Add type checks for 42 in ["a"] as invalid

Author: antonmedv

checker/checker.go

@@ -73,6 +73,12 @@ type varScope struct {
 type info struct {
 	method bool
 	fn     *ast.Function
+
+	// elem is element type of array or map.
+	// Arrays created with type []any, but
+	// we would like to detect expressions
+	// like `42 in ["a"]` as invalid.
+	elem reflect.Type
 }
 
 func (v *checker) visit(node ast.Node) (reflect.Type, info) {
@@ -227,7 +233,7 @@ func (v *checker) UnaryNode(node *ast.UnaryNode) (reflect.Type, info) {
 
 func (v *checker) BinaryNode(node *ast.BinaryNode) (reflect.Type, info) {
 	l, _ := v.visit(node.Left)
-	r, _ := v.visit(node.Right)
+	r, ri := v.visit(node.Right)
 
 	l = deref(l)
 	r = deref(r)
@@ -351,6 +357,9 @@ func (v *checker) BinaryNode(node *ast.BinaryNode) (reflect.Type, info) {
 			if !isComparable(l, r.Elem()) {
 				return v.error(node, "cannot use %v as type %v in array", l, r.Elem())
 			}
+			if !isComparable(l, ri.elem) {
+				return v.error(node, "cannot use %v as type %v in array", l, ri.elem)
+			}
 			return boolType, info{}
 		}
 		if isAny(l) && anyOf(r, isString, isArray, isMap) {
@@ -1067,8 +1076,21 @@ func (v *checker) ConditionalNode(node *ast.ConditionalNode) (reflect.Type, info
 }
 
 func (v *checker) ArrayNode(node *ast.ArrayNode) (reflect.Type, info) {
-	for _, node := range node.Nodes {
-		v.visit(node)
+	var prev reflect.Type
+	allElementsAreSameType := true
+	for i, node := range node.Nodes {
+		curr, _ := v.visit(node)
+		if i > 0 {
+			if curr == nil || prev == nil {
+				allElementsAreSameType = false
+			} else if curr.Kind() != prev.Kind() {
+				allElementsAreSameType = false
+			}
+		}
+		prev = curr
+	}
+	if allElementsAreSameType && prev != nil {
+		return arrayType, info{elem: prev}
 	}
 	return arrayType, info{}
 }

checker/checker_test.go

@@ -7,14 +7,15 @@ import (
 	"strings"
 	"testing"
 
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
 	"github.com/antonmedv/expr"
 	"github.com/antonmedv/expr/ast"
 	"github.com/antonmedv/expr/checker"
 	"github.com/antonmedv/expr/conf"
 	"github.com/antonmedv/expr/parser"
 	"github.com/antonmedv/expr/test/mock"
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
 )
 
 func TestCheck(t *testing.T) {
@@ -547,6 +548,11 @@ map(1..9, #unknown)
 unknown pointer #unknown (1:11)
  | map(1..9, #unknown)
  | ..........^
+
+42 in ["a", "b", "c"]
+cannot use int as type string in array (1:4)
+ | 42 in ["a", "b", "c"]
+ | ...^
 `
 
 func TestCheck_error(t *testing.T) {

expr_test.go

@@ -7,12 +7,13 @@ import (
 	"testing"
 	"time"
 
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
 	"github.com/antonmedv/expr"
 	"github.com/antonmedv/expr/ast"
 	"github.com/antonmedv/expr/file"
 	"github.com/antonmedv/expr/test/mock"
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
 )
 
 func ExampleEval() {
@@ -1997,4 +1998,4 @@ func TestIssue432(t *testing.T) {
 	out, err := expr.Run(program, env)
 	assert.NoError(t, err)
 	assert.Equal(t, float64(10), out)
-}
+}

test/fuzz/fuzz_corpus.txt

@@ -2711,7 +2711,6 @@ add == score != true
 add == score and i32 >= 1
 add == score or 0.5 < 1
 add in [div]
-add not in [f64]
 add not in sort(array)
 add(1, 1) ** i
 add(1, 1) ^ i
@@ -3113,7 +3112,6 @@ array == map(array, add)
 array == nil != nil
 array == nil != true ? 0.5 : 0.5
 array == nil && (false || ok)
-array in [i]
 array[-1]
 array[-i32]
 array[-i64]
@@ -6102,7 +6100,6 @@ foo == foo ? i : score
 foo == last(list)
 foo == nil == nil
 foo == nil || ok
-foo in [half]
 foo in filter(list, false)
 foo in list
 foo in list ? nil : i32

test/fuzz/fuzz_expr_seed_corpus.zip

@@ -2711,7 +2711,6 @@ add == score != true
 add == score and i32 >= 1
 add == score or 0.5 < 1
 add in [div]
-add not in [f64]
 add not in sort(array)
 add(1, 1) ** i
 add(1, 1) ^ i
@@ -3113,7 +3112,6 @@ array == map(array, add)
 array == nil != nil
 array == nil != true ? 0.5 : 0.5
 array == nil && (false || ok)
-array in [i]
 array[-1]
 array[-i32]
 array[-i64]
@@ -6102,7 +6100,6 @@ foo == foo ? i : score
 foo == last(list)
 foo == nil == nil
 foo == nil || ok
-foo in [half]
 foo in filter(list, false)
 foo in list
 foo in list ? nil : i32

testdata/examples.txt

@@ -237,11 +237,7 @@ func In(needle any, array any) bool {
 		if needle == nil {
 			value = v.MapIndex(reflect.Zero(v.Type().Key()))
 		} else {
-			n := reflect.ValueOf(needle)
-			if !n.IsValid() {
-				panic(fmt.Sprintf("cannot use %T as index to %T", needle, array))
-			}
-			value = v.MapIndex(n)
+			value = v.MapIndex(reflect.ValueOf(needle))
 		}
 		if value.IsValid() {
 			return true