Macros: undefined method `block' for nil:NilClass

[jstepien]

$ cat Macros.mirah 
class Macros
  def initialize
    @foo = "It works."
  end

  macro def attr_reader(name_node)
    name = name_node.string_value
    quote {
      def `name`
        @`name`
      end
    }
  end

  attr_reader :foo
end

mirahc Macros.mirah with Mirah 0.0.11 and JRuby 1.6.7 works fine, however translating to Java causes a following error.

$ mirahc --java Macros.mirah 
Parsing...
  Macros.mirah
Inferring types...
Compiling...
  Macros.mirah
Macros.mirah:15: undefined method `block' for nil:NilClass
  attr_reader :foo
^^^^^^^^^^^^^^^^^^
Mirah::InternalCompilerError: undefined method `block' for nil:NilClass
             compile at mirah-0.0.11-java/lib/mirah/compiler/structure.rb:32
                send at org/jruby/RubyKernel.java:2084
  <Class:0x1de40494> at file:jruby-complete-1.6.7.jar!/META-INF/jruby.home/lib/ruby/1.8/delegate.rb:292
         maybe_store at mirah-0.0.11-java/lib/mirah/jvm/compiler/java_source.rb:351
                body at mirah-0.0.11-java/lib/mirah/jvm/compiler/java_source.rb:357
                body at mirah-0.0.11-java/lib/mirah/jvm/compiler/base.rb:212
                body at mirah-0.0.11-java/lib/mirah/jvm/compiler/java_source.rb:356
             compile at mirah-0.0.11-java/lib/mirah/compiler/structure.rb:21
         maybe_store at mirah-0.0.11-java/lib/mirah/jvm/compiler/java_source.rb:351
                body at mirah-0.0.11-java/lib/mirah/jvm/compiler/java_source.rb:357
                body at mirah-0.0.11-java/lib/mirah/jvm/compiler/base.rb:212
                body at mirah-0.0.11-java/lib/mirah/jvm/compiler/java_source.rb:356
             compile at mirah-0.0.11-java/lib/mirah/compiler/structure.rb:21
        define_class at mirah-0.0.11-java/lib/mirah/jvm/compiler/java_source.rb:65
                with at mirah-0.0.11-java/lib/mirah/jvm/compiler/base.rb:260
        define_class at mirah-0.0.11-java/lib/mirah/jvm/compiler/java_source.rb:61
             compile at mirah-0.0.11-java/lib/mirah/compiler/class.rb:20
         maybe_store at mirah-0.0.11-java/lib/mirah/jvm/compiler/java_source.rb:351
                body at mirah-0.0.11-java/lib/mirah/jvm/compiler/java_source.rb:357
                body at mirah-0.0.11-java/lib/mirah/jvm/compiler/base.rb:212
                body at mirah-0.0.11-java/lib/mirah/jvm/compiler/java_source.rb:356
             compile at mirah-0.0.11-java/lib/mirah/compiler/structure.rb:21
         define_main at mirah-0.0.11-java/lib/mirah/jvm/compiler/base.rb:94
             compile at mirah-0.0.11-java/lib/mirah/compiler/structure.rb:50
         compile_ast at mirah-0.0.11-java/lib/mirah/compiler.rb:49
        compile_asts at mirah-0.0.11-java/lib/mirah/compiler.rb:40
                each at org/jruby/RubyArray.java:1615
        compile_asts at mirah-0.0.11-java/lib/mirah/compiler.rb:38
            generate at mirah-0.0.11-java/lib/mirah/generator.rb:38
             execute at mirah-0.0.11-java/lib/mirah/commands/compile.rb:26
        execute_base at mirah-0.0.11-java/lib/mirah/commands/base.rb:44
               catch at org/jruby/RubyKernel.java:1183
        execute_base at mirah-0.0.11-java/lib/mirah/commands/base.rb:42
             execute at mirah-0.0.11-java/lib/mirah/commands/compile.rb:23
             compile at mirah-0.0.11-java/lib/mirah.rb:40
              (root) at mirah-0.0.11-java/bin/mirahc:27
                load at org/jruby/RubyKernel.java:1058
              (root) at mirahc:19

[jstepien]

The issue is present on current master, a86c365. Apparently the error is caused by calling @method.block in Mirah::JVM::Compiler::JavaSource#scoped_body with @method being nil.

[baroquebobcat]

Thanks for the report, I'll look at it this weekend if someone else doesn't get to it.

[baroquebobcat]

It appears to have something to do w/ how the AST is handled when there isn't an implicit main method. https://github.com/mirah/mirah/blob/master/test/jvm/macros_test.rb#L63 has the same error if you comment out the implicit main.

[baroquebobcat]

Ah, maybe that's because when there's a main method, there's a @method in the generator the whole time.