This change defines stages for IR processing. The comments in RazorIRPass
really explain the details. I've also made the preliminary changes to the
stuff we've built so far to follow the new conventions.
This is building towards multitargeting for Razor, being able to target
both Razor Pages and Razor MVC Views from the same engine, being able to
target different codegen and methods from within the same engine.
- Previously we'd special case `@section` at code generation time; now we transform the directive into an IR node.
- Changed the expectations of `DefineSection` to not take in a section writer. It's now expected to modify what `Write`, `WriteLiteral` etc. write to when inside of the lambda. This is done today in TagHelpers via `StartTagHelperWritingScope`.
- Updated baseline files to reflect new `DefineSection` expectations.
- Updated IR tests since we no longer leave around `DirectiveIRNode`s.
#901
Ryan Nowak
N. Taylor Mullen