[clang] Return available function types for BindingDecls. (PR #102196)

[Samira Bazuzi via cfe-commits]

https://github.com/bazuzi created https://github.com/llvm/llvm-project/pull/102196

Only return nullptr when we don't have an available QualType.

>From 052eff82638bdfbc8c7b8a2b90bcd9a0c46e52c4 Mon Sep 17 00:00:00 2001
From: Samira Bazuzi <bazuzi at google.com>
Date: Tue, 6 Aug 2024 14:11:46 -0400
Subject: [PATCH] Return available function types for BindingDecls.

Only return nullptr when we don't have an available QualType.
---
 clang/lib/AST/DeclBase.cpp | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/clang/lib/AST/DeclBase.cpp b/clang/lib/AST/DeclBase.cpp
index 98a7746b7d997..129a119267890 100644
--- a/clang/lib/AST/DeclBase.cpp
+++ b/clang/lib/AST/DeclBase.cpp
@@ -1161,15 +1161,20 @@ int64_t Decl::getID() const {
 
 const FunctionType *Decl::getFunctionType(bool BlocksToo) const {
   QualType Ty;
-  if (isa<BindingDecl>(this))
-    return nullptr;
-  else if (const auto *D = dyn_cast<ValueDecl>(this))
+  if (const auto *D = dyn_cast<ValueDecl>(this))
     Ty = D->getType();
   else if (const auto *D = dyn_cast<TypedefNameDecl>(this))
     Ty = D->getUnderlyingType();
   else
     return nullptr;
 
+  if (Ty.isNull()) {
+    // BindingDecls do not have types during parsing, so return nullptr. This is
+    // the only known case where `Ty` is null.
+    assert(isa<BindingDecl>(this));
+    return nullptr;
+  }
+
   if (Ty->isFunctionPointerType())
     Ty = Ty->castAs<PointerType>()->getPointeeType();
   else if (Ty->isFunctionReferenceType())