[clang] fix(80474): Clang crash on improper use of __array_extent (PR #94173)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: Oleksandr T. (a-tarasyuk)

<details>
<summary>Changes</summary>

Fixes #<!-- -->80474

---
Full diff: https://github.com/llvm/llvm-project/pull/94173.diff


3 Files Affected:

- (modified) clang/docs/ReleaseNotes.rst (+1) 
- (modified) clang/lib/Parse/ParseExprCXX.cpp (+3) 
- (added) clang/test/SemaCXX/incomplete-array-extent.cpp (+5) 


``````````diff
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 0c700d23257bf..32515fbac64f6 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -823,6 +823,7 @@ Bug Fixes to C++ Support
   differering by their constraints when only one of these function was variadic.
 - Fix a crash when a variable is captured by a block nested inside a lambda. (Fixes #GH93625).
 - Fixed a type constraint substitution issue involving a generic lambda expression. (#GH93821)
+- Fix a crash caused by improper use of ``__array_extent``. (#GH80474)
 
 Bug Fixes to AST Handling
 ^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/clang/lib/Parse/ParseExprCXX.cpp b/clang/lib/Parse/ParseExprCXX.cpp
index 1558e3dcb8974..6f21a4f9bd826 100644
--- a/clang/lib/Parse/ParseExprCXX.cpp
+++ b/clang/lib/Parse/ParseExprCXX.cpp
@@ -4011,6 +4011,9 @@ ExprResult Parser::ParseArrayTypeTrait() {
     ExprResult DimExpr = ParseExpression();
     T.consumeClose();
 
+    if (DimExpr.isInvalid())
+      return ExprError();
+
     return Actions.ActOnArrayTypeTrait(ATT, Loc, Ty.get(), DimExpr.get(),
                                        T.getCloseLocation());
   }
diff --git a/clang/test/SemaCXX/incomplete-array-extent.cpp b/clang/test/SemaCXX/incomplete-array-extent.cpp
new file mode 100644
index 0000000000000..d59800f67a6ae
--- /dev/null
+++ b/clang/test/SemaCXX/incomplete-array-extent.cpp
@@ -0,0 +1,5 @@
+// RUN: %clang_cc1 -verify -std=c++11 %s
+
+auto f() { // expected-error {{'auto' return without trailing return type; deduced return types are a C++14 extension}}
+  return __array_extent(int, ); // expected-error {{expected expression}}
+}

``````````

</details>


https://github.com/llvm/llvm-project/pull/94173