fix Issue 7511 - attribute inference does not work for methods of templated aggregates
fix Issue 9258 - remove incorrect assertion
Merge pull request #1676 from 9rnsr/fix7511

[enh] Issue 7511 - attribute inference does not work for methods of templated aggregates
Merge pull request #1682 from 9rnsr/fix9258

fix Issue 9258 - remove incorrect assertion
fix Issue 9552 - DMD crashed when taking member delegate from __traits(getOverloads)

This is workaround fix, because essentially we should treat overloaded functions.
Merge pull request #1684 from 9rnsr/fix9552

[REG2.059] Issue 9552 - DMD crashed when taking member delegate from __traits(getOverloads)