initialize's default arguments are incorrectly evaluated at the class scope

[Codcore]

Code:
(http://carc.in/#/r/1kr)

class My
  def initialize(@name=self)
  end

  def display_self
    string = " #{@name.class}"
    puts string
  end
end

my = My.new
my.display_self

Output:

; ModuleID = 'My'

%String = type { i32, i32, i32, i8 }
%My = type { i32, i32 }
%"String::Builder" = type { i32, i8*, i32, i32, i1 }

@symbol_table = external global [1 x %String*]
@str = private constant { i32, i32, i32, [2 x i8] } { i32 1, i32 1, i32 1, [2 x i8] c" \00" }

define %My* @"*My::new:My"() {
entry:
  %0 = call %My* @"*My::new<My:Class>:My"(i32 330)
  ret %My* %0
}

define %My* @"*My::new<My:Class>:My"(i32 %name) {
alloca:
  %_ = alloca %My*
  br label %entry

entry:                                            ; preds = %alloca
  %0 = call i8* @__crystal_malloc(i32 trunc (i64 mul nuw (i64 ptrtoint (i32* getelementptr (i32* null, i32 1) to i64), i64 2) to i32))
  %1 = bitcast i8* %0 to %My*
  %2 = bitcast %My* %1 to i8*
  call void @llvm.memset.p0i8.i32(i8* %2, i8 0, i32 trunc (i64 mul nuw (i64 ptrtoint (i32* getelementptr (i32* null, i32 1) to i64), i64 2) to i32), i32 4, i1 false)
  %3 = getelementptr inbounds %My* %1, i32 0, i32 0
  store i32 72, i32* %3
  store %My* %1, %My** %_
  %4 = load %My** %_
  %5 = call i32 @"*My#initialize<My, My:Class>:My:Class"(%My* %4, i32 %name)
  %6 = load %My** %_
  %7 = call i1 @"*GC::add_finalizer<My>:Nil"(%My* %6)
  %8 = load %My** %_
  ret %My* %8
}

declare i8* @__crystal_malloc(i32)

; Function Attrs: nounwind
declare void @llvm.memset.p0i8.i32(i8* nocapture, i8, i32, i32, i1) #0

define i32 @"*My#initialize<My, My:Class>:My:Class"(%My* %self, i32 %name) {
entry:
  %0 = getelementptr inbounds %My* %self, i32 0, i32 1
  store i32 %name, i32* %0
  ret i32 %name
}

declare i1 @"*GC::add_finalizer<My>:Nil"(%My*)

define i1 @"*My#display_self<My>:Nil"(%My* %self) {
alloca:
  %string = alloca %String*

entry:                                            ; No predecessors!
  %0 = call %"String::Builder"* @"*String::Builder::new:String::Builder"()
  %1 = call %"String::Builder"* @"*String::Builder@IO#<<<String::Builder, String>:String::Builder"(%"String::Builder"* %0, %String* bitcast ({ i32, i32, i32, [2 x i8] }* @str to %String*))
}

declare %"String::Builder"* @"*String::Builder::new:String::Builder"()

declare %"String::Builder"* @"*String::Builder@IO#<<<String::Builder, String>:String::Builder"(%"String::Builder"*, %String*)

attributes #0 = { nounwind }

Bug: trying to downcast Class <- My
_init +170751 [0]
_init +3262746 [0]
_init +3257455 [0]
_init +3389123 [0]
_init +3311148 [0]
_init +3284496 [0]
_init +3356460 [0]
_init +3310937 [0]
_init +3284496 [0]
_init +3355957 [0]
_init +3310937 [0]
_init +3284496 [0]
_init +3442057 [0]
_init +3287946 [0]
_init +3287030 [0]
_init +3364619 [0]
_init +3360521 [0]
_init +3313364 [0]
_init +3284496 [0]
_init +3159268 [0]
_init +3145978 [0]
_init +2421205 [0]
_init +215240 [0]
_init +194090 [0]
__libc_start_main +247 [0]
_init +167719 [0]

Error: you've found a bug in the Crystal compiler. Please open an issue: https://github.com/manastech/crystal/issues

[asterite]

Thanks! I changed the subject, "Crystal bug found" is too generic :-)

The real bug is this:

class My
  getter name

  def initialize(name = self.foo)
    @name = name
  end

  def foo
    1
  end
end

my = My.new
puts my.name

Says "undefined method 'foo' for My:Class"... the default argument is being evaluated on the class scope, not the instance.

Then there's the other bug about the class casting.

[bcardiff]

¿Should be that allowed at all? Sending messages to self before it is initialized seems a bad idea.
The instance variables will not be set at all. In the sample @asterite foo is constant, but will leads to error or garbage. There will be too much dependency on how code like

class My
  getter name

  def initialize(@name, @caps = self.name.upcase)
  end
end

is expanding.

Allowing just self seems formally right thou.