Nested hash generation error - crystal-lang

Question

Given the following code:
require "big"
alias Type = Nil | String | Bool | Int32 | BigFloat | Array(Type) | Hash(String | Symbol, Type)
alias HOpts = Hash(String | Symbol, Type)
ctx = HOpts.new
ctx["test_int"] = 1
ctx["test_s"] = "hello"
c1 = Hash(String, Type).new
ctx["stuff"] = c1
ctx["stuff"]["foo"] = { "bar" => 1 }
I get:
Error in test.cr:13: instantiating 'Hash(String | Symbol, Type)#[]=(String, Hash(String, Type))'
ctx["stuff"] = c1
^
in /opt/crystal/src/hash.cr:43: instantiating 'insert_in_bucket(Int32, String, Hash(String, Type))'
entry = insert_in_bucket index, key, value
^~~~~~~~~~~~~~~~
in /opt/crystal/src/hash.cr:842: instantiating 'Hash::Entry(String | Symbol, Type)#value=(Hash(String, Type))'
entry.value = value
^~~~~
in /opt/crystal/src/hash.cr:881: expanding macro
property value : V
^
in macro 'property' expanded macro: macro_83313872:567, line 10:
1.
2.
3.
4. #value : V
5.
6. def value : V
7. #value
8. end
9.
> 10. def value=(#value : V)
11. end
12.
13.
14.
15.
instance variable '#value' of Hash::Entry(String | Symbol, Type) must be Type, not Hash(String, Type)
I would expect to be able to create any kind of nested hash but it does not work.

Answer 1

There's a couple of things wrong here.
The type of c1 is Hash(String, Type) which is not one of the types of the Type union. Hash(String, Type) is not compatible with Hash(String | Symbol, Type).
Either include Hash(String, Type) in the Type union, or give c1 the type Hash(String | Symbol, Type) (i.e. HOpts):
c1 = HOpts.new
You will also have another error on this line of code:
ctx["stuff"]["foo"] = { "bar" => 1 }
ctx["stuff"] will return an object of type Type and not a hash as you expect. If you know for certain that ctx["stuff"] is a hash (which we do from this example) then you need to restrict its type. Also { "bar" => 1 } is of type Hash(String, Int32) and not Hash(String, Type), so you need to specify this too:
ctx["stuff"].as(HOpts)["foo"] = HOpts{ "bar" => 1 }