more error propagation
[Refactoring] Reorder TemplateInstance member functions

Sort them based on the semantic order.
[Refactoring] bool TemplateInstance::hasNestedArgs(...)
[Refactoring] Add Module::isRoot()
fix Issue 11062 - inline ice with alias this and opIndexAssign
Merge pull request #2576 from 9rnsr/fix11062

[REG2.06a] Issue 11062 - inline ice with alias this and opIndexAssign
refactor enum code
Merge pull request #2568 from WalterBright/enum-refactor

refactor enum code to do forward references of members
Merge pull request #2574 from 9rnsr/refactor_root

[Refactoring] Add Module::isRoot()
Merge pull request #2573 from 9rnsr/refactor_template

[Refactoring] Reorder TemplateInstance member functions
Merge pull request #2535 from WalterBright/statement-errors

more error propagation