[clang][Interp] Use proper type for non-primitive reference dummies

Author: tbaederr

clang/lib/AST/Interp/Program.cpp

@@ -152,8 +152,7 @@ std::optional<unsigned> Program::getOrCreateDummy(const ValueDecl *VD) {
   if (std::optional<PrimType> T = Ctx.classify(QT))
     Desc = createDescriptor(VD, *T, std::nullopt, true, false);
   else
-    Desc = createDescriptor(VD, VD->getType().getTypePtr(), std::nullopt, true,
-                            false);
+    Desc = createDescriptor(VD, QT.getTypePtr(), std::nullopt, true, false);
   if (!Desc)
     Desc = allocateDescriptor(VD);
 

clang/test/AST/Interp/bitfields.cpp

@@ -102,3 +102,24 @@ namespace Compound {
   }
   static_assert(div() == 1, "");
 }
+
+namespace test0 {
+  extern int int_source();
+  struct A {
+    int aField;
+    int bField;
+  };
+
+  struct B {
+    int onebit : 2;
+    int twobit : 6;
+    int intField;
+  };
+
+  struct C : A, B {
+  };
+
+  void b(C &c) {
+    c.onebit = int_source();
+  }
+}