEXT: `-ConceptSpecializationExpr {{.*}} UsingShadow {{.*}} 'C'
 // CHECK: |-TemplateTypeParmDecl {{.*}} Concept {{.*}} 'C' (UsingShadow {{.*}} 'C') depth 0 index 2 V:auto
-
+// CHECK: FunctionProtoType
+// CHECK: `-Concept {{.*}} 'C'
+// CHECK: `-TemplateTypeParm {{.*}} 'V:auto'
 template <C... T, C auto U>
 auto FooFunc(C auto V) -> C decltype(auto) {
   // FIXME: TypeLocs inside of the function body cannot be dumped via -ast-dump for now.