map: fix delete (part 1) (#9579)

vlib/builtin/map_test.v

@@ -561,11 +561,28 @@ fn test_int_keys() {
 	m[5] += 24
 	m[5]++
 	assert m[5] == 25
-	m2 := map{
+	mut m2 := map{
 		3: 9
 		4: 16
 		5: 25
 	}
+
+	four := 4
+	m2.delete_1(3)
+	m2.delete_1(four)
+	m2.delete_1(5)
+	assert m2.len == 0
+	assert m2[3] == 0
+	assert m2[4] == 0
+	assert m2[5] == 0
+	assert m2.keys() == []
+
+	m2 = map{
+		3: 9
+		4: 16
+		5: 25
+	}
+
 	assert m2.len == 3
 	// clone
 	mc := m.clone()
@@ -580,6 +597,13 @@ fn test_int_keys() {
 		all << v
 	}
 	assert all == [3, 9, 4, 16, 5, 25]
+
+	mut m3 := map{
+		1: 'one'
+		2: 'two'
+	}
+	assert m3[1] == 'one'
+	m3.delete_1(1)
 }
 
 fn test_voidptr_keys() {

vlib/v/checker/checker.v

@@ -1461,7 +1461,7 @@ pub fn (mut c Checker) call_method(mut call_expr ast.CallExpr) ast.Type {
 	// FIXME: Argument count != 1 will break these
 	if left_type_sym.kind == .array && method_name in checker.array_builtin_methods {
 		return c.call_array_builtin_method(mut call_expr, left_type, left_type_sym)
-	} else if left_type_sym.kind == .map && method_name in ['clone', 'keys', 'move'] {
+	} else if left_type_sym.kind == .map && method_name in ['clone', 'keys', 'move', 'delete_1'] {
 		return c.call_map_builtin_method(mut call_expr, left_type, left_type_sym)
 	} else if left_type_sym.kind == .array && method_name in ['insert', 'prepend'] {
 		info := left_type_sym.info as ast.Array

vlib/v/gen/c/fn.v

@@ -550,6 +550,18 @@ fn (mut g Gen) method_call(node ast.CallExpr) {
 			else {}
 		}
 	}
+
+	if left_sym.kind == .map && node.name == 'delete_1' {
+		left_info := left_sym.info as ast.Map
+		elem_type_str := g.typ(left_info.key_type)
+		g.write('map_delete_1(&')
+		g.expr(node.left)
+		g.write(', &($elem_type_str[]){')
+		g.expr(node.args[0].expr)
+		g.write('})')
+		return
+	}
+
 	if left_sym.kind == .sum_type && node.name == 'type_name' {
 		g.write('tos3( /* $left_sym.name */ v_typeof_sumtype_${typ_sym.cname}( (')
 		g.expr(node.left)