In TopDownAnalyzerFacadeForJVM, we now always use the "load built-ins
from module dependencies" behavior that was previously only enabled with
the dedicated CLI argument -Xload-builtins-from-dependencies. However,
sometimes we compile code without kotlin-stdlib in the classpath, and we
don't want everything to crash because some standard type like
kotlin.Unit hasn't been found.
To mitigate this, we add another module at the end of the dependencies
list, namely a "fallback built-ins" module. This module loads all
built-in declarations from the compiler's class loader, as was done by
default previously. This prevents the compiler from crashing if any
built-in declaration is not found, but compiling the code against
built-ins found in the compiler is still discouraged, so we report an
error if anything is resolved to a declaration from this module, via a
new checker MissingBuiltInDeclarationChecker.
Also introduce a new CLI argument -Xsuppress-missing-builtins-error
specifically to suppress this error and to allow compiling code against
compiler's own built-ins.
#KT-19227 Fixed
#KT-28198 Fixed
Previously ReflectionTypes.find returned an error class in case a class
is not found in the module dependencies. The problem with this approach
is that each call site should call ErrorUtils.isError on the result and
report an error if needed, in order to stop this type from reaching the
codegen, which can't handle error types.
Now we create a MockClassDescriptor instance instead. It's not an error
class, so it'll be handled correctly in the codegen. Also its scope is
empty and errors are reported on any non-trivial usage (see
MissingDependencyClassChecker), so this approach is not worse than error
classes
#KT-16484 Fixed
Introduce a new method KotlinClassFinder#findBuiltInsData, which is only
implemented correctly in the JvmCliVirtualFileFinder because it's only used in
the compiler code at the moment.
Introduce JvmBuiltInsPackageFragmentProvider, the purpose of which is to look
for .kotlin_builtins files in the classpath and provide definitions of
built-ins from those files.
Also exclude script.runtime from compilation because, as other excluded
modules, it has no dependency on the stdlib and is no longer compilable from
the IDE now, because it cannot resolve built-ins from anywhere
Ilya Gorbunov