[Clang] Avoid null deref in lambda attribute compat warning #161096
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@llvm/pr-subscribers-clang Author: Oleksandr T. (a-tarasyuk) ChangesFixes #161070 This PR addresses the issue in llvm-project/clang/lib/Parse/ParseExprCXX.cpp Lines 1299 to 1302 in 48a6f2f llvm-project/clang/include/clang/Basic/DiagnosticParseKinds.td Lines 1143 to 1145 in 48a6f2f llvm-project/clang/include/clang/Basic/DiagnosticParseKinds.td Lines 1149 to 1152 in 48a6f2f Full diff: https://github.com/llvm/llvm-project/pull/161096.diff 3 Files Affected:
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 98c889c08b329..ecd46336c9196 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -432,6 +432,8 @@ Bug Fixes to C++ Support
- Fix an assertion failure when taking the address on a non-type template parameter argument of
object type. (#GH151531)
- Suppress ``-Wdouble-promotion`` when explicitly asked for with C++ list initialization (#GH33409).
+- Fixed a crash in the pre-C++23 warning for attributes before a lambda
+ declarator by unifying format args to ``%0``=attribute name, ``%1``=selector (#GH161070).
Bug Fixes to AST Handling
^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/clang/include/clang/Basic/DiagnosticParseKinds.td b/clang/include/clang/Basic/DiagnosticParseKinds.td
index 4d9e123eb4ef1..a098db58eac23 100644
--- a/clang/include/clang/Basic/DiagnosticParseKinds.td
+++ b/clang/include/clang/Basic/DiagnosticParseKinds.td
@@ -1147,7 +1147,7 @@ def ext_lambda_missing_parens : ExtWarn<
"lambda without a parameter clause is a C++23 extension">,
InGroup<CXX23>;
def warn_cxx20_compat_decl_attrs_on_lambda : Warning<
- "%select{an attribute specifier sequence|%1}0 in this position "
+ "%select{an attribute specifier sequence|%0}1 in this position "
"is incompatible with C++ standards before C++23">,
InGroup<CXXPre23Compat>, DefaultIgnore;
diff --git a/clang/test/Parser/cxx2b-lambdas-ext-warns.cpp b/clang/test/Parser/cxx2b-lambdas-ext-warns.cpp
index 7ffb7aae9d391..8af236881088d 100644
--- a/clang/test/Parser/cxx2b-lambdas-ext-warns.cpp
+++ b/clang/test/Parser/cxx2b-lambdas-ext-warns.cpp
@@ -3,8 +3,6 @@
// RUN: %clang_cc1 -std=c++23 -Wpre-c++23-compat %s -verify=precxx23
// RUN: %clang_cc1 -std=c++23 -pedantic %s -verify=cxx23
-//cxx23-no-diagnostics
-
auto L1 = [] constexpr {};
// cxx20-warning@-1 {{lambda without a parameter clause is a C++23 extension}}
auto L2 = []() static {};
@@ -14,3 +12,25 @@ auto L3 = [] static {};
// cxx20-warning@-1 {{lambda without a parameter clause is a C++23 extension}}
// cxx20-warning@-2 {{static lambdas are a C++23 extension}}
// precxx23-warning@-3 {{static lambdas are incompatible with C++ standards before C++23}}
+
+namespace GH161070 {
+void t1() { int a = [] __arm_streaming; }
+// precxx23-error@-1 {{'__arm_streaming' cannot be applied to a declaration}}
+// precxx23-error@-2 {{expected body of lambda expression}}
+// cxx23-error@-3 {{'__arm_streaming' cannot be applied to a declaration}}
+// cxx23-error@-4 {{expected body of lambda expression}}
+// cxx20-error@-5 {{'__arm_streaming' cannot be applied to a declaration}}
+// cxx20-error@-6 {{expected body of lambda expression}}
+// cxx20-warning@-7 {{'__arm_streaming' in this position is a C++23 extension}}
+// precxx23-warning@-8 {{'__arm_streaming' in this position is incompatible with C++ standards before C++23}}
+
+void t2() { int a = [] [[assume(true)]]; }
+// precxx23-error@-1 {{'assume' attribute cannot be applied to a declaration}}
+// precxx23-error@-2 {{expected body of lambda expression}}
+// cxx23-error@-3 {{'assume' attribute cannot be applied to a declaration}}
+// cxx23-error@-4 {{expected body of lambda expression}}
+// cxx20-error@-5 {{'assume' attribute cannot be applied to a declaration}}
+// cxx20-error@-6 {{expected body of lambda expression}}
+// cxx20-warning@-7 {{an attribute specifier sequence in this position is a C++23 extension}}
+// precxx23-warning@-8 {{an attribute specifier sequence in this position is incompatible with C++ standards before C++23}}
+}
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cor3ntin
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Sep 29, 2025
erichkeane
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LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/65/builds/23308 Here is the relevant piece of the build log for the reference |
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LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/59/builds/24951 Here is the relevant piece of the build log for the reference |
shafik
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) Fixes llvm#161070 --- This PR addresses the issue in `ext_decl_attrs_on_lambda` by using `%0`=_attribute name_ and `%1`=_selector_, which prevents a null `IdentifierInfo*`. https://github.com/llvm/llvm-project/blob/48a6f2f85c8269d8326c185016801a4eb8d5dfd6/clang/lib/Parse/ParseExprCXX.cpp#L1299-L1302 https://github.com/llvm/llvm-project/blob/48a6f2f85c8269d8326c185016801a4eb8d5dfd6/clang/include/clang/Basic/DiagnosticParseKinds.td#L1143-L1145 https://github.com/llvm/llvm-project/blob/48a6f2f85c8269d8326c185016801a4eb8d5dfd6/clang/include/clang/Basic/DiagnosticParseKinds.td#L1149-L1152
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Fixes #161070
This PR addresses the issue in
ext_decl_attrs_on_lambdaby using%1=attribute name and%0=selector, which prevents a nullIdentifierInfo*.llvm-project/clang/lib/Parse/ParseExprCXX.cpp
Lines 1299 to 1302 in 48a6f2f
llvm-project/clang/include/clang/Basic/DiagnosticParseKinds.td
Lines 1143 to 1145 in 48a6f2f
llvm-project/clang/include/clang/Basic/DiagnosticParseKinds.td
Lines 1149 to 1152 in 48a6f2f