- Added a `Diagnostics` and `HasDiagnostics` properties to `RazorIRNode`. The `HasDiagnostics` property was necessary in order to traverse nodes without forcibly instantiating their diagnostic lists.
- Added `GetAllDiagnostics` extension method for `RazorIRNode` to provide a way to retrieve all diagnostics that exist on and under a `RazorIRNode`.
- Updated `RazorIRNodeWriter` to display any diagnostics that exist on IR nodes.
- Internal `RazorIRNode`s do not have mutable `Diagnostics` because we don't currently add diagnostics to these elements.
- Added `DefaultIRLoweringPhaseTest` to validate that errors flow from syntax tree to IR document. Also added a missing test.
- Updated the `CSharpLoweringPhaseTest`s to properly validate that errors flow from IR document => csharp document. This resulted in movement of code to the ir lowering phase tests.
#1412
N. Taylor Mullen
Ryan Nowak