[clang] [Clang] Fixed a crash when instantiating an invalid out-of-line static data member definition in a local class (PR #196772)

[via cfe-commits]

https://github.com/TPPPP72 updated https://github.com/llvm/llvm-project/pull/196772

>From c03519a4223c2a46dd6e68cbf061205fa832b499 Mon Sep 17 00:00:00 2001
From: TPPPP <TPPPP72 at outlook.com>
Date: Sun, 10 May 2026 09:53:16 +0800
Subject: [PATCH 1/4] temp

---
 clang/lib/Sema/SemaDecl.cpp                    | 1 +
 clang/lib/Sema/SemaTemplateInstantiateDecl.cpp | 8 ++++++++
 2 files changed, 9 insertions(+)

diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index a9a4cb89d115f..d9ba3b30dcca9 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -7948,6 +7948,7 @@ NamedDecl *Sema::ActOnVariableDeclarator(
             Diag(D.getIdentifierLoc(),
                  diag::err_static_data_member_not_allowed_in_local_class)
                 << Name << RD->getDeclName() << RD->getTagKind();
+            Invalid = true;
           } else if (AnonStruct) {
             // C++ [class.static.data]p4: Unnamed classes and classes contained
             // directly or indirectly within unnamed classes shall not contain
diff --git a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
index c9bc613a7c4ea..2a4f459dbe40f 100644
--- a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -1799,6 +1799,14 @@ Decl *TemplateDeclInstantiator::VisitVarDecl(VarDecl *D,
   if (SemaRef.getLangOpts().OpenCL)
     SemaRef.deduceOpenCLAddressSpace(Var);
 
+  if (D->getQualifierLoc()) {
+    if (D->getLexicalDeclContext()->isDependentContext() &&
+        DC->isFunctionOrMethod()) {
+      Var->setInvalidDecl();
+      return nullptr;
+    }
+  }
+
   // Substitute the nested name specifier, if any.
   if (SubstQualifier(D, Var))
     return nullptr;

>From b8803bc218f49f06ac7bc1b8dfb6bdc78a857169 Mon Sep 17 00:00:00 2001
From: TPPPP <TPPPP72 at outlook.com>
Date: Sun, 10 May 2026 10:44:28 +0800
Subject: [PATCH 2/4] [Clang] Fixed a crash when instantiating an invalid
 out-of-line static data member definition in a local class

---
 clang/docs/ReleaseNotes.rst          |  2 +-
 clang/test/SemaTemplate/gh176152.cpp | 13 +++++++++++++
 2 files changed, 14 insertions(+), 1 deletion(-)
 create mode 100644 clang/test/SemaTemplate/gh176152.cpp

diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index c17143e3c0398..06adba419b192 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -581,7 +581,7 @@ Bug Fixes to C++ Support
 - Fixed a crash on ``typeid`` of incomplete local types during template instantiation. (#GH63242), (#GH176397)
 - Fixed a crash when an immediate-invoked ``consteval`` lambda is used as an invalid initializer. (#GH185270)
 - Fixed an assertion failure when using a global destructor with a target with a non-default program address space. (#GH186484)
-
+- Fixed a crash when instantiating an invalid out-of-line static data member definition in a local class. (#GH176152)
 - Inherited constructors in ``dllexport`` classes are now exported for ABI-compatible cases, matching
   MSVC behavior. Constructors with variadic arguments or callee-cleanup parameters are not yet supported
   and produce a warning. (#GH162640)
diff --git a/clang/test/SemaTemplate/gh176152.cpp b/clang/test/SemaTemplate/gh176152.cpp
new file mode 100644
index 0000000000000..feae5d0f0a825
--- /dev/null
+++ b/clang/test/SemaTemplate/gh176152.cpp
@@ -0,0 +1,13 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s
+
+template <class T> int f(T) {
+  struct A {
+    static int B;
+    // expected-error at -1 {{static data member 'staticField' not allowed in local struct 'MyClass'}}
+  };
+  int A::B;
+  int A::B = 1;
+  return 0;
+}
+
+int x = f(0);
\ No newline at end of file

>From 6f394a5df991acb2f62d653201af09f93f790a80 Mon Sep 17 00:00:00 2001
From: TPPPP <TPPPP72 at outlook.com>
Date: Sun, 10 May 2026 11:06:03 +0800
Subject: [PATCH 3/4] Add a blank line

---
 clang/test/SemaTemplate/gh176152.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/clang/test/SemaTemplate/gh176152.cpp b/clang/test/SemaTemplate/gh176152.cpp
index feae5d0f0a825..27cb1c53dcf16 100644
--- a/clang/test/SemaTemplate/gh176152.cpp
+++ b/clang/test/SemaTemplate/gh176152.cpp
@@ -10,4 +10,4 @@ template <class T> int f(T) {
   return 0;
 }
 
-int x = f(0);
\ No newline at end of file
+int x = f(0);

>From 2eae3d9f5f7bbdad964b76a24e462695d269121a Mon Sep 17 00:00:00 2001
From: TPPPP <TPPPP72 at outlook.com>
Date: Sun, 10 May 2026 12:03:20 +0800
Subject: [PATCH 4/4] fix test

---
 clang/test/SemaTemplate/gh176152.cpp | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/clang/test/SemaTemplate/gh176152.cpp b/clang/test/SemaTemplate/gh176152.cpp
index 27cb1c53dcf16..288b9d645faec 100644
--- a/clang/test/SemaTemplate/gh176152.cpp
+++ b/clang/test/SemaTemplate/gh176152.cpp
@@ -2,11 +2,10 @@
 
 template <class T> int f(T) {
   struct A {
-    static int B;
-    // expected-error at -1 {{static data member 'staticField' not allowed in local struct 'MyClass'}}
+    static int B; // expected-error {{static data member 'B' not allowed in local struct 'A'}}
   };
-  int A::B;
-  int A::B = 1;
+  int A::B; // expected-note {{previous definition is here}}
+  int A::B = 1; // expected-error {{redefinition of 'B'}}
   return 0;
 }