PR# 19441 [er] Typing issue with empty manifest array

When I write code like that:

~~~~
local
    a: ARRAY [INTEGER]
do 
    a := <<{INTEGER_8} 1>>
~~~~

the compiler will create an ARRAY [INTEGER] (not an ARRAY [INTEGER_8] as per the new types for manifest arrays) so that existing code still works.

However, when I write:

~~~~
local
    a: ARRAY [INTEGER]
do 
    a := <<>>
~~~~

the compiler does not create an ARRAY [INTEGER] but an ARRAY [NONE]. This is plain wrong because ARRAY [NONE] does not conform to ARRAY [INTEGER]. When I write:

~~~~
local
    a: ARRAY [INTEGER]
    n: ARRAY [NONE]
do 
    create n.make_empty
    a := n
~~~~

I get a compilation error as expected. So ARRAY [NONE} definitely does not conform to ARRAY [INTEGER]. But here:

~~~~
local
    a: ARRAY [INTEGER]
do 
    a := <<>>
    if not attached {ARRAY [INTEGER]} a then
        print ("Dynamic type does not conform to static type")
    end
~~~~

the message gets printed!

The solutions are  either to let the compiler create an empty ARRAY [INTEGER] instead of an ARRAY [NONE] (preferred solution), or emit a compilation error.

--
Eric Bezault