[clang][bytecode] Discard NullToPointer cast SubExpr (#104782)

So we still properly abort if they fail.

Author: tbaederr

clang/lib/AST/ByteCode/Compiler.cpp

@@ -327,6 +327,8 @@ bool Compiler<Emitter>::VisitCastExpr(const CastExpr *CE) {
 
   case CK_NullToPointer:
   case CK_NullToMemberPointer: {
+    if (!this->discard(SubExpr))
+      return false;
     if (DiscardResult)
       return true;
 

clang/test/AST/ByteCode/codegen.cpp

@@ -64,3 +64,12 @@ namespace Bitfield {
   // CHECK: store ptr @_ZGRN8Bitfield1rE_, ptr @_ZN8Bitfield1rE, align 8
   int &&r = S().a;
 }
+
+namespace Null {
+  decltype(nullptr) null();
+  // CHECK: call {{.*}} @_ZN4Null4nullEv(
+  int *p = null();
+  struct S {};
+  // CHECK: call {{.*}} @_ZN4Null4nullEv(
+  int S::*q = null();
+}