fix Issue 11039 - Undefined instantiation from circular imports
Fixes Issue 10099 - Better diagnostic for a disabled default constructor.
Merge pull request #2572 from AndrejMitrovic/Fix10099

Issue 10099 - Better diagnostic for a disabled default constructor.
Merge pull request #2556 from WalterBright/fix11039

fix Issue 11039 - Undefined instantiation from circular imports
Improve error propagation around template instantiation
fix Issue 11054 - ICE: interpret.c:357: virtual void Statement::ctfeCompile(CompiledCtfeFunction*): Assertion `0' failed.