handle constant conversionn of type alias

slither/slithir/convert.py

@@ -1667,7 +1667,10 @@ def convert_constant_types(irs):
                         if isinstance(ir.rvalue, TupleVariable):
                             # TODO: fix missing Unpack conversion
                             continue
-                        if ir.rvalue.type.type not in ElementaryTypeInt:
+                        if isinstance(ir.rvalue.type, TypeAlias):
+                            ir.rvalue.set_type(ElementaryType(ir.lvalue.type.name))
+                            was_changed = True
+                        elif ir.rvalue.type.type not in ElementaryTypeInt:
                             ir.rvalue.set_type(ElementaryType(ir.lvalue.type.type))
                             was_changed = True
             if isinstance(ir, Binary):

tests/ast-parsing/user_defined_value_type/constant-0.8.9.sol

@@ -1,5 +1,5 @@
 type T is int224;
-pragma solidity >= 0.8.12;
+pragma solidity ^0.8.9;
 contract C {
   T constant public s = T.wrap(int224(165521356710917456517261742455526507355687727119203895813322792776));
   T constant public t = s;