[clang] [clang] Migrate away from PointerUnion::dyn_cast (NFC) (PR #226390)

[Kazu Hirata via cfe-commits]

https://github.com/kazutakahirata created https://github.com/llvm/llvm-project/pull/226390

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 on
ExprWithCleanups::CleanupObject because it is always nonnull.
Specifically, ExprWithCleanups::getObjects() is populated from a slice
of Sema::ExprCleanupObjects, which only receives nonnull pointers in
the following places:

- Sema::BuildCompoundLiteralExpr
- Sema::ActOnBlockStmtExpr
- Sema::BuildBlockForLambdaConversion

Assisted-by: Antigravity


>From fef2dc2371d4d97cd6e5a351406004472f23f5c8 Mon Sep 17 00:00:00 2001
From: Kazu Hirata <kazu at google.com>
Date: Sun, 20 Sep 2026 15:29:53 -0700
Subject: [PATCH] [clang] 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 on
ExprWithCleanups::CleanupObject because it is always nonnull.
Specifically, ExprWithCleanups::getObjects() is populated from a slice
of Sema::ExprCleanupObjects, which only receives nonnull pointers in
the following places:

- Sema::BuildCompoundLiteralExpr
- Sema::ActOnBlockStmtExpr
- Sema::BuildBlockForLambdaConversion

Assisted-by: Antigravity
---
 clang/lib/AST/ASTImporter.cpp             | 2 +-
 clang/lib/CodeGen/CGBlocks.cpp            | 2 +-
 clang/lib/Serialization/ASTWriterStmt.cpp | 4 ++--
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/clang/lib/AST/ASTImporter.cpp b/clang/lib/AST/ASTImporter.cpp
index bec73d820d0099..091ad449f6144d 100644
--- a/clang/lib/AST/ASTImporter.cpp
+++ b/clang/lib/AST/ASTImporter.cpp
@@ -9544,7 +9544,7 @@ void ASTImporter::RegisterImportedDecl(Decl *FromD, Decl *ToD) {
 
 llvm::Expected<ExprWithCleanups::CleanupObject>
 ASTImporter::Import(ExprWithCleanups::CleanupObject From) {
-  if (auto *CLE = From.dyn_cast<CompoundLiteralExpr *>()) {
+  if (auto *CLE = dyn_cast<CompoundLiteralExpr *>(From)) {
     if (Expected<Expr *> R = Import(CLE))
       return ExprWithCleanups::CleanupObject(cast<CompoundLiteralExpr>(*R));
   }
diff --git a/clang/lib/CodeGen/CGBlocks.cpp b/clang/lib/CodeGen/CGBlocks.cpp
index 9edb9bc6bff71e..d653df2b6c8b9e 100644
--- a/clang/lib/CodeGen/CGBlocks.cpp
+++ b/clang/lib/CodeGen/CGBlocks.cpp
@@ -1094,7 +1094,7 @@ llvm::Value *CodeGenFunction::EmitBlockLiteral(const CGBlockInfo &blockInfo) {
       auto *EWC = llvm::dyn_cast_or_null<ExprWithCleanups>(RetExpr);
       if (EWC)
         for (auto &C : EWC->getObjects())
-          if (auto *BD = C.dyn_cast<BlockDecl *>())
+          if (auto *BD = dyn_cast<BlockDecl *>(C))
             if (BD == blockDecl)
               return true;
       return false;
diff --git a/clang/lib/Serialization/ASTWriterStmt.cpp b/clang/lib/Serialization/ASTWriterStmt.cpp
index 8fdc75c208ada3..249f1477a394c2 100644
--- a/clang/lib/Serialization/ASTWriterStmt.cpp
+++ b/clang/lib/Serialization/ASTWriterStmt.cpp
@@ -2152,10 +2152,10 @@ void ASTStmtWriter::VisitExprWithCleanups(ExprWithCleanups *E) {
   VisitExpr(E);
   Record.push_back(E->getNumObjects());
   for (auto &Obj : E->getObjects()) {
-    if (auto *BD = Obj.dyn_cast<BlockDecl *>()) {
+    if (auto *BD = dyn_cast<BlockDecl *>(Obj)) {
       Record.push_back(serialization::COK_Block);
       Record.AddDeclRef(BD);
-    } else if (auto *CLE = Obj.dyn_cast<CompoundLiteralExpr *>()) {
+    } else if (auto *CLE = dyn_cast<CompoundLiteralExpr *>(Obj)) {
       Record.push_back(serialization::COK_CompoundLiteral);
       Record.AddStmt(CLE);
     }