cgen: fix or expr with non option fn call return (fix #21660) (#21661)

vlib/v/gen/c/cgen.v

@@ -6956,7 +6956,7 @@ fn (mut g Gen) gen_or_block_stmts(cvar_name string, cast_typ string, stmts []ast
 							&& g.table.final_sym(return_type).kind == .array_fixed
 						if !is_array_fixed {
 							if g.inside_return && !g.inside_struct_init
-								&& expr_stmt.expr is ast.CallExpr
+								&& expr_stmt.expr is ast.CallExpr&& (expr_stmt.expr as ast.CallExpr).return_type.has_option_or_result()
 								&& g.cur_fn.return_type.has_option_or_result()
 								&& return_type.has_option_or_result()
 								&& expr_stmt.expr.or_block.kind == .absent {

vlib/v/tests/option_or_expr_with_non_opt_test.v

@@ -0,0 +1,40 @@
+pub struct Foo {
+	a int
+	b int
+}
+
+pub fn (f Foo) hello() ! {
+	println('Hello')
+}
+
+fn default_foo() IFoo {
+	return Foo{}
+}
+
+fn default_bar() IFoo {
+	return Foo{}
+}
+
+pub struct Bar {
+	foo ?IFoo
+	bar ?IFoo
+}
+
+pub interface IFoo {
+	hello() !
+}
+
+pub fn (b Bar) get_foo(baz string) !IFoo {
+	if baz == 'foo' {
+		return b.foo or { default_foo() }
+	} else if baz == 'bar' {
+		return b.bar or { default_bar() }
+	}
+	return error('unknown baz ${baz}')
+}
+
+fn test_main() {
+	a := Bar{}.get_foo('foo')!
+	a.hello()!
+	assert a is IFoo
+}