This refactoring moves code around between a few of the ngtsc subpackages,
with the goal of having a more logical package structure. Additional
interfaces are also introduced where they make sense.
The 'metadata' package formerly contained both the partial evaluator,
the TypeScriptReflectionHost as well as some other reflection functions,
and the Reference interface and various implementations. This package
was split into 3 parts.
The partial evaluator now has its own package 'partial_evaluator', and
exists behind an interface PartialEvaluator instead of a top-level
function. In the future this will be useful for reducing churn as the
partial evaluator becomes more complicated.
The TypeScriptReflectionHost and other miscellaneous functions have moved
into a new 'reflection' package. The former 'host' package which contained
the ReflectionHost interface and associated types was also merged into this
new 'reflection' package.
Finally, the Reference APIs were moved to the 'imports' package, which will
consolidate all import-related logic in ngtsc.
PR Close#27743
Template type-checking will make use of expression and statement
translation as well as the ImportManager, so this code needs to
live in a separate build target which can be depended on by both
the main ngtsc transform as well as the template type-checking
mechanism. This refactor introduces a separate build target
for that code.
PR Close#26203