Validation: Invalid Function return types

[riederm]

As far as the parser is concerned, a Function can return (and define!!) a lot of different types - but not everything makes sense:

valid return types:

• Array-Types (ARRAY[0..3] OF INT, ...)
• Pointer-Types (POINTER TO INT, ...)
• String-Types (STRING[23], WSTRING[100], ...)
• Scalar Types (INT, BOOL, etc.)

invalid return types:

• Struct-Types ... cannot be assigned because the type is unknown by any caller

FUNCTION foo : STRUCT x : INT; y : INT; END_STRUCT
 ... 
END_FUNCTION

• Enum-Type ... cannot be assigned because the type is unknown by any caller

FUNCTION foo : (green, yellow, red)
 ... 
END_FUNCTION

• VarArgs ... makes no sense

unclear ...

• SubRangeType ... maybe useful ... but will this be enforced by the compiler? i guess not?

[ghaith]

I assume the assignment of Subrange will be validated using the CHECK_XX method as every other variable. Not sure what else we could enforce there.

[riederm]

I assume the assignment of Subrange will be validated using the CHECK_XX method as every other variable. Not sure what else we could enforce there.

Good point ... So it could make sense to be used as a functions return

[create-issue-branch]

Branch issue-273-Validation_Invalid_Function_return_types created!