Catch invalid literals created from expression factories

checker/checker.go

@@ -18,6 +18,7 @@ package checker
 
 import (
 	"fmt"
+	"reflect"
 
 	"github.com/google/cel-go/common"
 	"github.com/google/cel-go/common/ast"
@@ -78,6 +79,8 @@ func (c *checker) check(e ast.Expr) {
 		case types.BoolType, types.BytesType, types.DoubleType, types.IntType,
 			types.NullType, types.StringType, types.UintType:
 			c.setType(e, literal.Type().(*types.Type))
+		default:
+			c.errors.unexpectedASTType(e.ID(), c.location(e), "literal", literal.Type().TypeName())
 		}
 	case ast.IdentKind:
 		c.checkIdent(e)
@@ -94,7 +97,7 @@ func (c *checker) check(e ast.Expr) {
 	case ast.ComprehensionKind:
 		c.checkComprehension(e)
 	default:
-		c.errors.unexpectedASTType(e.ID(), c.location(e), e)
+		c.errors.unexpectedASTType(e.ID(), c.location(e), "unspecified", reflect.TypeOf(e).Name())
 	}
 }
 

checker/checker_test.go

@@ -18,8 +18,10 @@ import (
 	"fmt"
 	"strings"
 	"testing"
+	"time"
 
 	"github.com/google/cel-go/common"
+	"github.com/google/cel-go/common/ast"
 	"github.com/google/cel-go/common/containers"
 	"github.com/google/cel-go/common/decls"
 	"github.com/google/cel-go/common/stdlib"
@@ -2542,6 +2544,23 @@ func TestCheckErrorData(t *testing.T) {
 	}
 }
 
+func TestCheckInvalidLiteral(t *testing.T) {
+	fac := ast.NewExprFactory()
+	durLiteral := fac.NewLiteral(1, types.Duration{Duration: time.Second})
+	// This is not valid syntax, just for illustration purposes.
+	src := common.NewTextSource(`1s`)
+	parsed := ast.NewAST(durLiteral, ast.NewSourceInfo(src))
+	reg := newTestRegistry(t)
+	env, err := NewEnv(containers.DefaultContainer, reg)
+	if err != nil {
+		t.Fatalf("NewEnv(cont, reg) failed: %v", err)
+	}
+	_, iss := Check(parsed, src, env)
+	if !strings.Contains(iss.ToDisplayString(), "unexpected literal type") {
+		t.Errorf("got %s, wanted 'unexpected literal type'", iss.ToDisplayString())
+	}
+}
+
 func testFunction(t testing.TB, name string, opts ...decls.FunctionOpt) *decls.FunctionDecl {
 	t.Helper()
 	fn, err := decls.NewFunction(name, opts...)

checker/errors.go

@@ -15,8 +15,6 @@
 package checker
 
 import (
-	"reflect"
-
 	"github.com/google/cel-go/common"
 	"github.com/google/cel-go/common/ast"
 	"github.com/google/cel-go/common/types"
@@ -85,6 +83,6 @@ func (e *typeErrors) unexpectedFailedResolution(id int64, l common.Location, typ
 	e.errs.ReportErrorAtID(id, l, "unexpected failed resolution of '%s'", typeName)
 }
 
-func (e *typeErrors) unexpectedASTType(id int64, l common.Location, ex ast.Expr) {
-	e.errs.ReportErrorAtID(id, l, "unrecognized ast type: %v", reflect.TypeOf(ex))
+func (e *typeErrors) unexpectedASTType(id int64, l common.Location, kind, typeName string) {
+	e.errs.ReportErrorAtID(id, l, "unexpected %s type: %v", kind, typeName)
 }