[clang] [clang-tools-extra] [llvm] [Concepts] Traverse the instantiation chain for parameter injection inside a constraint scope (PR #79568)
Younan Zhang via cfe-commits
cfe-commits at lists.llvm.org
Fri Jan 26 23:02:36 PST 2024
https://github.com/zyn0217 updated https://github.com/llvm/llvm-project/pull/79568
>From 386c17d55f68155b711672f87d803eb934372a70 Mon Sep 17 00:00:00 2001
From: Younan Zhang <zyn7109 at gmail.com>
Date: Fri, 26 Jan 2024 18:03:37 +0800
Subject: [PATCH 1/2] [Concepts] Traverse the instantiation chain for parameter
injection inside a constraint scope
We preserve the trailing requires-expression during the lambda
expression transformation. In order to get those referenced parameters
inside a requires-expression properly resolved to the instantiated
decls, we intended to inject these 'original' ParmVarDecls to the
current instantiaion scope, at `Sema::SetupConstraintScope`.
The previous approach seems to overlook nested instantiation chains,
leading to the crash within a nested lambda followed by a requires clause.
This fixes https://github.com/llvm/llvm-project/issues/73418.
---
clang/docs/ReleaseNotes.rst | 3 +++
clang/lib/Sema/SemaConcept.cpp | 8 ++++++--
clang/test/SemaTemplate/concepts-lambda.cpp | 18 ++++++++++++++++++
3 files changed, 27 insertions(+), 2 deletions(-)
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 392f694065a242b..72416a8b5ba59ac 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -1025,6 +1025,9 @@ Bug Fixes to AST Handling
- Fixed a bug where Template Instantiation failed to handle Lambda Expressions
with certain types of Attributes.
(`#76521 <https://github.com/llvm/llvm-project/issues/76521>`_)
+- Fixed a bug where variables referenced by requires-clauses inside
+ nested generic lambdas were not properly injected into the constraint scope.
+ (`#73418 <https://github.com/llvm/llvm-project/issues/73418>`_)
Miscellaneous Bug Fixes
^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/clang/lib/Sema/SemaConcept.cpp b/clang/lib/Sema/SemaConcept.cpp
index acfc00f41254074..88fc846c89e42c8 100644
--- a/clang/lib/Sema/SemaConcept.cpp
+++ b/clang/lib/Sema/SemaConcept.cpp
@@ -612,8 +612,12 @@ bool Sema::SetupConstraintScope(
// If this is a member function, make sure we get the parameters that
// reference the original primary template.
- if (const auto *FromMemTempl =
- PrimaryTemplate->getInstantiatedFromMemberTemplate()) {
+ // We walk up the instantiated template chain so that nested lambdas get
+ // handled properly.
+ for (FunctionTemplateDecl *FromMemTempl =
+ PrimaryTemplate->getInstantiatedFromMemberTemplate();
+ FromMemTempl;
+ FromMemTempl = FromMemTempl->getInstantiatedFromMemberTemplate()) {
if (addInstantiatedParametersToScope(FD, FromMemTempl->getTemplatedDecl(),
Scope, MLTAL))
return true;
diff --git a/clang/test/SemaTemplate/concepts-lambda.cpp b/clang/test/SemaTemplate/concepts-lambda.cpp
index 7e431529427dffa..694d048422a407f 100644
--- a/clang/test/SemaTemplate/concepts-lambda.cpp
+++ b/clang/test/SemaTemplate/concepts-lambda.cpp
@@ -149,3 +149,21 @@ void foo() {
auto caller = make_caller.operator()<&S1::f1>();
}
} // namespace ReturnTypeRequirementInLambda
+
+namespace GH73418 {
+void foo() {
+ int x;
+ [&x](auto) {
+ return [](auto y) {
+ return [](auto obj, auto... params)
+ requires requires {
+ sizeof...(params);
+ [](auto... pack) {
+ return sizeof...(pack);
+ }(params);
+ }
+ { return false; }(y);
+ }(x);
+ }(x);
+}
+} // namespace GH73418
>From 561876370d8a052dd0308c9c842c4cb69679eb0e Mon Sep 17 00:00:00 2001
From: Younan Zhang <zyn7109 at gmail.com>
Date: Sat, 27 Jan 2024 00:48:40 +0800
Subject: [PATCH 2/2] fixup && format
---
clang/docs/ReleaseNotes.rst | 2 +-
clang/test/SemaTemplate/concepts-lambda.cpp | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 72416a8b5ba59ac..63b04982629b096 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -1025,7 +1025,7 @@ Bug Fixes to AST Handling
- Fixed a bug where Template Instantiation failed to handle Lambda Expressions
with certain types of Attributes.
(`#76521 <https://github.com/llvm/llvm-project/issues/76521>`_)
-- Fixed a bug where variables referenced by requires-clauses inside
+- Fixed a bug where variables referenced by requires-clauses inside
nested generic lambdas were not properly injected into the constraint scope.
(`#73418 <https://github.com/llvm/llvm-project/issues/73418>`_)
diff --git a/clang/test/SemaTemplate/concepts-lambda.cpp b/clang/test/SemaTemplate/concepts-lambda.cpp
index 694d048422a407f..0b7580f91043c74 100644
--- a/clang/test/SemaTemplate/concepts-lambda.cpp
+++ b/clang/test/SemaTemplate/concepts-lambda.cpp
@@ -160,7 +160,7 @@ void foo() {
sizeof...(params);
[](auto... pack) {
return sizeof...(pack);
- }(params);
+ }(params...);
}
{ return false; }(y);
}(x);
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