fix

vlib/v/tests/generics/generic_selector_field_test.v

@@ -0,0 +1,29 @@
+module main
+
+struct Demo[T] {
+mut:
+	val T
+}
+
+type DemoType = int | []DemoType
+
+fn test_main() {
+	assert decode[Demo[[]DemoType]]() == Demo[[]DemoType]{}
+	assert decode[Demo[DemoType]]() == Demo[DemoType]{}
+}
+
+fn decode[T]() T {
+	mut typ := T{}
+	typ.val = decode_x(typ.val)
+	return typ
+}
+
+fn decode_x[T](_ T) T {
+	mut field := T{}
+	$if T is int {
+		field = 0
+	} $else $if T is $array {
+		field = []DemoType{}
+	}
+	return field
+}

vlib/v/type_resolver/generic_resolver.v

@@ -342,6 +342,9 @@ pub fn (mut t TypeResolver) resolve_args(cur_fn &ast.FnDecl, func &ast.Fn, mut n
 			} else {
 				comptime_args[k] = ctyp
 			}
+		} else if mut call_arg.expr is ast.SelectorExpr
+			&& call_arg.expr.expr_type.has_flag(.generic) {
+			comptime_args[k] = t.typeof_type(call_arg.expr, call_arg.expr.typ)
 		}
 	}
 	return comptime_args