c++ builder XE4, 10.2 Tokyo > Error: 부정한 부동 소수점 연산 명령이 나오는 이유

C++ Builder XE4
RAD Studio 10.2 Tokyo Update 2 (追記: 2017/12/27)

code

//---------------------------------------------------------------------------

#include <vcl.h>
#pragma hdrstop

#include "Unit1.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm1 *Form1;
//---------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner)
    : TForm(Owner)
{
}

float __fastcall TForm1::TestFunc(void)
{

}
//---------------------------------------------------------------------------
void __fastcall TForm1::Button1Click(TObject *Sender)
{
    TestFunc();
}
//---------------------------------------------------------------------------

//---------------------------------------------------------------------------

#ifndef Unit1H
#define Unit1H
//---------------------------------------------------------------------------
#include <System.Classes.hpp>
#include <Vcl.Controls.hpp>
#include <Vcl.StdCtrls.hpp>
#include <Vcl.Forms.hpp>
//---------------------------------------------------------------------------
class TForm1 : public TForm
{
__published:    // IDE で管理されるコンポーネント
    TButton *Button1;
    void __fastcall Button1Click(TObject *Sender);
private:    // ユーザー宣言
    float __fastcall TestFunc(void);
public:     // ユーザー宣言
    __fastcall TForm1(TComponent* Owner);
};
//---------------------------------------------------------------------------
extern PACKAGE TForm1 *Form1;
//---------------------------------------------------------------------------
#endif

이유

void __fastcall TForm1::Button1Click(TObject *Sender)
{
    TestFunc();
}

float 형 함수에 return이 없을 때

float __fastcall TForm1::TestFunc(void)
{

}