Desugar reflected types in a loop, rather than relying on a fixed order.

Closes #41.
bloomberg · May 19, 2024 · 3c4d695 · 3c4d695
1 parent e7d7620
commit 3c4d695
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Showing 2 changed files with 32 additions and 13 deletions.
diff --git a/clang/lib/AST/Reflection.cpp b/clang/lib/AST/Reflection.cpp
@@ -41,20 +41,25 @@ QualType ReflectionValue::getAsType() const {
  assert(getKind() == RK_type && "not a type");
 
  QualType QT = QualType::getFromOpaquePtr(Entity);
- if (const auto *LIT = dyn_cast<LocInfoType>(QT))
- QT = LIT->getType();
- if (const auto *ET = dyn_cast<ElaboratedType>(QT)) {
- QualType New = ET->getNamedType();
- New.setLocalFastQualifiers(QT.getLocalFastQualifiers());
- QT = New;
- }
- if (const auto *STTPT = dyn_cast<SubstTemplateTypeParmType>(QT))
- QT = STTPT->getReplacementType();
- if (const auto *RST = dyn_cast<ReflectionSpliceType>(QT))
- QT = RST->getUnderlyingType();
- if (const auto *DTT = dyn_cast<DecltypeType>(QT))
- QT = DTT->desugar();
 
+ void *AsPtr;
+ do {
+ AsPtr = QT.getAsOpaquePtr();
+
+ if (const auto *LIT = dyn_cast<LocInfoType>(QT))
+ QT = LIT->getType();
+ if (const auto *ET = dyn_cast<ElaboratedType>(QT)) {
+ QualType New = ET->getNamedType();
+ New.setLocalFastQualifiers(QT.getLocalFastQualifiers());
+ QT = New;
+ }
+ if (const auto *STTPT = dyn_cast<SubstTemplateTypeParmType>(QT))
+ QT = STTPT->getReplacementType();
+ if (const auto *RST = dyn_cast<ReflectionSpliceType>(QT))
+ QT = RST->getUnderlyingType();
+ if (const auto *DTT = dyn_cast<DecltypeType>(QT))
+ QT = DTT->desugar();
+ } while (QT.getAsOpaquePtr() != AsPtr);
  return QT;
 }
 

diff --git a/libcxx/test/std/experimental/reflection/template-arguments.pass.cpp b/libcxx/test/std/experimental/reflection/template-arguments.pass.cpp
@@ -184,4 +184,18 @@ static_assert(template_arguments_of(^WithReflection<^int>).size() == 1);
 static_assert(template_arguments_of(^WithReflection<^int>)[0] == ^int);
 } // namespace non_auto_non_types
 
+ // =======================================
+ // bb_clang_p2996_issue_41_regression_test
+ // =======================================
+
+namespace bb_clang_p2996_issue_41_regression_test {
+template<class T> struct TCls {};
+
+TCls<int> obj1;
+TCls<decltype(obj1)> obj2;
+
+static_assert(has_template_arguments(template_arguments_of(^decltype(obj2))[0]) ==
+ has_template_arguments(^TCls<int>));
+} // namespace bb_clang_p2996_issue_41_regression_test
+
 int main() { }