fix

Author: Backl1ght

clang/docs/ReleaseNotes.rst

@@ -967,6 +967,7 @@ Bug Fixes to C++ Support
 - Fixed an assertion failure about invalid conversion when calling lambda. (#GH96205).
 - Fixed a bug where the first operand of binary ``operator&`` would be transformed as if it was the operand
   of the address of operator. (#GH97483).
+- Fixed an assertion failure about constant expression did not evaluate to integer. (#GH96670).
 
 Bug Fixes to AST Handling
 ^^^^^^^^^^^^^^^^^^^^^^^^^

clang/lib/AST/ExprConstant.cpp

@@ -15858,7 +15858,7 @@ static bool FastEvaluateAsRValue(const Expr *Exp, Expr::EvalResult &Result,
   }
 
   if (const auto *CE = dyn_cast<ConstantExpr>(Exp)) {
-    if (CE->hasAPValueResult()) {
+    if (CE->hasAPValueResult() && !CE->getAPValueResult().isLValue()) {
       Result.Val = CE->getAPValueResult();
       IsConst = true;
       return true;

clang/test/SemaCXX/eval-crashes.cpp

@@ -61,3 +61,13 @@ struct array {
   array() : data(*new int[1][2]) {}
 };
 }
+
+namespace GH96670 {
+inline constexpr long ullNil = -1;
+
+template<typename T = long, const T &Nil = ullNil>
+struct Test {};
+
+inline constexpr long lNil = -1;
+Test<long, lNil> c;
+}