Bug 24249 – compiler error in templated class in templated interface implementation class is masked if templated class imports self and interface is instantiated from third module

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.

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