A quirk of the Angular template parser is that when parsing templates in the
"default" mode, with options specified by the user, the source mapping
information in the template AST may be inaccurate. As a result, the compiler
parses the template twice: once for "emit" and once to produce an AST with
accurate sourcemaps for diagnostic production.
Previously, only the first parse was performed during analysis. The second
parse occurred during the template type-checking phase, just in time to
produce the template type-checking file.
However, with the reuse of analysis results during incremental builds, it
makes more sense to do the diagnostic parse eagerly during analysis so that
the work isn't unnecessarily repeated in subsequent builds. This commit
refactors the `ComponentDecoratorHandler` to do both parses eagerly, which
actually cleans up some complexity around template parsing as well.
PR Close#34334
af95dddd7e