Convert self to ClassInstance when #initialize method

[ksss]

In a class, the #initialize method is often copied as the type for the .new method.
In this case, if self is used in the type definition, they are copied as is.
As a result, a problem has been reported by @rhiroe where self is treated as singleton(Foo) even though it was written as self in the context of #initialize.

I aim to solve this by dynamically rewriting the type when it is copied from #initialize to .new.

Real problem

bn = OpenSSL::BN.new(1)
OpenSSL::BN.new(bn)

$ bundle exec steep check
# Type checking files:

.F

sample.rb:9:0: [error] Cannot find compatible overloading of method `new` of type `singleton(::OpenSSL::BN)`
│ Method types:
│   def new: (singleton(::OpenSSL::BN)) -> ::OpenSSL::BN
│          | (::Integer) -> ::OpenSSL::BN
│          | (::string) -> ::OpenSSL::BN
│          | (::string, (0 | 2 | 10 | 16)) -> ::OpenSSL::BN
│
│ Diagnostic ID: Ruby::UnresolvedOverloading
│
└ OpenSSL::BN.new(bn)
  ~~~~~~~~~~~~~~~~~~~

Detected 1 problem from 1 file

With Generics

# foo.rbs
class Foo[T]
  def initialize: () { (self, class, instance) -> void } -> void
end

Before

# foo.rb
Foo.new do |s, c, i|
  s #=> singleton(Foo)
  c #=> singleton(Foo)
  i #=> Foo[untyped]
end

After

# foo.rb
Foo.new do |s, c, i|
  s #=> Foo[untyped]         <- Fixed only here
  c #=> singleton(Foo)
  i #=> Foo[untyped]
end

[ksss]

Before the changes

Failure: test_new(OpenSSLBNSingletonTest):
  Call trace does not match one of method definitions:
    #<struct RBS::Test::CallTrace method_name=:new, method_call=<RBS::Test::ArgumentsReturn:@arguments: [#<OpenSSL::BN:0x00000001279b8b38>], @exit_value: #<OpenSSL::BN:0x0000000127951e10>, @exit_type: :return>, block_calls=[], block_given=false>
    (self) -> ::OpenSSL::BN | (::Integer) -> ::OpenSSL::BN | (::string) -> ::OpenSSL::BN | (::string, 0 | 2 | 10 | 16) -> ::OpenSSL::BN.
  <false> is not true.
/Users/ksss/src/github.com/ksss/rbs/lib/rbs/unit_test/type_assertions.rb:187:in 'block in RBS::UnitTest::TypeAssertions#assert_send_type'
/Users/ksss/src/github.com/ksss/rbs/lib/rbs/unit_test/type_assertions.rb:168:in 'RBS::UnitTest::TypeAssertions#send_setup'
/Users/ksss/src/github.com/ksss/rbs/lib/rbs/unit_test/type_assertions.rb:172:in 'RBS::UnitTest::TypeAssertions#assert_send_type'
test/stdlib/OpenSSL_test.rb:237:in 'OpenSSLBNSingletonTest#test_new'
     234:   end
     235:
     236:   def test_new
  => 237:     assert_send_type "(::OpenSSL::BN) -> OpenSSL::BN",
     238:       OpenSSL::BN, :new, OpenSSL::BN.new(3)
     239:   end
     240: end