• d-bugmail puremagic.com (73/73) Nov 19 2023 https://issues.dlang.org/show_bug.cgi?id=24249

d-bugmail puremagic.com writes:

https://issues.dlang.org/show_bug.cgi?id=24249

          Issue ID: 24249
           Summary: compiler error in templated class in templated
                    interface implementation class is masked if templated
                    class imports self and interface is instantiated from
                    third module
           Product: D
           Version: D2
          Hardware: x86_64
                OS: Linux
            Status: NEW
          Severity: major
          Priority: P1
         Component: dmd
          Assignee: nobody puremagic.com
          Reporter: d.bugs webfreak.org

reproduction:
```
// console.d
module console;

final class PosixEventDriverConsole(T) {
        import posixdriver;

        void compilerError(int x)
        {
                foo(x.nonExistant);
        }
}
```

```
// posixdriver.d
module posixdriver;

import console;

interface EventDriver {
        bool dispose();
}

final class PosixEventDriver(Loop) : EventDriver {
        private {
                alias ConsoleDriver = PosixEventDriverConsole!Loop;

                ConsoleDriver m_console;
        }

        override bool dispose()
        {
                return false;
        }
}
```

```
// app.d
import posixdriver;

alias EpollEventDriver = PosixEventDriver!int;
```

compiling with `dmd app.d console.d posixdriver.d` errors with:

```
posixdriver.d(9): Error: class
`posixdriver.PosixEventDriver!int.PosixEventDriver` interface function `bool
dispose()` is not implemented
app.d(3): Error: template instance `posixdriver.PosixEventDriver!int` error
instantiating
posixdriver.d(11): Error: template instance
`console.PosixEventDriverConsole!int` error instantiating
app.d(3):        instantiated from here: `PosixEventDriver!int`
```

when you remove the `import posixdriver;` inside console.d the error message
changes to the expected one:

```
console.d(8): Error: undefined identifier `foo`
posixdriver.d(11): Error: template instance
`console.PosixEventDriverConsole!int` error instantiating
app.d(3):        instantiated from here: `PosixEventDriver!int`
```

In big code bases this makes the coding error almost impossible to find since
the error indicates a vastly different location.

--