[yuyi98]

This PR check enum method duplicated (fix #20924).

• Check enum method duplicated.
• Add test.

@[flag]
enum Flags {
	bit0
	bit1
	bit2
	bit3
	bit4
	bit5
	bit6
	bit7
}

fn (f Flags) has(f2 Flags) bool {
	return f & f2 > 0
}

fn main() {}

PS D:\Test\v\tt1> v run .
tt1.v:13:14: error: duplicate method `has`, `has` is an enum type built-in method
   11 | }
   12 | 
   13 | fn (f Flags) has(f2 Flags) bool {
      |              ~~~
   14 |     return f & f2 > 0
   15 | }

[Delta456]

Good work

[spytheman]

Good work, but please also check if the name is in ['is_empty', 'has', 'all', 'set', 'set_all', 'clear', 'clear_all', 'toggle', 'zero', 'from'], otherwise the message can become a bit misleading for a case like this:

@[flag]
enum Flags {
	bit0
	bit1
}

fn (f Flags) zzz(f2 Flags) bool {
	return f & f2 > 0
}

fn (f Flags) zzz(f2 Flags) bool {
	return f & f2 > 0
}

Currently it will show that the method name zzz is a builtin method:

#0 11:34:51 ^ fix_enum_flag_has /v/oo>v ee.v
ee.v:13:14: error: duplicate method `zzz`, `zzz` is an enum type built-in method
   11 | }
   12 |
   13 | fn (f Flags) zzz(f2 Flags) bool {
      |              ~~~
   14 |     return f & f2 > 0