Fix Issue 3918 - Parameter use before its use in an AndAnd expression with reals treats NaN as false
[Refactoring] fix indent in IsExp::semantic()
fix Issue 13350 - is(typeof(fun)) causes link error when template fun calls undefined reference

Evaluate the type in IsExp, then unspeculative declared symbols.
Merge pull request #3894 from 9rnsr/fix13350

Issue 13350 - is(typeof(fun)) causes link error when template fun calls undefined reference
Merge pull request #3812 from yebblies/issue3918

Issue 3918 - Parameter use before its use in an AndAnd expression with reals treats NaN as false
[Refactoring] TemplateInstance::semantic()

- Remove a goto jump
- Reduce code indent level
- Use ModToStc in TemplateThisParameter resolution
[Refactoring] Add Module::rootImports() and use it in TemplateInstance::needsCodegen()

it would make compilation a little faster so `rootImports` cache the result.
[Refactoring] Remove the hack code introduced in #1760

AST identity issue has been properly fixed in #3383 (fceb16bbf7).
fix Issue 13417 - segmentation fault when deduce template type
Merge pull request #3945 from 9rnsr/refactor_template

[Refactoring] template.c
fix Issue 13424 - Initialization of delegate to do-nothing default causes segfault at runtime
Merge pull request #3950 from 9rnsr/fix13417

[REG2.066] Issue 13417 - segmentation fault when deduce template type
Merge pull request #3951 from 9rnsr/fix13424

[REG2.066] Issue 13424 - Initialization of delegate to do-nothing default causes segfault at runtime
Remove un-convertable comment
Merge pull request #3955 from yebblies/comment4

[DDMD] Remove un-convertable comment