Kotlin

Last verified end to end: 2026-07-30 (query_code schema version 1).

For exact inbound and outbound symbol edges, proof tiers, and adapter-specific caveats, see Reference Traversal.

Kotlin’s grammar is field-poor: callees, navigation members, and named-argument labels are recovered positionally rather than through dedicated tree-sitter fields. The normalized adapter keeps named arguments in kwargs, while real val/var declarations remain assignment facts even though a named argument’s code = "named" shares assignment-like syntax.

Fixture

package app

import kotlin.math.max

@Deprecated("use Service2")
class Service(var name: String) {
    fun run(code: String): String {
        audit(code)
        val password = "hunter2"
        val callback = { value: String ->
            value
        }
        listOf(1).forEach { value ->
            audit(value.toString())
        }
        auditNamed(code = "named")
        this.name = "updated"
        return code
    }
}

fun audit(code: String): String {
    return code
}

fun auditNamed(code: String): String {
    return code
}

Named arguments and block calls

Use kwargs for Kotlin named arguments. A block argument can be queried with has, which selects the forEach call containing an audit descendant.

(language kotlin
  (call :callee (name "auditNamed")
    :kwargs [(code (string_literal :capture "value"))]))

{"languages":["kotlin"],"match":{"kind":"call","callee":{"name":"auditNamed"},"kwargs":{"code":{"kind":"string_literal","capture":"value"}}}}

{
  "results": [
    {
      "captures": [
        {"name": "value", "start_line": 16, "text": "\"named\""}
      ],
      "enclosing_symbol": "app.Service.run",
      "end_line": 16,
      "kind": "call",
      "language": "kotlin",
      "result_type": "structural_match",
      "path": "kotlin/App.kt",
      "start_line": 16,
      "text": "auditNamed(code = \"named\")"
    }
  ],
  "truncated": false
}

(language kotlin
  (call :callee (name "forEach")
    :args [(has (call :callee (name "audit")))]))

{"languages":["kotlin"],"match":{"kind":"call","callee":{"name":"forEach"},"args":[{"has":{"kind":"call","callee":{"name":"audit"}}}]}}

{
  "results": [
    {
      "enclosing_symbol": "app.Service.run",
      "end_line": 15,
      "kind": "call",
      "language": "kotlin",
      "result_type": "structural_match",
      "path": "kotlin/App.kt",
      "start_line": 13,
      "text": "listOf(1).forEach { value ->…"
    }
  ],
  "truncated": false
}

Assignment precision and annotations

The assignment query finds the real val password declaration. It must not mistake auditNamed(code = "named") for an assignment, even though Kotlin represents the named argument with assignment-shaped syntax. Annotations are normalized as decorators on the enclosing class.

(language kotlin
  (assignment :left (name "password")
    :right (string_literal :capture "value")))

{"languages":["kotlin"],"match":{"kind":"assignment","left":{"name":"password"},"right":{"kind":"string_literal","capture":"value"}}}

{
  "results": [
    {
      "captures": [
        {"name": "value", "start_line": 9, "text": "\"hunter2\""}
      ],
      "enclosing_symbol": "app.Service.run",
      "end_line": 9,
      "kind": "assignment",
      "language": "kotlin",
      "result_type": "structural_match",
      "path": "kotlin/App.kt",
      "start_line": 9,
      "text": "val password = \"hunter2\""
    }
  ],
  "truncated": false
}

(language kotlin (class :decorators [(name "Deprecated")]))

{"languages":["kotlin"],"match":{"kind":"class","decorators":[{"name":"Deprecated"}]}}

{
  "results": [
    {
      "enclosing_symbol": "app.Service",
      "end_line": 20,
      "kind": "class",
      "language": "kotlin",
      "result_type": "structural_match",
      "path": "kotlin/App.kt",
      "start_line": 5,
      "text": "@Deprecated(\"use Service2\")…"
    }
  ],
  "truncated": false
}

Imports and receivers

An import node exposes its imported name through module. Receiver and field roles similarly keep this.name = "updated" structurally separate from its terminal name.

(language kotlin (import :module (name "max")))

{"languages":["kotlin"],"match":{"kind":"import","module":{"name":"max"}}}

{
  "results": [
    {
      "end_line": 3,
      "kind": "import",
      "language": "kotlin",
      "result_type": "structural_match",
      "path": "kotlin/App.kt",
      "start_line": 3,
      "text": "import kotlin.math.max"
    }
  ],
  "truncated": false
}

Traverse Indexed Types And Members

open class QueryRoot {
    fun rootMember() {
    }
}

class QueryLeaf : QueryRoot() {
    fun leafMember() {
    }
}

(supertypes :transitive true (enclosing-decl (language kotlin (class :name "QueryLeaf"))))

{"languages":["kotlin"],"match":{"kind":"class","name":"QueryLeaf"},"steps":[{"op":"enclosing_decl"},{"op":"supertypes","transitive":true}]}

{
  "results": [
    {
      "end_line": 4,
      "fq_name": "QueryRoot",
      "kind": "class",
      "language": "kotlin",
      "path": "kotlin/QueryHierarchy.kt",
      "provenance": [
        {
          "seed": {
            "end_line": 9,
            "kind": "class",
            "path": "kotlin/QueryHierarchy.kt",
            "result_type": "structural_match",
            "start_line": 6
          },
          "steps": [
            {
              "op": "enclosing_decl",
              "result": {
                "end_line": 9,
                "fq_name": "QueryLeaf",
                "kind": "class",
                "path": "kotlin/QueryHierarchy.kt",
                "result_type": "declaration",
                "start_line": 6
              }
            },
            {
              "op": "supertypes",
              "result": {
                "end_line": 4,
                "fq_name": "QueryRoot",
                "kind": "class",
                "path": "kotlin/QueryHierarchy.kt",
                "result_type": "declaration",
                "start_line": 1
              }
            }
          ]
        }
      ],
      "result_type": "declaration",
      "signature": "open class QueryRoot {",
      "start_line": 1
    }
  ],
  "truncated": false
}

(owner (members (subtypes (enclosing-decl (language kotlin (class :name "QueryRoot"))))))

{"languages":["kotlin"],"match":{"kind":"class","name":"QueryRoot"},"steps":[{"op":"enclosing_decl"},{"op":"subtypes"},{"op":"members"},{"op":"owner"}]}

{
  "results": [
    {
      "end_line": 9,
      "fq_name": "QueryLeaf",
      "kind": "class",
      "language": "kotlin",
      "path": "kotlin/QueryHierarchy.kt",
      "provenance": [
        {
          "seed": {
            "end_line": 4,
            "kind": "class",
            "path": "kotlin/QueryHierarchy.kt",
            "result_type": "structural_match",
            "start_line": 1
          },
          "steps": [
            {
              "op": "enclosing_decl",
              "result": {
                "end_line": 4,
                "fq_name": "QueryRoot",
                "kind": "class",
                "path": "kotlin/QueryHierarchy.kt",
                "result_type": "declaration",
                "start_line": 1
              }
            },
            {
              "op": "subtypes",
              "result": {
                "end_line": 9,
                "fq_name": "QueryLeaf",
                "kind": "class",
                "path": "kotlin/QueryHierarchy.kt",
                "result_type": "declaration",
                "start_line": 6
              }
            },
            {
              "op": "members",
              "result": {
                "end_line": 8,
                "fq_name": "QueryLeaf.leafMember",
                "kind": "function",
                "path": "kotlin/QueryHierarchy.kt",
                "result_type": "declaration",
                "start_line": 7
              }
            },
            {
              "op": "owner",
              "result": {
                "end_line": 9,
                "fq_name": "QueryLeaf",
                "kind": "class",
                "path": "kotlin/QueryHierarchy.kt",
                "result_type": "declaration",
                "start_line": 6
              }
            }
          ]
        }
      ],
      "result_type": "declaration",
      "signature": "class QueryLeaf : QueryRoot() {",
      "start_line": 6
    }
  ],
  "truncated": false
}