ponylang/ponyc 0.60.6

on GitHub

Add Alpine 3.23 support

We've added support for Alpine 3.23. Builds will be available for both arm64 and amd64.

Fix crash when ephemeral type used in parameter with default argument

We've fixed an error where attempting to assign an ephemeral type to a variable caused an assertion failure in the compiler.

The following code will now cause the pony compiler to emit a helpful error message:

class Foo

actor Main
  fun apply(x: Foo iso^ = Foo) => None

  new create(env: Env) => None

Error:
main.pony:4:16: invalid parameter type for a parameter with a default argument: Foo iso^
  fun apply(x: Foo iso^ = Foo) => None
               ^

Update Docker Image Base to Alpine 3.23

We've updated the base image for our ponyc images from Alpine 3.21 to Alpine 3.23.

Fix incorrect array element type inference for union types

Due to a small bug in the type system implementation, the following correct code would fail to compile. We have fixed this bug so it will now compiler.

type Foo is (Bar box | Baz box | Bool)

class Bar
  embed _items: Array[Foo] = _items.create()

  new create(items: ReadSeq[Foo]) =>
    for item in items.values() do
      _items.push(item)
    end

class Baz

actor Main
  new create(env: Env) =>
    let bar = Bar([
      true
      Bar([ false ])
    ])
    env.out.print("done")

Fix segfault when lambda captures uninitialized field

Previously, the following illegal code would successfully compile, but produce a segfault on execution.

class Foo
  let n: USize

  new create(n': USize) =>
    n = n'

class Bar
  let _foo: Foo
  let lazy: {(): USize} = {() => _foo.n }

  new create() =>
    _foo = Foo(123)

actor Main
  let _bar: Bar = Bar

  new create(env: Env) =>
    env.out.print(_bar.lazy().string())

Now it correctly refuses to compile with an appropriate error message.

Error:
main.pony:9:34: can't use an undefined variable in an expression
  let lazy: {(): USize} = {() => _foo.n }
                                 ^

Fix compiler crash when assigning ephemeral capability types

Assigning ephemeral capability to a variable was causing the compiler to crash. We've updated to provide a descriptive error message.

Where previously code like:

actor Main
  new create(env: Env) => 
    let c: String iso^ = String

caused a segfault, you will now get a helpful error message instead:

Error:
/tmp/main.pony:3:24: Invalid type for field of assignment: String iso^
    let c: String iso^ = String

[0.60.6] - 2026-02-06

Fixed

• Fix crash when ephemeral type used in parameter with default argument (PR #4796)
• Fix incorrect array element type inference for union types (PR #4794)
• Fix segfault when lambda captures uninitialized field (PR #4791)
• Fix compiler crash when assigning to ephemeral capability type (PR #4790)

Added

• Add Alpine 3.23 support (PR #4803)

Changed

• Update Docker Image Base to Alpine 3.23 (PR #4804)