checker: fix map of function as argument and direct call of function in map (#8494)

vlib/v/checker/check_types.v

@@ -85,8 +85,8 @@ pub fn (mut c Checker) check_basic(got table.Type, expected table.Type) bool {
 		// fn == 0
 		return true
 	}
-	// array fn
-	if got_type_sym.kind == .array && exp_type_sym.kind == .array {
+	// array/map fn
+	if got_type_sym.kind in [.array, .map] && exp_type_sym.kind == got_type_sym.kind {
 		if c.table.type_to_str(got) == c.table.type_to_str(expected).trim('&') {
 			return true
 		}

vlib/v/checker/checker.v

@@ -1707,6 +1707,12 @@ pub fn (mut c Checker) call_fn(mut call_expr ast.CallExpr) table.Type {
 			if elem_typ.info is table.FnType {
 				return elem_typ.info.func.return_type
 			}
+		} else if sym.kind == .map {
+			info := sym.info as table.Map
+			value_typ := c.table.get_type_symbol(info.value_type)
+			if value_typ.info is table.FnType {
+				return value_typ.info.func.return_type
+			}
 		} else if sym.kind == .array_fixed {
 			info := sym.info as table.ArrayFixed
 			elem_typ := c.table.get_type_symbol(info.elem_type)

vlib/v/tests/map_and_array_with_fns_test.v

@@ -72,8 +72,7 @@ fn test_map_and_array_with_fns_typeof_and_direct_call() {
 	assert a[0]('hello') == 15
 	b := {'one': foo3}
 	assert typeof(b).name == 'map[string]fn (string) int'
-	// TODO: enable this
-	// assert b['one']('hi') == 12
+	assert b['one']('hi') == 12
 }
 
 fn bar1(mut a []fn (string) int) int {
@@ -91,3 +90,19 @@ fn test_array_of_fns_as_argument() {
 	a2 := [foo3]
 	assert bar2(a2) == 15
 }
+
+fn bar3(m map[string]fn (string) int) int {
+	return m['fn']('hi')
+}
+
+fn bar4(mut m map[string]fn (string) int) int {
+	m['fn'] = foo4 
+	return m['fn']('hi')
+}
+
+fn test_map_of_fns_as_argument() {
+	m1 := {'fn': foo3}
+	assert bar3(m1) == 12
+	mut m2 := {'fn': foo3}
+	assert bar4(mut m2) == 22
+}