compiler-errors - w3toppers.com

SFINAE tried with bool gives compiler error: “template argument ‘T::value’ involves template parameter” [duplicate]

Actually what you’re doing is forbidden by section §14.5.4/9 which says, A partially specialized non-type argument expression shall not involve a template parameter of the partial specialization except when the argument expression is a simple identifier. The trick could be using a type for second template parameter as well, encapsulating the non-type value, as described … Read more

constexpr not working if the function is declared inside class scope

Yes, it is ill-formed. Here’s why: A constexpr function needs to be defined (not just declared) before being used in a constant expression. So for example: constexpr int f(); // declare f constexpr int x = f(); // use f – ILLEGAL, f not defined constexpr int f() { return 5; } // define f, … Read more

Assert that code does NOT compile

template<class T>struct sink{typedef void type;}; template<class T>using sink_t=typename sink<T>::type; template<typename T, typename=void>struct my_test:std::false_type{}; template<typename T>struct my_test<T, sink_t<decltype( put code here. Note that it must “fail early”, ie in the signature of a function, not in the body )> >:std::true_type {}; The above generates a test if the “put code here” can be evaluated. To determine … Read more

“Are you missing an assembly reference?” compile error – Visual Studio

In my case it was a project defined using Target Framework: “.NET Framework 4.0 Client Profile ” that tried to reference dll projects defined using Target Framework: “.NET Framework 4.0”. Once I changed the project settings to use Target Framework: “.NET Framework 4.0” everything was built nicely. Right Click the project->Properties->Application->Target Framework

Android resource IDs suddenly not final, switch()’es broken

This happened about yesterday, when the SDK/ADT 14 got released: As of ADT 14, resource constants in library projects are no longer final. This is explained in greater detail in http://tools.android.com/tips/non-constant-fields There’s a quickfix available from ADT 14: http://tools.android.com/recent/switchstatementconversion To quote from the rationale: When multiple library projects are combined, the actual values of the … Read more

Error: No module named ‘fcntl’

The fcntl module is not available on Windows. The functionality it exposes does not exist on that platform. If you’re trying to lock a file, there are some other Python modules available which provide that functionality. One I’ve seen referenced in other answers is portalocker.

dereferencing pointer to incomplete type

I saw a question the other day where someone inadvertently used an incomplete type by specifying something like struct a { int q; }; struct A *x; x->q = 3; The compiler knew that struct A was a struct, despite A being totally undefined, by virtue of the struct keyword. That was in C++, where … Read more

IntelliJ Idea, run code regardless of errors in unrelated project files

Modify your configuration to use Make, no error check option instead of Make. For more information see this answer Note that this may not be enough in your use case. Last resort is to use the solution provided by Vics answer.

Why does this Java 8 lambda fail to compile?

Your lambda needs to be congruent with BiConsumer<String, String>. If you refer to JLS #15.27.3 (Type of a Lambda): A lambda expression is congruent with a function type if all of the following are true: […] If the function type’s result is void, the lambda body is either a statement expression (§14.8) or a void-compatible … Read more

How do I call a pointer-to-member-function?

p->pfn is a pointer of pointer-to-member-function type. In order to call a function through such a pointer you need to use either operator ->* or operator .* and supply an object of type C as the left operand. You didn’t. I don’t know which object of type C is supposed to be used here – … Read more