fix #186 improving abstract class based closure support

lib/mirah/ast/structure.rb

@@ -143,15 +143,23 @@ def initialize(parent, position, &block)
 
     def prepare(typer, method)
       mirah = typer.transformer
-      interface = method.argument_types[-1]
+      interface_or_abstract_class = method.argument_types[-1]
       outer_class = scope.defining_class
 
       binding = scope.binding_type(mirah)
 
       name = "#{outer_class.name}$#{mirah.tmp}"
 
       klass = mirah.define_closure(position, name, outer_class)
-      klass.interfaces = [interface]
+      case
+      when interface_or_abstract_class.interface?
+        klass.interfaces = [interface_or_abstract_class]
+      when interface_or_abstract_class.abstract?
+        klass.superclass = interface_or_abstract_class
+      else
+        raise "#{interface_or_abstract_class.name} isn't an interface or abstract"
+      end
+
       klass.define_constructor(position,
                                ['binding', binding]) do |c|
           mirah.eval("@binding = binding", '-', c, 'binding')
@@ -205,7 +213,7 @@ def add_methods(klass, binding, typer)
 
     def build_method(klass, binding, typer)
       # find all methods which would not otherwise be on java.lang.Object
-      impl_methods = find_methods(klass.interfaces).select do |m|
+      impl_methods = find_abstract_methods(klass).select do |m|
         begin
           # Very cumbersome. Not sure how it got this way.
           mirror = BiteScript::ASM::ClassMirror.for_name('java.lang.Object')
@@ -241,14 +249,18 @@ def build_method(klass, binding, typer)
       end
     end
 
-    def find_methods(interfaces)
+    def find_abstract_methods(klass)
       methods = []
-      interfaces = interfaces.dup
+      interfaces = klass.interfaces.dup
       until interfaces.empty?
         interface = interfaces.pop
         methods += interface.declared_instance_methods.select {|m| m.abstract?}
         interfaces.concat(interface.interfaces)
       end
+
+      if klass.superclass && klass.superclass.abstract?
+        methods += klass.superclass.declared_instance_methods.select{|m| m.abstract? }
+      end
       methods
     end
   end

lib/mirah/jvm/method_lookup.rb

@@ -21,6 +21,7 @@ def log(msg); end
 
       def find_method(mapped_type, name, mapped_params, meta)
         raise ArgumentError if mapped_params.any? {|p| p.nil?}
+
         if name == 'new'
           if meta
             name = "<init>"

lib/mirah/jvm/types/type.rb

@@ -52,6 +52,10 @@ def interface?
           # mirrors for all incoming types without blowing up on e.g. 'boolean' or 'int'
           (@type || BiteScript::ASM::ClassMirror.for_name(@name)).interface? rescue nil
         end
+
+        def abstract?
+          (@type || BiteScript::ASM::ClassMirror.for_name(@name)).abstract? rescue nil
+        end
 
         def dynamic?
           false
@@ -76,7 +80,7 @@ def assignable_from?(other)
           return true if other.error? || other.unreachable?
 
           # TODO should we allow more here?
-          return interface? if other.block?
+          return interface? || abstract? if other.block?
 
           return true if jvm_type && (jvm_type == other.jvm_type)
 
@@ -170,4 +174,4 @@ def aload(builder)
       end
     end
   end
-end
+end

lib/mirah/transform/helper.rb

@@ -762,4 +762,4 @@ def transform_annotation(node, parent)
       end
     end
   end
-end
+end

test/jvm/blocks_test.rb

@@ -24,7 +24,7 @@ def setup
   def parse_and_type code, name=tmp_script_name
     parse_and_resolve_types name, code
   end
-  
+
   #this should probably be a core test
   def test_empty_block_parses_and_types_without_error
     assert_nothing_raised do
@@ -259,4 +259,20 @@ def foo(a:Bar)
         end
       CODE
   end
+
+  def test_method_requiring_subclass_of_abstract_class_finds_abstract_method
+    cls, = compile(<<-EOF)
+      import java.io.OutputStream
+      def foo x:OutputStream
+        x.write byte(1)
+      rescue
+      end
+      foo do |b:int|
+        puts "writing"
+      end
+    EOF
+    assert_output "writing\n" do
+      cls.main(nil)
+    end
+  end
 end