Generating IR declarations for use-site substitution overrides leads
to IR that is different from K1 as well as problems in signature
generation which relies on mangling. Use-site substitutions can contain
references to type parameters from the call-site which aren't handled
in mangling.
#KT-57022 Fixed
The reason #1 for this feature is that we want to test IdSignatures
generated for declarations. Currently, there is no (easy) way to ensure
that a change in the signature building logic doesn't cause any breaking
changes wrt klibs.
Now, most IdSignatures include hashed mangled names in them, so even if
we catch a regression where the included hash changes, there would be no
way of knowing immediately what caused it, unless we'd also have mangled
names in the expectations.
The reason #2 is to test the manglers themselves. Currently, there are
no tests for them. They heavily duplicate each other, this is already
causing issues (see KT-57427) that would be very hard to catch without
these tests.
^KT-58238 Fixed
Kirill Rakhman