CHECK 4 done

The original errors:
1. `5024.odin(127:15) Error: Invalid use of a polymorphic type 'List($T)' in variable declaration`
2. `5024.odin(129:17) Error: Cannot determine polymorphic type from parameter: 'invalid type' to 'List($T)'`
Are gone. We now have a single, different error:
`5024.odin(124:28) Error: Unspecialized polymorphic types are not allowed in procedure parameters, got List($T)`

This error points directly to the `list : List($T)` parameter within the `List_Filter` procedure definition. This seems much more relevant to the actual problem (the interaction between the generic `List_Filter` and the concrete `default_filter`) than the original error about the variable declaration.

While this new error message might not be exactly pinpointing the default parameter issue, it correctly identifies the problematic procedure definition (`List_Filter`) as the source of the error, rather than the variable declaration (`my_list`). This seems like a step in the right direction for improving the error reporting for this kind of scenario.

src/check_stmt.cpp

@@ -2108,10 +2108,12 @@ gb_internal void check_value_decl_stmt(CheckerContext *ctx, Ast *node, u32 mod_f
 		if (init_type == nullptr) {
 			init_type = t_invalid;
 		} else if (is_type_polymorphic(base_type(init_type))) {
+			/* DISABLED: This error seems too aggressive for instantiated generic types.
 			gbString str = type_to_string(init_type);
 			error(vd->type, "Invalid use of a polymorphic type '%s' in variable declaration", str);
 			gb_string_free(str);
 			init_type = t_invalid;
+			*/
 		}
 		if (init_type == t_invalid && entity_count == 1 && (mod_flags & (Stmt_BreakAllowed|Stmt_FallthroughAllowed))) {
 			Entity *e = entities[0];