compiler-errors

问题 I have this error How to fix it? Caused by: java.lang.IllegalArgumentException: Unsupported class file major version 57 I have such POM <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.1.5.RELEASE</version> </parent> <properties> <java.version>13</java.version> </properties> Project has many literals, so Java 13 is required. 回答1: Changing Spring boot version in the pom.xml solved this issue for me. <parent> <groupId>org

问题 There are two projects, one is a library targeting .NET Standard 2.0, while the other is a console app targeting .NET Core 2.2. Now this piece of code is working on .NET Standard 2.0 library, but not on .NET Core 2.2. for (int i = 0; i < 1; i++) { var y = new int[1].First(i => i == 0); // Conflict i name error here in .NET Core 2.2. Console.WriteLine("Hello " + y); } I understand from this question that simple names should not have different meanings, and thus, even .NET Standard 2.0 library

问题 How can I ensure that a type implements an interface at compile time? The typical way to do this is by failure to assign to support interfaces from that type, however I have several types that are only converted dynamically. At runtime this generates very gruff error messages, without the better diagnostics given for compile time errors. It's also very inconvenient to find at run time that types I expected to support interfaces, do in fact not. 回答1: Assuming the question is about Go, e.g. var

问题 How can I ensure that a type implements an interface at compile time? The typical way to do this is by failure to assign to support interfaces from that type, however I have several types that are only converted dynamically. At runtime this generates very gruff error messages, without the better diagnostics given for compile time errors. It's also very inconvenient to find at run time that types I expected to support interfaces, do in fact not. 回答1: Assuming the question is about Go, e.g. var

问题 I'm getting a "Compile Error: Syntax Error" when running the code below using Excel 2019. It works with the older version Excel, but not on 2019. How can I fix this and what's causing it? the error line ReportSheet.ExportAsFixedFormat Type:=xlTypePDF, Filename:= _ ThisWorkbook.Path & "\" & Cell, _ Quality:=xlQualityStandard, IncludeDocProperties:=True, _ IgnorePrintAreas:=True, OpenAfterPublish:=False The entire code Option Explicit Private Sub CommandButton1_Click() Dim MyFolder As String,

问题 I have been getting the following error message when trying to apply the switchMap operator to my Observable: Property 'switchMap' does not exist on type 'Observable'. I'm currently using rxjs version 5.5.2, and in my component, I have it imported like so: import 'rxjs/operator/switchMap'; However, I still get a compilation error. I have looked at similar questions and have not found a proper solution to this, any suggestions on what could be the issue here? get appUser$() : Observable

问题 I am trying to use a type in another type. However, I just cannot make it compile. It is strange to me: the select type thing works in the main program but it doesn't work in a subroutine the type. module ModBuffer implicit none private type, abstract, public :: Buffer contains procedure, public :: Constructor endtype Buffer type, extends(Buffer), public :: BufferR real(8), allocatable, public :: BufData(:,:,:) endtype BufferR type, extends(Buffer), public :: BufferI complex(8), allocatable,

问题 For example: use futures::future::Future; fn main() { let (stop_tokio, time_to_stop) = tokio::sync::oneshot::channel::<()>(); let handler = std::thread::spawn(|| { tokio::run( time_to_stop, // .map_err(|_| ()) ); }); handler.join().expect("join failed"); } The compiler prints the error: error[E0271]: type mismatch resolving `<tokio_sync::oneshot::Receiver<()> as futures::future::Future>::Error == ()` --> src/main.rs:6:9 | 6 | tokio::run( | ^^^^^^^^^^ expected struct `tokio_sync::oneshot:

问题 For example: use futures::future::Future; fn main() { let (stop_tokio, time_to_stop) = tokio::sync::oneshot::channel::<()>(); let handler = std::thread::spawn(|| { tokio::run( time_to_stop, // .map_err(|_| ()) ); }); handler.join().expect("join failed"); } The compiler prints the error: error[E0271]: type mismatch resolving `<tokio_sync::oneshot::Receiver<()> as futures::future::Future>::Error == ()` --> src/main.rs:6:9 | 6 | tokio::run( | ^^^^^^^^^^ expected struct `tokio_sync::oneshot:

问题 I get a compiler error when using an Objective-C object within a switch statement: switch (myConstant) { case 0: UIViewController *myController = [[[UIViewController alloc] init] autorelease]; [self.navigationController pushViewController:myViewController animated:YES]; break; case 1: // stuff break; default: break; } The error states: Expected expression before 'UIViewController' 'myViewController' undeclared (first use in this function) I understand that the second error is a direct result