Generic callin to generic base method

[stephan]

Currently, type parameters for callin methods are only intended for capturing covariant base method returns. This should be extended to also allow propagating base method type parameters like in

class MyBase {
  <T> T getIt(T it) { return it; }
}
team class MyTeam {
  protected class MyRole playedBy MyBase {
    callin <T> T rm(T it) { return base.rm(it); }
    <T> T rm(T it) <- replace <T> T getIt(T it);
  }
}

Here the type parameters <T> of both sides of the callin binding should be identified.

This requires the following changes (otjld and compiler):

• type parameters of callin method must be discriminated into free parameters (capturing covariant return) and propagating parameters
• type parameters of role and base method specs need to be checked against each other
• rule OTJLD §4.1(a) can not be checked inspecting only the callin method but requires the callin binding, too. Thus, the mentioned paragraph must be rephrased.
• Also propagating type parameters should be mentioned in the rules.

The disabled test A.1.1-otjld_generic-feature-in-base-3ci serves as a witness.

[stephan]

Thinking more about it appears that there is no use in specifying type parameters in a callin RHS. Thus the above example must be updated to

class MyBase {
  <T> T getIt(T it) { return it; }
}
team class MyTeam {
  protected class MyRole playedBy MyBase {
    callin <T> T rm(T it) { return base.rm(it); }
    <T> T rm(T it) <- replace T getIt(T it);
  }
}

As a consequence bullet 2 of above list is obsolete.

r22413 implements the new syntax error message -- tested by A.1.1-otjld-generic-feature-in-base-3cif.

A.1.1-otjld-generic-feature-in-base-3cig additionally tests plainly unresolved type in this kind of callin.

[stephan]

The OTJLD is updated in r22415.

[stephan]

Eugene Hutorny reported similar problems, see new (disabled) tests A.1.1-otjld_generic-feature-in-base-3cib and A.1.1-otjld_generic-feature-in-base-3cibf.

[stephan]

r23201 (implementation) and r23202 (tests) should solve this issue, full test run pending.

[stephan]

Tests passed. Closing.