Move to semantic pass

compiler/kernel/expr.go

@@ -13,7 +13,6 @@ import (
 	"github.com/brimdata/zed/runtime/op/traverse"
 	"github.com/brimdata/zed/zbuf"
 	"github.com/brimdata/zed/zson"
-	"golang.org/x/exp/slices"
 	"golang.org/x/text/unicode/norm"
 )
 
@@ -398,9 +397,6 @@ func (b *Builder) compileRecordExpr(record *dag.RecordExpr) (expr.Evaluator, err
 	for _, elem := range record.Elems {
 		switch elem := elem.(type) {
 		case *dag.Field:
-			if slices.ContainsFunc(elems, func(r expr.RecordElem) bool { return r.Name == elem.Name }) {
-				return nil, fmt.Errorf("record expression: %w", &zed.DuplicateFieldError{Name: elem.Name})
-			}
 			e, err := b.compileExpr(elem.Value)
 			if err != nil {
 				return nil, err

compiler/semantic/expr.go

@@ -155,10 +155,15 @@ func (a *analyzer) semExpr(e ast.Expr) (dag.Expr, error) {
 			Where: where,
 		}, nil
 	case *ast.RecordExpr:
+		fields := map[string]struct{}{}
 		var out []dag.RecordElem
 		for _, elem := range e.Elems {
 			switch elem := elem.(type) {
 			case *ast.Field:
+				if _, ok := fields[elem.Name]; ok {
+					return nil, fmt.Errorf("record expression: %w", &zed.DuplicateFieldError{Name: elem.Name})
+				}
+				fields[elem.Name] = struct{}{}
 				e, err := a.semExpr(elem.Value)
 				if err != nil {
 					return nil, err
@@ -169,6 +174,10 @@ func (a *analyzer) semExpr(e ast.Expr) (dag.Expr, error) {
 					Value: e,
 				})
 			case *ast.ID:
+				if _, ok := fields[elem.Name]; ok {
+					return nil, fmt.Errorf("record expression: %w", &zed.DuplicateFieldError{Name: elem.Name})
+				}
+				fields[elem.Name] = struct{}{}
 				v, err := a.semID(elem)
 				if err != nil {
 					return nil, err