[clang] Consistently handle consteval constructors for variables. #144970
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@llvm/pr-subscribers-coroutines @llvm/pr-subscribers-clang Author: Eli Friedman (efriedma-quic) ChangesThis is a simple extension of 443377a to also handle the implicit expressions created by default initialization. This usually doesn't matter, but it's relevant if the constructor stores "this" as a member. Fixes #135281 . Full diff: https://github.com/llvm/llvm-project/pull/144970.diff 2 Files Affected:
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index bbd63372c168b..e10dc65897b8a 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -14423,6 +14423,9 @@ void Sema::ActOnUninitializedDecl(Decl *RealDecl) {
Var->getType().getAddressSpace() == LangAS::hlsl_input)
return;
+ if (getLangOpts().CPlusPlus)
+ ActOnCXXEnterDeclInitializer(nullptr, Var);
+
// C++03 [dcl.init]p9:
// If no initializer is specified for an object, and the
// object is of (possibly cv-qualified) non-POD class type (or
@@ -14458,6 +14461,9 @@ void Sema::ActOnUninitializedDecl(Decl *RealDecl) {
}
CheckCompleteVariableDeclaration(Var);
+
+ if (getLangOpts().CPlusPlus)
+ ActOnCXXExitDeclInitializer(nullptr, Var);
}
}
diff --git a/clang/test/SemaCXX/cxx2b-consteval-propagate.cpp b/clang/test/SemaCXX/cxx2b-consteval-propagate.cpp
index dd5063cb29c5b..aa5d79af589ca 100644
--- a/clang/test/SemaCXX/cxx2b-consteval-propagate.cpp
+++ b/clang/test/SemaCXX/cxx2b-consteval-propagate.cpp
@@ -576,3 +576,21 @@ int f() {
//expected-note@-2 {{read of non-const variable 'a' is not allowed in a constant expression}}
}
}
+
+#if __cplusplus >= 202302L
+namespace GH135281 {
+ struct B {
+ const void* p;
+ consteval B() : p{this} {}
+ };
+ B b;
+ B b2{};
+ B &&b3{};
+ void f() {
+ static B b4;
+ B b5; // expected-error {{call to consteval function 'GH135281::B::B' is not a constant expression}} \
+ // expected-note {{pointer to temporary is not a constant expression}} \
+ // expected-note {{temporary created here}}
+ }
+}
+#endif
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shafik
reviewed
Jun 30, 2025
|
ActOnCXXExitDeclInitializer does three things:
The special handling for variables is specifically relevant for variables... I don't see why we'd need it anywhere else? Except, hmm... I guess we need the same handling if we're instantiating a template, like: But I can't think of anything else. Any suggestions for how to refactor? |
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Came up with a different approach: I moved the check to PopExpressionEvaluationContext(). This required annotating the ExpressionEvaluationContextRecord to indicate we're handling a variable initializer. |
443377a handled simple variables definitions, but it didn't handle uninitialized variables with a constexpr constructor, and it didn't handle template instantiation. Fixes llvm#135281 .
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cor3ntin
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443377a handled simple variable definitions, but it didn't handle uninitialized variables with a consteval constructor, and it didn't handle template instantiation.
Fixes #135281 .