all: allow using aliases as keys in map (#8589)

vlib/v/gen/c/cgen.v

@@ -3724,7 +3724,7 @@ fn (mut g Gen) map_init(node ast.MapInit) {
 	key_typ_str := g.typ(node.key_type)
 	value_typ_str := g.typ(node.value_type)
 	value_typ := g.table.get_type_symbol(node.value_type)
-	key_typ := g.table.get_type_symbol(node.key_type)
+	key_typ := g.table.get_final_type_symbol(node.key_type)
 	hash_fn, key_eq_fn, clone_fn, free_fn := g.map_fn_ptrs(key_typ)
 	size := node.vals.len
 	mut shared_styp := '' // only needed for shared &[]{...}

vlib/v/parser/parse_type.v

@@ -73,12 +73,18 @@ pub fn (mut p Parser) parse_map_type() table.Type {
 	}
 	p.check(.lsbr)
 	key_type := p.parse_type()
+	is_alias := p.table.get_type_symbol(key_type).kind == .alias
 	if key_type.idx() == 0 {
 		// error is reported in parse_type
 		return 0
 	}
-	if !(key_type in [table.string_type_idx, table.voidptr_type_idx]
+	if is_alias && !(key_type in [table.string_type_idx, table.voidptr_type_idx]
 		|| ((key_type.is_int() || key_type.is_float()) && !key_type.is_ptr())) {
+		p.error('cannot use the alias type as the parent type is unsupported')
+		return 0
+	}
+	if !(key_type in [table.string_type_idx, table.voidptr_type_idx]
+		|| ((key_type.is_int() || key_type.is_float() || is_alias) && !key_type.is_ptr())) {
 		s := p.table.type_to_str(key_type)
 		p.error_with_pos('maps only support string, integer, float, rune or voidptr keys for now (not `$s`)',
 			p.tok.position())

vlib/v/table/types.v

@@ -550,7 +550,7 @@ pub fn (t &TypeSymbol) is_pointer() bool {
 
 [inline]
 pub fn (t &TypeSymbol) is_int() bool {
-	return t.kind in [.i8, .i16, .int, .i64, .byte, .u16, .u32, .u64, .int_literal]
+	return t.kind in [.i8, .i16, .int, .i64, .byte, .u16, .u32, .u64, .int_literal, .rune]
 }
 
 [inline]

vlib/v/tests/map_alias_key_test.v

@@ -0,0 +1,22 @@
+type Type = int
+type RType = rune
+
+fn test_map_key_alias() {
+	mut m_int := map{12: '12', 2: '2'}
+	m_int[14] = '14'
+	m_int[Type(15)] = '15'
+	assert m_int.str() == "{12: '12', 2: '2', 14: '14', 15: '15'}"
+	//// /// ///// //
+	mut m_rune := map{`a`: '12', `l`: '14'} 
+	m_rune[`g`] = '12'
+	m_rune[RType(`$`)] = '16'
+	assert m_rune.str() == "{`a`: '12', `l`: '14', `g`: '12', `$`: '16'}"
+}
+
+fn test_map_alias_key_init() {
+	m_int := map{Type(12): '12', Type(2): '2'}
+	assert m_int.str() == "{12: '12', 2: '2'}"
+	//// // ///// //
+	m_rune := map{RType(`a`): '12', RType(`l`): '14'}
+	assert m_rune.str() == "{`a`: '12', `l`: '14'}"
+}