https://github.com/cor3ntin created
https://github.com/llvm/llvm-project/pull/125658
In the presence of an invalid structured binding decomposition, some binding
packs may be invalid and trying to transform them would produce a recovery
expression that does not contains a pack, leading to assertions in places where
we would expect a pack at that stage.
Fixes #125165
>From b3a85c89c5219356ce089615f45139c0af43e651 Mon Sep 17 00:00:00 2001
From: Corentin Jabot <corentinja...@gmail.com>
Date: Tue, 4 Feb 2025 10:14:12 +0100
Subject: [PATCH] [Clang] Do not try to transform invalid bindings
In the presence of an invalid structured binding decomposition,
some binding packs may be invalid and trying to transform them
would produce a recovery expression that does not contains a pack,
leading to assertions in places where we would expect a pack
at that stage.
Fixes #125165
---
clang/lib/Sema/SemaTemplateInstantiate.cpp | 2 +-
clang/test/SemaCXX/cxx2c-binding-pack.cpp | 16 ++++++++++++++++
2 files changed, 17 insertions(+), 1 deletion(-)
diff --git a/clang/lib/Sema/SemaTemplateInstantiate.cpp
b/clang/lib/Sema/SemaTemplateInstantiate.cpp
index dc3bfa97eff399..fb3df8fbd39075 100644
--- a/clang/lib/Sema/SemaTemplateInstantiate.cpp
+++ b/clang/lib/Sema/SemaTemplateInstantiate.cpp
@@ -2481,7 +2481,7 @@ TemplateInstantiator::TransformDeclRefExpr(DeclRefExpr
*E) {
if (BindingDecl *BD = dyn_cast<BindingDecl>(D); BD && BD->isParameterPack())
{
BD = cast_or_null<BindingDecl>(TransformDecl(BD->getLocation(), BD));
- if (!BD)
+ if (!BD || BD->isInvalidDecl())
return ExprError();
if (auto *RP =
dyn_cast_if_present<ResolvedUnexpandedPackExpr>(BD->getBinding()))
diff --git a/clang/test/SemaCXX/cxx2c-binding-pack.cpp
b/clang/test/SemaCXX/cxx2c-binding-pack.cpp
index 5ca249f52b3d8e..3340243f7be583 100644
--- a/clang/test/SemaCXX/cxx2c-binding-pack.cpp
+++ b/clang/test/SemaCXX/cxx2c-binding-pack.cpp
@@ -188,3 +188,19 @@ void other_main() {
static_assert(f<int>() == 2);
}
} // namespace
+
+
+namespace GH125165 {
+
+template <typename = void>
+auto f(auto t) {
+ const auto& [...pack] = t;
+ // expected-error@-1 {{cannot decompose non-class, non-array type 'char
const'}}
+ (pack, ...);
+};
+
+void g() {
+ f('x'); // expected-note {{in instantiation}}
+}
+
+}
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