Disable new test fail_compilation/test20859.d for LDC

Author: kinke

dmd/aggregate.h

@@ -307,9 +307,11 @@ class ClassDeclaration : public AggregateDeclaration
 
     void addObjcSymbols(ClassDeclarations *classes, ClassDeclarations *categories) override final;
 
+#if !IN_LLVM
     // Back end
     Dsymbol *vtblsym;
     Dsymbol *vtblSymbol();
+#endif
 
     ClassDeclaration *isClassDeclaration() override final { return (ClassDeclaration *)this; }
     void accept(Visitor *v) override { v->visit(this); }

dmd/dclass.d

@@ -922,6 +922,8 @@ version (IN_LLVM) {} else
         .objc.addSymbols(this, classes, categories);
     }
 
+version (IN_LLVM) { /* not needed */ } else
+{
     // Back end
     Dsymbol vtblsym;
 
@@ -939,6 +941,7 @@ version (IN_LLVM) {} else
         }
         return vtblsym;
     }
+}
 
     extern (D) final bool isErrorException()
     {

gen/llvmhelpers.cpp

@@ -1491,13 +1491,6 @@ DValue *DtoSymbolAddress(const Loc &loc, Type *type, Declaration *decl) {
       LLValue *m = DtoResolveTypeInfo(tid);
       return new DImValue(type, m);
     }
-    // special vtbl symbol, used by LDC as alias to the actual vtbl (with
-    // different type and mangled name)
-    if (vd->isClassMember() && vd == vd->isClassMember()->vtblsym) {
-      Logger::println("vtbl symbol");
-      auto cd = vd->isClassMember();
-      return new DLValue(type, getIrAggr(cd)->getVtblSymbol());
-    }
     // nested variable
     if (vd->nestedrefs.length) {
       Logger::println("nested variable");

tests/dmd/fail_compilation/test20859.d

@@ -1,4 +1,4 @@
-/**
+/** DISABLED: LDC // succeeds, as LDC doesn't add a (undocumented) magic __vtbl member variable (unused `ClassDeclaration.vtblSymbol()`)
 TEST_OUTPUT:
 ---
 fail_compilation/test20859.d(8): Error: variable `test20859.ICE.__vtbl` conflicts with variable `test20859.ICE.__vtbl` at fail_compilation/test20859.d(10)