parser: fix -5.str() precedence

cmd/tools/vtest-fixed.v

@@ -7,7 +7,6 @@ import v.pref
 const (
 	skip_test_files     = [
 		'vlib/v/tests/enum_bitfield_test.v',
-		'vlib/v/tests/num_lit_call_method_test.v',
 		'vlib/v/tests/pointers_test.v',
 		'vlib/v/tests/pointers_str_test.v',
 		'vlib/net/http/http_httpbin_test.v',

vlib/v/parser/pratt.v

@@ -220,7 +220,12 @@ fn (mut p Parser) prefix_expr() ast.PrefixExpr {
 	// p.warn('unsafe')
 	// }
 	p.next()
-	right := p.expr(token.Precedence.prefix)
+	mut right := ast.Expr{}
+	if op == .minus {
+		right = p.expr(token.Precedence.call)
+	} else {
+		right = p.expr(token.Precedence.prefix)
+	}
 	p.is_amp = false
 	return ast.PrefixExpr{
 		op: op