Classfiles getting lost in case-insensitive filesystems

[nicolasstucki]

Compiling

class Foo { def a = 1 }
object Foo { def b = 1 }

produces

public final class Foo$ {
    public static final Foo$ MODULE$;

    static {
        new Foo$();
    }

    public Foo$() {
        MODULE$ = this;
    }

    public int b() {
        return 1;
    }
}

public class Foo {
    public static int b() {
        return Foo$.MODULE$.b();
    }

    public Foo() {
    }

    public int a() {
        return 1;
    }
}

---

Compiling

object Foo { def b = 1 }

produces

public final class Foo$ {
    public static final Foo$ MODULE$;

    static {
        new Foo$();
    }

    public Foo$() {
        MODULE$ = this;
    }

    public int b() {
        return 1;
    }
}

public final class Foo {
    public static int b() {
        return Foo$.MODULE$.b();
    }
}

---

Compiling

class Foo { def a = 1 }
object foo { def b = 1 }

produces

public final class foo$ {
    public static final foo$ MODULE$;

    static {
        new foo$();
    }

    public foo$() {
        MODULE$ = this;
    }

    public int b() {
        return 1;
    }
}

public class Foo {
    public Foo() {
    }

    public int a() {
        return 1;
    }
}

Note that in a case-insensitive filesystem we will try to emit Foo.cass and foo.class and one will overwrite the other.

[nicolasstucki]

tests/pos/test4a.scala and tests/pos/test4refine.scala fail FromTastyTests on Mac. Fix in #4120

[smarter]

If you do:

class Foo
class foo

we warn:

  |Class Foo differs only in case from foo. Such classes will overwrite one another on case-insensitive filesystems.

Apparently we're missing a similar warning when doing:

class Foo
object foo

But otherwise there's nothing we can do, the tests should be fixed by using different names.