chore: import upstream snapshot with attribution

server/ast/create_cast.go

@@ -0,0 +1,84 @@
+// Copyright 2026 Dolthub, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package ast
+
+import (
+	vitess "github.com/dolthub/vitess/go/vt/sqlparser"
+
+	"github.com/dolthub/doltgresql/core/casts"
+	"github.com/dolthub/doltgresql/postgres/parser/sem/tree"
+	"github.com/dolthub/doltgresql/server/auth"
+	pgnodes "github.com/dolthub/doltgresql/server/node"
+)
+
+// nodeCreateCast handles *tree.CreateCast nodes.
+func nodeCreateCast(ctx *Context, node *tree.CreateCast) (vitess.Statement, error) {
+	if node == nil {
+		return nil, nil
+	}
+	_, sourceType, err := nodeResolvableTypeReference(ctx, node.Source, false)
+	if err != nil {
+		return nil, err
+	}
+	_, targetType, err := nodeResolvableTypeReference(ctx, node.Target, false)
+	if err != nil {
+		return nil, err
+	}
+	var funcName tree.TableName
+	var funcParams []pgnodes.RoutineParam
+	switch node.Type {
+	case tree.CreateCastType_WithFunction:
+		funcName = node.FuncName.ToTableName()
+		funcParams = make([]pgnodes.RoutineParam, len(node.FuncArgs))
+		for i, arg := range node.FuncArgs {
+			funcParams[i].Name = arg.Name.String()
+			_, funcParams[i].Type, err = nodeResolvableTypeReference(ctx, arg.Type, false)
+			if err != nil {
+				return nil, err
+			}
+		}
+	case tree.CreateCastType_WithoutFunction:
+		// TODO: restrict to superusers only with error: "must be superuser to create a cast WITHOUT FUNCTION"
+	case tree.CreateCastType_Inout:
+		// Nothing to do
+	default:
+		panic("unhandled case")
+	}
+	var scope casts.CastType
+	switch node.Scope {
+	case tree.CreateCastScope_Explicit:
+		scope = casts.CastType_Explicit
+	case tree.CreateCastScope_Assignment:
+		scope = casts.CastType_Assignment
+	case tree.CreateCastScope_Implicit:
+		scope = casts.CastType_Implicit
+	}
+	return vitess.InjectedStatement{
+		Statement: pgnodes.NewCreateCast(
+			sourceType,
+			targetType,
+			scope,
+			node.Type,
+			funcName.Schema(),
+			funcName.Table(),
+			funcParams,
+		),
+		Auth: vitess.AuthInformation{
+			AuthType:    auth.AuthType_CREATE,
+			TargetType:  auth.AuthTargetType_TODO,
+			TargetNames: []string{},
+		},
+	}, nil
+}