Improve MemberNode checker

Author: antonmedv

checker/checker.go

@@ -387,13 +387,15 @@ func (v *visitor) MemberNode(node *ast.MemberNode) (reflect.Type, info) {
 		return anyType, info{}
 
 	case reflect.Map:
-		// TODO: check key type == prop
+		if !prop.AssignableTo(base.Key()) {
+			return v.error(node.Property, "cannot use %v to get an element from %v", prop, base)
+		}
 		t, c := deref(base.Elem())
 		node.Deref = c
 		return t, info{}
 
 	case reflect.Array, reflect.Slice:
-		if !isInteger(prop) {
+		if !isInteger(prop) && !isAny(prop) {
 			return v.error(node.Property, "array elements can only be selected using an integer (got %v)", prop)
 		}
 		t, c := deref(base.Elem())

checker/checker_test.go

@@ -67,6 +67,7 @@ var successTests = []string{
 	"!ArrayOfAny[0].next.goes['any thing']",
 	"ArrayOfFoo[0].Bar.Baz == ''",
 	"ArrayOfFoo[0:10][0].Bar.Baz == ''",
+	"!ArrayOfAny[Any]",
 	"Bool && Any",
 	"FuncParam(true, 1, 'str')",
 	"FuncParamAny(nil)",
@@ -467,6 +468,11 @@ filter(42, {#})
 builtin filter takes only array (got int) (1:8)
  | filter(42, {#})
  | .......^
+
+MapOfAny[0]
+cannot use int to get an element from map[string]interface {} (1:10)
+ | MapOfAny[0]
+ | .........^
 `
 
 func TestCheck_error(t *testing.T) {