Fix CallFastTyped detection

checker/checker.go

@@ -583,11 +583,11 @@ func (v *visitor) checkFunc(fn reflect.Type, method bool, node *ast.CallNode, na
 					continue funcTypes
 				}
 			}
-			if typed.NumIn() != len(arguments) {
+			if typed.NumIn() != fn.NumIn() {
 				continue
 			}
-			for j, arg := range arguments {
-				if typed.In(j) != arg.Type() {
+			for j := 0; j < typed.NumIn(); j++ {
+				if typed.In(j) != fn.In(j) {
 					continue funcTypes
 				}
 			}

checker/checker_test.go

@@ -703,3 +703,22 @@ func TestCheck_TypeWeights(t *testing.T) {
 		}
 	}
 }
+
+func TestCheck_CallFastTyped(t *testing.T) {
+	env := map[string]interface{}{
+		"fn": func([]interface{}, string) string {
+			return "foo"
+		},
+	}
+
+	tree, err := parser.Parse("fn([1, 2], 'bar')")
+	require.NoError(t, err)
+
+	config := conf.New(env)
+
+	_, err = checker.Check(tree, config)
+	require.NoError(t, err)
+
+	require.False(t, tree.Node.(*ast.CallNode).Fast)
+	require.Equal(t, 22, tree.Node.(*ast.CallNode).Typed)
+}

expr_test.go

@@ -1630,7 +1630,24 @@ func TestCompile_allow_to_use_interface_to_get_an_element_from_map(t *testing.T)
 	})
 }
 
+func TestFastCall(t *testing.T) {
+	env := map[string]interface{}{
+		"func": func(in interface{}) float64 {
+			return 8
+		},
+	}
+	code := `func("8")`
+
+	program, err := expr.Compile(code, expr.Env(env))
+	assert.NoError(t, err)
+
+	out, err := expr.Run(program, env)
+	assert.NoError(t, err)
+	assert.Equal(t, float64(8), out)
+}
+
 // Mock types
+
 type mockEnv struct {
 	Any                  interface{}
 	Int, One, Two, Three int