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+import type { Visitor } from '../src';
+import { NodePath, visit, walk } from '../src';
+
+// AST literals below are real libpg_query (PG18) parse output. Concrete
+// typed embedded fields (e.g. CreatePolicyStmt.table: RangeVar) are bare
+// untagged objects in libpg_query JSON — no `{RangeVar: {...}}` wrapper.
+
+const createPolicyAst = {
+  CreatePolicyStmt: {
+    policy_name: 'p',
+    table: { schemaname: 'app', relname: 'posts', inh: true, relpersistence: 'p', location: 19 },
+    cmd_name: 'select',
+    permissive: true,
+    roles: [{ RoleSpec: { roletype: 'ROLESPEC_PUBLIC', location: -1 } }],
+    qual: { A_Const: { boolval: { boolval: true }, location: 47 } }
+  }
+};
+
+const indexStmtAst = {
+  IndexStmt: {
+    idxname: 'idx',
+    relation: { schemaname: 'app', relname: 'posts', inh: true, relpersistence: 'p', location: 20 },
+    accessMethod: 'btree',
+    indexParams: [
+      { IndexElem: { name: 'id', ordering: 'SORTBY_DEFAULT', nulls_ordering: 'SORTBY_NULLS_DEFAULT' } }
+    ]
+  }
+};
+
+const createTrigAst = {
+  CreateTrigStmt: {
+    trigname: 'trg',
+    relation: { schemaname: 'app', relname: 'posts', inh: true, relpersistence: 'p', location: 36 },
+    funcname: [{ String: { sval: 'f' } }],
+    timing: 2,
+    events: 4
+  }
+};
+
+const alterTableAst = {
+  AlterTableStmt: {
+    relation: { schemaname: 'app', relname: 'posts', inh: true, relpersistence: 'p', location: 12 },
+    cmds: [
+      {
+        AlterTableCmd: {
+          subtype: 'AT_AddColumn',
+          def: {
+            ColumnDef: {
+              colname: 'x',
+              typeName: {
+                names: [{ String: { sval: 'pg_catalog' } }, { String: { sval: 'int4' } }],
+                typemod: -1,
+                location: 35
+              },
+              is_local: true,
+              location: 33
+            }
+          },
+          behavior: 'DROP_RESTRICT'
+        }
+      }
+    ],
+    objtype: 'OBJECT_TABLE'
+  }
+};
+
+describe('walk — typed embedded fields (untagged)', () => {
+  it('visits RangeVar for CreatePolicyStmt.table', () => {
+    const visited: NodePath[] = [];
+    walk(createPolicyAst, { RangeVar: (path) => { visited.push(path); } });
+
+    expect(visited).toHaveLength(1);
+    expect(visited[0].node.schemaname).toBe('app');
+    expect(visited[0].node.relname).toBe('posts');
+    expect(visited[0].tag).toBe('RangeVar');
+    expect(visited[0].path).toEqual(['table']);
+    expect(visited[0].parent?.tag).toBe('CreatePolicyStmt');
+  });
+
+  it('visits RangeVar for IndexStmt.relation', () => {
+    const visited: NodePath[] = [];
+    walk(indexStmtAst, { RangeVar: (path) => { visited.push(path); } });
+
+    expect(visited).toHaveLength(1);
+    expect(visited[0].node.relname).toBe('posts');
+    expect(visited[0].path).toEqual(['relation']);
+  });
+
+  it('visits RangeVar for CreateTrigStmt.relation', () => {
+    const visited: NodePath[] = [];
+    walk(createTrigAst, { RangeVar: (path) => { visited.push(path); } });
+
+    expect(visited).toHaveLength(1);
+    expect(visited[0].node.relname).toBe('posts');
+    expect(visited[0].path).toEqual(['relation']);
+  });
+
+  it('visits RangeVar for AlterTableStmt.relation', () => {
+    const visited: NodePath[] = [];
+    walk(alterTableAst, { RangeVar: (path) => { visited.push(path); } });
+
+    expect(visited).toHaveLength(1);
+    expect(visited[0].node.relname).toBe('posts');
+    expect(visited[0].path).toEqual(['relation']);
+  });
+
+  it('visits TypeName for ColumnDef.typeName (untagged typed field)', () => {
+    const visited: NodePath[] = [];
+    walk(alterTableAst, { TypeName: (path) => { visited.push(path); } });
+
+    expect(visited).toHaveLength(1);
+    expect(visited[0].node.names).toHaveLength(2);
+    expect(visited[0].parent?.tag).toBe('ColumnDef');
+  });
+
+  it('visits RawStmt for the array-typed ParseResult.stmts field', () => {
+    const parseResult = {
+      ParseResult: {
+        version: 180004,
+        stmts: [
+          { stmt: createPolicyAst, stmt_len: 52 },
+          { stmt: indexStmtAst, stmt_len: 34 }
+        ]
+      }
+    };
+    const rawStmts: NodePath[] = [];
+    const rangeVars: NodePath[] = [];
+    walk(parseResult, {
+      RawStmt: (path) => { rawStmts.push(path); },
+      RangeVar: (path) => { rangeVars.push(path); }
+    });
+
+    expect(rawStmts).toHaveLength(2);
+    expect(rawStmts[0].tag).toBe('RawStmt');
+    expect(rawStmts[0].path).toEqual(['stmts', 0]);
+    expect(rawStmts[1].path).toEqual(['stmts', 1]);
+    expect(rangeVars).toHaveLength(2);
+  });
+
+  it('returning false from a synthesized-tag visitor skips its children', () => {
+    const ast = {
+      IndexStmt: {
+        idxname: 'idx',
+        relation: {
+          relname: 'posts',
+          inh: true,
+          relpersistence: 'p',
+          alias: { aliasname: 'a' }
+        },
+        accessMethod: 'btree'
+      }
+    };
+    const aliases: NodePath[] = [];
+    walk(ast, {
+      RangeVar: () => false,
+      Alias: (path) => { aliases.push(path); }
+    });
+    expect(aliases).toHaveLength(0);
+
+    walk(ast, { Alias: (path) => { aliases.push(path); } });
+    expect(aliases).toHaveLength(1);
+    expect(aliases[0].node.aliasname).toBe('a');
+  });
+
+  it('visits Query and its nested typed fields for IntoClause.viewQuery', () => {
+    // IntoClause.viewQuery and RangeTblEntry.subquery are the two concrete
+    // Query-typed fields in the PG18 runtime schema.
+    const ast = {
+      CreateTableAsStmt: {
+        into: {
+          rel: { relname: 'mv', inh: true, relpersistence: 'p' },
+          viewQuery: {
+            commandType: 'CMD_SELECT',
+            rtable: [
+              {
+                RangeTblEntry: {
+                  rtekind: 'RTE_SUBQUERY',
+                  subquery: {
+                    commandType: 'CMD_SELECT',
+                    jointree: { fromlist: [] as any[] }
+                  },
+                  eref: { aliasname: 'inner_q' }
+                }
+              }
+            ],
+            jointree: {
+              fromlist: [{ RangeVar: { relname: 'src', inh: true, relpersistence: 'p' } }]
+            }
+          }
+        },
+        objtype: 'OBJECT_MATVIEW'
+      }
+    };
+
+    const tags: string[] = [];
+    walk(ast, (path) => { tags.push(path.tag); });
+
+    // outer Query via IntoClause.viewQuery, inner Query via RangeTblEntry.subquery
+    expect(tags.filter((t) => t === 'Query')).toHaveLength(2);
+    // FromExpr synthesized for both Query.jointree fields
+    expect(tags.filter((t) => t === 'FromExpr')).toHaveLength(2);
+    // RangeVar: IntoClause.rel (untagged) + tagged one inside fromlist
+    expect(tags.filter((t) => t === 'RangeVar')).toHaveLength(2);
+    // Alias synthesized for RangeTblEntry.eref
+    expect(tags).toContain('Alias');
+    expect(tags).toContain('RangeTblEntry');
+    expect(tags).toContain('IntoClause');
+  });
+
+  it('handles empty untagged typed values and mixed tagged/untagged arrays', () => {
+    const emptyRel = { IndexStmt: { relation: {} } };
+    const visited: NodePath[] = [];
+    walk(emptyRel, { RangeVar: (path) => { visited.push(path); } });
+    expect(visited).toHaveLength(1);
+    expect(visited[0].node).toEqual({});
+
+    // ParseResult.stmts with one bare RawStmt and one already-tagged entry
+    const mixed = {
+      ParseResult: {
+        version: 180004,
+        stmts: [
+          { stmt: indexStmtAst, stmt_len: 34 },
+          { RawStmt: { stmt: createTrigAst, stmt_len: 66 } }
+        ]
+      }
+    };
+    const rawStmts: NodePath[] = [];
+    walk(mixed, { RawStmt: (path) => { rawStmts.push(path); } });
+    expect(rawStmts).toHaveLength(2);
+  });
+
+  it('keeps existing behavior for tagged nodes', () => {
+    const visited: string[] = [];
+    const visitor: Visitor = {
+      CreatePolicyStmt: (path) => { visited.push(`CreatePolicyStmt:${path.node.policy_name}`); },
+      RoleSpec: (path) => { visited.push(`RoleSpec:${path.node.roletype}`); },
+      A_Const: () => { visited.push('A_Const'); }
+    };
+    walk(createPolicyAst, visitor);
+    expect(visited.sort()).toEqual([
+      'A_Const',
+      'CreatePolicyStmt:p',
+      'RoleSpec:ROLESPEC_PUBLIC'
+    ]);
+  });
+});
+
+describe('visit — typed embedded fields (untagged)', () => {
+  it('visits RangeVar for CreatePolicyStmt.table', () => {
+    const visited: any[] = [];
+    visit(createPolicyAst, {
+      RangeVar: (node, ctx) => { visited.push({ node, ctx }); }
+    });
+
+    expect(visited).toHaveLength(1);
+    expect(visited[0].node.relname).toBe('posts');
+    expect(visited[0].ctx.path).toEqual(['table']);
+  });
+
+  it('visits RawStmt for the array-typed ParseResult.stmts field', () => {
+    const parseResult = {
+      ParseResult: {
+        version: 180004,
+        stmts: [{ stmt: indexStmtAst, stmt_len: 34 }]
+      }
+    };
+    const rawStmts: any[] = [];
+    const rangeVars: any[] = [];
+    visit(parseResult, {
+      RawStmt: (node) => { rawStmts.push(node); },
+      RangeVar: (node) => { rangeVars.push(node); }
+    });
+
+    expect(rawStmts).toHaveLength(1);
+    expect(rangeVars).toHaveLength(1);
+    expect(rangeVars[0].relname).toBe('posts');
+  });
+
+  it('keeps existing behavior for tagged nodes', () => {
+    const visited: string[] = [];
+    visit(createPolicyAst, {
+      CreatePolicyStmt: (node) => { visited.push(`CreatePolicyStmt:${node.policy_name}`); },
+      RoleSpec: (node) => { visited.push(`RoleSpec:${node.roletype}`); }
+    });
+    expect(visited).toEqual(['CreatePolicyStmt:p', 'RoleSpec:ROLESPEC_PUBLIC']);
+  });
+});