cgen: fix hash functions for map[Enum]Value, and enum Enum as u64 { (fix #23630)

vlib/v/gen/c/cgen.v

@@ -3328,14 +3328,14 @@ fn (mut g Gen) gen_clone_assignment(var_type ast.Type, val ast.Expr, typ ast.Typ
 	return true
 }
 
-fn (mut g Gen) map_fn_ptrs(key_typ ast.TypeSymbol) (string, string, string, string) {
+fn (mut g Gen) map_fn_ptrs(key_sym ast.TypeSymbol) (string, string, string, string) {
 	mut hash_fn := ''
 	mut key_eq_fn := ''
 	mut clone_fn := ''
 	mut free_fn := '&map_free_nop'
-	match key_typ.kind {
+	match key_sym.kind {
 		.alias {
-			alias_key_type := (key_typ.info as ast.Alias).parent_type
+			alias_key_type := (key_sym.info as ast.Alias).parent_type
 			return g.map_fn_ptrs(g.table.sym(alias_key_type))
 		}
 		.u8, .i8, .char {
@@ -3348,8 +3348,11 @@ fn (mut g Gen) map_fn_ptrs(key_typ ast.TypeSymbol) (string, string, string, stri
 			key_eq_fn = '&map_eq_int_2'
 			clone_fn = '&map_clone_int_2'
 		}
-		.int, .i32, .u32, .rune, .f32, .enum {
-			// XTODO i64
+		.enum {
+			einfo := (key_sym.info) as ast.Enum
+			return g.map_fn_ptrs(g.table.sym(einfo.typ))
+		}
+		.int, .i32, .u32, .rune, .f32 {
 			hash_fn = '&map_hash_int_4'
 			key_eq_fn = '&map_eq_int_4'
 			clone_fn = '&map_clone_int_4'
@@ -3374,7 +3377,7 @@ fn (mut g Gen) map_fn_ptrs(key_typ ast.TypeSymbol) (string, string, string, stri
 			free_fn = '&map_free_string'
 		}
 		else {
-			verror('map key type `${key_typ.name}` not supported')
+			verror('map key type `${key_sym.name}` not supported')
 		}
 	}
 	return hash_fn, key_eq_fn, clone_fn, free_fn

vlib/v/tests/enums/maps_with_enum_flag_keys_test.v

@@ -0,0 +1,47 @@
+// vfmt off
+@[flag]
+enum Bits8 as u8 {
+	a1 b1 c1 d1 e1 f1 g1 h1
+}
+@[flag]
+enum Bits16 as u16 {
+	a1 b1 c1 d1 e1 f1 g1 h1
+	a2 b2 c2 d2 e2 f2 g2 h2
+}
+@[flag]
+enum Bits32 as u32 {
+	a1 b1 c1 d1 e1 f1 g1 h1
+	a2 b2 c2 d2 e2 f2 g2 h2
+	a3 b3 c3 d3 e3 f3 g3 h3
+	a4 b4 c4 d4 e4 f4 g4 h4
+}
+@[flag]
+enum Bits64 as u64 {
+	a1 b1 c1 d1 e1 f1 g1 h1
+	a2 b2 c2 d2 e2 f2 g2 h2
+	a3 b3 c3 d3 e3 f3 g3 h3
+	a4 b4 c4 d4 e4 f4 g4 h4
+	a5 b5 c5 d5 e5 f5 g5 h5
+	a6 b6 c6 d6 e6 f6 g6 h6
+	a7 b7 c7 d7 e7 f7 g7 h7
+	a8 b8 c8 d8 e8 f8 g8 h8
+}
+// vfmt on
+
+fn check_map[T](size int) {
+	println('>>> checking map of ${T.name:10} enum keys, size should be: ${size}')
+	mut m := map[T]u32{}
+	for i in 0 .. size {
+		n := u64(1) << i
+		m[unsafe { T(n) }] = i
+		// eprintln('>>> i: ${i:2} | n: ${n:20} | m.len: ${m.len}')
+	}
+	assert m.len == size
+}
+
+fn test_maps_with_enum_keys_work() {
+	check_map[Bits8](8)
+	check_map[Bits16](16)
+	check_map[Bits32](32)
+	check_map[Bits64](64)
+}