[clang] [Sema] Migrate away from PointerUnion::dyn_cast (NFC) (PR #125811)

[Kazu Hirata via cfe-commits]

https://github.com/kazutakahirata created https://github.com/llvm/llvm-project/pull/125811

Note that PointerUnion::dyn_cast has been soft deprecated in
PointerUnion.h:

  // FIXME: Replace the uses of is(), get() and dyn_cast() with
  //        isa<T>, cast<T> and the llvm::dyn_cast<T>

Literal migration would result in dyn_cast_if_present (see the
definition of PointerUnion::dyn_cast), but this patch uses dyn_cast
because we expect Specialized to be nonnull.  Note that if Specialized were
null, dereferencing Tmpl would trigger a segfault.


>From a16fb8ef54e15812672d4a143c8919db2f214b80 Mon Sep 17 00:00:00 2001
From: Kazu Hirata <kazu at google.com>
Date: Tue, 4 Feb 2025 09:26:00 -0800
Subject: [PATCH] [Sema] Migrate away from PointerUnion::dyn_cast (NFC)

Note that PointerUnion::dyn_cast has been soft deprecated in
PointerUnion.h:

  // FIXME: Replace the uses of is(), get() and dyn_cast() with
  //        isa<T>, cast<T> and the llvm::dyn_cast<T>

Literal migration would result in dyn_cast_if_present (see the
definition of PointerUnion::dyn_cast), but this patch uses dyn_cast
because we expect Specialized to be nonnull.  Note that if Specialized were
null, dereferencing Tmpl would trigger a segfault.
---
 clang/lib/Sema/SemaTemplateInstantiate.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/clang/lib/Sema/SemaTemplateInstantiate.cpp b/clang/lib/Sema/SemaTemplateInstantiate.cpp
index 44bca0d667f764..ee964d42c80afd 100644
--- a/clang/lib/Sema/SemaTemplateInstantiate.cpp
+++ b/clang/lib/Sema/SemaTemplateInstantiate.cpp
@@ -190,7 +190,7 @@ HandleVarTemplateSpec(const VarTemplateSpecializationDecl *VarTemplSpec,
   llvm::PointerUnion<VarTemplateDecl *, VarTemplatePartialSpecializationDecl *>
       Specialized = VarTemplSpec->getSpecializedTemplateOrPartial();
   if (VarTemplatePartialSpecializationDecl *Partial =
-          Specialized.dyn_cast<VarTemplatePartialSpecializationDecl *>()) {
+          dyn_cast<VarTemplatePartialSpecializationDecl *>(Specialized)) {
     if (!SkipForSpecialization)
       Result.addOuterTemplateArguments(
           Partial, VarTemplSpec->getTemplateInstantiationArgs().asArray(),