diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index d5571b958ebed..e054a6d0cc0b7 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -287,6 +287,8 @@ Non-comprehensive list of changes in this release
   stack space when running on Apple AArch64 based platforms. This means that
   stack traces of Clang from debuggers, crashes, and profilers may look
   different than before.
+- Fixed a crash when a VLA with an invalid size expression was used within a
+  ``sizeof`` or ``typeof`` expression. (#GH138444)
 
 New Compiler Flags
 ------------------
diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index 1963e048d6e78..1fcae796ebbcc 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -4700,6 +4700,10 @@ ExprResult Sema::CreateUnaryExprOrTypeTraitExpr(TypeSourceInfo *TInfo,
       TInfo->getType()->isVariablyModifiedType())
     TInfo = TransformToPotentiallyEvaluated(TInfo);
 
+  // It's possible that the transformation above failed.
+  if (!TInfo)
+    return ExprError();
+
   // C99 6.5.3.4p4: the type (an unsigned integer type) is size_t.
   return new (Context) UnaryExprOrTypeTraitExpr(
       ExprKind, TInfo, Context.getSizeType(), OpLoc, R.getEnd());
diff --git a/clang/test/SemaCXX/vla.cpp b/clang/test/SemaCXX/vla.cpp
index 3657ab2d156e4..31796b0805cc2 100644
--- a/clang/test/SemaCXX/vla.cpp
+++ b/clang/test/SemaCXX/vla.cpp
@@ -41,3 +41,17 @@ void func(int expr) {
   int array[sizeof(Ty) ? sizeof(Ty{}) : sizeof(int)];
   int old_style_assert[expr ? Ty::one : Ty::Neg_one]; // We don't diagnose as a VLA until instantiation
 }
+
+namespace GH138444 {
+struct S {         // expected-note {{candidate constructor (the implicit copy constructor) not viable: no known conversion from 'int' to 'const S &' for 1st argument}} \
+                      expected-note {{candidate constructor (the implicit move constructor) not viable: no known conversion from 'int' to 'S &&' for 1st argument}}
+  S(const char *); // expected-note {{candidate constructor not viable: no known conversion from 'int' to 'const char *' for 1st argument}}
+  int size() const;
+};
+
+void test() {
+  S vec1 = 2; // expected-error {{no viable conversion from 'int' to 'S'}}
+  // Previously, this call to sizeof would cause a crash.
+  sizeof(int[vec1.size()]);
+}
+}